Use of a variable alpha region to create a functional T-cell receptor delta chain.

Two categories of T-cell antigen-specific receptor have been described. Most mature T lymphocytes have, on their membrane, an antigen receptor consisting of alpha and beta subunits, while early T cells and thymocytes possess a heterodimeric receptor termed gamma-delta. The DS6 clone, isolated from the peripheral blood of a patient with immunodeficiency, is a CD3+, CD4-, CD8- human T-cell line that expresses the disulfide-linked form of the gamma-delta antigen receptor. The nucleotide sequence analysis of DS6 cDNA makes clear that its variable region is a member of an alpha variable-region gene family. We have cloned and sequenced the germ-line joining and variable regions used to create the DS6 delta mRNA. Comparison of these sequences does not show evidence of extensive somatic mutations. The major difference between the germ-line and the T-cell antigen receptor delta cDNA sequence is an insertion of three consecutive nucleotides between the variable and joining segments and is evocative of somatic diversification rather than of the use of a germ-line-encoded diversity region.     

Cell surface characterization of malignant T cells from lymphoblastic lymphoma using monoclonal antibodies: evidence for phenotypic differences between malignant T cells from patients with acute lymphoblastic leukemia and lymphoblastic lymphoma

A series of monoclonal antibodies was used for the characterization of malignant T cells from 21 patients with lymphoblastic lymphoma (LL). The tumor population from these patients showed a marked degree of phenotypic heterogeneity and a proportion (one-third) of patients had tumor cells that did not conform exactly with the cells normally detected in the thymus. However, these cell populations could be related to the early or common or late thymocyte population (about one- third of the patients in each category). This contrast, with the characterization of malignant T cells from 43 patients with acute lymphoblastic leukemia (ALL) that could be related to either early or common thymocytes, with an exception of two patients categorized as having a tumor population related to late thymocytes. Further phenotypic differences between cells from ALL and LL could be demonstrated by investigation with two additional monoclonal antibodies, A50 and U4. Among patients with malignant T cells related to common thymocyte, 0/12 patients with ALL had cells recognized by A50, where 5/8 patients with LL had A50+ cells. Among patients with early thymocytes, only patients with ALL had cells recognized by U4. In addition, 5 LL patients had cells reactive with J5, a monoclonal antibody recognizing the common ALL antigen (CALLA). Since CALLA was found on cells related to common and late thymocytes, CALLA is neither lineage specific, nor can it be viewed as being peculiar to malignant lymphoid cells arrested at very immature stages of differentiation.     

Construction and characterization of a yeast artificial chromosome library containing seven haploid human genome equivalents.

Prior to constructing a library of yeast artificial chromosomes (YACs) containing very large human DNA fragments, we performed a series of preliminary experiments aimed at developing a suitable protocol. We found an inverse relationship between YAC insert size and transformation efficiency. Evidence of occasional rearrangement within YAC inserts was found resulting in clonally stable internal deletions or clonally unstable size variations. A protocol was developed for preparative electrophoretic enrichment of high molecular mass human DNA fragments from partial restriction digests and ligation with the YAC vector in agarose. A YAC library has been constructed from large fragments of DNA from an Epstein-Barr virus-transformed human lymphoblastoid cell line. The library presently contains 50,000 clones, 95% of which are greater than 250 kilobase pairs in size. The mean YAC size of the library, calculated from 132 randomly isolated clones, is 430 kilobase pairs. The library thus contains the equivalent of approximately seven haploid human genomes.     

Exuberant restriction fragment length polymorphism associated with the DQ alpha-chain gene and the DX alpha-chain gene.

Cellular DNAs from individuals of 23 families were digested with five restriction endonucleases (Pvu II, EcoRI, HindIII, BamHI, and EcoRV) and then probed with a DX alpha-chain gene probe. Seventeen allogenotopes were observed, each of which could be assigned to a serologically defined haplotype by noting its segregation in families. Six sets of allogenotopes forming allelic series were noted. In comparison with restriction maps of the DQ alpha and the DX alpha regions, each of these series has been assigned to the DQ alpha or the DX alpha locus. Allogenotopes of the four DQ alpha series constitute three clusters correlating with the supertypic groups of class II histocompatibility antigens DQw1 (DR1, DR2, and DRw6), DRw53 (DR4, DR7, and DR9), and DR3 plus DR5 plus DR8. These 13 DQ alpha fragments constitute 22 different patterns. The two DX alpha series constitute two clusters, one of which is not found to be correlated strongly with DR specificities, whereas the other is correlated loosely (r = 0.45) with DR5 and DR7. This absence of strong linkage disequilibrium between the DX alpha series and the DR series contrasts with the DQ alpha series and suggests a recombination point between DQ alpha and DX alpha loci.     

Audiovisual documentation of oral consent: a new method of informed consent for illiterate populations

Informed consent is a legal and ethical requirement of most research in human beings, but obtaining proof of consent in illiterate populations can prove problematic. We used audiovisual documentation of oral consent (video and audiotape recording and photography), a new method of informed consent designed for illiterate populations, in the Guarani Indians Project, a genetic study in the Paraguayan Guarani Indians. We obtained consent from 42 of about 100 potential participants. We believe that our procedure allowed more than half the potential participants to exercise their freedom of refusal. We propose to include this new method as a standard procedure for clinical research in illiterate populations as an alternative to written and signed consent.     

Relationship between postvaccinal anti-influenza antibodies, blood magnesium levels, and HLA antigens

Seventy-eight healthy subjects belonging to 16 different families were submitted to an anti-influenza vaccination. The antibody titers and the red blood cell and plasma Mg concentrations were determined before and 30 days after vaccination. The population study performed on 32 subjects showed the occurrence of a higher antibody response (P less than 0.01) and a lower red blood cell Mg level, among the Bw35 individuals. These findings are confirmed by family studies: HLA identical sibs have values much closer to those of the propositi than to those of the HLA different sibs. The relationships between HLA, immune response, and Mg revealed by the present investigation are discussed in light of the literature together with the known associations between HLA Bw35 antigen and diseases.     

An immunochemical study of the lymphocyte A, Atri system

The anti-Atri lymphocytotoxic antibodies reacting only with 5.19% of A, ABH-secreting individuals have been tested by an inhibition assay with 19 oligosaccharidic structures carrying the A, B, H or Lewis structures. The inhibitions observed dissociate the A and H blood group substances from the Atri substance, and seem to indicate the role of fucosyl residues, particularly that of fucosyl alpha (1 leads to 3), which may be the immunodominant of the Atri substance.     

Joint Report of the B Lymphocyte Specificities Workshop of the France-one Region by FRANCE-ONE with the collaboration of

The analysis of 182 selected anti-B cell sera on 102 cells allowed us to identifysseveral clusters of sera. They showed no correlation with HLA-A, B or C specificities but many associations with the HLA-D determinants. In 10 families, most of these sera segregated with HLA, and five recombinants showed a linkage with the BD or D end part of the MHC. The panel distribution and the family analysis indicated that at least one (the Ly-Li system) and probably two segregant series could exist close to the HLA-D locus.