FIV-specific suppressor activity in chronically infected cats. Mitogen-activated lymphoblasts were prepared from the blood (a and b), lymph nodes (c and d), and spleen (e and f) of two cats, 22 months following infection with FIVGL-8, and were cocultured with either FIVPET-infected (▪) or FIVGL-8-infected (•) MYA-1 cells at ratios of 4:1 (---), 2:1 (– – –), and 1:1 (· · ·). Control cultures contained FIV-infected MYA-1 cells alone (——). Replication of FIV was indicated by the detection of viral p24 in the culture supernatant by ELISA. The results shown represent the mean OD values at 650 nm for the two cats ± 2 SD, error bars are not discernible where the SD is small.