Allelic heterogeneity of HLA‐B35 subtypes in different populations as assessed by DNA typing

Abstract

HLA-B35, a class I antigen differentially associated to several diseases in different ethnic groups, comprises at least eight alleles which differ among them by one to six amino acids. In the present work a rapid DNA typing procedure was used to investigate the distribution of the various HLA-B35 alleles in different populations. The approach is based on a group-specific PCR amplification of a set of closely related HLA-B alleles sharing a Thr in position 45 of the alpha-1 domain. The amplified DNA was then hybridized to a panel of sequence-specific oligonucleotide (SSO) probes designed to recognize the polymorphic residues in previously reported HLA-B35 subtypes. This methodology was successfully tested in 100 individuals of four different populations, previously typed by serology as HLA-B35, and in six reference panel cells of the 10th International Histocompatibility Workshop. HLA-B*3501 was the predominant subtype in all populations. B*3502, B*3503 and, to a lesser extent B*3508, were also found. Among Mexican Mestizos, thirteen individuals had patterns of SSO hybridization suggestive of new B35 alleles. The evolutionary considerations on the different B35 alleles and their extended B35,Cw4 haplotypes are discussed.

Generation of cytotoxic T cell responses directed to human leucocyte antigen Class I restricted epitopes from theAspergillusf16 allergen

“…B*3502 differs from B*3501 at 3 aa while B*3503 and B*3508 differ at just one amino acid, position 116 and position 156, respectively, as shown in Fig. 4 [46]. Position 116 lies in the floor of the peptide binding groove while position 156 is on the exterior surface of the a-helix in a position that is likely to contact the TCR.…”

“…B*3501 and B*3503 share leucine, a highly hydrophobic amino acid (hydrophobicity index of 3·8) at position 156, which is replaced by arginine, a much larger amino acid that is only partly hydrophobic (hydrophobicity index of -4·5) in B*3508, a difference that may well affect interaction with TCR. While B*3502 shares leucine 156 with B*3501 it contains two disparities, positions 114 and 116, that both lie in the floor of the peptide-binding groove and may affect the ability of the peptide to bind to the MHC molecule and one disparity at position 109 that lies in the a-helix that may affect presentation [46]. The serine to phenylalanine difference between B*3501 and B*3503 at position 116 appears to permit binding of peptides YFK and GTR but not peptide LPL.…”

The HLA Likes and Dislikes of Allospecific and Non‐MHC‐Restricted Cytotoxic T Lymphocytes

“…The frequency of the subtypes varies among individuals of difTerent ethnic origin (Ragupathi et al 1995) and some are only found in Amerindian tribes (Belich et al 1992, Watkins et al 1992, Gomez-Casado et al 1995. Five subtypes, B*3501, B*3502, B*35O3, B*35O7 and B*35O8, are found in the Caucasian population (Satz et al 1995), and it was expected that they could be present in our local donor panel. This was found to be the case when the molecular subtypes of our target cell panel were defined by sequencing (Ennis et al 1990.…”

Rare HLA alleles and their predicted haplotypes in Tzu Chi Taiwanese marrow donor registry

“…The authenticity of the rare alleles was confirmed at least by a second molecular HLA typing method. Based on the NMDP definition, amongst the 68 uncommon HLA typings observed in the Tzu Chi Registry's database, a total of 34 alleles met the NMDP description for rare alleles (Tables 1 and 2 were not on the NMDP list, suggesting that although these nine alleles were uncommon in Taiwanese they were not uncommonly observed in the US (Browning et al, 1995;Ragupathi et al, 1995;Ramos et al, 1995;Satz et al, 1995;Adami et al, 1996;Marcos et al, 1999;Steiner et al, 2003). Incidentally, B*15:32, B*40:40, and DRB1*12:05 were first identified in oriental population and allele B*15:32 was reported to be more prevalent in northern Han of China (Yang et al, 2010).…”