LAUSR

Aim The Swine Leukocyte Antigen (SLA) system is among the most well characterized major histocompatibility complex (MHC) systems in non-human animal species. Methods The ISAG/IUIS SLA Nomenclature Committee was established 15 years ago with primary objectives to: (1) validate newly identified SLA sequences according to the guidelines established for maintaining high quality standards of the accepted sequences; (2) assign appropriate nomenclatures for new alleles as they are validated; and (3) serve as a curator of the IPD-MHC SLA Sequence Database ( www.ebi.ac.uk/ipd/mhc/group/SLA ), which is the repository for all recognized SLA genes, their allelic sequences and haplotypes. The newly released and improved IPD-MHC Database version 2.0 has incorporated the latest sequence updates, provide new tools that enhance database queries and improve the submission process (Maccari et al., Nucleic Acids Res 2017; 45(D1):D860–D864). Results The SLA Nomenclature Committee met at the 2016 ISAG meeting and made some major revisions to the allele naming system. The Committee decided to retire the provisional alphanumerical naming system for unconfirmed alleles and re-designate each allele an official number, adopting the HLA Nomenclature System with colons as field separators (e.g. SLA-1∗01rh28 → SLA-1∗01:03). Phylogeny will remain the primary approach for assigning SLA-1, −2, −3, DRA, DRB1, DQA and DQB1 alleles into allele groups with similar sequence motifs, while alleles of SLA-5, −6, −7, −8, −12, DMA, DMB, DOA, DOB1, DRB2, DRB3, DRB4, DRB5 are designated sequentially as they are discovered. Naming convention for alleles of other loci (SLA-4, −9, −11, DQB2, DOB2, DYB, MIC1, MIC2, TAP1, TAP2) is to be determined as sequences accumulate. There are currently 223 class I, 214 class II, 2 SLA-related and 2 non-SLA alleles officially designated. There are also 61 class I (SLA-1-3-2) and 49 class II (DRB1-DQB1) haplotypes designated at allele level resolution. Conclusions This systematic nomenclature for SLA genes is critical to the understanding of the architecture and polymorphism of the SLA system and their role in swine diseases, vaccine development and allo- or xeno-responses in transplantation research.