PROTEIN A-POSITIVE STAPHYLOCOCCI SERVE AS A SELECTIVE B-CELL MITOGEN FOR LYMPHOCYTES FROM PRIMARY IMMUNODEFICIENCY PATIENTS

Abstract

Staphylococcus aureus protein A-positive bacteria were recently proposed as selective B [bone marrow-derived] lymphocyte mitogens. The lymphocyte response to such mitogens in normal subjects and in patients with primary immunodeficiencies was studied. Patients with primary T [thymus-derived] cell defects show a normal response to protein A-positive bacteria and impaired responses to PHA [phytohemagglutinin] and Con [concanavalin] A. Patients with Bruton agammaglobulinaemia respond normally to these T cell mitogens but not to the bacteria. Thus, protein A-positive bacteria fulfil the criteria for being a T cell-independent B cell mitogen for human peripheral blood cells.