Recognition of foreignness in invertebrates. II. In vitro studies of cockroach phagocytic haemocytes.

Active uptake of sheep and chicken erythrocytes onto the surfaces of cockroach phagocytic haemocytes has been demonstrated to occur in the absence of haemolymph. Haemocytes were treated with various enzymes and chemicals in attempts to elucidate the nature of the receptor site for vertebrate erythrocytes. Uptake was abolished by pretreatment of haemocytes with trypsin and not restored by incubation in haemolymph. No opsonic activity was demonstrable for cockroach haemolymph regarding uptake of vertebrate erythrocytes. Cockroach haemocytes do not possess a receptor site for γ-globulin on their surfaces.