Title | The role of B-cells and IgM antibodies in parasitemia, anemia, and VSG switching in Trypanosoma brucei-infected mice. |
Publication Type | Journal Article |
Year of Publication | 2008 |
Authors | Magez, S., A. Schwegmann, R. Atkinson, F. Claes, M. Drennan, P. De Baetselier, and F. Brombacher |
Journal | PLoS Pathog |
Volume | 4 |
Issue | 8 |
Pagination | e1000122 |
Date Published | 2008 |
Type of Article | parasites |
ISSN | 1553-7374 |
Keywords | Anemia, Animals, Antibodies, Protozoan, B-Lymphocytes, Female, Immunoglobulin M, Mice, Mice, Inbred BALB C, Mice, Knockout, Parasitemia, Trypanosoma brucei brucei, Trypanosomiasis, African |
Abstract | African trypanosomes are extracellular parasitic protozoa, predominantly transmitted by the bite of the haematophagic tsetse fly. The main mechanism considered to mediate parasitemia control in a mammalian host is the continuous interaction between antibodies and the parasite surface, covered by variant-specific surface glycoproteins. Early experimental studies have shown that B-cell responses can be strongly protective but are limited by their VSG-specificity. We have used B-cell (microMT) and IgM-deficient (IgM(-/-)) mice to investigate the role of B-cells and IgM antibodies in parasitemia control and the in vivo induction of trypanosomiasis-associated anemia. These infection studies revealed that that the initial setting of peak levels of parasitemia in Trypanosoma brucei-infected microMT and IgM(-/-) mice occurred independent of the presence of B-cells. However, B-cells helped to periodically reduce circulating parasites levels and were required for long term survival, while IgM antibodies played only a limited role in this process. Infection-associated anemia, hypothesized to be mediated by B-cell responses, was induced during infection in microMT mice as well as in IgM(-/-) mice, and as such occurred independently from the infection-induced host antibody response. Antigenic variation, the main immune evasion mechanism of African trypanosomes, occurred independently from host antibody responses against the parasite's ever-changing antigenic glycoprotein coat. Collectively, these results demonstrated that in murine experimental T. brucei trypanosomiasis, B-cells were crucial for periodic peak parasitemia clearance, whereas parasite-induced IgM antibodies played only a limited role in the outcome of the infection. |
DOI | 10.1371/journal.ppat.1000122 |
Alternate Journal | PLoS Pathog. |
PubMed ID | 18688274 |
PubMed Central ID | PMC2483930 |
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