Antigen presentation

Abstract

Antigen presentation is a critical step in the initiation of immune response. Many types of cells can serve this function but the macrophages are the principal cells. The antigen-presenting cells (APC) must express Ia antigens and most of them produce interleukin-1. Macrophages bind, endocytose, catabolize and then express the antigen on the surface in the context if Ia and present it to T and B lymphocytes. On the other hand, B-lymphocytes present the native antigen (without catabolism) in the context of Ia antigen to helper T cells. The nature of APC, their functions and factors modulating them have been discussed.