Quantitation of HIV-1 p24 Antibody Expressed as Relative Binding Capacity p24 Antigen (p24 RBC) in Infants Born to HIV-1 Seropositive Mothers: Correlation of This Serological Marker with the HIV-1 Maternal Antibody Course and p24 Antigenemia Detection

The antibody content to HIV-1 p24 Ag expressed as relative binding capacity to the target antigen (p24 RBC) was retrospectively quantified in serum samples from 20 HIV-1-uninfected infants born to HIV-1 seropositive mothers. p24 RBC values quantified at birth were included either in a low (0–20%) or high (80–100%) range of values, classified as group A (11 infants) and group B (9 infants), respectively. The course of maternal antibodies to HIV-1 antigens p17, p24, p31, gp41, p51, p66, gp120, and gp160 was studied in each group. A substantial difference in the amount and subsequently in the decline of maternal antibodies to gag proteins p17, p24, and p55 and to pol proteins p51 and p66 was observed in the two infant groups in contrast with a similar content and decline of the remaining antibodies. In 7 HIV-1-infected infants of whom 4 resembled infant group A and 3 infant group B for p24 RBC values, a relationship appeared between p24 antibody decline and p24 antigenemia detection.