'Partial inhibition' of anti-Rg and anti-Ch reagents. II. Demonstration of separable antibodies for different determinants.

Partial inhibition (p.i.) of anti-Rg (Rodgers) and anti-Ch (Chido) has been detected by antisera considered to be polyspecific. By using cells and C4 from individuals that are p.i. of Rg and Ch in absorption and elution experiments with selected antisera, it has been possible to separate several specificities. 2 Rg determinants, Rg1 and Rg2, and 3 Ch determinants, Ch1, Ch2, and Ch3, are defined by specific antisera. Partial inhibitors for Rg lack Rg2 and for Ch lack Ch2 or Ch3. The results are discussed in relation to other complexities of C4 polymorphism.