Maintaining the immunological balance in parasitic infections: A role for TGF-beta?

Transforming growth factor beta (TGF-beta) is an important regulator of inf lammation, being proinflammatory at low concentrations and anti-inflammator y at high concentration ions. As such, TGF-beta might be important in maint aining the balance between control and clearance of infections organisms on the one hand and prevention of immune-mediated pathology on the other. In this article, Fakhereldin Omer, Jorgen Kurtzhals and Eleanor Riley review t he immunoregulatory properties of TGF-beta in the context of parasitic infe ctions. Data from murine malaria infections suggest that TGF-beta modifies the severity of the disease, and a number of potential protective mechanism s are discussed. Evidence is accumulating that TGF-beta is important for th e regulation of other host-parasite interactions and that parasites might d irectly influence TGF-beta-dependent pathways via the synthesis of TGF-beta or TGF-beta-receptor homologies.