These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Interleukin-4-dependent immunoglobulin G1 isotype switch in the presence of a polarized antigen-specific Th1-cell response to the trypanosome variant surface glycoprotein.
    Author: Schopf LR, Filutowicz H, Bi XJ, Mansfield JM.
    Journal: Infect Immun; 1998 Feb; 66(2):451-61. PubMed ID: 9453595.
    Abstract:
    This study examines B-cell immunoglobulin (Ig) class-switching events in the context of parasite antigen-specific Th-cell responses in experimental African trypanosomiasis. Inbred mice were infected with Trypanosoma brucei rhodesiense, and the coordinate stimulation of Th-cell cytokine responses and B-cell responses to the trypanosome variant surface glycoprotein (VSG) was measured. The cytokines produced by T cells in response to VSG, at both the transcript and protein levels, were gamma interferon and interleukin-2 (IL-2) but not IL-4 or IL-5. Isotype profiles of antibodies specific for VSG showed that IgG1, IgG2a, and IgG3 switch responses predominated; no VSG-specific IgE responses were detected. To determine whether cryptic IL-4 responses played a role in promoting the unexpected IgG1 switch response, IL-4 knockout mice were infected; the cytokine responses and Ig isotype profiles of IL-4 knockout mice were identical to those of the wild-type control mice except for dramatically reduced IgG1 levels in response to VSG. Thus, these results revealed an IL-4-dependent component of the VSG-driven B-cell Cmu-to-Cgamma1 switch. We speculate that an IL-4 response is mediated primarily by cells other than T lymphocytes since IL-4-secreting but parasite antigen-unresponsive, "background" cells were detected in all infected mice and since infected nude mice also displayed a detectable IgG1 switch response. Overall, our results suggest that B-cell clonal stimulation, maturation, and Ig class switching in African trypanosomiasis may be partially regulated by unusual mechanisms that do not include antigen-specific Th1 or Th2 cells.
    [Abstract] [Full Text] [Related] [New Search]