Lymphocyte stimulation by cell wall constituents

T cells recognize peptides in association with self-MHC structures on antigen-presenting cells and become activated upon ligand binding to the T cell receptor. It is not known whether T cells are also able to recognize carbohydrate antigens. As a model system, we have investigated the human T cell immune response to the group-specific carbohydrate of A streptococci. This antigen stimulated specific antibody production in B cells very effectively, but was unable to stimulate proliferation in T cell lines or clones that reacted specifically to streptococcal A particles. Therefore, streptococcus A-specific T cells seem to recognize other structures of the particulate antigen than the carbohydrate, as was confirmed by the persistence of stimulation after periodate treatment.