The Fc?Rs are immune cell surface proteins that bind IgG and facilitate cytokine production, phagocytosis, and Ab-dependent, cell-mediated cytotoxicity. Fc?Rs play a critical role in immunity; variation in these genes is implicated in autoimmunity and other diseases. Cynomolgus macaques are an excellent animal model for many human diseases, and Mauritian cynomolgus macaques (MCMs) are particularly useful because of their restricted genetic diversity. Previous studies of MCM immune gene diversity have focused on the MHC and killer cell Ig-like receptor. In this study, we characterize Fc?R diversity in 48 MCMs using PacBio long-read sequencing to identify novel alleles of each of the four expressed MCM Fc?R genes. We also developed a high-throughput Fc?R genotyping assay, which we used to determine allele frequencies and identify Fc?R haplotypes in more than 500 additional MCMs. We found three alleles for Fc?R1A, seven each for Fc?R2A and Fc?R2B, and four for Fc?R3A; these segregate into eight haplotypes. We also assessed whether different Fc?R alleles confer different Ab-binding affinities by surface plasmon resonance and found minimal difference in binding affinities across alleles for a panel of wild type and Fc-engineered human IgG. This work suggests that although MCMs may not fully represent the diversity of Fc?R responses in humans, they may offer highly reproducible results for mAb therapy and toxicity studies. Copyright © 2018 by The American Association of Immunologists, Inc.
Journal: Journal of immunology