A major allogenic leukocyte antigen in the agnathan hagfish

作者：Takaba Hiroyuki; Imai Takeshi; Miki Shoji; Morishita Yasuyuki; Miyashita Akihiro; Ishikawa Naoko; Nishizumi Hirofumi; Sakano Hitoshi^*

来源：Scientific Reports, 2013, 3: 1716.

DOI：10.1038/srep01716

All vertebrates, from jawless fish to mammals, possess adaptive immune systems that can detect and inactivate non-self-antigens through a vast repertoire of antigen receptors. Unlike jawed vertebrates, the hagfish utilizes variable lymphocyte receptors (VLRs) that are unrelated to immunoglobulin molecules but are diversified by copy-choice gene conversion mechanism. Here, we report that hagfish VLRs react with allogenic leukocyte antigens but not with self-antigens. We found that a highly polymorphic membrane protein, NICIR3, is recognized by VLRs as an allogenic leukocyte antigen (ALA). In a serological cross-reactivity test, a close correlation was observed between the amino acid differences in the protein sequences and the VLR cross-reactivities. This leukocyte antigen was predominantly expressed in phagocytic leukocytes, where it was associated with phagocytosed protein antigens. These findings suggest that a polymorphic leukocyte antigen, NICIR3/ALA, plays a pivotal role in jawless vertebrate adaptive immunity.

• 出版日期2013-4-24