Journal article
Babesia bovis: characterization of the T helper cell response against the 42-kDa merozoite surface antigen (MSA-1) in cattle
Experimental parasitology, Vol.77(1), pp.97-110
08/1993
Handle:
https://hdl.handle.net/2376/118198
PMID: 8344411
Abstract
The Babesia bovis major merozoite surface antigen (MSA-1) is a 42-kDa integral membrane glycoprotein previously shown to induce immunodominant antibody responses in cattle protectively immune to B. bovis and to induce neutralizing antibody. Recent studies have also shown that MSA-1 B cell epitopes common to New World strains of B. bovis are not present in either Israel or Australia strains. To understand the potential role of this protein in protective immunity, T helper cell responses specific for MSA-1 were characterized in Babesia-immune cattle. Peripheral blood mononuclear cells from immune cattle proliferated against affinity-purified recombinant MSA-1 protein expressed in Escherichia coli. MSA-1 preferentially stimulated the growth of CD4+ T cells in cell lines cultured with antigen for 4 weeks. MSA-1-reactive cell lines responded to a membrane fraction of B. bovis merozoites, suggesting recognition of the native protein. However, B. bovis-reactive T cell lines and T helper clones established by stimulation with crude parasite membrane antigen failed to respond to recombinant MSA-1, indicating that this antigen is not immunodominant for T cells. The majority of MSA-1-specific T helper clones reacted to unfractionated merozoite membrane antigen from New World B. bovis strains, but none of the clones responded to Australia B. bovis or to a Mexico strain of Babesia bigemina. Several T helper clones produced low levels of cytokines when stimulated with concanavalin A and interleukin-2. Northern blot analysis revealed the expression of interleukin-2, interleukin-4, interferon-gamma, and tumor necrosis factor-alpha messenger RNA in mitogen-stimulated T helper clones, showing that the clones examined expressed an unrestricted T helper phenotype. We conclude that the MSA-1 protein, although serologically immunodominant and capable of inducing neutralizing antibodies as well as a T helper cell response, is not an immunodominant T cell antigen. Furthermore, the parasite strain specificity of the Th clones supports previous findings of extensive polymorphism in the MSA-1 glycoprotein and suggests that like B cell epitopes, T cell epitopes reside in a nonconserved portion of the protein.
Metrics
6 Record Views
Details
- Title
- Babesia bovis: characterization of the T helper cell response against the 42-kDa merozoite surface antigen (MSA-1) in cattle
- Creators
- W C Brown - Department of Veterinary Pathobiology, Texas A&M University, College Station 77843G H PalmerT F McElwainS A HinesD A Dobbelaere
- Publication Details
- Experimental parasitology, Vol.77(1), pp.97-110
- Academic Unit
- Veterinary Medicine, College of; Veterinary Microbiology and Pathology, Department of; Paul G. Allen School for Global Animal Health
- Publisher
- United States
- Grant note
- AI-130136-01 / NIAID NIH HHS
- Identifiers
- 99900548291801842
- Language
- English
- Resource Type
- Journal article