Character of non-precipitating antibodies.

A minority of rabbits immunized daily with soluble preparations of heterologous serum albumin respond with the formation of non-precipitating antibodies. Precipitating and non-precipitating antibodies, in the present study, were similar with regard to electrophoretic distribution, molecular size, and elution appearing on DEAE Sephadex. Guinea-pig antisera against purified non-precipitating antibodies did not recognize unique antigenic determinants. The present studies suggest that non-precipitating antibodies result from a limited recognition of multiple antigenic determinants on complex antigens.