Evaluation of immunoregulatory T cell activity in common variable immunodeficiency by using <i>Staphylococcus aureus</i> Cowan 1

Abstract

Pokeweed mitogen (PWM) is widely used to induce immunoglobulin production of PBL. Since PWM predominantly stimulates suppressor T cells, it is sometimes impossible to evaluate correctly the function of B cells or helper T cells. It is known that Staphylococcus aureus Cowan 1 (SAC) induces T cell-independent proliferation of B cells and T cell-dependent differentiation of B cells. To study the activation of T cells stimulated by SAC, two surface antigens (T4, T8 and Tac) were determined simultaneously by indirect immunofluorescence. By this method, SAC was demonstrated predominantly to activate the T4+ T cells, but not the T8+ T cell subset.Suppressor T cells are believed to be involved in the pathogenesis of some cases of common variable immunodeficiency (CVID). Such cells suppress PWM induced Ig production in coculture of normal and patient lymphocytes. Peripheral blood lymphocytes (PBL) and T cells of two patients with CVID and a patient with agammaglobulinemia were shown to suppress PWM induced Ig production of control PBL. However T cells of these three patients showed normal helper activity in SAC induced Ig production. The data indicate that the parallel use of SAC and PWM is always needed for studying the mechanisms responsible for altered immunoregulation in patients with hypogammaglobulinemia.