Antibody response to human immunodeficiency virus after primary infection

The antibody response to human immunodeficiency virus (HIV) after primary infection was monitored in eight homosexual men with the acute mononucleosis-like illness associated with seroconversion. Multiple sera from each subject, taken at frequent intervals after onset of acute illness, were tested for antibody to HIV by IgM and IgG immunofluorescent assays (IFAs), four commercial enzyme-linked immunosorbent assays (ELISAs), and Western immunoblot (WB). Antibody to HIV was detected first by IgM IFA (mean +/- SD, 5 +/- 3 days), followed by IgG IFA (11 +/- 3 days); the IgM antibody titer peaked at 24 +/- 17 days and disappeared by 81 +/- 27 days, whereas the IgG antibody titer peaked at 133 +/- 63 days and has not disappeared in any subject. Antibody to HIV was first detected by ELISA from 31 +/- 14 to 58 +/- 32 days, depending on the assay kit used. Antibody to p24 and gp41 was first detected by WB at 24 +/- 10 days, followed by antibody to p55 (40 +/- 20 days), p68 (57 +/- 19 days), and p34 (71 +/- 22 days).