Figure 2.

Virus-specific lymphoproliferative activity in the study cats. At the times indicated relative to the first FIV-MDC inoculum, PBMCs were exposed to intact FIV-M2 virions (a) or to pooled FIV-M2 Gag oligopeptides (b) and then examined for ³H-thymidine incorporation. Columns represent the stimulation index (S.I.) of individual animals, which was considered positive when above threshold dotted line (S.I. > 2). All cats responded to the nonspecific stimulus Concavalin A with counts per minute ranging from 10,000 to 38,000 counts per minute, while background proliferation in medium alone ranged between 100 and 1,100. At each sampling point, the animals are represented in the same order as shown in Figure 1.