New method for quantifying anti-HIV1-gp160 antibodies in saliva, cervicovaginal secretions, and serum of infected women

Antibody titers or units as measured by ELISA or similar assays represent o nly a semi-quantitative measurement of the antibody concentration. In the p resent study, a truly quantitative assay for evaluating antibody concentrat ions was developed. In the new assay, IgG and IgA antibody concentrations a re expressed in absolute gravimetric units (weight/ml) rather than by more ambiguous terms such as titers or units. The procedure is based on the comp arison of known concentrations of IgG or IgA bound to anti-F(ab)(2)' with t he binding of an unknown concentration of antibodies to a specific antigen. We applied the new assay to the measurement of HIV1-gp160 specific IgG and IgA concentrations in cervicovaginal secretions (CVS), saliva, and sera of infected women. Measurement of antibody activity was obtained by comparing the amount of specific antibodies to the amount of total immunoglobulins f ound in the same compartment. Because of its quantitative and comparative n ature, the assay was named comparative antibody gravimetric evaluation assa y (CAGE). (C) 2000 Wiley-Liss. Inc.