Subversion of host cell signalling by the protozoan parasite Leishmania

D. J. GREGORY a1 and M. OLIVIER a1a2c1
a1 Centre for the Study of Host Resistance at the Research Institute of the McGill University Health Centre, and Departments of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
a2 Experimental Medicine, McGill University, Montréal, Québec, Canada

Article author query
gregory dj   [PubMed][Google Scholar] 
olivier m   [PubMed][Google Scholar] 


The protozoa Leishmania spp. are obligate intracellular parasites that inhabit the macrophages of their host. Since macrophages are specialized for the identification and destruction of invading pathogens, both directly and by triggering an innate immune response, Leishmania have evolved a number of mechanisms for suppressing some critical macrophage activities. In this review, we discuss how various species of Leishmania distort the host macrophage's own signalling pathways to repress the expression of various cytokines and microbicidal molecules (nitric oxide and reactive oxygen species), and antigen presentation. In particular, we describe how MAP Kinase and JAK/STAT cascades are repressed, and intracellular Ca2+ and the activities of protein tyrosine phosphatases, in particular SHP-1, are elevated.

Key Words: Leishmania; macrophage; SHP-1; PTP; STAT1; nitric oxide; MHC class II.

c1 McGill University, Department of Microbiology and Immunology, Duff Medical Building, Room 610, 3775 University Street, Montréal, Québec, H3A 2B4, Canada. Tel: 514-398-5592/1302. Fax: 514-398-7052. E-mail: