Two different primate species express an identical functional MHC class I allele

Area of Science:

• Immunology
• Evolutionary Biology
• Genetics

Background:

• The Major Histocompatibility Complex (MHC) class I molecules are vital for host defense against pathogens.
• While MHC alleles can be similar in related species, functional allele sharing between species has not been previously documented.

Purpose of the Study:

• To investigate the presence of identical functional MHC class I molecules in different primate species.
• To determine if a shared MHC class I allele can confer cross-species immune function.

Main Methods:

• Comparative sequencing of MHC class I alleles from two tamarin species: Saguinus geoffroyi and Saguinus oedipus.
• Functional assessment using influenza virus-specific cytotoxic T lymphocytes (CTLs) to test cross-species recognition.

Main Results:

• Identical coding sequences were found for an MHC class I allele (Sage-G*01) in Saguinus geoffroyi and (Saoe-G*08) in Saguinus oedipus.
• Influenza virus-specific CTLs from cotton-top tamarins successfully recognized and killed red-crested tamarin lymphocytes presenting the influenza nucleoprotein (NP).
• The identified MHC class I molecule is likely functional in both species for recognizing influenza NP.

Conclusions:

• This study presents the first evidence of a functional MHC class I molecule being maintained identically across two distinct primate species.
• The findings suggest a potential mechanism for cross-species immune recognition and highlight the evolutionary stability of certain immune genes.