Early detection of human immunodeficiency virus type 1-specific B-lymphocyte-derived antibodies in a high-risk population.

Diagnosis of acute human immunodeficiency virus (HIV) infection, a key driver of the HIV epidemic, remains a public health challenge. The PlasmAcute technology offers an opportunity to detect early anti-HIV antibody responses. B lymphocytes (B cells) were isolated from the blood of seronegative miners in South Africa by using the PlasmAcute method. B-cell lysates and paired sera were tested for anti-HIV-1 antibodies by two different enzyme-linked immunosorbent assays; immunoreactivity was confirmed by Western blotting. All volunteers were tested for HIV type 1 (HIV-1) viral load, p24 antigen, and CD4 count. Sera from HIV-seronegative men who had positive viral loads and were positive for p24 antigen were retested for anti-HIV antibodies after immune complex dissociation. Anti-HIV antibodies were detected in lysates from 16/259 subjects without immunoreactivity in paired sera. Four subjects, one of whom had a positive viral load initially, subsequently seroconverted. Six subjects showed transient anti-HIV-1 antibodies in the lysates and tested negative for all markers at the follow-up. Five subjects without follow-up data initially had lysate-positive/serum-negative samples, and these cases were classified as inconclusive. One subject had lysate antibodies and a detectable viral load but was seronegative at follow-up. In conclusion, lysate-derived anti-HIV-1 B-cell antibodies can be detected prior to seroconversion and earlier than or contemporary with HIV-1 RNA detection.

Antibody detection and kinetics of antibody production during early stages of immunization with hepatitis B virus vaccine.

Antibodies to influenza virus and human immunodeficiency virus are detectable in B cells during the early stages of the immune response, prior to their occurrence in plasma. To investigate similar phenomena in a model of immunization against hepatitis B virus (HBV) infection, medical students in Ghana were screened for HBV markers, HBV surface (HBs) antigen (HBsAg), and HBV core antibodies (anti-HBc). Consenting volunteers, 24 of whom were seronegative (susceptible) and 2 of whom were positive for anti-HBc (prior infection), were vaccinated on day 0, day 40, and 6 months. Two sets of 10 blood samples, sequentially collected at intervals of 2 days following each immunization on days 0 and 40, were processed into B-cell lysates and plasma. Solid-phase HBsAg coated on microtiter plates for enzyme immunoassay or nitrocellulose membranes for dot blot assay was used to detect anti-HBs activity by an indirect antiglobulin assay. A commercially procured sandwich immunoassay was used, along with an enzyme-linked immunosorbent assay and a dot blot assay, for the detection of anti-HBs in B-cell lysates and plasma. Following the first injection of vaccine, a single sample of B-cell lysate collected between 5 and 21 days revealed anti-HBs in 18/21 subjects with no plasma antibodies detectable by sandwich immunoassay. After the booster dose was injected on day 40, a single sample of B-cell lysate collected between 44 and 49 days showed anti-HBs in 16/19 subjects, and this was accompanied by plasma antibodies in 8 subjects. In contrast, between 8 and 13 days, both subjects with prior HBV infection showed anti-HBs in B-cell lysates and plasma. Thus, primary immunization with the HBV vaccine appears to transiently elicit low-affinity anti-HBs in B-cell lysates into plasma.