Use of SEM and lectins to study Bulinus africanus leukocyte groups and their in vitro behavior over a time period

Abstract

The external morphology and in vitro behavior of the leukocytes of the freshwater snail Bulinus africanus were studied by means of SEM while the possible existence of leukocyte subpopulations was investigated with the use of lectins. On the basis of morphological characteristics, two cell types namely the granulocytes (with a mean diameter of 6.5 μm) and hyalinocytes (with a mean diameter of 2.6 μm) were distinguished. Studies of the in vitro behavior of the granulocytes revealed a consecutive development of lamellipodium-like protruberances, microspikes (filopodia), and lamellipodia (pseudopodia). The spreading behavior of the granulocytes was apparently not dependent on serum factors since no differences were found in the spread of granulocytes in serum or in phosphate-buffered saline. With the lectin studies it was found that the lectins isolated from Canavalia ensiformis (concanavalin A) and Ricinus communis (castor bean agglutinin) were reactive with surface determinants of all the granulocytes whereas the lectin binding activity of Glycine max (soybean agglutinin) and Triticum vulgaris (wheat germ agglutinin) could not be inhibited by the appropriate inhibition sugars. No association could be found between granulocyte size and snail mass.