Identification, at the genomic level, of an HLA-DR restriction element for cloned antigen-specific T4 cells

Dual antigenic recognition by cloned human gamma delta T cells

The function of gamma delta T cells is still elusive. The nature of the antigens that they recognize and the mode of presentation of these antigens are largely unknown. The majority of human peripheral gamma delta T cells bear a V gamma 9/V delta 2 T cell receptor, and display nonclonal reactivity to mycobacteria, without restriction by MHC. It is unknown whether these cells have clonal antigenic specificity as well. Here we describe rheumatoid arthritis-derived V gamma 9/V delta 2 T cell clones, displaying dual antigenic recognition: a nonclonal, MHC-unrestricted recognition of mycobacteria, and a clonal recognition of a short tetanus toxin peptide presented by HLA-DRw53, a nonpolymorphic class II MHC molecule associated with susceptibility to rheumatoid arthritis. This is the first evidence that V gamma 9/V delta 2 T cells can recognize nominal antigenic peptides presented by class II MHC molecules. These results suggest that much like alpha beta T cells, V gamma 9/V delta 2 cells may contribute to the immune response against foreign antigens in an antigen-specific and MHC-restricted manner. The reactivity of these gamma delta T cells to mycobacteria may represent a superantigen-like phenomenon.

Mapping of a restriction fragment length polymorphism associated with defective DR beta 4 chain expression to the HLA-DRB1 gene

The HLA-DR beta 4 chain, encoded by the DRB4 gene, carries two DRw53 determinants normally expressed by DR4, DR7, and DR9 individuals. However, some DR7 individuals (DR7, Dw11) fail to express the DR beta 4 chain. At the genomic level, a HindIII restriction fragment length polymorphism can be detected in these individuals with a DR beta cDNA probe. The association of this altered HindIII fragment with defective beta 4 chain expression suggested the possibility that the polymorphic fragment was derived from the DRB4 gene and might, therefore, be related to the defect in expression. However, detailed Southern blot analysis has now mapped the polymorphic fragment to the 3' end of the DRB1 gene, approximately 100 kb away from the defective DRB4 gene. Although the alteration in the DRB1 gene might involve sequences important in regulating the expression of the DRB4 gene, it is more likely that the association results from strong positive linkage disequilibrium between these DR beta chain genes.

Polymorphism and complexity of HLA-DR: evidence for intra-HLA-DR region crossing-over events

HLA-DR molecules were isolated from HLA-DR3, -5, and -w6 positive homozygous B-cell lines by immunoprecipitation with monoclonal antibodies and analyzed by gel electrophoretic techniques. DNA isolated from the same cell lines was digested with the restriction enzyme Taq I and hybridized with a DR beta full-length cDNA probe. We demonstrated that certain DR beta I alleles are found in combination with different DR beta III alleles as defined by Southern blotting, protein chemistry, a functional assay using purified protein derivative-specific T-cell lines, and, in one case, also alloreactive T-cell reagents. Our results indicate that within the family of HLA-DRw52-associated haplotypes DR beta chain genes may have been transferred from one haplotype to another. The implications of these findings are discussed.

HLA-DR-DQ haplotypes defined by restriction fragment analysis. Correlation to serology

Through the analysis of RFLP (restriction fragment length polymorphism) of the HLA-DR beta, -DQ alpha, and -DQ beta genes from 70 serologically well-characterized individuals, we have established unique HLA-DR-DQ RFLP haplotypes correlating to all of the DR1-w14 specificities. The RFLP of DR beta, DQ alpha, and DQ beta genes is very high using the restriction enzyme TaqI and 21 DR-DQ RFLP haplotypes were defined with this restriction enzyme. Our analysis confirms the strong linkage disequilibrium between alleles in the DR and DQ loci. DR beta RFLP indicates a common ancestor for the DR alleles within either of the supertypic DRw52 and DRw53 specificities. The DQ beta gene shows a high degree of RFLP, and the RFLP alleles partly reflect the serologic DQw1-w3 specificities. The results presented here also demonstrate the heterogeneity of DRw6 (DRw13 and DRw14) associated haplotypes, and the DRw13 related Dw18 and Dw19 specificities were found to have distinct DR-DQ haplotypes. The DQw1 positive haplotypes DR1, 2, w10, w13, and w14 are related with regard to DQ alpha and DQ beta RFLPs and the DRw52 positive haplotypes DR3, w11, and w12, as well as the DRw53 positive haplotypes DR4, 7, and w9, are related with regard to DR beta and DQ alpha RFLPs. These findings indicate that polymorphic sequences around the DQ alpha gene are associated with DR beta and DQ beta polymorphism, which suggests a location of the DQ alpha gene between DR beta and DQ beta.

Molecular localization of LB-Q1, a DRw52-like T-cell recognition epitope and identification at the genomic level of associated shared hybridizing fragments

In this paper we report on the molecular localization of LB-Q1, a supertypic HLA class II determinant which we previously identified by the use of proliferative T cells. The population distribution shows that each of the DRw52 associated specificities DR3, DR5, and DRw6 may occur with and without LB-Q1. DNA from nine DR3, six DR5, and 14 DRw6 homozygous B-cell lines were digested with the enzymes TaqI, EcoRI, and PvuII. Using a DR beta cDNA probe, shared hybridizing fragments were observed that correlate completely with the presence or absence of LB-Q1. T-cell recognition of LB-Q1 can be blocked with a monoclonal antibody (7.3.19.1) which in some haplotypes selectively reacts with the DR beta III chains, but cannot be blocked with a monoclonal antibody (I-LR2) reacting in those same haplotypes exclusively with DR beta I chains. Therefore, LB-Q1 maps to the DR beta III molecule. These data suggest the occurrence of relatively frequent previous recombinations between the two DR beta chain genes present in DRw52 haplotypes.

Determination of the HLA-DR profile of an HLA class II negative carcinoma cell line by restriction fragment length polymorphism (RFLP) analysis

The human colonic adenocarcinoma cell line HT-29 does not normally express HLA class II molecules. By restriction fragment length polymorphism (RFLP) analysis of DNA with a DR beta-probe, we analysed the genomic DR beta polymorphism of this cell-line, and compared it with the RFLP patterns seen in DNA from a reference panel of different DR homozygous and heterozygous cells. The HT-29 cell-line expressed DR beta fragments similar to the sum of the fragments expressed by DR4 and DR7 homozygous cells. The DR4 and DR7 haplotypes of HT-29 was further confirmed by comparing the RFLP patterns of four DR4/7 heterozygotes with that of HT-29. Furthermore, the HT-29 cell line expressed a Hind III 9.3 kb fragment previously found to be strongly associated to DRw53. Following treatment with gamma-interferon, the HT-29 cells could be induced to express class II molecules. Serological typing revealed the presence of the DR4, DR7 and DRw53 antigenic determinants.

Molecular characterization of a subtype of DQw1 recognized by hapten-specific T cells

Previous studies of HLA-restricted antigen recognition by cloned T cells have frequently demonstrated reactivity that did not correlate precisely with the expression of serologically defined HLA specificities. To further explore such discrepancies, we utilized monoclonal antibody (MoAb) blocking, partial NH2-terminal amino acid sequencing, and Southern blot hybridization techniques to analyze the fine specificity of four autologous trinitrophenyl-specific T cell lines restricted to DR2-linked epitopes. MoAb blocking studies demonstrated that two of these lines recognized determinants on DR molecules while the other two recognized determinants on the same molecule that expresses the DQw1 determinant. However, these latter two lines appeared to recognize a DQw1-related determinant found primarily in association with DR2, but not the other DQw1-associated DR alleles, DR1 and DRw6. To ascertain whether these lines were defining a functional split of DQw1, we performed partial NH2-terminal amino acid sequencing of the molecules precipitated with a DQw1-specific MoAb (Genox 3.53) from different stimulator lines. The results showed that these T cell lines recognized a subtype of DQw1 that is in linkage disequilibrium with DR2. Moreover, we identified characteristic restriction fragment length polymorphisms with a DQ beta-specific cDNA that correlated with stimulatory capacity for the DQw1-restricted lines. These results demonstrate that: DQ molecules may provide restriction determinants that are incorrectly assigned to DR molecules on stimulator panel analyses; cloned antigen-specific T cell lines recognize polymorphic regions of class II molecules not distinguished by either conventional typing antisera or xenogeneic MoAb; and the DQw1 epitope(s) is located on a heterogeneous group of DQ molecules that differ from each other in the primary sequence of their beta chains.

Presentation of Candida albicans and purified protein derivative soluble antigens by Epstein-Barr virus-transformed human lymphoblastoid B-cell lines

Cells other than the macrophage can function as antigen-presenting cells (APCs). These class II-bearing accessory cells include dendritic cells, epidermal Langerhans cells, B cells, murine B-cell tumors, and human Epstein-Barr virus-transformed lymphoblastoid cell lines (EBV-LCL). We investigated the ability of EBV-LCL to present two soluble antigens, Candida albicans and purified protein derivative of tuberculin (PPD). The EBV-LCL derived from B cells of two different individuals can present both antigens to bulk cultures of autologous antigen-primed peripheral blood lymphocytes. The responses of PPD-reactive T-cell clones were weaker to PPD when presented by EBV-LCL than by PBL-APCs, with some clones responding only to PPD presented by PBL-APCs. This suggests that EBV-LCL are not equivalent to PBL monocytes in APC function, and that expression of class II major histocompatibility complex antigen is not sufficient in enabling antigen-presenting capability.