T-CELL INDEPENDENT ANTIGENS

T cell independent antigens type 2 (Tl-2), which are represented predo minantly by polysaccharide antigens, stimulate humoral antibody respon ses in the absence of T-cell help. We and others have recently reporte d that natural killer cells and/or natural killer cell derived lymphok ines may provide a form of 'help' that is necessary for the induction and maintenance of Tl-2 responses. Two natural killer cell derived lym phokines, interferon-gamma and granulocyte-macrophage colony-stimulati ng factor, show synergistic stimulatory activity in inducing Ig secret ion in B cells stimulated by a multivalent ligand that mimics Tl-2 ant igens. The recent finding that natural killer cells have receptors for various classes of polysaccharides supports a role for these cells in regulating responses to Tl-2 antigens.