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Long‐term in vivo depletion of functional CD4 + T lymphocytes from calves requires both thymectomy and anti‐CD4 monoclonal antibody treatment
Author(s) -
Valdez R. A.,
McGuire T. C.,
Brown W. C.,
Davis W. C.,
Knowles D. P.
Publication year - 2001
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.2001.01211.x
Subject(s) - thymectomy , in vivo , monoclonal antibody , lymphocyte , antibody , ovalbumin , biology , immunology , ex vivo , lymphatic system , spleen , t lymphocyte , immune system , myasthenia gravis , microbiology and biotechnology
Summary In vivo depletion of lymphocyte subsets is a direct approach used for dissection of the mechanisms of protective immunity. Long‐term in vivo depletion of bovine T lymphocyte subpopulations with monoclonal antibody (mAb) treatment alone has been difficult to achieve. The objective of this study was to determine whether both thymectomy and anti‐CD4 mAb treatment would optimize long‐term in vivo depletion of functional bovine CD4 + T lymphocytes. Calves were thymectomized and treated with high doses of anti‐CD4 mAb (approximately 5 mg/kg) over 4 days followed by subsequent lower doses (approximately 0·3 mg/kg) administered twice weekly for an additional 7 weeks. Depletion of CD4 + T lymphocytes from blood, spleen and peripheral lymph nodes was significantly improved in thymectomized calves compared to thymus‐intact anti‐CD4 mAb‐treated calves. Significant differences in percentages of CD4 + T lymphocytes between thymectomized and thymus‐intact calves were sustained for the duration of the 8‐week study. Depletion of CD4 + T lymphocytes from thymectomized calves resulted in complete abrogation of lymphoproliferative responses to ovalbumin. In addition, thymectomized calves treated with anti‐CD4 mAb had significantly reduced immunoglobulin G1 and no detectable immunoglobulin G2 ovalbumin‐specific antibody responses compared to thymus‐intact anti‐CD4 mAb‐treated calves. The results of this study demonstrate that both thymectomy and treatment with anti‐CD4 mAb are required for long‐term in vivo depletion of functional bovine CD4 + T lymphocytes.