Radioimmune western blotting in comparison with conventional western blotting, second and third generation ELISA assays for the serodiagnosis of HIV-1 infection.

We compared the performance of second and third generation ELISA assays to detect antibodies to HIV-1 virus with conventional Western blotting (WB) and radioimmune Western blotting (RIWB). Both sera from commercial seroconversion panels and serial dilutions of a serum for HIV-1 antibodies were tested with Murex HIV Recombinant, Vidas bioMérieux HIV 1/2 (2nd generation ELISA) Murex HIV 1-2 (3rd generation ELISA), as well as with WB and RIWB. In seroconversion panels all ELISA assays were positive for the same serum with the exception of the first serum of Panel D which was negative with both sample Murex assays and borderline with Vidas assay. This serum was negative with WB but evidenced antibodies to gp160 p66, p51, p24 HIV-1 proteins when assayed by RIWB. In only two cases did WB reveal antibodies to HIV-1 proteins before ELISA assays (Panel A and E); not only did RIWB show the same sensitivity as WB in the two last panels, but it also detected antibodies to HIV-1 proteins earlier than WB, ranging from a few days (Panel C) to approximately 12 weeks (Panel D). The results obtained by testing the dilutions of the serum positive for anti HIV-1 antibodies showed the following degrees of sensitivity: Murex HIV 1-2 (the most sensitive), Murex HIV Recombinant and Vidas bioMérieux HIV 1/2. Although WB was more sensitive than the ELISA assays and picked out antibodies to gp160, gp120 and p24 HIV proteins at 1/4000 serum dilution, the most sensitive test was RIWB which at 1/20,000 serum dilution enabled detection of antibodies to gp160, p66 and p24 HIV proteins.