Stimulation of Natural Antibodies by Self Antigens

Abstract

The lymphoid organs of normal mice contain numerous background plaque forming cells specific for buried self antigens on mouse erythrocytes revealed by treatment with the proteolytic enzyme bromelain (1,2). We have documented elsewhere (3) the extent of this reactivity by measuring the number of B cells making αBrM antibody to the total number of B cells producing immuno-globulin (Ig) irrespective of specificity. The proportion of α BrM reactive B cells is very high — depending on the organ examined between 1% to > 50% of the ongoing or potential Ig secreting cells are BrM specific. This result is probably not unique. There are many reports showing that autoantibodies are a common occurrence in normal healthy individuals and include those specific for “buried” or “enzyme revealed” antigens on erythrocytes and lymphocytes, Ig molecules and reproductive organs (2,3). These facts have led us to suggest that much of the “natural” Ig synthesis of an animal is directed towards buried self components (3). Rather than deleting immunocompetent cells autoantigens of this type (at least) seem to prime them, contributing to the development of the immune repertoire. This paper documents the very significant effect which the BrM auto-antigen has on the developing immune system.