Previous Article | Next Article 
Journal of Virology, February 2000, p. 1132-1139, Vol. 74, No. 3
Immunology Division and Division of Molecular
Virology, Jichi Medical School, Tochigi-Ken
329-0498,1 Institute of Immunology,
Tokyo 112-0004,2 First Department of
Internal Medicine, Yamanashi Medical University, Yamanashi-Ken
409-3898,3 Kumamoto Primates Park, Sanwa
Kagaku Kenkyusho Co., Ltd., Kumamoto-Ken
869-3201,4 Department of Medical
Sciences, Toshiba General Hospital, Tokyo
140-8522,5 Japanese Red Cross Saitama
Blood Center, Saitama-Ken 338-0001,6 and
Miyakawa Memorial Research Foundation, Tokyo
107-0062,7 Japan
Received 1 October 1999/Accepted 19 October 1999
Viruses resembling human TT virus (TTV) were searched for in sera
from nonhuman primates by PCR with primers deduced from well-conserved
areas in the untranslated region. TTV DNA was detected in 102 (98%) of
104 chimpanzees, 9 (90%) of 10 Japanese macaques, 4 (100%) of 4 red-bellied tamarins, 5 (83%) of 6 cotton-top tamarins, and 5 (100%)
of 5 douroucoulis tested. Analysis of the amplification products of 90 to 106 nucleotides revealed TTV DNA sequences specific for each
species, with a decreasing similarity to human TTV in the order of
chimpanzee, Japanese macaque, and tamarin/douroucouli TTVs. Full-length
viral sequences were amplified by PCR with inverted nested primers
deduced from the untranslated region of TTV DNA from each species. All
animal TTVs were found to be circular with a genomic length at 3.5 to
3.8 kb, which was comparable to or slightly shorter than human TTV.
Sequences closely similar to human TTV were determined by PCR with
primers deduced from a coding region (N22 region) and were detected in
49 (47%) of the 104 chimpanzees; they were not found in any animals of
the other species. Sequence analysis of the N22 region (222 to 225 nucleotides) of chimpanzee TTV DNAs disclosed four genetic groups that
differed by 36.1 to 50.2% from one another; they were 35.0 to 52.8%
divergent from any of the 16 genotypes of human TTV. Of the 104 chimpanzees, only 1 was viremic with human TTV of genotype 1a. It was
among the 53 chimpanzees which had been used in transmission
experiments with human hepatitis viruses. Antibody to TTV of genotype
1a was detected significantly more frequently in the chimpanzees
that had been used in transmission experiments than in those that had not (8 of 28 [29%] and 3 of 35 [9%], respectively; P = 0.038). These results indicate that species-specific TTVs are
prevalent in nonhuman primates and that human TTV can cross-infect chimpanzees.
A novel DNA virus has been recovered
from patients with posttransfusion hepatitis of unknown etiology and
named TT virus (TTV) after the initials of the index patient (19,
22). TTV is an unenveloped, single-stranded, circular DNA virus
with a genomic length of 3,808 to 3,853 nucleotides (nt) (2, 5,
13, 14, 23). Due to a circular genomic structure, TTV has been
placed tentatively into the Circoviridae family
(10). TTV DNA is detected in liver tissues at titers from 10 to 100 times higher than those in the corresponding sera
(22). TTV is transmitted not only parenterally (19,
22) but also nonparenterally by a fecal-oral route, because it is
excreted into the bile and then the feces of infected individuals
(21, 35). The presumed dual mode of transmission may enhance
the deep and broad penetration of TTV infection in the community in
every country examined (1, 6, 18, 24, 26, 40;
L. E. Prescott, P. Simmonds, and International Collaborators,
Letter, N. Engl. J. Med. 339:776-777, 1998).
For a DNA virus, TTV has a markedly wide range of sequence divergence,
in which it is classified into at least 16 genotypes separated by a
difference of >30% within a partial sequence in the coding region
(N22 region) spanning 222 to 231 nt (15, 21-24, 26,
29-32). Since sequence divergence is more marked in coding than
noncoding regions, primers deduced from various genomic regions crucially influence the detection of TTV DNA by PCR (24,
28). PCR with primers deduced from noncoding regions can detect
TTV DNA, irrespective of various genotypes, while PCR with primers from
coding regions may be used to detect TTV DNA of particular genotypes
(24).
Viruses resembling human hepatitis viruses have been identified in
various animal species. They include counterparts of hepatitis B virus
(HBV) in woodchucks (3), ground squirrels (25),
ducks (11), herons (27), gibbons (20),
and orangutans (39), as well as that of hepatitis E virus in
pigs (12). Furthermore, HBV of a particular genotype has
been found in chimpanzees and is presumed to infect them naturally
(36).
Chimpanzees are susceptible to infection with TTV (14).
Recently, TTV DNA sequences have been found in nonhuman primates and
farm animals (9, 37). It remains to be seen, however, whether a single species of TTV infects humans and animals, as proposed
(9), or they are infected with distinct TTVs characteristic of their own species. In this study, TTV DNA sequences were searched for in sera from nonhuman primates by two PCR methods with primers deduced from noncoding and coding regions (21, 22, 24). The
results indicate that nonhuman primates are infected with TTVs of their
own species, having marked sequence divergence from human TTV,
and that chimpanzees can be cross-infected with human TTV.
Nonhuman primates.
Ten Japanese macaques (Macaca
fuscata), four red-bellied tamarins (Saguinus
labiatus), six cotton-top tamarins (Saguinus oedipus), and five douroucoulis (Aotes trivirgatus) were caught in the
wild in 1977 and their sera were collected. A total of 104 chimpanzees (Pan troglodytes) were kept at Kumamoto Primates Park (Sanwa
Kagaku Kenkyusho Co. Ltd., Kumamoto, Japan). Of these, 46 were wild
caught and the remaining 58 were bred at the Primates Park. Sera were collected from the chimpanzees during September 1991 through October 1997 during their health checkups. The serum samples had been kept at
Extraction of nucleic acids and amplification by PCR.
Nucleic acids were extracted from 50 to 100 µl of serum by using a
High Pure Viral Nucleic Acid kit (Boehringer, Mannheim, Germany) and
dissolved in 40 to 80 µl of nuclease-free distilled water, and a
20-µl portion served as a template for amplification by PCR. TTV DNA
was detected by the following two methods in the presence of
Perkin-Elmer AmpliTaq DNA polymerase (Roche Molecular Systems, Inc.,
Branchburg, N.J.) and the primers listed in Table 1.
0022-538X/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Species-Specific TT Viruses and Cross-Species
Infection in Nonhuman Primates
ABSTRACT
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
INTRODUCTION
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
MATERIALS AND METHODS
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
20°C until testing. The animals studied were maintained and
monitored under conditions that met all relevant requirements for the
humane care and ethical use of primates in an approved facility.
TABLE 1.
Positions and nucleotide sequences of
oligonucleotide primers
(i) UTR PCR. UTR PCR was performed by the method described previously (24). The first round of PCR was performed with primers NG133 (sense) and NG147 (antisense) for 35 cycles (94°C for 30 s, 60°C for 30 s, and 72°C for 40 s, with an additional 7 min for the last cycle), and the second round was carried out with primers NG134 (sense) and NG132 (antisense) for 25 cycles under the same conditions. The amplification products of the first round of PCR were 143 bp long, and those of the second round were 110 bp.
(ii) N22 PCR. N22 PCR was performed as documented elsewhere by PCR with seminested primers (21, 22). The first round of PCR was performed with primers NG059 (sense) and NG063 (antisense) for 35 cycles (94°C for 30 s, 60°C for 45 s, and 72°C for 45 s, with an additional 7 min for the last cycle), and the second round was carried out with primers NG061 (sense) and NG063 (antisense) for 25 cycles under the same conditions. The amplification products of the first round of PCR were 286 bp, and those of the second round were 271 bp.
PCR with inverted nested primers for the amplification of full-length TTV genomes of nonhuman primates. Full-length TTV genomes of nonhuman primates were amplified by PCR with inverted nested primers in the presence of TaKaRa LA Taq with GC buffer (TaKaRa Shuzo, Shiga, Japan). DNAs extracted from chimpanzee sera were used as templates in the first round of PCR with primers NG255 (sense) and NG256 (antisense) for 35 cycles (94°C for 45 s, with an additional 3 min in the first cycle; 63°C for 45 s; and 72°C for 4 min, with an additional 7 min for the last cycle). The second round of PCR was performed, on a 1-µl portion of the products of the first-round PCR, for 25 cycles with primers NG257 (sense) and NG258 (antisense) under the same conditions. The final products of PCR were run by electrophoresis on 1% (wt/vol) SeaKem GTG agarose gel (FMC BioProducts, Rockland, Maine) to detect the band with the size of full genomic TTV (3.5 to 3.8 kb).
To amplify the genomic DNA of Japanese macaque TTV, DNA extracted from serum was amplified by first-round PCR with primers NG232 and NG233 followed by second-round PCR with primers NG234 and NG235, and for amplification of DNA of douroucouli TTV, DNA was amplified by first-round PCR with primers NG236 and NG237 and then by second-round PCR with primers NG238 and NG239 under the same conditions.Genotyping human and chimpanzee TTVs. Human TTV was classified into four common genotypes, 1, 2, 3, and 4 (24). By using amplification products of the first-round PCR with primers NG059 and NG063 as a template (286 bp), PCR was performed with type-specific primers in the presence of Perkin-Elmer AmpliTaq Gold (Roche Molecular Systems) for 25 cycles (95°C for 30 s, with an additional 9 min in the first cycle; 58°C for 30 s; and 72°C for 40 s, with an additional 7 min in the last cycle). The primer pairs specific for genotypes 1 to 4, respectively, were NG162-NG165, NG198-NG174, NG193-NG180, and NG177-NG178 (Table 1). The amplification products were subjected to electrophoresis on a 2 to 4% NuSieve 3:1 agarose gel (FMC BioProducts) to detect bands compatible with genotypes 1 to 4, which were sized at 150, 161, 74, and 195 bp, respectively.
Genetic groups of chimpanzee TTV were determined by PCR with primers specific for two groups designated A and B. The primer pair for group A was NG241-NG242, and that for group B was NG243-NG244; they generated amplification products of 135 and 71 bp, respectively.Determination of TTV sequences. The amplification products separated on agarose gel electrophoresis were extracted and ligated into pT7 BlueT-Vector (Novagen Inc., Madison, Wisc.) or M13 phage vector (New England Biolabs, Beverly, Mass.). Escherichia coli was transformed with them, and by using the obtained recombinant DNA as a template, both strands were sequenced by the Thermo Sequenase fluorescence-labelled primer cycle-sequencing kit with 7-deaza-dGTP (Amersham Pharmacia Biotech, Little Chalfont, England) or BigDyeTerminator Cycle Sequencing Ready Reaction kit (PE Applied Biosystems, Foster City, Calif.). At least three clones each were sequenced for the PCR products, and when they showed less than a 3% difference, the consensus sequence was adopted. When two or more kinds of clones with greater than 10% sequence difference were obtained, three clones each of a kind were sequenced to determine the consensus sequence. They were distinguished by Roman numerals after the clone name.
Computer analysis of nucleotide sequences. Sequence analysis was performed with Genetyx-Mac version 10.1 (Software Development, Tokyo, Japan) and ODEN version 1.1.1 of DNA DataBank of Japan (National Institute of Genetics, Mishima, Japan) (7). A phylogenetic tree was constructed by the unweighted pair group method with arithmetic mean (16).
Detection of antibodies to human TTV of genotype 1a. Anti-TTV antibody of a specificity for genotype 1a was determined by immunoprecipitation with ICN/Cappel goat antiserum to human immunoglobulin G (IgG) (whole molecule) (ICN Pharmaceuticals, Inc., Aurora, Ohio) by the method described previously (34). In brief, the test serum was incubated with TTV particles of genotype 1a extracted from human feces and then separated into supernatant and precipitate fractions. Thereafter, TTV DNAs in both fractions were determined by PCR with a primer pair (NG164-NG165) specific for genotype 1a. The amplification products were subjected to electrophoresis and scanned for a band at an expected size (126 bp). The presence of a higher density of TTV DNA in the precipitate than in the supernatant fraction was taken as evidence for anti-TTV antibody of genotype 1a in the test serum.
Nucleotide sequence accession numbers. The nucleotide sequence data in this paper have been deposited in the DDBJ/EMBL/GenBank nucleotide sequence databases under accession no. AB032277 to AB032346.
| |
RESULTS |
|---|
|
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
|
|---|
Detection of TTV DNA in sera from nonhuman primates. By means of UTR PCR (24), TTV DNA was detected in sera from 102 (98%) of 104 chimpanzees, 9 (90%) of 10 Japanese macaques, 4 (100%) of 4 red-bellied tamarins, 5 (83%) of 6 cotton-top tamarins, and all 5 (100%) of 5 douroucoulis. Thus, TTV DNA was highly prevalent in nonhuman primates, being detected in 125 (97%) of the 129 animals tested. Unlike the detection of TTV DNA in human sera, TTV DNAs in sera from nonhuman primates, except for those from chimpanzees, were amplified by the first but not the second round of PCR.
UTR sequences of TTV DNA in nonhuman primates. Amplification products of the first round of UTR PCR measuring 90 to 106 bp (primer sequences at both ends excluded) were sequenced for nine randomly selected chimpanzees and all 23 animals of the other species testing positive, including 9 Japanese macaques, 9 red-bellied or cotton-top tamarins and 5 douroucoulis. They were analyzed phylogenetically along with corresponding sequences of 10 human TTV isolates of various genotypes for which the entire sequence is determined (Fig. 1). The tree revealed phylogenetic differences of TTV depending on the species. Due to these phylogenetic differences, TTV of chimpanzees (Pan troglodytes) is referred to as Pt-TTV, that of Japanese macaques (Macaca fuscata) is referred to as Mf-TTV, that of red-bellied tamarins (Saguinus labiatus) is referred to as Sl-TTV, that of cotton-top tamarins (Saguinus oedipus) is referred to as So-TTV, and that of douroucoulis (Aotes trivirgatus) is referred to as At-TTV.
|
Circular structure and genomic length of TTVs from nonhuman primates. Primers were deduced from the UTR sequences of Pt-TTV, Mf-TTV, and At-TTV which spanned 98, 100, and 98 nt (primer sequences at both ends excluded), respectively (Fig. 2). They were used as inverted nested primers for amplification of the full-length circular TTV genomes by PCR. Five Pt-TTV isolates, three Mf-TTV isolates, and three At-TTV isolates were amplified, and the products of the second-round PCR were subjected to agarose gel electrophoresis to estimate the genomic size (Fig. 3). They migrated to positions of 3.5 to 3.8 kb, which are comparable to or a little smaller than human TTV DNAs, which are 3,808 to 3,853 nt (2, 5, 13, 14, 23).
|
|
Detection of human TTV DNA in nonhuman primates. On the assumption that species specificity of TTV would be expressed more explicitly in the nucleotide sequence of coding regions, in spite of the universal detection of animal TTVs by UTR PCR, a sequence resembling human TTV DNA was searched for in sera from nonhuman primates by PCR with seminested primers deduced from the N22 region (21, 22); it is located in open reading frame 1 of the human TTV genome. Sera from 49 (47%) of the 104 chimpanzees tested positive for TTV DNA by N22 PCR. One-third of the chimpanzee TTV DNAs were amplified only by the first round of N22 PCR or only weakly by the second round of N22 PCR.
Genotypes of TTV DNAs in chimpanzees were determined by PCR with primer pairs specific for one or the other of genotypes 1 to 4 of human TTV (Table 2). TTV DNA in only one chimpanzee was determined to be genotype 1; TTV DNAs in the remaining 46 chimpanzees were not classified into any of genotypes 1 to 4. By contrast, TTV DNAs in 29 Japanese blood donors with viremia were classified into genotypes 1 to 4 or mixed genotypes (Table 2).
|
Sequence analysis and genotypes of Pt-TTV. Five chimpanzees were randomly selected from among the 49 chimpanzees that tested positive for TTV DNA by N22 PCR in serum. Then sequences within the N22 region of Pt-TTV DNAs were determined. The five Pt-TTV isolates were classified into one group of three and one group of two, with an intragroup similarity of 87.8 to 91.9% and 92.4%, respectively, and an intergroup similarity of 61.7 to 67.4%. They were assigned to genetic groups A and B, respectively, both of which would be specific for Pt-TTV.
Primers specific for groups A and B were deduced from sequences of the N22 region for classifying Pt-TTV by PCR. By using products by the first round of N22 PCR as a template, grouping was performed on TTV DNAs from 49 chimpanzees (Table 2). Group A was detected in 17 (35%) of them, group B was detected in 11 (22%), and a mixed infection with groups A and B was detected in 11 (22%); neither group A nor group B was detected in the remaining 10 (20%). Group A was found less often and mixed infection with groups A and B was more frequent in the 18 chimpanzees bred in the institution than in the 31 chimpanzees caught in the wild. The single chimpanzee infected with human TTV of genotype 1a was doubly infected with Pt-TTVs of groups A and B. The occurrence of groups A and B, as well as a mixed infection with the two groups, was no different between bred and wild-caught chimpanzees, or between the chimpanzees with and without previous transmission experiments. Group A or B was not detected in any TTV DNAs from the 29 human carriers. Sequence analysis was performed on TTV DNAs from 10 chimpanzees not classifiable into group A or B. Sequences of the DNA from nine of them were 90.5 to 100% similar to one another, indicating that they belonged to the same genetic group. The remaining sequence was only 52.8 to 55.8% similar to the others, and so it belonged to another genetic group. The 10 sequences were less than 59% similar to group A or B sequences. The genetic group represented by the nine Pt-TTVs was provisionally designated group C, and that represented by the single Pt-TTV was tentatively named group D. Sequences were determined for TTV DNAs isolated from five chimpanzees and classified into group A by PCR with type-specific primers (Pt-TTV14 to Pt-TTV18) and those isolated from seven chimpanzees and classified into group B (Pt-TTV21 to Pt-TTV27). They were found to be similar to the sequences of three isolates of group A (Pt-TTV11 to Pt-TTV13) and those of two isolates of group B (Pt-TTV19 and Pt-TTV20), respectively, for which sequences had been determined for designing type-specific primers. A pairwise analysis was performed on sequences of 222 to 225 nt in the N22 region of Pt-TTV DNAs from 27 chimpanzees, along with those of human TTV DNAs representing 16 distinct genotypes (2, 5, 14, 22-24). It gave rise to four distinct genetic groups of Pt-TTV (A, B, C, and D), which were clearly distinguished from any of the 16 genotypes of human TTV and were separated by a sequence difference of 35.0 to 52.8% from one another. A phylogenetic tree was constructed on the basis of 27 sequences of Pt-TTV DNA, including 8 of genotype A, 9 of genotype B, 9 of genotype C, and 1 of genotype D, as well as on sequences of human TTV DNA of 16 distinct genotypes (Fig. 4). The tree exhibited four genetic groups of Pt-TTV (A through D) and 16 genotypes of human TTV (1 through 16). Genetic groups of Pt-TTV or genotypes of TTV did not cluster to make clades of their own but, rather, intermingled with one another.
|
Detection of TTV DNA by UTR PCR and N22 PCR in chimpanzees in
various age groups.
The 58 bred chimpanzees were aged 5 months to
11 years, while the 46 wild-caught chimpanzees were estimated to be
aged 12 to 26 years (Table 3). TTV DNA
was tested for by UTR PCR and N22 PCR.
|
Antibodies to human TTV in chimpanzee sera.
The detection of
TTV of genotype 1a in a single chimpanzee, previously inoculated with
human materials, indicated that other chimpanzees may have been exposed
to and infected with human TTV during transmission experiments but
resolved the infection. Anti-TTV specific for genotype 1a was tested
for in sera from 53 chimpanzees by immune precipitation
(34); the results are shown in Table 4. Anti-TTV was found more frequently in
the chimpanzees that had undergone transmission experiments than in
those that had not in the total (8 of 28 [29%] and 3 of 35 [9%];
P = 0.038), bred (2 of 4 [50%] and 3 of 29 [10%];
P = 0.038), and wild-caught (6 of 14 [43%] and 0 of
6 [0%]; P = 0.055) populations. There were no
appreciable differences, however, in the prevalence of anti-TTV between
bred and wild-caught chimpanzees (6 of 20 [30%] and 5 of 33 [15%], respectively; P = 0.196).
|
| |
DISCUSSION |
|---|
|
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
|
|---|
There have been accumulating lines of evidence to indicate that TTV commonly infects humans (1, 15, 19, 22, 30-32, 34; L. E. Prescott, P. Simmonds, and International Collaborators, Letter, N. Engl. J. Med. 339:776-777, 1998). Although TTV was discovered recently, in 1997 (19), it seems to be well-adapted virus of humans and has been a persistent source of infection since the distant past. TTV has an extraordinarily wide range of sequence divergence, on the basis of which it is classified into at least 16 genotypes based on a difference of >30% in the sequence of a coding region (open reading frame 1) spanning 222 to 231 nt (the N22 region) (15, 21-24, 26, 29-32). The nucleotide sequence of the noncoding region is much more highly conserved, and PCR with primers deduced from it enables the detection of TTV DNA, irrespective of various genotypes (24, 28).
By using UTR PCR (24), nucleotide sequences resembling the human TTV genome were tested for in sera from nonhuman primates. Sera from 125 (97%) of 129 animals of the five species examined, including chimpanzees, Japanese macaques, red-bellied and cotton-top tamarins, and douroucoulis, tested positive for TTV DNA by UTR PCR. In normal blood donors, TTV DNA is also detected by UTR PCR very frequently (93 to 97%) (24, 28). In general, sequences of UTR of TTV DNAs from each nonhuman primate clustered in a phylogenetic analysis, indicating that there are TTVs similar to human TTV but specific for nonhuman primates. In addition, genetic groups with considerable sequence divergence were detected for TTV of each species.
With the use of PCR involving inverted nested primers, deduced from UTR sequences of animal TTVs, full-length genomic TTV DNAs were amplified for all nonhuman primates. The genomic lengths of animal TTVs ranged from 3.5 to 3.8 kb, comparable to or a little shorter than the reported human TTV genomes sized 3,808 to 3,853 nt (2, 5, 13, 14, 23). By the principle of PCR with inverted primers, they were circular like human TTV (13, 14, 23). There remains little doubt about a family of viruses characterized by a circular DNA genome of 3.5 to 3.9 kb infecting humans and nonhuman primates with very high prevalence rates.
Recently, Leary et al. (9) reported frequent detection of TTV DNA in farm animals, including 19% of chickens, 20% of pigs, 25% of cows, and 30% of sheep, by their improved PCR methods. On the basis of their findings, they speculated that domesticated farm animals would serve as a source of TTV infection in humans. Whether species-specific TTVs are present or whether TTV represents a single virus taxon infecting humans and animals alike is a matter of great concern, because it should influence the epidemiology of TTV infection in humans.
It should be determined whether the TTV DNA sequences found by Leary et al. (9) are relevant to the work of Tischer et al. (33), who found antibodies cross-reactive with porcine circovirus in many cows, mice, and humans. However, the genomic DNAs of three reported circoviruses, i.e., porcine circovirus, chicken anemia virus, and beak and feather disease virus of parrots, have sizes of 1,768 to 2,319 nt (17); they are much smaller than those of human and nonhuman primate TTVs.
Although human TTV shares UTR sequences TTVs of nonhuman primates and those of farm animals, it may differ in sequences in coding regions, reflecting species-specific TTVs. This concept was borne out by the detection of TTV DNA by PCR with seminested primers deduced from a coding-region sequence (N22 region) in open reading frame 1. By means of N22 PCR, TTV DNA was detected in sera from 49 (48%) of the 102 chimpanzees that tested positive for TTV DNA by UTR PCR. By contrast, TTV DNA was not detected by N22 PCR in any of the other 23 nonhuman primates, although they possessed TTV DNA detectable by UTR PCR. Hence, Pt-TTV would be more closely related to human TTV than to TTVs of the other nonhuman primates. Our results corroborate those of Verschoor et al. (37), who detected TTV DNAs in 60 (49%) of 123 chimpanzees of P. troglodytes verus species and 4 (67%) of 6 chimpanzees of P. paniscus species by PCR with primers deduced from the N22 region. They could not detect TTV DNAs by the N22 PCR in any other primates; we could not, either.
At least four genetic groups of Pt-TTV were identified which differ by >30% in the N22 region sequence of 222 to 225 nt. They were provisionally designated groups A, B, C, and D and differ from any of the 16 genotypes of TTV by >30% in sequence (Fig. 4). The four genetic groups of Pt-TTV, however, did not cluster in a clade separate from the 16 TTV genotypes in a phylogenetic tree. Human TTV genotypes intermingled with genetic groups of Pt-TTV. Furthermore, some Pt-TTVs had noncoding region sequences which were very similar to that of human TTV (Fig. 1). Hence, although no group A or B Pt-TTV sequences were detected in any sera containing TTV DNA from 29 Japanese blood donors tested, it is possible that some Pt-TTVs belong to unknown genotypes of human TTV. These results are in line with the report of Verschoor et al. (37); they observed that P. troglodytes verus TTV strains cluster with human TTV of a certain genotype while P. paniscus TTV strains cluster with that of another genotype. The relationship between these animal TTVs and a particular genotype of human TTV was much closer than that among human TTV strains of distinct genotypes. A situation like this was observed also for TTVs from tamarins and douroucoulises (Fig. 1).
Human and chimpanzee TTVs do not cluster into species-specific monophyla. Rather, some genetic groups of human and chimpanzee TTVs cluster to make human/chimpanzee clades, as has been reported for T-cell leukemia virus type 1 and human immunodeficiency virus type 1 (4, 8, 39). Therefore, some genetic groups of Pt-TTV are closer to certain genotypes of human TTV and vice versa. How this happened is a matter of conjecture. There might have been a common ancestor of TTV that infected both species before they divided some 3 million years ago.
It is more likely that cross-species infection occurred from chimpanzee to humans via animal handling, particularly for viruses transmitted through contamination of blood, represented by retroviruses. Interspecies infection would be much easier for TTV, which is excreted in the feces for a possible fecal-oral transmission route (21). It would be worthwhile to test for Pt-TTV in sera from the individuals in Africa, where the chimpanzees were caught and analyze it phylogenetically.
One of our chimpanzees was infected with human TTV of genotype 1a, confirming cross-species infection as reported by Mushahwar et al. (14). This chimpanzee was among the 53 that participated in transmission experiments with human hepatitis viruses in the past. When anti-TTV of genotype 1a was tested for in the other 53 chimpanzees by immunoprecipitation (34), it was detected in 11. Anti-TTV of genotype 1a was detected significantly more frequently in the chimpanzees used in transmission experiments than in those not used in these experiments. Hence, at least 11 more chimpanzees had been infected with TTV of genotype 1a, most probably through human materials contaminated with TTV of this genotype, and resolved the infection by raising humoral antibodies. The low rate of persistent infection (1 of 12) suggested that infection of chimpanzees with human TTV would tend to be transient. This view is consistent with the resolution of TTV infection in both chimpanzees inoculated with human TTV (14).
Cross-species infection with human and chimpanzee viruses in limited genetic groups is not unprecedented. Some genetic groups of simian T-cell leukemia virus type 1 cluster with human T-cell leukemia virus type 1, and, on that basis, an interspecies transmission is postulated (8, 38). Recently, Gao et al. reported a lineage of simian immunodeficiency virus of chimpanzees that is closely related to all groups of human immunodeficiency virus type 1 (4) and speculated that chimpanzees are the primary reservoir of this virus.
It would be premature to conceive a single taxon of TTV based on the frequent detection of TTV DNAs by UTR PCR in humans, nonhuman primates, and farm animals and to presume invariable zoonotic infection among them (9). Despite a common UTR sequence which forms TTVs of various species into a family, there may be species specificity for TTVs and cross-species infection would be restricted to closely related species. Comparison of full-length sequences of animal TTV DNAs will disclose similarities and differences in genomic areas among the members of the TTV family and will help classify TTVs and define their zoonotic infections. It is now feasible, by means of PCRs with inverted nested primers, to amplify the full-length genomic DNA of TTVs of chimpanzees and other nonhuman primates.
| |
FOOTNOTES |
|---|
* Corresponding author. Mailing address: Minamikawachi-Machi, Tochigi-Ken 329-0498, Japan. Phone: 81-285-58-7404. Fax: 81-285-44-1557. E-mail: immundiv{at}jichi.ac.jp.
| |
REFERENCES |
|---|
|
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
|
|---|
| 1. | Charlton, M., P. Adjei, J. Poterucha, N. Zein, B. Moore, T. Therneau, R. Krom, and R. Wiesner. 1998. TT-virus infection in North American blood donors, patients with fulminant hepatic failure, and cryptogenic cirrhosis. Hepatology 28:839-842[CrossRef][Medline]. |
| 2. | Erker, J. C., T. P. Leary, S. M. Desai, M. L. Chalmers, and I. K. Mushahwar. 1999. Analyses of TT virus full-length genomic sequences. J. Gen. Virol. 80:1743-1750[Abstract]. |
| 3. |
Galibert, F.,
T. N. Chen, and E. Mandart.
1982.
Nucleotide sequence of a cloned woodchuck hepatitis virus genome: comparison with the hepatitis B virus sequence.
J. Virol.
41:51-65 |
| 4. | Gao, F., E. Bailes, D. L. Robertson, Y. Chen, C. M. Rodenburg, S. F. Michael, L. B. Cummins, L. O. Arthur, M. Peeters, G. M. Shaw, P. M. Sharp, and B. H. Hahn. 1999. Origin of HIV-1 in the chimpanzee Pan troglodytes troglodytes. Nature 397:436-441[CrossRef][Medline]. |
| 5. | Hijikata, M., K. Takahashi, and S. Mishiro. 1999. Complete circular DNA genome of a TT virus variant (isolate name SANBAN) and 44 partial ORF2 sequences implicating a great degree of diversity beyond genotypes. Virology 260:17-22[CrossRef][Medline]. |
| 6. | Hohne, M., T. Berg, A. R. Muller, and E. Schreier. 1998. Detection of sequences of TT virus, a novel DNA virus, in German patients. J. Gen. Virol. 79:2761-2764[Abstract]. |
| 7. |
Ina, Y.
1994.
ODEN: a program package for molecular evolutionary analysis and database search of DNA and amino acid sequences.
Comput. Appl. Biosci.
10:11-12 |
| 8. |
Koralnik, I. J.,
E. Boeri,
W. C. Saxinger,
A. L. Monico,
J. Fullen,
A. Gessain,
H. G. Guo,
R. C. Gallo,
P. Markham, and V. Kalyanaraman.
1994.
Phylogenetic associations of human and simian T-cell leukemia/lymphotropic virus type I strains: evidence for interspecies transmission.
J. Virol.
68:2693-2707 |
| 9. |
Leary, T. P.,
J. C. Erker,
M. L. Chalmers,
S. M. Desai, and I. K. Mushahwar.
1999.
Improved detection systems for TT virus reveal high prevalence in humans, non-human primates and farm animals.
J. Gen. Virol.
80:2115-2120 |
| 10. | Lukert, P. D., G. F. de Boer, J. L. Dale, P. Keese, M. S. McNulty, J. W. Randers, and I. Tisher. 1995. Family Circoviridae, p. 166-168. In F. A. Murphy, C. M. Fauquet, D. H. L. Bishop, S. A. Ghabrial, A. W. Jarvis, G. P. Martelli, M. A. Mayo, and M. D. Summers (ed.), Virus taxonomy. Classification and nomenclature of viruses: sixth report of the International Committee on Taxonomy of Viruses. Springer-Verlag, New York, N.Y. |
| 11. |
Mandart, E.,
A. Kay, and F. Galibert.
1984.
Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison with woodchuck and human hepatitis B virus sequences.
J. Virol.
49:782-792 |
| 12. |
Meng, X. J.,
P. G. Halbur,
M. S. Shapiro,
S. Govindarajan,
J. D. Bruna,
I. K. Mushahwar,
R. H. Purcell, and S. U. Emerson.
1998.
Genetic and experimental evidence for cross-species infection by swine hepatitis E virus.
J. Virol.
72:9714-9721 |
| 13. |
Miyata, H.,
H. Tsunoda,
A. Kazi,
A. Yamada,
M. A. Khan,
J. Murakami,
T. Kamahora,
K. Shiraki, and S. Hino.
1999.
Identification of a novel GC-rich 113-nucleotide region to complete the circular, single-stranded DNA genome of TT virus, the first human circovirus.
J. Virol.
73:3582-3586 |
| 14. |
Mushahwar, I. K.,
J. C. Erker,
A. S. Muerhoff,
T. P. Leary,
J. N. Simons,
L. G. Birkenmeyer,
M. L. Chalmers,
T. J. Pilot-Matias, and S. M. Dexai.
1999.
Molecular and biophysical characterization of TT virus: evidence for a new virus family infecting humans.
Proc. Natl. Acad. Sci. USA
96:3177-3182 |
| 15. | Naoumov, N. V., E. P. Petrova, M. G. Thomas, and R. Williams. 1998. Presence of a newly described human DNA virus (TTV) in patients with liver disease. Lancet 352:195-197[CrossRef][Medline]. |
| 16. | Nei, M. 1987. Phylogenetic trees, p. 287-326. In M. Nei (ed.), Molecular evolutionary genetics. Columbia University Press, New York, N.Y. |
| 17. | Niagro, F. D., A. N. Forsthoefel, R. P. Lawther, L. Kamalanathan, B. W. Ritchie, K. S. Latimer, and P. D. Lukert. 1998. Beak and feather disease virus and porcine circovirus genomes: intermediates between the geminiviruses and plant circoviruses. Arch. Virol. 143:1723-1744[CrossRef][Medline]. |
| 18. | Niel, C., J. M. de Oliveira, R. S. Ross, S. A. Gomes, M. Roggendorf, and S. Viazov. 1999. High prevalence of TT virus infection in Brazilian blood donors. J. Med. Virol. 57:259-263[CrossRef][Medline]. |
| 19. | Nishizawa, T., H. Okamoto, K. Konishi, H. Yoshizawa, Y. Miyakawa, and M. Mayumi. 1997. A novel DNA virus (TTV) associated with elevated transaminase levels in posttransfusion hepatitis of unknown etiology. Biochem. Biophys. Res. Commun. 241:92-97[CrossRef][Medline]. |
| 20. | Norder, H., J. W. Ebert, H. A. Fields, I. K. Mushahwar, and L. O. Magnius. 1996. Complete sequencing of a gibbon hepatitis B virus genome reveals a unique genotype distantly related to the chimpanzee hepatitis B virus. Virology 218:214-223[CrossRef][Medline]. |
| 21. | Okamoto, H., Y. Akahane, M. Ukita, M. Fukuda, F. Tsuda, Y. Miyakawa, and M. Mayumi. 1998. Fecal excretion of a nonenveloped DNA virus (TTV) associated with posttransfusion non-A-G hepatitis. J. Med. Virol. 56:128-132[CrossRef][Medline]. |
| 22. | Okamoto, H., T. Nishizawa, N. Kato, M. Ukita, H. Ikeda, H. Iizuka, Y. Miyakawa, and M. Mayumi. 1998. Molecular cloning and characterization of a novel DNA virus (TTV) associated with posttransfusion hepatitis of unknown etiology. Hepatol. Res. 10:1-16. |
| 23. | Okamoto, H., T. Nishizawa, M. Ukita, M. Takahashi, M. Fukuda, H. Iizuka, Y. Miyakawa, and M. Mayumi. 1999. The entire nucleotide sequence of a TT virus isolate from the United States (TUS01): comparison with reported isolates and phylogenetic analysis. Virology 259:437-448[CrossRef][Medline]. |
| 24. | Okamoto, H., M. Takahashi, T. Nishizawa, M. Ukita, M. Fukuda, Y. Miyakawa, and M. Mayumi. 1999. Marked genomic heterogeneity and frequent mixed infection of TT virus demonstrated by PCR with primers from coding and noncoding regions. Virology 259:428-436[CrossRef][Medline]. |
| 25. |
Seeger, C.,
D. Ganem, and H. E. Varmus.
1984.
Nucleotide sequence of an infectious molecularly cloned genome of ground squirrel hepatitis virus.
J. Virol.
51:367-375 |
| 26. | Simmonds, P., F. Davidson, C. Lycett, L. E. Prescott, D. M. MacDonald, J. Ellender, P. L. Yap, C. A. Ludlam, G. H. Haydon, J. Gillon, and L. M. Jarvis. 1998. Detection of a novel DNA virus (TTV) in blood donors and blood products. Lancet 352:191-195[CrossRef][Medline]. |
| 27. |
Sprengel, R.,
E. F. Kaleta, and H. Will.
1988.
Isolation and characterization of a hepatitis B virus endemic in herons.
J. Virol.
62:3832-3839 |
| 28. | Takahashi, K., H. Hoshino, Y. Ohta, N. Yoshida, and S. Mishiro. 1998. Very high prevalence of TT virus (TTV) infection in general population of Japan revealed by a new set of PCR primers. Hepatol. Res. 12:233-239. |
| 29. | Takayama, S., S. Yamazaki, S. Matsuo, and S. Sugii. 1999. Multiple infection of TT virus (TTV) with different genotypes in Japanese hemophiliacs. Biochem. Biophys. Res. Commun. 256:208-211[CrossRef][Medline]. |
| 30. | Tanaka, H., H. Okamoto, P. Luengrojanakul, T. Chainuvati, F. Tsuda, T. Tanaka, Y. Miyakawa, and M. Mayumi. 1998. Infection with an unenveloped DNA virus (TTV) associated with posttransfusion non-A to G hepatitis in hepatitis patients and healthy blood donors in Thailand. J. Med. Virol. 56:234-238[CrossRef][Medline]. |
| 31. | Tanaka, Y., M. Mizokami, E. Orito, T. Nakano, T. Kato, X. Ding, T. Ohno, R. Ueda, S. Sonoda, K. Tajima, T. Miura, and M. Hayami. 1999. A new genotype of TT virus (TTV) infection among Colombian native Indians. J. Med. Virol. 57:264-268[CrossRef][Medline]. |
| 32. | Tanaka, Y., M. Mizokami, E. Orito, T. Ohno, T. Nakano, T. Kato, H. Kato, M. Mukaide, Y. M. Park, B. S. Kim, and R. Ueda. 1998. New genotypes of TT virus (TTV) and a genotyping assay based on restriction fragment length polymorphism. FEBS Lett. 437:201-206[CrossRef][Medline]. |
| 33. | Tischer, I., L. Bode, J. Apodaca, H. Timm, D. Peters, R. Rasch, S. Pociuli, and E. Gerike. 1995. Presence of antibodies reacting with porcine circovirus in sera of humans, mice, and cattle. Arch. Virol. 140:1427-1439[CrossRef][Medline]. |
| 34. | Tsuda, F., H. Okamoto, M. Ukita, T. Tanaka, Y. Akahane, K. Konishi, H. Yoshizawa, Y. Miyakawa, and M. Mayumi. 1999. Determination of antibodies to TT virus (TTV) and application to blood donors and patients with post-transfusion non-A to G hepatitis in Japan. J. Virol. Methods 77:199-206[CrossRef][Medline]. |
| 35. | Ukita, M., H. Okamoto, N. Kato, Y. Miyakawa, and M. Mayumi. 1999. Excretion into bile of a novel unenveloped DNA virus (TT virus) associated with acute and chronic non-A-G hepatitis. J. Infect. Dis. 179:1245-1248[CrossRef][Medline]. |
| 36. |
Vaudin, M.,
A. J. Wolstenholme,
K. N. Tsiquaye,
A. J. Zuckerman, and T. J. Harrison.
1988.
The complete nucleotide sequence of the genome of a hepatitis B virus isolated from a naturally infected chimpanzee.
J. Gen. Virol.
69:1383-1389 |
| 37. |
Verschoor, E. J.,
S. Langenhuijzen, and J. L. Heeney.
1999.
TT virus (TTV) of non-human primates and their relationship to the human TTV genotypes.
J. Gen. Virol.
80:2491-2499 |
| 38. | Voevodin, A. F., B. K. Johnson, E. I. Samilchuk, G. A. Stone, R. Druilhet, W. J. Greer, and C. J. Gibbs, Jr. 1997. Phylogenetic analysis of simian T-lymphotropic virus Type I (STLV-I) in common chimpanzees (Pan troglodytes): evidence for interspecies transmission of the virus between chimpanzees and humans in Central Africa. Virology 238:212-220[CrossRef][Medline]. |
| 39. |
Warren, K. S.,
J. L. Heeney,
R. A. Swan,
Heriyanto, and E. J. Verschoor.
1999.
A new group of hepadnaviruses naturally infecting orangutans (Pongo pygmaeus).
J. Virol.
73:7860-7865 |
| 40. | Woodfield, D. G., E. Gane, and H. Okamoto. 1998. Hepatitis TT virus is present in New Zealand. N. Z. J. Med. 111:195-196. |
Journal of Virology, February 2000, p. 1132-1139, Vol. 74, No. 3
0022-538X/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Ninomiya, M., Takahashi, M., Hoshino, Y., Ichiyama, K., Simmonds, P., Okamoto, H.
(2009). Analysis of the entire genomes of torque teno midi virus variants in chimpanzees: infrequent cross-species infection between humans and chimpanzees. J. Gen. Virol.
90: 347-358
[Abstract] [Full Text] -
Ninomiya, M., Nishizawa, T., Takahashi, M., Lorenzo, F. R., Shimosegawa, T., Okamoto, H.
(2007). Identification and genomic characterization of a novel human torque teno virus of 3.2 kb. J. Gen. Virol.
88: 1939-1944
[Abstract] [Full Text] -
Barnett, O. E., Worobey, M., Holmes, E. C., Cooper, A.
(2004). DETECTION OF TT VIRUS AMONG CHIMPANZEES IN THE WILD USING A NONINVASIVE TECHNIQUE. J Wildl Dis
40: 230-237
[Abstract] [Full Text] -
Okamoto, H., Takahashi, M., Nishizawa, T., Tawara, A., Fukai, K., Muramatsu, U., Naito, Y., Yoshikawa, A.
(2002). Genomic characterization of TT viruses (TTVs) in pigs, cats and dogs and their relatedness with species-specific TTVs in primates and tupaias. J. Gen. Virol.
83: 1291-1297
[Abstract] [Full Text] -
Okamoto, H., Nishizawa, T., Takahashi, M., Tawara, A., Peng, Y., Kishimoto, J., Wang, Y.
(2001). Genomic and evolutionary characterization of TT virus (TTV) in tupaias and comparison with species-specific TTVs in humans and non-human primates. J. Gen. Virol.
82: 2041-2050
[Abstract] [Full Text] -
Bendinelli, M., Pistello, M., Maggi, F., Fornai, C., Freer, G., Vatteroni, M. L.
(2001). Molecular Properties, Biology, and Clinical Implications of TT Virus, a Recently Identified Widespread Infectious Agent of Humans. Clin. Microbiol. Rev.
14: 98-113
[Abstract] [Full Text] -
Kamahora, T., Hino, S., Miyata, H.
(2000). Three Spliced mRNAs of TT Virus Transcribed from a Plasmid Containing the Entire Genome in COS1 Cells. J. Virol.
74: 9980-9986
[Abstract] [Full Text] -
Okamoto, H., Takahashi, M., Kato, N., Fukuda, M., Tawara, A., Fukuda, S., Tanaka, T., Miyakawa, Y., Mayumi, M.
(2000). Sequestration of TT Virus of Restricted Genotypes in Peripheral Blood Mononuclear Cells. J. Virol.
74: 10236-10239
[Abstract] [Full Text] -
Okamoto, H., Ukita, M., Nishizawa, T., Kishimoto, J., Hoshi, Y., Mizuo, H., Tanaka, T., Miyakawa, Y., Mayumi, M.
(2000). Circular Double-Stranded Forms of TT Virus DNA in the Liver. J. Virol.
74: 5161-5167
[Abstract] [Full Text]
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»