Physiological variation of blood lymphocyte reactivity: T-cell subsets, immunoglobulin production, and mixed-lymphocyte reactivity.

Highly purified blood lymphocytes from healthy individuals were obtained from samples collected before and after a standardized bicycle ergometer test. In accordance with previous findings physical work resulted in a marked increase of circulating lymphocytes, with a proportionate decrease of T lymphocytes and increase of non-T lymphocytes including B cells. The decrease of T lymphocytes was accounted for by a reduction of cells reactive with the monoclonal OKT4 serum (helper/inducer), whereas the proportion of OKT8-positive cells (suppressor/cytotoxic) remained unchanged. The lymphocyte production of IgG, IgM, and IgA after 7 days culture with pokeweed mitogen and the lymphocyte DNA synthesis after activation by allogeneic cells was reduced during work. It is concluded that nonspecific stress changes the composition of T-lymphocyte subsets with depression of T-cell stimulation and T-cell-dependent immunoglobulin production.