In vivo depletion of leukocytes and platelets following injection of T cell-specific antibodies into mice.

In vivo T cell depletion experiments are widely used to establish the role of these cells in a variety of immunological processes. Different clones of monoclonal antibody targeting the CD3 molecular complex (mainly 145-2C11 and 17A2) have been successfully used for T cell depletion. In the present work, we assessed the specificity of monoclonal antibody-mediated CD3 T cell depletion in mouse peripheral blood. We showed that treatment of BALB/C mice with monoclonal antibodies (clones 145-2C11 and 17A2) not only efficiently depletes T cells in vivo, but also leads to a substantial reduction in B cell, granulocyte and platelet counts. In contrast, T cell depletion using a combination of anti-CD4 and anti-CD8 antibodies was efficient and produced less deleterious effects on other blood cell populations. Therefore, the results obtained from T cell depletion experiments using anti-CD3 antibodies must be interpreted with caution prior to draw definitive conclusions on the role of T cells in a given immunological process.