HAEMAGGLUTININ LEVELS IN HAEMOLYMPH FROM THE COLONIAL ASCIDIAN BOTRYLLOIDES LEACHII FOLLOWING INJECTION WITH SHEEP OR CHICKEN ERYTHROCYTES

Haemolymph was collected from colonies of Botrylloides leachii killed at various times after injection with sheep or chicken erythrocytes and the agglutination titre for sheep, chicken and guinea-pig erythrocytes was determined. Controls included haemolymph from groups of uninjected colonies and from others injected with balanced salt solution. Animals given a single injection of erythrocytes exhibited no change in titre until the second week when a marginal (2- to 4-fold) but statistically significant rise in titre was detected using each of the 3 types of indicator erythrocytes. A return to control values was observed by 6 weeks. The response to a second injection of erythrocytes, given 6 weeks after the first, appeared to be identical in magnitude and time of onset to the primary response, i.e. there was no indication of an anamnestic response. The increased haemagglutinating activity apparent 2 weeks after each injection was attributable to a rise in the HA-2 agglutinin specifically, since the activity of the HA-1 agglutinin (a calcium-dependent lectin which binds to guinea-pig erythrocytes only) remained unchanged. The results are considered in relation to self: non-self recognition in this species.