NEUTRALIZING ANTIBODIES AGAINST HIGHLY CYTOPATHIC ZAIRIAN HUMAN IMMUNODEFICIENCY TYPE-1 VIRUS (HIV-1) NDK ARE PRESENT IN SERA OUTSIDE AFRICA

The prototype virus HIV-1 LAV and highly cytopathic Zairian virus HIV- 1 NDK belong to the genetic subtypes B and D and represent low and hig hly cytopathic phenotypes, respectively. Their neutralization pattern and serotype were studied with respect to differences in their genotyp es and phenotypes. Sera front HIV-1-infected persons living in four ge ographically distant areas, Philadelphia (USA), Ribeirao Preto (Brazil ), Marseille (France) and Kinshasa (Zaire), were tested for the presen ce of type-specific and group-specific cross-reacting neutralizing ant ibodies against HIV-1 LAV and HIV-1 NDK in a continuous cell line MT4. The majority of type-specific antibodies were directed against HIV-1 LAV in Philadelphia, Ribeirao Preto and Marseille, and against HIV-1 N DK in Kinshasa. However, some sera with an HIV-1 NDK type-specific neu tralization pattern were also found in Philadelphia, Ribeirao Preto an d Marseille. These results indicate that strains with an HIV-1 NDK-lik e serotype could be found outside Africa. The presence of type-specifi c neutralizing antibodies against HIV-1 NDK in sera from North and Sou th America and Europe should be taken into account during attempts to serotype HIV as well as in the course of selection of HIV-1 candidate strains for an AIDS vaccine.