FIG. 2.

Regional differences in the attachment of promastigotes from various Leishmania spp. to human monocytes. Human peripheral blood monocytes (10⁶) were incubated with either L. major, L. donovani, or L. aethiopica promastigotes (10⁷) in the presence of fFCS for 15 min. The bars represent the relative frequencies of the attachment sites observed with randomly chosen promastigotes, given as mean ± SEM of duplicate determinations. Essentially the same results were observed in two additional experiments using phagocytes from different donors. Promastigotes from L. major and L. aethiopica attach predominantly with the flagellar tip and only occasionally with the flagellar base or posterior pole, whereas L. donovani promastigotes attach with either the flagellar tip or the posterior pole in approximately equal proportions.