Long-term staphylococcal enterotoxin C1 exposure induces soluble factor-mediated immunosuppression by bovine CD4+ and CD8+ T cells

Keun Seok Seo; Sang Un Lee; Yong Ho Park; William C Davis; Lawrence K Fox; Gregory A Bohach

doi:10.1128/IAI.01358-06

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Long-term staphylococcal enterotoxin C1 exposure induces soluble factor-mediated immunosuppression by bovine CD4+ and CD8+ T cells

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Long-term staphylococcal enterotoxin C1 exposure induces soluble factor-mediated immunosuppression by bovine CD4+ and CD8+ T cells

Keun Seok Seo, Sang Un Lee, Yong Ho Park, William C Davis, Lawrence K Fox and Gregory A Bohach

Infection and immunity, Vol.75(1), pp.260-269

01/2007

DOI: https://doi.org/10.1128/IAI.01358-06

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https://hdl.handle.net/2376/112906

PMCID: PMC1828382

PMID: 17030573

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Abstract

T-Lymphocyte Subsets - immunology

Cell Proliferation

Staphylococcal Infections - immunology

Cells, Cultured

Male

Superantigens - immunology

Reverse Transcriptase Polymerase Chain Reaction

Cattle - immunology

Staphylococcal Infections - veterinary

T-Lymphocytes, Regulatory - immunology

Lymphocyte Activation - immunology

Animals

Flow Cytometry

Enterotoxins - immunology

Time Factors

Leukocytes, Mononuclear - immunology

Staphylococcus aureus - immunology

CD8-Positive T-Lymphocytes - immunology

Regulatory T cells (T(regs)) help control the development and maintenance of protective immunity and can lead to aberrant immune responses to some pathogens. Several lines of evidence suggest that T(regs) are induced by exposure to superantigens (SAgs) in vitro or in vivo. In this study, bovine peripheral blood mononuclear cells (PBMC) were exposed in vitro to a relatively low dose (5 ng/ml) of staphylococcal enterotoxin C1 (SEC1) for up to 10 days. Upon stimulation, CD4+ and CD8+ T cells initially proliferated at similar rates. Subsequently, from days 6 through 10, most CD4+ and CD8+ T cells proliferated regardless of Vbeta specificity, but the proliferation of CD8+ T cells occurred more vigorously. The transcription of CD25 and CD152 genes increased, whereas that of interleukin-2 (IL-2) decreased. gammadelta T cells appeared to be unresponsive. An increase in the transcription of IL-10 and transforming growth factor beta (TGF-beta) genes in SEC1-stimulated cultures was attributed to the CD4+ CD25+ T-cell subpopulation. The expression of Foxp3 mRNA also increased and was accompanied by the upregulation of CD152 and the downregulation of IL-2 transcription, suggesting that cells in this subpopulation are T(regs). Functionally, SEC1-stimulated CD4+ T cells suppressed the proliferation of naive PBMC in response to heat-killed-fixed Staphylococcus aureus. The suppression was partially mediated by IL-10 and TGF-beta, another characteristic of certain types of T(regs.) The CD8+ T-cell population also suppressed naive PBMC through another mechanism not mediated by IL-10 or TGF-beta. These results provide further insight into the potential mechanisms by which SAgs could contribute to evasion of the immune response, affecting the outcome of infection or colonization.

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Title: Long-term staphylococcal enterotoxin C1 exposure induces soluble factor-mediated immunosuppression by bovine CD4+ and CD8+ T cells
Creators: Keun Seok Seo - Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, South Line Street, Agricultural Biotechnology Building 222, Moscow, ID 83844, USA
Sang Un Lee
Yong Ho Park
William C Davis
Lawrence K Fox
Gregory A Bohach
Publication Details: Infection and immunity, Vol.75(1), pp.260-269
Academic Unit: Veterinary Clinical Sciences, Department of; Veterinary Microbiology and Pathology, Department of
Publisher: United States
Grant note: P20 RR016454 / NCRR NIH HHS U54 AI057141 / NIAID NIH HHS P20 RR015587 / NCRR NIH HHS U54AI57141 / NIAID NIH HHS P20 RR15587 / NCRR NIH HHS
Identifiers: 99900547902001842
Language: English
Resource Type: Journal article