This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Abatacept is ? \nSelect and explain. \nA. TNF alpha inhibitor, B. Inhibitor of co-stimulation of T cells, C. IL-1 receptor antagonist, D. Monoclonal antibody against IL-6 receptor', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Inhibitor of co-stimulation of T cells T-cell costimulatory blockers Abatacept It is a fusion protein that combines the extracellular domain of the molecule CTLA4 (CD 154) with the Fc poion of a human immunoglobulin. It interferes with the interactions between antigen presenting cells and T lymphocytes. Therefore, it affects early stages in the pathogenic cascade of event in RA. CTLA4 has high affinity for CD 28 when abatacept binds to CD28 on T cell surface, it prevents the second signal from being delivered, thus turning down the T cell response. Additional effects are decreasing the production of T cell-derived cytokines including TNF.", 'role': 'assistant'}]