TABLE 2.

Persistent IFN-γ ELISPOT responses of rhesus monkeys immunized with HIV gag DNA vaccinesa

ExptVaccineDose (mg)Gag-specific IFN-γ ELISPOT response (SFC per 106 PBMCs) at wk:
04812/132024283399
1 gag DNA50194512265337280303176
04253181125275294100119
260102114901347415107
0.7 40.3 66.7 139.0 93.3 248.7 216.0 139.3 134.0
108597911822312511257
3483489731099017545
4501521389401163835
2.3 35.3 36.0 127.0 93.3 124.0 110.3 108.3 45.7
tPA-gag DNA5019410157486841172
53493895330
026443118208205103255
1.7 153.7 64.3 71.0 88.3 92.7 49.0 152.3
2gag DNA51208441358144161
014812126633785
344484166116
1.3 133.3 203.3 221.7 182.3 120.7
16468361066
04613510181111
198349499273568
2.3 49.3 184.0 212.0 121.3 248.3
  • a Plasmid DNA containing a modified codon sequence of the HIV gag gene with or without the tPA leader sequence was injected i.m. into rhesus monkeys at 0, 4, and 8 weeks. In experiment 1, the monkeys were boosted at week 20. At the indicated times, PBMCs were seeded into 96-well ELISPOT plates at 4 × 105 cells per well and stimulated with a pool of overlapping 20-mer peptides (offset by 10 amino acids) encompassing the Gag protein. Cells were incubated for ∼20 h, and then the plates were processed for development of ELISPOTs. Results shown are net responses after subtraction of spots formed in medium control wells. The mean response for each group is shown in bold typeface for each time point.