CYTOTOXIC T-LYMPHOCYTE ACTIVITY AND CD8 SUBPOPULATIONS IN CHILDREN ATRISK OF HIV-INFECTION

HIV-specific cytotoxic T lymphocytes (CTL) are thought to play a major role in viral control in HIV-infected adults. Changes in the relative proportions of CD8 lymphocyte subpopulations are also thought to be a ssociated with disease progression. Less is known about the relative e ffectiveness of CTL against different HIV targets, or about the relati onship, if any, between CTL activity and CD8 subpopulations. We have m easured CTL activity against four HIV gene products (gag, tat, pol and env) and expression of CD45RO, CD45RA, HLA-DR, CD29, S6F1, and CD57 s urface markers on CD8 cells from nine HIV-infected and 11 HIV-uninfect ed children. Of nine HIV-infected children, six showed antigen-specifi c CTL activity on at least one occasion: 4/6 directed against tat, 6/6 against pol, 1/6 against env, and 1/6 against gag. However, the speci ficity of the CTL activity varied between children and within individu al children with time. Furthermore, two uninfected children showed CTL activity, one to HIV-gag, -pol and -tat, and the other to HIV-pol. Al l the HIV-infected and two uninfected children had abnormal proportion s of CD8 subpopulations in whole blood compared with age-matched contr ols. There was no correlation between CTL activity and CD8 subsets in whole blood. Five children changed from CTL-positive to CTL-negative ( or vice versa) during the study. In these, the occasions when CTL acti vity was detected coincided with an increase in CD8 cells, an expansio n of HLA-DR(+) CD8 cells and a loss of CD45RA(+) CD8 cells.