LEISHMANIA-MAJOR - EFFECT OF INFECTIOUS DOSE ON T-CELL SUBSET DEVELOPMENT IN BALB C MICE/

Leishmania major; the causative agent of cutaneous leishmaniasis in hu mans, causes either a local cutaneous lesion or a fatal, disseminated infection in different strains of mice. It has been well established t hat the BALB/c strain of mice is extremely susceptible to L. major inf ection, due to the preferential development of Th2 responses. It has a lso been shown, however, that these mice have the potential to develop protective Th1 responses under appropriate conditions. In this paper we confirm earlier reports that BALB/c mice are capable of developing immunity when challenged with low doses of L, major and show that this is dependent on the induction of a Thl response which can be manipula ted with anti-cytokine antibodies in the same way as more conventional experimental infections. Moreover, our data indicate that the develop ment of immunity or susceptibility to L, major in the BALB/c mouse may reflect factors specific to infection such as persistance of the path ogen, infection of APC, or relative cytokine levels rather than simple antigen load, a finding which may be of general significance in infec tious disease. (C) 1996 Academic Press, Inc.