AGGLUTINATION OF LEISHMANIA PROMASTIGOTES BY MIDGUT LECTINS FROM VARIOUS SPECIES OF PHLEBOTOMINE SANDFLIES

Lectins which agglutinate Leishmania promastigotes were demonstrated i n gut lysates from laboratory colonies of five Phlebotomus and two Lut zomyia species. In general, the highest agglutination titres were foun d in P. halepensis and Lu. longipalpis (Jacobina). Marked difference w ere found in the agglutination of promastigotes of various Leishmania species and strains and high agglutination titres were observed in som e natural vector-parasite combinations, such as Phlebotomus argentipes and Le. donovani. Intraspecific variability, in agglutination of Le m ajor strains, could be related to the varying infectivity of the strai ns to laboratory animals. Similar carbohydrates, of which the most eff ective were D-mannosamine and N-acetyl-D-glucosamine, inhibited the ag glutination of Le. major and Le. donovani promastigotes by midgut extr acts from P. papatasi and Lu. longipalpis. D-Mannosamine and N-acetyl- D-glucosamine inhibited agglutination of promastigotes in all vectors- parasite combinations. The results of the carbohydrate-inhibition test s indicate that the lectin specificities in Phlebotomus are similar to those in Lutzomyia.