This inference was assessed at multiple meetings and a decision was taken during meeting 121 on May 8th, 2023.

TRBV7-7*01_C315T has been inferred in seventeen genotypes in the VDJbase P4 data set, including in VDJbase P4_I9_S1, a haplotypable data set (based on heterozygocity in TRBJ1-6). The genotype is also implied to carry TRBV7-7*01. No other gene apart from IGHV7-6 (alleles of which also carry C315) in the IMGT database is highly similar to these alleles of TRBV7-7. The novel allele is the most expressed allele in the repertoire (58% allelic frequency; 0.16% of the total error-free population). It is represented by 37 error-free sequences and 33 unique CDR3s in the error-free set. Haplotyping based on allelic diversity in TRBJ1-6 demonstrates association of TRBV7-7*01_C315T with only one of the haplotypes (only few recorded cases; TRBV7-7*01 was not associated with any allele of TRBJ1-6).

IARC affirms the sequence based on inference of expression data alone at Level 1 up to and including base 325. It is acknowledged that the allele most likely carries 1 additional base, typically C, at base position 326. Trailing “.” indicates IARC’s opinion that the sequence is likely to contain additional 3’-nucleotides for which there is insufficient evidence to make an affirmation.

>TRBV7-7*i01 (TRBV7-7*01_C315T)
GGTGCTGGAGTCTCCCAGTCTCCCAGGTACAAAGTCACAAAGAGGGGACAGGATGTAACTCTCAGGTGTGATCCAATTTCGAGTCATGCAACCCTTTATTGGTATCAACAGGCCCTGGGGCAGGGCCCAGAGTTTCTGACTTACTTCAATTATGAAGCTCAACCAGACAAATCAGGGCTGCCCAGTGATCGGTTCTCTGCAGAGAGGCCTGAGGGATCCATCTCCACTCTGACGATTCAGCGCACAGAGCAGCGGGACTCAGCCATGTATCGCTGTGCTAGCAGCTTAG.

The allele has also been identified in a separate study as TRBV7-7*01_S0326 and Sanger validated (GenBank MZ339373) (Corcoran et al. (2023) Immunity 56, 635-652.E6 (DOI: 10.1016/j.immuni.2023.01.026)). It has been seen in a total of six Sanger sequenced genomic clones derived from two subjects.

>MZ339373
TTGAGAGAGGAAGTGATGTCACTGTGGGAACTGCCCTGTGGAGACAAGGACATCCCTCATCCTCCGCTCCTGCTCACAGTGACACTGATCTGGTAAAGCCCCCATCCTGGTCTGACACTGTCATGGGTACCAGTCTCCTATGCTGGGTGGTCCTGGGTTTCCTAGGGACAGGTGAGTCCTCAAAACACAAAGTAGTTTCATATTTTTTCTGTATGTAGGTGTGTGTGTGTATGCATGTGTGTCTGTGTGTGTGTGTGTGTGTGTGTGTGTGTGTGAGATGACTACAAATGTTTTCCTTATTCTGTTGCCAGATTCTGTTTCCACAGATCACACAGGTGCTGGAGTCTCCCAGTCTCCCAGGTACAAAGTCACAAAGAGGGGACAGGATGTAACTCTCAGGTGTGATCCAATTTCGAGTCATGCAACCCTTTATTGGTATCAACAGGCCCTGGGGCAGGGCCCAGAGTTTCTGACTTACTTCAATTATGAAGCTCAACCAGACAAATCAGGGCTGCCCAGTGATCGGTTCTCTGCAGAGAGGCCTGAGGGATCCATCTCCACTCTGACGATTCAGCGCACAGAGCAGCGGGACTCAGCCATGTATCGCTGTGCTAGCAGCTTAGCCACAGCATGGCACAGTCGCCTCCTTCCTGTTCACAAACCTCATCCTTCT

It has also been identified in a BAC clone with accession number AC229888.

IARC affirms the sequence based on combined inference and genomic evidence at Level 1 up to and including base 326.

>TRBV7-7*i01 (TRBV7-7*01_C315T)
GGTGCTGGAGTCTCCCAGTCTCCCAGGTACAAAGTCACAAAGAGGGGACAGGATGTAACTCTCAGGTGTGATCCAATTTCGAGTCATGCAACCCTTTATTGGTATCAACAGGCCCTGGGGCAGGGCCCAGAGTTTCTGACTTACTTCAATTATGAAGCTCAACCAGACAAATCAGGGCTGCCCAGTGATCGGTTCTCTGCAGAGAGGCCTGAGGGATCCATCTCCACTCTGACGATTCAGCGCACAGAGCAGCGGGACTCAGCCATGTATCGCTGTGCTAGCAGCTTAGC