a new agent was developed to increase the recognition of foreign antigens by antigen presenting cells .true regarding the physiological aspects of APCs

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