Antibody and cell-mediated immunity in phytohemagglutinin-treated chickens

The effects of phytohemagglutinin (PHA) on humoral and homograft immunity in young chickens were studied. Intravenous (IV) injections of PHA stimulated the antibody production while intraperitoneal (IP) injections suppressed the antibody production. IP injected PHA failed to prolong the survival of the homografts. The route and time of PHA administration must be considered when evaluating the influence which PHA exerts on homograft survival and hemagglutinin production in the chiicken. The results obtained in this study suggest that there may be two different target cell lines involved in PHA's action. The reduced antibody production following IP injections of PHA may be due to its interference with the peritoneal macrophages and T cells and in the case ov IV administration PHA may be activating both macrophages and T cells. Possibly, there may be a difference in the effective PHA concentration after IP versus IV administration to account for different responses observed.