Monoclonal antibodies against human immunodeficiency virus (HIV) type 2 core proteins: cross-reactivity with HIV type 1 and simian immunodeficiency virus.

Four mouse monoclonal antibodies were developed after immunization with one human immunodeficiency virus (HIV) type 2 isolate and were tested for reactivity with different HIV-1, HIV-2, and simian immunodeficiency virus (SIV) isolates in an immunofluorescence assay and by immunological blot analysis. One of them, an anti-capsid (p24) antibody, called R1C7, reacted with all HIV-1, HIV-2, and SIV isolates tested, thus identifying an epitope shared by all HIV and SIV. Another anti-capsid antibody, named A4F6, reacted with three HIV-2 isolates (HIV-2NIH-Z, LAV-2Rod, and LK001 ST9), some SIV isolates (STLV-IIIAGM, SIV-251, and SIV-309), but no HIV-1 isolates. Two anti-matrix (p16) antibodies, named R5C4 and R5F6, reacted strongly only with the HIV-2 isolates. The use of these monoclonal antibodies for rapid discrimination and identification of acquired immunodeficiency syndrome-related retroviruses is discussed.