ABSTRACT
Recognition of Self and Non-Self The histocompatability antigens are a set o f protein products that constitute the
self-identity that is unique in each individual. T-cells are educated to identify and tolerate self antigen, whereas the encounter with any non-self antigen will lead to the initiation of immune response. The most recognized histocompatibility antigens are the class I and class II glycoproteins of the major histocompatibility complex (MHC) (Fig. 1, Table 1). Class I is expressed on all nucleated cells and in general is responsible for activating Τ-cells bearing the CD8 surface molecule (CD8+). O f the several class I genes, A and B are the most important for clinical transplantation. M H C class II glycoproteins are expressed primarily on dendritic cells, B-cells, and macrophages. As a group, these cells are also referred to as antigen presenting cells, due to their avidity by which they display peptide in conjunction with MHC.
