Immunological agnosis: a state that derives from T suppressor cell inhibition of antigen-presenting cells.

The biologically active mediators of antigen-specific T suppressor cells can combine with antigen on cells that are specialized to present antigen (APC) and render these APC incapable of presenting not only the specific antigen that the product of the T suppressor cell sees but also any other antigen in or on the APC. Thus, antigen-bearing suppressed APC fail to activate either the helper or suppressor system involved in the regulation of contact sensitivity responses. These results demonstrate that APC are targets of T suppressor cells. They also imply that a metabolic event is required for functional antigen presentation and that T suppressor cells can block that metabolic pathway.