Ss. Balla-jhagjhoorsingh et al., Conserved CTL epitopes shared between HIV-infected human long-term survivors and chimpanzees, J IMMUNOL, 162(4), 1999, pp. 2308-2314
Certain HIV-1 infected humans that do not progress to AIDS have been docume
nted to share particular MHC class I alleles that appear to correlate with
long-term survival. HIV-1-infected chimpanzees are relatively resistant to
progression to AIDS. Out of a group of 10 chimpanzees with CTE activity and
nonprogressive HIV-1 infection, 2 animals with prominent cytolytic CD3(+)C
D8(+) T cell responses to HIV-1 Ags were studied in detail. Characterizatio
n of these CTL revealed that they contained the granzymes A and B, T cell i
ntracellular Ag-1, and perforin and induced calcium-dependent cytolysis tha
t correlated with the presence of apoptotic nuclei in target cells. These C
TL responses were directed against two gag peptides, which were found to be
identical to previously described epitopes recognized in the context of HL
A-B27 and HLA-B57 molecules. The latter two restriction elements occur with
increased frequency in human long-term survivor cohorts. Phylogenetic comp
arisons revealed that the chimpanzee restriction elements, Patr-B*02 and -B
*03, described here do not show any obvious similarity with the HLA-B*27 an
d -B*57 alleles, suggesting that CTL responses to HIV-1 in distinct primate
species may be controlled by different types of HLA-B-like molecules. The
CTL responses in these two chimpanzees are directed, however, against highl
y conserved epitopes mapping across the majority of HIV-1 clades.