Paul I. Terasaki Foundation Laboratory

Epitopes of the HLA-A, B, C, DR, DQ and MICA Antigens

Nadim El-Awar, Paul I. Terasaki, Junchao Cai, Chun-Tsan Deng,
Mikki Ozawa and Anh Nguyen

One Lambda Inc., Canoga Park, CA
Terasaki Foundation Laboratory, Los Angeles, CA

INTRODUCTION

For the past 40 years in transplantation, we have focused attention on the HLA antigen as the target for anti-HLA antibodies. The common perception was that one HLA antibody recognizes one HLA antigen. Monospecific sera (those that reacted with a single HLA specificity) were sought after as serologic reagents for HLA typing and although monospecific antibodies were found for many antigens, their number was small relative to the much larger number of sera that reacted with multiple HLA specificities. Some cross-reacting groups (CREGs) of HLA antigens that often reacted with sera containing HLA antibodies were identified in early studies of HLA antisera and their frequent occurrence suggested that a single HLA antibody could react with more than one HLA antigen.