Blastogenic potency of concanavalin-A-bound L1210 leukemic vaccine associated with its immunogenic activity.

Glutaraldehyde-treated L1210 murine leukemic cells induced immune resistance in mice when concanavalin-A (Con-A) was bound to their surface. They were not immunogenic when Con-A was separately inoculated, indicating requirement of vaccine-bound Con-A for enhancing immunogenic potency of the vaccine. Based on the finding that vaccine-bound Con-A induced in vitro blastogenesis of spleen cells 10 times as efficiently as unbound Con-A did, the association of blastogenic potency of Con-A-bound vaccine with its immunogenic activity was examined. The possibility of their association was supported by the finding that induction of immune resistance by vaccines was reduced when their blastogenic activities had been reduced by treatment of the vaccine with anti-Con-A antisera or by substituting succinyl-Con-A or other lectins for Con-A. Moreover, the fact that combined inoculations of Con-A-bound vaccine, assumed to be blastogenic to T cells, with anti-thymocyte sera, but not with cyclophosphamide or carrageenan, resulted in reduced production of resistant animals was also consistent with, but not proving, this possibility. Feasibility of this possibility was further supported by the finding that Con-A-bound vaccine did not induce immune resistance in animals that had been abrogated in blastogenic activity of spleen cells by prior administration of Con-A.