This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
[{'content': 'a new agent was developed to increase the recognition of foreign antigens by antigen presenting cells .true regarding the physiological aspects of APCs \nSelect and explain. \nA. antigen is presented MHC-1 complexes, B. APCs are required before a response to viruses are generated, C. direct antibody stimulation still requires APCs, D. antigen processed by APC are recognised by CD 4+ tcells', 'role': 'user'}, {'content': 'Answer: D \nExplanation: EXOGENOUS ANTIGENS ARE FIRST PHAGOCYTOSED BY APCs THEN THEY ARE PROCESSED BY APC s and presented on the surface of apc along with mhc 2 to be recognised by cd4+ t cells antigen Presenting Cells Antigen-presenting cells (APCs) are specialized cells, which include macrophages, B lymphocytes, and dendritic cells, are distinguished by two propeies: (1)they express class II MHC molecules on their me branes, and # (2) they are able to deliver a co-stimulatory signal that is n cessary for TH-cell activation. antigen presentation : foreign protein antigen are degraded into small antigenic peptides that form complexes with class I or class II MHC molecules. # This conversion of proteins into MHC-associated pep iale fragments is called antigen processing and pr entation. # ether a paicular antigen will be processed and resented together with class I MHC or class II HC molecules appears to be determined by the route that the antigen takes to enter a cell. ref : ananthanaryana 9th ed', 'role': 'assistant'}]