The agglutination of erythrocytes and Leishmania parasites by sandfly gut extracts: evidence for lectin activity.

Lysates of heads, hind- and midguts of male and female Phlebotomus papatasi were found to contain lectins or lectin-like molecules capable of agglutinating human red blood cell types of the ABO(H) system and promastigotes of Leishmania aethiopica, L. major and L. donovani but not L. hertigi hertigi promastigotes or Crithidia fasciculata choanomastigotes. The agglutination of erythrocytes from the human O Rhesus positive blood group by sandfly midgut extracts was inhibited by two disaccharides; trehalose and turanose. This is the first report of haemagglutinating and parasite agglutinating activity in sandflies (Psychodidae).