Immunology of cutaneous and visceral Leishmaniasis: a perspective.

Visceral and cutaneous Leishmaniasis have been widely recognised as in vitro models for the differentia! regulation of CD4+ T cell subsets. These subsets are characterised on the basis of partially non-overlapping patterns of cytokine production. Thus, Th l type cells produce IL-2 and IFN y, whereas Th 2 cells produce IL-4 and IL-5. Both cell types are capable of producing other cytokines such as IL-3. The relationship between the functional expression of these populations and disease outcome has become a central focus for vaccine design, with potentially protective antigen formulations being screened for their ability to specifically induce cytokines, characteristic of the host protective reponse. Observations such as these are important in designing therapy and vaccines for most infectious diseases.