Immunohistochemical Examination of PDGF-AB, TGF-β and their Receptors in the Hemocytes of a Tick, Ornithodoros moubata (Acari: Argasidae)

Abstract

Growth factors, Platelet Derived Growth Factor (PDGF) and Transforming Growth Factor (TGF)-β, were demonstrated in vertebrate and invertebrate immmunocytes. It is generally known that the growth factors are important in various biological processes, such as the regulation of cell differentiation, development and wound healing. In the present study, the presence of TGF-β1 and PDGF-receptor-α in plasmatocytes and PDGF-AB in granulocytes of a soft tick, Ornithodoros moubata, was confirmed immunohistochemically. The tick midgut might be damaged by intracellular digestion and penetration of protozoa. Therefore, it is considered that PDGF from granulocytes may affect the PDGF-receptor-α in plasmatocytes and TGF-β from plasmatocytes may function to repair the midgut. The results obtained here add to the elucidation of the functions of tick hemocytes.