Bovine milk lymphocytes display the phenotype of memory T cells and are predominantly CD8+.
The phenotype of bovine milk lymphocytes was investigated and compared to peripheral blood lymphocytes using monoclonal antibodies specific for bovine leukocyte differentiation antigens and flow cytometry. T lymphocytes traffic selectively into bovine milk while B lymphocytes represent a minor population in milk by comparison to peripheral blood. The vast majority of T cells in milk express alpha beta T cell receptors and are predominantly CD8+. T cells in milk express twofold higher levels of CD2 and fivefold lower levels of CD45R, characteristics associated with memory T cells. Grouping of cows by lactational stage and analysis of lymphocyte subpopulation percentages indicated that CD4+ T cells are present in relatively low numbers in milk of cows in the first 50 days of lactation and have a significant tendency to increase in number as lactation progresses.
Taylor
B C
BC
Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California at Davis 95616-8739.
Dellinger
J D
JD
Cullor
J S
JS
Stott
J L
JL
D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D002417:Cattle; D005260:Female; D007156:Immunologic Memory; D007774:Lactation; D008892:Milk / Q000166:cytology / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte