Neutralizing Antibody Responses to Viral Infections Are Linked to the Non-classical MHC Class II Gene H2-Ob

Area of Science:

• Immunology
• Genetics
• Virology

Background:

• Adaptive immunity, including neutralizing antibodies, is crucial for controlling persistent viral infections in humans and animals.
• The genetic underpinnings of this control, particularly antibody production, remain largely unknown.
• Major histocompatibility complex (MHC) molecules play a central role in immune regulation and antigen presentation.

Purpose of the Study:

• To identify the specific gene responsible for the production of retrovirus-neutralizing antibodies in I/LnJ mice.
• To elucidate the role of the non-classical MHC class II-like molecule H2-O in adaptive immune responses.
• To investigate the implications of H2-O and its human homolog, HLA-DO, in controlling viral infections like HBV and HCV.

Main Methods:

• Positional cloning was employed to identify the gene associated with neutralizing antibody production in I/LnJ mice.
• Bioinformatics and functional analyses were conducted on the mouse H2-O gene and its human homolog, HLA-DOB.
• The study involved analyzing the impact of different alleles on antibody production and immune control.

Main Results:

• The gene responsible for neutralizing antibody production in I/LnJ mice was identified as encoding the beta subunit of H2-O, an MHC-II-like molecule.
• A recessive, functionally null H2-O allele (H2-Ob) in I/LnJ mice enabled virus-neutralizing antibody production independent of the classical MHC haplotype.
• Human HLA-DOB alleles exhibited both loss- and gain-of-function variations, potentially impacting control of HBV and HCV infections.

Conclusions:

• The non-classical MHC-II-like molecule H2-O (and its human homolog HLA-DO) plays a significant, previously unappreciated role in immunity to viral infections.
• Understanding the genetic basis of H2-O function can inform strategies for developing effective neutralizing immunity against viruses.
• Variations in HLA-DOB may influence an individual's susceptibility or resistance to persistent viral infections.