Costimulatory factor for T cell include all except

CD80 - B7-1 CD86 - B7-2 Co-stimulatory signal Helps in self-tolerance if this signal is impaired: high risk of autoimmune diseases Impoant in pathogenesis of rheumatoid ahritis. Drug - Abatacept blocks co-stimulatory signal CD 40 - CD40L interaction (T-cell) | Class switching of antibodies IgM - Ig G/A/E If CD40-CD40L interaction is impaired= Hyper IgM syndrome Anergy: Lymphocytes that recognize self-antigens may be rendered functionally unresponsive this phenomenon is called as Anergy. Activation of Ag-specific T-cells requires 2 signals. Recognition of peptide-ag in association with self MHC molecules on surface of APCs & a set of co-stimulatory signals from APCs. If Ag is presented to T-cell without adequate levels of co-stimulatory signals the cells become anergic. .