Multiple epitopes of HLA-DRB1*0411 are recognized by T-cell clones originated from individuals carrying other DR4 subtypes

HLA polymorphism dictates the binding and recognition of specific peptides, leading to variations in individual immune responses and may contribute to autoimmune disorders and outcome in organ transplantation. We have studied the molecular basis for the cellular recognition of DRB1*0411 in individuals carrying other sequence-related DR4-alleles by characterization of T-cell clones (TLC). A set of 166 TLC were raised by priming cells from DRB1*0401,0402 and DRB1*0405,0901 individuals and 52 of them recognized DRB1*0411. Five distinct patterns of T-cell allorecognition were found: DRB1*0411 alone, DRB1*0411 and 0405, DRB1*0411 and 0406, DRB1*0411 and 0407 and DRB1*0411, 0406 and 0407, depending on responder phenotypes and epitopes recognized by their T cells. A stretch of 30 amino acids on DRB1*0411 from positions 57 to 86 behaves as a functional domain and residues S57, R71, E74 and V86 seem to be crucial in forming immunogenic determinants recognized by these TLC. The knowledge of shared amino acid residues between closely related DR4 alleles, which show similar patterns of recognition by T cells could also be useful in the selection of prospective donors for clinical transplantation of solid organs or bone marrow.     

Characterization of self-glutamic acid decarboxylase 65-reactive CD4+ T-cell clones established from Japanese patients with insulin-dependent diabetes mellitus

To investigate autoimmunity to glutamic acid decarboxylase (GAD) 65 in Japanese patients with insulin-dependent diabetes mellitus (IDDM, type I diabetes), we established seven CD4+ T-cell clones, by stimulating peripheral blood mononuclear cells (PBMC) of six IDDM patients, using a mixture of overlapping human GAD65 peptides. No GAD65 autoreactive T-cell clones were evidenced in four healthy controls. Specificities of T-cell clones were as follows: (a) two clones specific to GAD65 p111-131 (residue 111 to 131) + DR53 (DRB4*0103); (b) one clone specific to GAD65 p413-433 + DR1 (DRB1*0101); (c) two clones specific to GAD65 p200-217 + either DR9 (DRB1*0901) or DR8 (DRB1*0802); and (d) two clones specific to GAD65 p368-388 + DP2 (DPA1*01 or 0201-DPB1*0201). Two DR53-restricted and one DR1-restricted T-cell clones, responded to a recombinant human GAD65 protein, and showed cytotoxicity against B lymphoblastoid cell lines pre-pulsed with the peptides. Six T-cell clones exhibited the Th1-like phenotype. Interestingly, two DR53-restricted T-cell clones killed a Fas-deficient B lymphoblastoid cell line, thereby indicating that cytotoxicity was not completely dependent on a Fas-Fas ligand interaction. Thus, the T-cell epitopes were mapped in a limited portion of GAD65 protein, with a tendency to be restricted by disease-associated HLA-DR, but not DQ molecules.     

Recognition of HLA-DR1/DRB1*0101 molecules presenting HLA-A2 derived peptides by a human recombinant antibody, Fab-5 A1

MHC molecules present peptides in their binding groove to T-cell receptors inducing proliferation or cytotoxicity of alloreactive T cells. A previously generated human monoclonal antibody (mAb) UL-5 A1, recognizing a conformational epitope formed by HLA DR1/DRB1*0101 molecules and HLA-A2 derived peptides, demonstrates T-cell-like recognition of the peptide/MHC complex (PMC). To study the genes of the antigen binding region, the nucleotide sequences of the rearranged genes in the variable regions of UL-5 A1 were determined and the V-gene usage (VH3, V lambda 2) was identified by comparison with published germlines. The genes encoding heavy (Fd) and light (L) chains of UL-5 A1 were linked and expressed in a bacterial system. Specificity of the recombinant Fab-5 A1 was determined with HLA-typed LCLs by flow cytometric analysis. As demonstrated in competitive inhibition assays, UL-5 A1 and Fab-5 A1 recognize the same PMC epitope on HLA-A2+, -DR1/DRB1*0101+ typed LCLs. Additionally, mAb UL-5 A1 and Fab-5 A1 both recognize HLA-A2-, -DR1/DRB1*0101+ LCLs exogenously loaded with HLA-A2 peptides (105-117, 103-117). UL-5 A1-like antibodies against peptide/MHC complexes could prove valuable tools for research on T-cell recognition and MHC function.     

Kindling induced mossy fiber sprouting has no functional significance in developing seizure discharges in rats]

The influence of host immunogenetics on the outcome of vertically transmitted HIV infection in children was examined in a multicenter cross sectional study of long term survivors and rapid progressors. Sequence-based typing was performed for the DRB1, DQB1 and HLA-A loci. 36.7% of 30 children surviving more than 8 years had one or more of the HLA-DR13 alleles, versus none of 14 rapidly progressing children who died within 2 years of age, p = 0.009, Haldane RR = 17.1. The alleles variably associated with this beneficial response to HIV were: DRB1*1301, DRB1*1302, DRB1*1303 and DRB1*1310, suggesting that the DR13 effect acted as a dominant trait. An additional 6 children were typed only by the SSOP method resulting in 44.4% of 36 long term surviving children with a DR13 allele and none of 14 rapid progressors, p = 0.002, Haldane RR = 23.3. No single DQB1 allele accounted for the HLA-DR13 allele association. In contrast, the presence of HLA A*2301 was associated with rapid progression to AIDS, 4% of long term survivors vs. 57.1% of 7 rapid progressors, p = 0.0006, RR = 0.031. Although the sample size is small, the marked differences in allele frequency along with differences between the peptide binding pockets of the HLA-A9 group of alleles including HLA A*2301 and the remainder of the HLA-A alleles suggest a structural basis for the dominant disadvantageous immune response to HIV conferred by A*2301.     

Indirect allorecognition of major histocompatibility complex allopeptides in human renal transplant recipients with chronic graft dysfunction

BACKGROUND: It has been suggested that T cells primed by processed donor major histocompatibility complex antigen (the "indirect" pathway of allorecognition) may be responsible for mediating chronic allograft rejection. The purpose of this study was to develop a clinically useful assay to study the occurrence of indirect allorecognition during chronic rejection in humans. METHODS: A panel of 20 mer peptides corresponding to the hypervariable regions of HLA-DRB1*0101, DRB1*1501, and DRB1*0301 were synthesized. Lymphocytes obtained from renal allograft recipients were cocultured with these peptides. Proliferation was assayed by DNA incorporation of [3H]thymidine, and positive proliferation was defined by a statistically significant increase in counts per minute over background with a minimum stimulation index of 2. The precursor frequency of allopeptide reactive T cells was determined by limiting dilution analysis. RESULTS: Lymphocytes from 82% of patients who were mismatched for at least one of the three DR molecules and had chronic allograft dysfunction specifically proliferated to the mismatched allopeptides (n=11). Proliferation was seen in only 6% of control subjects (2/33, P<0.0001). The proliferative response was low grade and was best detected on day 7-8 of culture in vitro. The precursor frequency of peptide-specific T cells was more than 10-fold higher compared with controls (P<0.001). CONCLUSIONS: These data demonstrate for the first time that T cells of patients with chronic graft dysfunction are primed to recognize and respond to specific donor-derived major histocompatibility complex allopeptides. Our results support the hypothesis that T cells primed via the indirect pathway of allorecognition may be important mediators of chronic rejection and provide the rationale to develop specific therapeutic strategies to prevent or interrupt this process.     

Early-onset myasthenia gravis: a recurring T-cell epitope in the adult-specific acetylcholine receptor epsilon subunit presented by the susceptibility allele HLA-DR52a

No immunodominant T-cell epitopes have yet been reported in the human acetylcholine receptor (AChR), the target of the pathogenic autoantibodies in myasthenia gravis (MG). We have selected and characterized T cells from MG patients by restimulation in culture with recombinant human AChR to alpha, gamma and epsilon subunits; the gamma and epsilon distinguish the fetal and adult AChR isoforms, respectively. We obtained clones specific for the epsilon, rather than the alpha or gamma, subunit in 3 of the first 4 early-onset MG cases tested. They all responded to peptide epsilon201-219 and to low concentrations of adult but not fetal AChR. Moreover, although using different T-cell receptor genes, they were all restricted to HLA-DR52a (DRB3*0101), a member of the strongly predisposing HLA-A1-B8-DR3 haplotype. This apparently immunodominant epsilon201-219 epitope (plus DR52a) was also recognized by clones from an elderly patient whose MG had recently been provoked by the drug D-penicillamine. In all 4 cases, however, the serum antibodies reacted better with fetal than adult AChR and may thus be end products of determinant spreading initiated by adult AChR-specific T cell responses. Furthermore, as these T cells had a pathogenic Th1 phenotype, with the potential to induce complement-activating antibodies, they should be important targets for selective immunotherapy.     

Crystal structure of HLA-DR2 (DRA*0101, DRB1*1501) complexed with a peptide from human myelin basic protein

Susceptibility to multiple sclerosis is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 (DRB1*1501) haplotype. The structure of HLA-DR2 was determined with a bound peptide from human myelin basic protein (MBP) that is immunodominant for human MBP-specific T cells. Residues of MBP peptide that are important for T cell receptor recognition are prominent, solvent exposed residues in the crystal structure. A distinguishing feature of the HLA-DR2 peptide binding site is a large, primarily hydrophobic P4 pocket that accommodates a phenylalanine of the MBP peptide. The necessary space for this aromatic side chain is created by an alanine at the polymorphic DRbeta 71 position. These features make the P4 pocket of HLA-DR2 distinct from DR molecules associated with other autoimmune diseases.     

On T-cell recognition of nickel as a hapten

T-cells recognize antigens as peptides associated with self-molecules encoded by genes of the HLA region. In patients with contact allergy to nickel, T-cells that are specific for non-peptide haptens have been described. Previously, we have isolated HLA class II-restricted nickel-specific T-cell clones from patients with nickel sensitivity. In this paper, data on the fine specificity of a nickel-specific HLA-DR4-restricted clone have been reevaluated. Genomic tissue typing employing polymerase chain reaction and sequence-specific primers were used. Nickel was presented to the T-cell clone by all three subtypes of HLA-DR4 included in our panel. Two different DRB4*0404-positive cells presented nickel, whereas only 3 of the 7 DRB1*0401-positive and one of the 3 DRB1*0408-positive cells restimulated the T-cell clone. These findings are compatible with the notion that nickel interacts with endogenous peptides in the antigen-presenting groove of the HLA molecule, thereby changing these peptides' antigenicity rather than their ability to bind to the HLA molecule. Variations of the endogenous peptide in the antigen-presenting groove as well as differences of the HLA molecules give the DR4 specificity of the nickel-specific clone MCE2.     

Major histocompatibility complex class II DR alleles DRB1*1501 and those encoding HLA-DR13 are preferentially associated with a diminution in maternally transmitted human immunodeficiency virus 1 infection in different ethnic groups: determination by an automated sequence-based typing method

Transmission of human immunodeficiency virus 1 (HIV-1) from an infected women to her offspring during gestation and delivery was found to be influenced by the infant's major histocompatibility complex class II DRB1 alleles. Forty-six HIV-infected infants and 63 seroreverting infants, born with passively acquired anti-HIV antibodies but not becoming detectably infected, were typed by an automated nucleotide-sequence-based technique that uses low-resolution PCR to select either the simpler Taq or the more demanding T7 sequencing chemistry. One or more DR13 alleles, including DRB1*1301, 1302, and 1303, were found in 31.7% of seroreverting infants and 15.2% of those becoming HIV-infected [OR (odds ratio) = 2.6 (95% confidence interval 1.0-6.8); P = 0.048]. This association was influenced by ethnicity, being seen more strongly among the 80 Black and Hispanic children [OR = 4.3 (1.2-16.4); P = 0.023], with the most pronounced effect among Black infants where 7 of 24 seroreverters inherited these alleles with none among 12 HIV-infected infants (Haldane OR = 12.3; P = 0.037). The previously recognized association of DR13 alleles with some situations of long-term nonprogression of HIV suggests that similar mechanisms may regulate both the occurrence of infection and disease progression after infection. Upon examining for residual associations, only only the DR2 allele DRB1*1501 was associated with seroreversion in Caucasoid infants (OR = 24; P = 0.004). Among Caucasoids the DRB1*03011 allele was positively associated with the occurrence of HIV infection (P = 0.03).     

Self-reported energy intake and energy expenditure in elderly women

HLA-DRB1, -DQB1 and -DPB1 allele frequencies were investigated in a sample of the Slovak population by PCR-SSP and PCR-RFLP methods. The most frequent DRB1 alleles were DRB1*1101-5 (0.2038), DRB1*0701-2 (0.1423), and DRB1*1501-2 (0.1231). The most rare alleles found were DRB1*0901 (0.0038), and DRB1*1201 (0.015). The most common DQB1 alleles were DQB1*0301 (0.2448), DQB1*0201 (0.2098), and DQB1*0501 (0.1119), respectively. The alleles with the least occurrence rate were DQB1*0601 (0.0035) and DQB1*0401 (0.007). The most common DPB1 alleles found were DPB1*0401 (0.4329), DPB1*0402 (0.2089), and DPB1*0201 (0.1438), respectively. The least frequent alleles were DPB1*0601, *1101, and *1501 (0.0034). Allele frequencies found in our study were compared to those in Czech, Austrian, and German populations. No statistically significant differences were observed.     

Evidence that HLA class II-restricted human CD4+ T cells specific to p53 self peptides respond to p53 proteins of both wild and mutant forms

By stimulating peripheral blood mononuclear cells of four healthy donors with a mixture of overlapping peptides representing the core domain of p53, we established two CD4+ alphabeta T cell clones and four lines that recognized wild-type and mutant p53 proteins as well as p53 self peptides in an HLA class II-restricted fashion. Two T cell lines established from two unrelated donors reacted to the p53 peptide (p)153-166 and p108-122, respectively, in the context of DP5 molecules. Two T cell clones established from two other unrelated donors were specific for p193-204 in the context of DRB1*1401 and for p153-165 in the context of DP5, respectively. These two T cell clones responded almost equally to both wild-type and four mutant recombinant p53 proteins. The proliferative responses of these T cell clones to p53 recombinant proteins were augmented by heat denaturing, thereby suggesting that altered conformation of the protein facilitates proteolytic processing to produce antigenic peptides. The DRB1*1401-restricted T cell clone specific for p193-204 killed a B lymphoblastoid cell line homozygous for HLA-DRB1*1401 when the cell line was pre-pulsed with p53 protein as well as peptide. These results indicate that CD4+ T cells reactive to p53 do exist in healthy individuals and the epitopes are probably ignored by the immune system under physiological conditions. It is suggested that such epitopes stimulate T cells to induce anti-p53 antibody production in cancer patients as previously reported by others. The possible involvement of p53-reactive T cells in anti-tumor immunity is discussed.     

Modulation of HLA-DQ-restricted collagen-induced arthritis by HLA-DRB1 polymorphism

Mouse class II-deficient HLA-DQB1*0302, DQA1*0301 (DQ8) transgenic mice are susceptible to severe collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis. To examine whether polymorphism at the DRB1 locus can modulate DQ-restricted arthritis, we generated double-transgenic (DR/DQ) mice. HLA-DRB1*1502 (DR2) and DRB1*0301 (DR3) were introduced separately into CIA susceptible DQ8.Abeta transgenic mice to generate DQ8/DR2.Abeta and DQ8/ DR3.AbetaO mice. The HLA-DR molecules in these mice were found to be functional on the basis of their positive/negative selection of the Vbeta T cell repertoire. Introduction of the DR2 gene led to a significant decrease in disease incidence in DQ8.Abeta mice, while the DR3 transgene had no effect. In vitro T cell proliferative responses against bovine Cll collagen in primed mice were higher in DQ8/DR3 mice compared with DQ8/DR2 mice. Cytokine analysis showed a Th2 profile in DQ8/DR2 mice, while DQ8/DR3 mice showed a Th1 profile. These results suggest that DRB1 polymorphism can modulate the disease.     

Weak peptide agonists reveal functional differences in B7-1 and B7-2 costimulation of human T cell clones

The influence of costimulation on the T cell response to altered peptide ligands that act as either partial or weak agonists for human CD4+ T cell clones was examined. Using stable Chinese hamster ovary (CHO) cell transfectants expressing DR2 (DRB1*1501) and human B7-1 or B7-2 as APC, presentation of native myelin basic protein (MBP) p85-99 peptide Ag or a partial agonist of MBP p85-99 induced equivalent T cell activation as measured by [3H]TdR incorporation and cytokine secretion. In marked contrast, presentation of cross-reactive peptides of MBP p85-99 that act as weak agonists with B7-1, but not B7-2, costimulation resulted in significant T cell activation as measured by [3H]TdR incorporation and cytokine secretion. These data suggest that decreasing the strength of the signal provided to the TCR allows differences in B7-1 and B7-2 signaling to be observed. Thus, the costimulatory environment during T cell activation may be a mechanism of regulating T cell cross-reactivity in the periphery.     

Identification of naturally processed T cell epitopes from glutamic acid decarboxylase presented in the context of HLA-DR alleles by T lymphocytes of recent onset IDDM patients

Glutamic acid decarboxylase (GAD) has been defined as a major target antigen in insulin-dependent diabetes mellitus (IDDM). To identify the molecular ligands triggering a T cell response to GAD, a panel of human GAD65-specific T lymphocyte lines was generated from peripheral blood of three recent onset IDDM patients. All lines derived from a patient expressing the high-risk-conferring HLA-DR*0301/ *0401 haplotypes recognized a single epitope localized between amino acid positions 270 and 283 of GAD65, a stretch that is located in close proximity to the homology region shared with Coxsackie virus P2-C protein. All lines with this specificity were restricted to the DRA, B1*0401 product of the DR4 haplotype. Analysis of the GAD-specific T cell response in a second patient homozygous for DR4 haplotypes demonstrated that the same DRA, B1*0401 allele selected T cells specific for a different determinant. The T cell response profile in a third patient showed that DR*1501/ *1601-encoding haplotypes could present at least three different epitopes to GAD65-specific T lymphocytes. One of these epitopes was presented by a DR allele associated with the resistance-conferring DRB1*1501 haplotype. GAD-specific T cell lines could not be isolated from HLA class II-matched normal individuals. Our data reveal that (a) the T cell response to GAD65 is quite heterogenous in recent onset IDDM patients; (b) HLA-DR, not DQ, seems to be the principal restriction element used by T cells present at the onset of the disease; and (c) T cells responding to epitopes containing identical sequences to Coxsackie virus P2-C protein were not detected.     

The inter-locus recombinant HLA-B*4601 has high selectivity in peptide binding and functions characteristic of HLA-C

The vast majority of new human HLA class I alleles are formed by conversions between existing alleles of the same locus. A notable exception to this rule is HLA-B*4601 formed by replacement of residues 66-76 of the alpha 1 helix of B*1501 by the homologous segment of Cw*0102. This inter-locus recombination, which brings together characteristic elements of HLA-B and HLA-C structure, is shown here to influence function dramatically. Naturally processed peptides bound by B*4601 are distinct from those of its parental allotypes B*1501 and Cw*0102 and dominated by three high abundance peptides. Such increased peptide selectivity by B*4601 is unique among HLA-A,B,C allotypes. For other aspects of function, presence of the small segment of HLA-C-derived sequence in an otherwise HLA-B framework converts B*4601 to an HLA-C-like molecule. Alloreactive cytotoxic T lymphocytes (CTL), natural killer (NK) cells, and cellular glycosidases all recognize B*4601 as though it were an HLA-C allotype. These unusual properties are those of an allotype which has frequencies as high as 20% in south east Asian populations and is associated with predisposition to autoimmune diseases and nasopharyngeal carcinoma.     

Contribution of DRB1*04 variants to predisposition to or protection from insulin dependent diabetes mellitus is independent of dq

Certain DQ alpha/beta dimeric molecules have been shown to play a major role in determining susceptibility or resistance to IDDM. Whether or not predisposition associated with DR4 haplotypes is exclusively due to linkage to DQB1*0302 and DQA1*0301 alleles is still a controversial issue. A modifying effect of certain DRB1*04 subtypes on the susceptibility encoded by DQ alleles is possible, since not all DRB1*04-DQB1*0302 haplotypes are associated with the disease. The distribution of DRB1*04 subtypes was analysed in 240 DR4-positive Caucasian IDDM patients and 110 DR4-positive healthy controls using allele-specific hybridization after genomic amplification. Although an important contribution to IDDM predisposition was encoded by the DQB1*0302 allele which was found in the majority of patients (94.2% vs 64.7% in controls, Odd's ratio OR = 8.8, P < 0.0001), differences between DRB1*04 variants persisted after the effect of the DQB1 locus was removed by matching patients and controls for DQB1*0302. Thus, the DRB1*0402 allele conferred a strong IDDM-predisposing effect (OR = 3.1, P < 0.02) which was highly significant in the absence of DR3 on the second haplotype (OR = 5.6, P < 0.0001) but was not visible among DR3/4 heterozygote individuals. Conversely, the DRB1*0404 allele conferred a strong protective effect (OR = 0.26, P < 0.0001) which was dominant even in the presence of the associated high risk DR3 haplotype (OR = 0.21, P < 0.03). These data indicate that DQ molecules are not the sole contributors to the DR4-associated IDDM predisposition, and that peculiar DR4 subtypes play a significant role in susceptibility to or protection from the disease. DRB1*0402 differs from DRB1*0404 by only two acidic residues at positions 70 and 71 within the peptide binding groove, instead of amide and basic amino acids. This might induce changes of peptide binding specificity that correlate with the genetic linkage of IDDM predisposition.     

Characteristics of the innervation of the head and neck

The association of HLA-DRB1 and DQB1 genes with IDDM in Koreans was assessed using 115 IDDM patients and 140 nondiabetic controls. DQB1*0201 is the only DQB1 allele positively associated with IDDM while DQB*0602, *0601 and *0301 are negatively associated. Three DRB1 alleles (DRB1*0301, DRB1*0407 and DRB1*0901) are positively associated while four DR allele groups (DRB1*15, DRB1*12, DRB1*10 and DRB1*14) are negatively associated. However, Haplotype analyses indicated that DQB1*0302, DRB1*0405 and DRB1*0401 may confer susceptibility because the DRB1*0405-DQB*0302 and DRB1*0401-DQB1*0302 haplotypes are positively associated with the disease. The lack of association in Koreans with the DQB1*0302 allele, which appears predisposing in studies of non-Orientals, is due to its strong linkage disequilibrium (LD) with the protective DRB1*0403 and *0406 alleles, while the lack of association with DRB1*0405 is because of its strong LD with the protective DQB1*0401 allele. Nine DR/DQ genotypes confer significantly increased risk to IDDM. Seven of the nine genotypes (DR3/4s, DR1/4s, DR4s/13, DR4s/8, DR4s/7, DR9/13 and DR3/9) were also found to be at high risk to IDDM in other populations, while the two others (DR1/9 and DR9/9) are only found in Koreans. Surprisingly, DR4/4 homozygotes are not associated with high risk to IDDM in Koreans. This observation can be explained by the high frequency of protective DR4 subtypes and the protective DQ alleles (0301 and 0401) associated with the susceptible DR4 alleles. Our analyses indicate that the counterbalancing act between susceptible DRB1 and protective DQB1, and vice versa, that has already been observed in Chinese and Japanese, is the major factor responsible for the low incidence of diabetes in Koreans.     

Pocket 4 of the HLA-DR(alpha,beta 1*0401) molecule is a major determinant of T cells recognition of peptide

To investigate the functional roles of individual HLA-DR residues in T cell recognition, transfectants expressing wild-type or mutant DR(alpha,beta 1*0401) molecules with single amino acid substitutions at 14 polymorphic positions of the DR beta 1*0401 chain or 19 positions of the DR alpha chain were used as antigen-presenting cells for five T cell clones specific for the influenza hemagglutinin peptide, HA307-19. Of the six polymorphic positions in the DR beta floor that were examined, mutations at only two positions eliminated T cell recognition: positions 13 (four clones) and 28 (one clone). In contrast, individual mutations at DR beta positions 70, 71, 78, and 86 on the alpha helix eliminated recognition by each of the clones, and mutations at positions 74 and 67 eliminated recognition by four and two clones, respectively. Most of the DR alpha mutations had minimal or no effect on most of the clones, although one clone was very sensitive to changes in the DR alpha chain, with loss of recognition in response to 10 mutants. Mutants that abrogated recognition by all of the clones were assessed for peptide binding, and only the beta 86 mutation drastically decreased peptide binding. Single amino acid substitutions at polymorphic positions in the central part of the DR beta alpha helix disrupted T cell recognition much more frequently than substitutions in the floor, suggesting that DR beta residues on the alpha helix make relatively greater contributions than those in the floor to the ability of the DR(alpha,beta 1*0401) molecule to present HA307-19. The data indicate that DR beta residues 13, 70, 71, 74, and 78, which are located in pocket 4 of the peptide binding site in the crystal structure of the DR1 molecule, exert a major and disproportionate influence on the outcome of T cell recognition, compared with other polymorphic residues.     

Effect of matching of class I HLA alleles on clinical outcome after transplantation of hematopoietic stem cells from an unrelated donor. Japan Marrow Donor Program

BACKGROUND: The requirements with respect to HLA compatibility and the relative importance of matching for individual class I and class II HLA alleles in the transplantation of hematopoietic stem cells from unrelated donors have not yet been established. METHODS: We performed retrospective DNA typing of alleles at 11 polymorphic loci of HLA genes in 440 recipients of hematopoietic stem cells from unrelated donors who were serologically identical with their respective recipients for HLA-A, B, and DR antigens. Of these recipients, 80 percent had leukemia; the rest had lymphoma, marrow failure, or a congenital disorder. RESULTS: Multivariate analysis showed that incompatibility for HLA-A alleles and incompatibility for HLA-C alleles were independent risk factors for severe acute graft-versus-host disease (GVHD) (HLA-A, P=0.006; HLA-C, P=0.001). Mismatching of HLA-A, but not of HLA-C, alleles was an independent risk factor for death (P<0.001). Matching [corrected] of HLA-C alleles was a significant risk factor for relapse of leukemia (P=0.035). HLA-B disparity was a significant risk factor for both GVHD and death in the univariate analysis, but not in multivariate analysis. Disparities in class II HLA alleles of the DRB1, DQA1, DQB1, DPA1, and DPB1 loci were not identified as significant risk factors for acute GVHD or death in the multivariate analysis. CONCLUSIONS: Genomic typing of class I HLA alleles adds substantially to the success of transplantation of hematopoietic stem cells from unrelated donors, even if the donors are serologically identical to their recipients with respect to HLA-A, B, and DR antigens.     

Identification of HLA-A3-restricted cytotoxic T lymphocyte epitopes from carcinoembryonic antigen and HER-2/neu by primary in vitro immunization with peptide-pulsed dendritic cells

The human carcinoembryonic antigen (CEA) and HER-2/neu are potential target antigens for CTL specific immunotherapy for common malignancies such as breast, lung, colon, and gastric carcinomas. Several CTL epitopes restricted by HLA-A2, the most common human histocompatibility molecule, have been previously reported. However, to develop CTL-based immunotherapies for the general population, it is necessary to identify epitopes restricted by other common histocompatibility alleles. Here, we describe two HLA-A3-restricted CTL epitopes from the CEA and HER-2/neu antigens. HLA-A3 binding synthetic peptides from CEA and HER-2/neu were tested for immunogenicity by in vitro primary CTL induction protocol using peripheral blood mononuclear cells from normal healthy volunteers. One peptide from CEA (CEA[9(61)]: HLFGYSWYK) and one peptide from HER-2/neu (HER2[9(754)]: VLRENTSPK) were shown to induce CTL that was capable of killing a tumor cell line expressing HLA-A3 and the corresponding tumor-associated antigen. Additional MHC binding studies with the most common HLA molecules belonging to the HLA-A3 superfamily (HLA-A*1101, -A*3101, -A*3301, and -A*6801), demonstrated that CEA[9(61)] binds five of five A3 supertype molecules with high affinity, and the HER2[9(754)] epitope was able to bind to four of the same five alleles. These results indicate that these two new CTL epitopes should be immunogenic in individuals expressing either HLA-A3, or other members of the HLA-A3 superfamily.