Haemagglutination activity (HA) was found and characterized in a midgut homogenate of Ixodes ricinus (L.). HA was induced by tick feeding; it was not detected in starved ticks. In a haemagglutination inhibition test, HA showed an affinity for some carbohydrates (N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, rhamnose, and dulcit) and glycoconjugates (especially lipopolysaccharides). Midgut protein components of 37, 60, 65, and 73 kDa were identified by immunoblotting as potential structural subunits of the new agglutinin.
Two distinct hemocyte populations are determined in the hemolymph of the triatomine bug Triatoma infestans Klug, oenocytoids and plasmatocytes, and their independent origin from separate stem cells is shown. Both hemocyte populations differ considerably in their morphology, ultrastructure and lectin-binding properties. While oenocytoids are quite uniform with easily definable cells which do not to bind any assayed lectin, the plasmatocytes are a very polymorphic population possessing several morphological types and displaying a positive reactivity with lectins.