NATURALLY-OCCURRING IGG ANTI-HLA ALLOANTIBODY DOES NOT CORRELATE WITHHIV TYPE-1 RESISTANCE IN NAIROBI PROSTITUTES

In an effort to identify an immunological basis for natural resistance to HIV-1 infection, me have examined serum antibody responses to HLA class I antigens in female prostitutes of the Nairobi Sex Workers Stud y, Anti-HLA antibodies are known to block HIV infectivity in vitro and can be protective against SIV challenge in macaques immunized with pu rified class I HLA. Thus, it was postulated that broadly cross-reactiv e alloantibodies recognizing common HLA alleles in the client populati on might contribute to the prevention of heterosexual transmission of HIV, In fact, 12% of the women were found to have serum IgG antibodies against class I alloantigens, However, this alloantibody did not corr elate with the HIV status of the women and was found in a similar prop ortion of HIV-positive and HIV-resistant women, The observed levels of alloantibody did not increase with HIV infection in susceptible indiv iduals, suggesting that potential antigenic mimicry between HIV and ho st HLA class I antigens does not significantly increase levels of anti -class I antibodies, The lack of correlation between serum anti-allo-c lass I HLA antibodies and the risk of sexual transmission indicates th at this humoral immune response is unlikely to be the natural mechanis m behind the HIV-resistance phenotype of persistently HIV-seronegative women, This result, however, does not preclude the further investigat ion of alloimmunization as an artificial HIV immunization strategy.