Roles of MHC Molecules in Immune Responses and Accomplishment of Viral Vaccines

Abstract

It is believed that viral vaccine is a powerful tool to prevent viral infection. Occasion-

ally, there were  reports of the low  efficiency  of viral vaccines  some  of which can be less than

50%. Major histocompatibility complex (MHC) is the polymorphic molecule that plays an important role in inducing cell-mediated  immune response of helper T cells (Th) and cytotoxic T cells (Tc). There are two classes of MHC molecules,  class I and II. Both classes have three major loci: HLA-A,  -B and -C in class I and HLA-DP,  -DQ and -DR in class II. To date, over thousand alleles for each MHC gene locus have been characterized. Based on genetic inheritance, individuals  have  variation  of MHC alleles. To induce specific T-lymphocyte clones, T-cell epitopes require the association of the compatible MHC molecule to form an MHC-peptide complex to induce specific T cell clone through T cell receptor (TCR) molecule. Thus, lacking of appropriate MHC allele can be the cause of negative seroconversion in some individuals for some particular antigen. This article discusses the association of MHC molecules and immune response in prevention of viral transmission by the viral vaccine. A prospective plan for managing seroconversion in vaccinated individuals is also proposed as a package of the viral vaccine administration, particularly, the role of medical technologist.