Receptors for polysaccharides of group A streptococci on human thymic lymphocytes. Stimulation of their expression by action of adenosine, theophylline and supernatant of thymocytes

It was established by indirect immunofluorescence that thymic lymphocytes bear receptors for polysaccharide of group A streptococci (Rps). The ability of thymic lymphocytes to express Rps depends on the cAMP concentration in the cell, because the treatment of thymocytes with adenosine and theophylline increases the number of cells with Rps (Tps cells). Supernatant of thymic lymphocytes is also capable of stimulating expression of Rps. Because the A-polysaccharide has common antigenic determinant with thymus epithelium antigen it can be assumed that A-polysaccharide links with the thymocytes via receptor for this epithelial antigen. This assumption needs a detailed study in view of the hypothesis about the important role of cross-reactive antigens of group A streptococci in generating autoimmune process during rheumatic fever and other streptococcal diseases. It should also be noted that Rps may be a useful marker for identification and studying the changes of Tps subpopulation in the thymus and peripheral lymphoid organs of patient with different streptococcal diseases.