|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
Journal of Cell Science, Vol 112, Issue 19 3187-3192, Copyright © 1999 by Company of Biologists
JOURNAL ARTICLES |
CM Turner
Division of Infection and Immunity, IBLS, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK. m.turner@bio.gla.ac.uk
Trypanosoma brucei parasites undergo clonal phenotypic (antigenic) variation to promote their transmission between mammals and tsetse-fly vectors. This process is classically considered to be a mechanism for evading humoral immune responses, but such an explanation cannot account for the high rate of switching between variable antigens or for their hierarchical (i.e. non-random) expression. I suggest that these anomalies can be explained by a new model: that antigenic variation has evolved as a bifunctional, rather than as a unifunctional, strategy that not only evades humoral immune responses but also enables competition between parasite strains in concomitantly infected hosts. This competition causes a depression of cellular responses. My proposal gives rise to a number of testable predictions. First, low numbers of trypanosomes should express some variable antigen types (VATs) in infections several weeks before these VATs are detectable. Second, as an infection progresses, the number of VATs expressed simultaneously in the population should decrease. Third, immunisation to generate a T helper 1 response against those VATs that are expressed most frequently should lower parasitaemias and reduce virulence.
This article has been cited by other articles:
![]() |
M. Del Poeta Role of Phagocytosis in the Virulence of Cryptococcus neoformans Eukaryot. Cell, October 1, 2004; 3(5): 1067 - 1075. [Full Text] [PDF] |
||||