CD8⁺ cell noncytotoxic antiviral response in HIV-infected individuals with different CD4⁺ cell numbers.

CD8⁺ cells from HIV-seropositive individuals were isolated from PHA-stimulated PBMCs and cocultured at different input cell ratios with PHA-stimulated seronegative CD4⁺ cells, acutely infected with HIV-1_SF33. The ratio of CD8⁺:CD4⁺ cells required to reach more than or equal to 90% suppression of HIV replication is indicated for each infected individual (A) within a range of CD4⁺ cells/μL (○) and (B) after dividing the subjects into 2 groups either with less than (▴) or greater than (▪) 300 CD4⁺ cells/μL. Percent suppression is calculated from the amount of RT activity14 in the supernatants of the cocultures of CD8⁺ and CD4⁺ cells compared to the RT activity in the supernatants from infected CD4⁺ cells cultured alone. Solid lines represent the average CD8:CD4⁺ cell ratio for more than or equal to 90% suppression.