Reactivity of rabbit antisera against the 19-mer and 11-mer peptides of cytoplasmic tail of CR1. Rabbit sera were tested at a dilution of 1:100 in an ELISA system in which native CR1 was captured from detergent neutrophil extracts (NE) onto wells precoated with F(ab′)2 of mouse MoAb to the extracellular domain of CR1. Binding of rabbit IgG to the captured CR1 was detected with peroxidase-conjugated goat antirabbit antibody and o-phenylene diamine. The sera were tested in parallel in wells that received neutrophil extract containing CR1 (+NE) but nonimmune rabbit IgG and in wells that did not receive CR1 (−NE). The reactivity in wells with immune sera that had not received NE was equal to or less than the values obtained for nonimmune sera with NE. The results represent the mean of duplicate determinations from two separate experiments.
