Characteristics of tick, Rhipicephalus appendiculatus, glands distinguished by surface lectin binding

Incubation of fluorescein-conjugated and biotinylated lectins with Rhipicephalus appendiculatus salivary glands revealed differences between the basal laminae of the haemocoelic surfaces of the three acinal types. There were some similarities in the lectin binding characteristics of the surfaces of type II and type III acini when Con A, PNA and TVA were applied, indicating the presence of galactose, mannose and glucose moieties on the acinal surfaces. The binding of BPA, HPA and HAA lectins, specific for galactosyl and glycosyl ligands, which occurred only on the surface of type III acini, was moderate to intense. The remaining galactose-reactive lectins (GMA, DBA and VVA) also bound only to type III acini and the level of binding was weak to moderate. Although the relationship between the haemocoelic surface of the R. appendiculatus salivary gland acini and Theileria kinetes is not known, the consistent differences in the surface carbohydrate composition of the acini confirm the existence of differences in the basic physiology of the acini which may correlate with the specific susceptibility of the type III acinus to Theileria parva infection.