A preliminary analysis of the 11th International Histocompatibility Workshop monoclonal antibodies

In the 11th International Histocompatibility Workshop prescreening study, HLA Class I and Class II monoclonal antibodies (mAb) were tested on panels of peripheral T and B cells and homozygous typing cell (HTC) lymphoblastoid lines. The 102 Class I mAb, of which 64 were new, were screened on 63 HTC lines and 20 peripheral T cells. The 144 Class II mAb were tested on 63 HTC lines, 20 peripheral B and 10 peripheral T cells. For Class I, 45 of the 102 mAbs tested proved to have clear and identifiable reaction patterns on both PBL and HTC lines and included several interesting new HLA-A and -C locus antibodies. Of the 144 Class II mAb, of which 99 were new, 18 DR, 22 DQ and 7 DP antibodies were judged excellent. The DR antibodies included some which were antigen-specific but the majority were complex antibodies, while the DQ antibodies, as previously, identified the majority of DQ antigens both singly and in combinations. The encouraging number of DP antibodies was interesting in the limited range of sites they appear to detect.     

Progress in Rhesus Histocompatibility Typing Resulting from the Second International Nonhuman Primate Histocompatibility Workshop (1973)

The Second International Nonhuman Primate Histocompatibility Workshop permitted comparison of rhesus monkey alloantisera developd in various laboratories on a single common panel of related and unrelated monkeys. Analysis of the data permits the conclusion that at least nine specificities are recognized by more than one laboratory, including six at the first locus and three at the second locus.     

SSOP typing of the Tenth International Histocompatibility Workshop reference cell lines for HLA-C alleles

Abstract: HLA-C gene products are the most poorly understood of the HLA class I molecules because they express at low level on the cell surface compared to HLA-A and -B. However, recent evidence shows that HLA-C molecules are functionally competent in eliciting T-cell responses and in controlling NK-cell recognition. Approximately 20 to 50% of HLA-C alleles type "blank" in most populations. To provide a better definition of the HLA-C alleles, we analyzed 98 extensively characterized B-cell lines from the 10th International Histocompatibility Workshop. Selective HLA-C-specific DNA amplification of exons 2 and 3 from DNA prepared from the cell panel was achieved with the use of two sets of locus-specific primers. We used 64 sequence-specific oligonucleotide probes (SSOPs) complementary to variable sites in exons 2 and 3 to generate hybridization patterns. Twenty-five alleles were found among these patterns, including seven new alleles in the homozygous cell lines and seven potential new alleles in heterozygous cell lines. Differences between the new alleles and known alleles were generally small. Five major groups were identified in the Cw "blank" cells by the SSOP patterns. In addition, linkage between HLA-B specificities and HLA-C alleles was similar to previous observations. The present study demonstrated that SSOP typing was effective in identifying new alleles in homozygous typing cells but not in the heterozygous cells. Also, DNA typing can facilitate the identification of all HLA-C alleles, including those that serologically type as blanks. The HLA-C locus may be more polymorphic than was previously recognized.     

Oligotyping of Italian celiac patients with the 11th International Histocompatibility Workshop reagents.

Oligotyping for HLA-DRB1, DQA1 and DQB1 specificities has been performed on PCR-amplified DNA from 55 Italian celiac children, living in Rome, and 50 blood donors. 52.6% of CD patients were DR3;DQA1*0501;DQB1*0201-positive versus 14% of controls (RR = 6.85) and 34.5% were DR5,7;DQA1*DQB1*0201-positive versus 2% of controls (RR = 25.86). 7 patients (12.7%) were negative for the DQA1*0501/B1*0201 dimer: 3 of them were DR4 (5.4%) and the others typed as DR1,5; 1,7; 5,7 and w6,7. No patient was negative for both DQA1*0501 and DQB1*0201 alleles.     

Oligotyping of celiac multiplex families with the 11th International Histocompatibility Workshop reagents.

Using PCR and SSO probes from the 11th International Histocompatibility Workshop, we oligotyped for HLA-DRB1 gene and DQA1*0501, DQB1*0201 alleles 10 celiac families each with 2 affected children. All families belong to the Italian population except for one, whose mother is originally from Cape Verde island. 8/10 sibling pairs share the DQA1*0501/B1*0201 heterodimer, inherited in cis or in trans arrangement. All the dimer-negative patients were DR4-positive.     

A multi-laboratory characterization of the KIR genotypes of 10th International Histocompatibility Workshop cell lines

Killer immunoglobulinlike receptors (KIRs) are expressed on natural killer and T cells. Both inhibitory and noninhibitory forms have been described, leading to inhibition or continuation of cellular killing activity. The natural ligands identified so far of KIRs are class I human leukocyte antigens (HLA). In particular, the interaction of some KIRs with HLA-Cw has been well characterized. Recent work has implicated KIRs in affecting the outcome of hematopoietic stem-cell transplant (HSCT). This may well lead to a requirement for prospective KIR typing of donor and recipient. We have utilized different typing systems (two using polymerase chain reaction-sequence-specific primers, and one using polymerase chain reaction-sequence-specific oligonucleotide probes) in three separate laboratories to characterize the KIR gene complement of 25 cell lines from the 10th International Histocompatibility Workshop. There were consistent results in 22, and minor differences in 3. When compared with previous results for some of these cell lines, no further differences were found. The differences are due to typing of KIRs KIR2DL1 and KIR2DS5, and may be explained by technical differences or the inability to type new variants. Further improvements in typing may be required if population and clinical studies are to produce accurate results.     

Molecular typing for HLA class I using ARMS-PCR: further developments following the 12th International Histocompatibility Workshop

Molecular typing for HLA class I was introduced in the 12th International Histocompatibility Workshop. Following a pilot study using three methods, sequence specific oligotyping (SSO), reverse dot blot and amplification refractory mutation system (ARMS)-PCR, the ARMS-PCR method was selected for use. A great advantage of an ARMS-PCR method is that, unlike the other two methods, it can determine whether sequence motifs are in cis or in trans, as ARMS-PCR detects two cis located motifs per reaction using forward and reverse sequence specific primers. Resolution was designed to be low to medium level for HLA-A, -B and -C alleles. Two hundred and fifty class I kits and 83 HLA-A2 subtyping kits were distributed. The A2 subtyping kit used a two round nested PCR system to identify all of the A2 alleles known at the time. Typing results on control DNA samples distributed with both the kits showed a very satisfactory performance. Since the 12th Workshop, the kits have been developed with the addition of new primers and primer mixes to increase the resolution of the test.