Interaction of L antibody with low potassium-type sheep red cells: resolution of two separate functional antibodies.

Antibodies of two specificities in alloimmune sheep anti-L sera, anti-Lp and anti-L1, were separated by a new technique and characterized. Absorption of anti-L serum with trypsinized LK(LL) sheep red cells left anti-Lp antibodies; the absorbed anti-L1 antibodies were then eluted. Anti-Lp was only weakly lytic in the presence of complement; it had no effect on passive K influx, but stimulated active K influx. The stimulation could be reversed by eluting the antibody in glycine buffer at low pH. Stimulatory activity in the eluted cells could be restored by resensitization with anti-Lp. Anti-L1 was more strongly lytic than anti-Lp in the presence of complement; it had no effect on active K influx, but inhibited passive K influx. Pig anti-ruminant IgG conjugated to hemocyanin was used to visualize by electron microscopy the number of Lp and L1 antigen sites on LL sheep red cells sensitized with anti-Lp an L1 antigen sites on LL sheep red cells sensitized with anti-Lp and anti-L1. The values obtained were 590 Lp sites/cell and 847 L1 sites/cell.