Landscape of IGH germline genes of Chiroptera and the pattern of Rhinolophus affinisbat IGH CDR3 repertoire

The emergence and re-emergence of a number of viruses from bats that impact human and animal health has resulted in a resurgence of interest in bat immunology. Characterizing the immune receptor repertoire is critical to understanding how bats coexist with viruses in the absence of disease and developing new therapeutics to target viruses in humans and susceptible livestock. We annotated IGH germline genes of Rhinolophus ferrumequinum (RF), Phyllostomus discolor (RD) and Pipistrellus pipistrellus (PP), and investigated the evolutionary relationship between bat germline genes and that of human, mouse, cow, and dog. The IGH repertoire characteristics of Rhinolophus affinis bat (RA) were also analyzed. The V gene families of all three bat species can be classified into three Clan, although PD is special with the abnormal length of IGH locus and 22 reverse V genes. Moreover, the bats germline genes are quite differed from those of human, mouse, cow, and dog in evolution, but the three bat species have high homology. The CDR3 repertoire of RA are unique in many aspects including CDR3 subclass, V/J genes access and pairing, CDR3 clones and somatic high-frequency mutation compared with that of human and mouse, which may be the immunologic basis for the asymptomatic nature of viral infection in bats. This study provide immune genome information and extensive reference for the basic research of bat and virus infection mechanism.