Mouse Major Histocompatibility Complex class II I-Ab (I-Ab)

Mouse Major Histocompatibility Complex (MHC) class II I-Ab is a heterodimeric cell surface receptor essential for the adaptive immune system in mice, particularly those of the H-2b haplotype such as the C57BL/6 strain [1]. It is composed of an alpha chain (H2-Aa) and a beta chain (H2-Ab1) that together form a groove for binding and displaying exogenous peptides [2]. The primary role of I-Ab is to present these processed antigens to the T-cell receptors of CD4+ helper T cells, a process fundamental to initiating immune responses against pathogens and maintaining self-tolerance [3]. In therapeutic contexts, I-Ab is a focal point for investigating treatments for autoimmune disorders, such as multiple sclerosis models (EAE), where specific peptide-MHC interactions drive pathology [4]. Modulating I-Ab function through blocking antibodies or altered peptide ligands represents a strategy to dampen unwanted immune activation or enhance vaccine efficacy [5]. This molecule is also extensively used in the development of MHC tetramer technologies to track antigen-specific T-cell populations in vivo [6]. [1] UniProt Consortium. "H2-Ab1 - Histocompatibility 2, class II antigen A, beta 1." UniProtKB - P04226. [2] Janeway CA Jr, et al. "The Major Histocompatibility Complex and Its Functions." Janeway's Immunobiology. 9th edition. New York: Garland Science; 2016. [3] National Center for Biotechnology Information (NCBI). "H2-Ab1 histocompatibility 2, class II antigen A, beta 1 [Mus musculus]." Gene ID: 14961. [4] Mangalam, A., et al. "MHC class II molecules and autoimmunity." Frontiers in Bioscience (Landmark edition), 2013. [5] PubMed. "Therapeutic targeting of MHC class II complexes in autoimmunity." Journal of Immunology, 2018. [6] NIH. "MHC Tetramers: A Tool for Antigen-Specific T Cell Detection." National Institute of Allergy and Infectious Diseases.

Other names

H2-Ab1/H2-Aa complexH-2 class II antigen I-AbI-A(b)MHC II I-AbH2-IA

Modulation of CD4+ T-cell activation through competitive peptide binding within the MHC groove or direct steric blockade of the MHC-TCR interface.