Article Figures & Data
Figures
- FIG. 1.
Lung virus titers following primary (A) or secondary (B) challenge of I-Ab+/+ and I-Ab−/− mice. Naïve (A) or PR8-primed (108.5 EID50 i.p. 6 weeks earlier) (B) mice were given 106.8 EID50 i.n. and sampled at the intervals shown. Log10 dilutions of lung homogenate were used to infect embryonated chicken eggs, and endpoint titrations were determined by a hemagglutination inhibition assay of allantoic fluid. The data are expressed as means ± standard deviations (SD) for groups of five mice each. No virus was recovered from five naïve I-Ab−/− mice sampled at 19 days after infection with the HKx31 virus strain.
- FIG. 2.
Peptide-specific CTL activity in the inflammatory cell population recovered by BAL of the infected respiratory tract following secondary i.n. challenge with the HK31 influenza A virus 8 days earlier (see the legend for Fig. 1). The EL4 (H2b) target cells were pulsed with either the NP366 or the PA224 peptide prior to use in a standard 6-h 51Cr release assay. Lytic activities were calculated for the CD8+ DbNP366+ and CD8+ DbPA224+ tetramers as determined by tetramer staining (data not shown).
- FIG. 3.
Kinetic analysis of the DbNP366 and DbPA224 epitope-specific CD8+-T-cell response in I-Ab+/+ and I-Ab−/− mice following primary i.n. challenge with the HKx31 influenza virus. Enriched spleen (A and B), MLN (C and D), and BAL (E and F) samples were stained with anti-CD8 antibody and either the DbNP366 or the DbPA224 tetramer. Each data point represents the mean ± SD of values for the spleen samples and pooled MLN and BAL samples for five mice. Similar results were obtained from two further experiments.
- FIG. 4.
Secondary DbNP366 and DbPA224 epitope-specific CD8+-T-cell responses in the spleen (A and B), MLN (C and D), and BAL (E and F) samples from I-Ab+/+ (A, C, and E) and I-Ab−/− (B, D, and F) mice. The mice had been primed i.p. with the PR8 virus 6 weeks before i.n. challenge with the HKx31 virus. Each data point represents the mean ± SD of values for the spleen samples and pooled MLN and BAL samples for five mice. Similar results were obtained from two further experiments.
- FIG. 5.
Simulation of infection in I-Ab+/+ and I-Ab−/− hosts according to the mathematical model discussed herein. It is assumed that the I-Ab−/− mice lacking help from CD4+ T cells differ from the I-Ab+/+ controls in two parameters: the rate of expansion (A) and the life span (B) of their CTLs. Both simulations predict similar dynamics. The infection is resolved less efficiently in I-Ab−/− mice than in I-Ab+/+ mice. At the same time, the CTL dynamics are similar in the presence and absence of T-cell help. The chosen values of parameters were as follows: λ was 10; d was 0.1; β was 0.08; a was 0.2; and p was 1. (A) c equals 0.1 in wild-type hosts and 0.05 in mutant hosts; (B) b equals 0.01 in wild-type hosts and 0.1 in mutant hosts.
Tables
- TABLE 1.
Comparison of the CD8+-T-cell responses by tetramer and IFN-γ staininga
Tetramer No. of days after challenge with HKx31 % of epitope-specific CD8+ T cells in spleens ofb: I-Ab+/+ mice I-Ab−/− mice Tetramer staining IFN-γ staining Tetramer staining IFN-γ staining DbNP366 0 1 ± 0.24 (P < 0.02) 0.4 ± 0.2 0.6 ± 0.14 0.2 ± 0.1 5 1.4 ± 0.4 (P < 0.0025) 1.5 ± 0.7 0.1 ± 0.1 0.75 ± 1.4 7 20.4 ± 5.9 (P < 0.0025) 13.6 ± 4.3 3.2 ± 2.0 1.8 ± 1.3 10 24.1 ± 11.4 (P < 0.01) 21.5 ± 9.6 8.3 ± 2.8 7.1 ± 2.2 DbPA224 0 0.5 ± 0.1 (P < 0.02) 0.2 0.3 ± 0.1 0.1 ± 0.1 5 0.3 0.2 0.04 0.04 7 2 ± 0.6 (P < 0.0025) 1.4 ± 0.6 0.4 ± 0.1 0.1 ± 0.1 10 2.5 ± 0.8 (P < 0.05) 1.9 ± 0.6 1.3 ± 0.8 0.7 ± 0.6 ↵ a The I-Ab+/+ and I-Ab−/− mice were primed i.p. with PR8 virus and challenged i.n. with the HKx31 virus 56 days later as described in the legend for Fig. 1. The epitope-specific CD8+ T cells were identified by tetramer staining or by short-term (5-h) stimulation with peptide in the presence of Brefeldin A.
↵ b Groups of five mice were analyzed at each time point. The results are expressed as mean percentages of CD8+ T cells that were specific for the DbNP366+ or DbPA224+ epitope ± SD, and values in parentheses reflect the results of a statistical analysis comparing the values for the tetramer-positive cells in I-Ab+/+ and I-Ab−/− mice.
