Development and characterization of a monoclonal antibody specific for the bovine low-affinity interleukin-2 receptor, BoCD25.
An IgM monoclonal antibody, UC-2C2 was produced using splenocytes from mice immunized with cultures of interleukin-2 (IL-2)-dependent bovine peripheral blood lymphocytes. UC-2C2 was found to recognize a cell surface antigen of apparent molecular weight 52,000-54,000 present on activated bovine peripheral blood mononuclear leucocytes (PBML) but not on resting PBML or cells of the bovine lymphoblastoid cell line BL3. The 52,000-54,000 MW antigen was expressed early following activation of PBML by mitogens or alloantigens, with the majority of cells positive by 48 h of culture. UC-2C2 was unable to block binding of phycoerythrin (PE)-conjugated human recombinant IL-2 to PHA-stimulated bovine PBML as determined by flow cytometric analysis. However, two-colour analyses indicated that the antigen recognized by UC-2C2 was present on the same cell population that expressed IL-2 receptors. All activated T lymphocytes of BoCD4, BoCD8 and gamma delta receptor positive phenotypes expressed the target antigen of UC-2C2 and IL-2 receptors. Monocytes and B lymphocytes expressed the target antigen of UC-2C2 and IL-2 receptors at a lower density. This differential expression by the various PBML subpopulations parallels that described for expression of the low-affinity IL-2 receptor (CD25) on human leucocyte subpopulations. Based upon the relative molecular weight, time-course of expression and cellular distribution of the antigen identified by UC-2C2, it is inferred that UC-2C2 recognizes an epitope on the bovine homologue of CD25 which is not involved in binding IL-2.
Taylor
B C
BC
Department of Veterinary Microbiology and Immunology, University of California, Davis 95616.
Stott
J L
JL
Scibienski
R J
RJ
Redelman
D
D
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D002417:Cattle / Q000276:immunology*; D002478:Cells, Cultured; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015375:Receptors, Interleukin-2