Quantitation of antibody uptake on a group erythrocytes using immunoautoradiography and monoclonal IgM anti-A

Summary The number of antibody molecules on individual erythrocytes was counted in A₁, A₂, A₃ B and A group individuals using immunoautoradiography (IAR) and monoclonal IgM anti-A₁. Quantitation was also done for A group pregnant women. The number of antibody molecules on different red cells of an individual varied widely. Gross variations were also noted in cells of different individuals from one and the same group. The mean values of the uptake of the number of antibody molecules showed the following range A₁>A₂>A_x>A₃B. When compared to the average for total A₁ adults, red cells of pregnant women and newborn infants showed a 10.7% and 19.7% reduction respectively, in antibody uptake. The mean number of antibody molecules per A₁ adult red cells was 5.6±3×10⁴, while A₂ had 0.85±0.35×10⁴ molecules, thus showing a significant quantitative variation.