Haemagglutinins and parasite agglutinins in haemolymph and gut of Glossina.

Agglutinating activity was found in the haemolymph and in extracts of midgut and hindgut of Glossina austeni against calf, guinea pig and chicken erythrocytes for the first time. Trypanosoma brucei procyclic forms were also agglutinated by midgut and hindgut extracts, but not by haemolymph. The 3 fractions tested failed to react with erythrocytes of four other vertebrates and other trypanosomatids (Leishmania hertigi and Crithidia fasciculata) examined. The reciprocal titre of agglutinating activity of the 3 fractions against calf, guinea pig and chicken erythrocytes were approximately the same at a dilution of 64. Both midgut and hindgut agglutinins showed higher titres against T. brucei at reciprocal dilutions of 128 and 256 respectively. Sialidase treatment, reduced the agglutinating activity to half its normal range while trypsinisation had no effect. The results of attempts to inhibit the agglutinating activity using a variety of sugars and glycoproteins revealed that midgut and hindgut were specific for D+glucosamine suggesting that midgut and hindgut agglutinin were possibly of the same origin. This is the first report of haemagglutinating and parasite agglutinating activity in Glossina tissues which may play a role not only in insect defence reactions but also in the determination of parasite establishment and infection in vectors.