Earthworm leukocyte interactions during early stages of graft rejection

The earliest phase of graft rejection in earthworms, the recognition of foreign tissue antigens, has been subjected to analysis by confronting host leukocytes with foreign erythrocytes. Only rabbit and rat erythrocytes significantly prevented healing of allografts when grafts were transplanted and erythrocytes injected simultaneously. In contrast, autografts and allografts transplanted on worms injected 1 or 2 days before grafting were never affected. Since earthworms readily produce higher titers of erythrocyte agglutinins at 24 h postinjection than at later times, we propose a hypothetical scheme of earthworm leukocyte interactions that may occur during the early phases of graft healing and of agglutinin synthesis.