Plaque forming cell assay to measure responses in mice to the random copolymer (Glu60Phe40)

A plaque-forming cell (PFC) assay to measure the immune response of mice to the synthetic random copolymer of glutamic acid and phenylalanine (GPhe) is described here. GPhe can be coupled to sheep red blood cells (SRBC) using "aged" CrCl3. Both IgM and IgG plaques are detected in the murine GPhe response. Mice of H-2 haploytpes p and q are high responders, a and k are medium or low responders and b, d and s are nonresponders as detected by the PFC assay.