Differences in human immunodeficiency virus type 1 (HIV-1) anti-p24 reactivities in serum of HIV-1-infected and uninfected subjects: analysis of indeterminate western blot reactions.

Anti-p24 reactions in sera from 42 human immunodeficiency virus type 1 (HIV-1)-infected and 36 uninfected people with indeterminate Western blot antibody tests for HIV-1 were studied. Anti-p24 reactivity in HIV-1-infected people was completely blocked by HIV-1 recombinant p24 antigen, whereas the reaction in uninfected individuals with indeterminate patterns was inhibited partly or not at all. In contrast to infected individuals, anti-p24 reactivity from uninfected individuals could not be detected by an inhibition ELISA for HIV-1 p24 antibody. These results suggest a practical way to distinguish anti-p24 reactivity in sera from patients with HIV-1 infection from that seen in uninfected patients with indeterminate Western blot reactions.