Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mouse L cells expressing HLA genes are potentially useful for producing and analyzing monoclonal antibodies (mAb) to HLA molecules. This paper describes the preparation of transfectants using uncloned human DNA and three methods to isolate the HLA-expressing transfectants. Transfectant libraries were made by cotransfecting mouse thymidine kinase (tk)-deficient L cells with a calcium phosphate precipitate containing genomic DNA and tk plasmid DNA. Transfectants expressing HLA genes were isolated using these methods: immunomagnetism, replicate-plating combined with cellular enzyme-linked immunoassay, and sorting using a fluorescence-activated cell sorter. Two HLA-A2 transfectant were isolated using immunomagnetism, two HLA-A24 transfectants by replicate plating, and one HLA-Bw60 transfectant by FACS. However, no transfectants were isolated that stably expressed class II genes. The class I transfectants have been useful in characterizing several locally prepared mAbs which bind to monomorphic determinants on class I HLA molecules. Two of the transfectant lines, one expressing HLA-A2 (8001) and the other HLA-A24 (8008), have been included in the collection of lines distributed for use in the Eleventh International Histocompatibility Workshop.
 ...
PMID:Transfection of HLA genes using genomic DNA. 165 84

We have found that human lymphoblastoid cell line RPMI-6410t is a biochemical mutant for gene of thymidine kinase and has chromosome markers in the karyotype. Thus, this cell line can be used as a partner in somatic hybridization, in particular for producing hybridomas, synthesizing human monoclonal antibodies. We have discovered that line RPMI-6410t carries HLA-A2, -B7 and -B12 antigens of human histocompatibility complex on the cell surface. The cell membrane of this cell line contains immunoglobulins of M and D classes. RPMI-6410t cells secrete IgM molecules. It is demonstrated that induction of the switch of immunoglobulin heavy-chain classes by the factors of foetal calf serum takes place in the cells of RPMI-6410t line. Thus, the corresponding stage of B-lymphocytes differentiation in vivo is reproduced in 6410t line in vitro.
 ...
PMID:[Induction of the switch in the synthesis of immunoglobulin classes in the RPM 1-6410t lymphoblast cell line and its clones as affected by fetal calf serum factors]. 309 62

Murine L cells expressing HLA-A2 or -B7 antigens were isolated after cotransformation of thymidine kinase-negative cells with the herpes simplex virus thymidine kinase gene and the genomic clones containing either the HLA-A2 or -B7 genes. Monoclonal antibody binding analyses demonstrated the stable cell surface expression of HLA antigens by these cells at levels of up to 40% of the amount expressed by the human B lymphoblastoid cell line, JY. The HLA-A2 and -B7 antigens expressed by the L cells retained all of the antibody-defined, heavy-chain-associated antigenic determinants but lacked those determinants associated with human beta 2-microglobulin. These HLA transformants were capable of functioning as targets for monoclonal cytotoxic T lymphocytes (CTL) that specifically recognize the HLA-B7 or -A2 antigens expressed by JY cells. However, the efficiency of lysis, relative to the JY cell line, was 50-99% for individual CTL. In addition, not all of these CTL were capable of lysing the appropriate transformants. Because the antigens appear by serological criteria to be structurally intact and expressed at high levels, these results suggest that the complementation of the HLA heavy chains with mouse, rather than human, beta 2-microglobulin may alter the antigenic determinants that are important for CTL recognition.
 ...
PMID:Recognition by xenogeneic cytotoxic T lymphocytes of cells expressing HLA-A2 or HLA-B7 after DNA-mediated gene transfer. 619 47

Genes coding for the heavy chain of the class I antigens HLA-A2 or HLA-B7 of the human major histocompatibility complex have been introduced into mouse LtK- cells by cotransfection with the herpes simplex virus thymidine kinase gene. HAT-resistant colonies were isolated expressing either HLA-A2 or HLA-B7 as monitored by indirect immunofluorescence. Immunoprecipitation analysis of both antigens by either sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) or isoelectric focusing (IEF) showed that they were identical to the HLA-A2 and HLA-B7 expressed in the human lymphoblastoid cell line JY (homozygous HLA-A2, HLA-B7). However, human cytotoxic T lymphocytes (CTL) generated against JY and CTL clones specific for HLA-A2 or HLA-B7 were unable to recognize the transfectants as targets. These results indicate that the human HLA-A2 (or B7) complexed with the murine beta 2-microglobulin could be an inappropriate target structure for the CTL. However, because the transfectants are not killed by human CTL even in the presence of lectins, it is suggested that other molecules that are not able to overcome the human-mouse species barrier may be involved in the killing mechanism.
 ...
PMID:Expression of the major histocompatibility antigens HLA-A2 and HLA-B7 by DNA-mediated gene transfer. 635 10

We have screened a large number of isolated human genomic clones that hybridize to a cloned HLA cDNA probe for their ability to direct the synthesis of HLA-A, -B, and -C surface antigens on mouse L cells following DNA-mediated gene transfer. The surface expression of human histocompatibility antigens, monitored by indirect immunofluorescence and the fluorescence-activated cell sorter, was examined at 60 hr after transfection and on hypoxanthine/aminopterin/thymidine-resistant (HATR) populations derived from cotransfer with the herpes simplex virus thymidine kinase gene. Two unique genomic clones designated JY B3.2 and JY 158, isolated from the human lymphoblastoid cell line JY (homozygous HLA-A2, -B7), were shown to contain gene sequences capable of directing expression of an HLA-A, -B, -C determinant. By using allo-specific antibodies, the gene products of these clones were identified as HLA-A2 and HLA-B7, respectively. HATR clonal populations isolated from cotransfections with these genomic clones displayed varying levels of surface HLA expression that correlated with the number of intact donor HLA sequences present in the cells. In general, these levels of expression were stable during 3 months in culture. This system provides a powerful tool for the study of human surface antigen gene structure, expression, and function on a mouse cell background.
 ...
PMID:Identification of human genomic clones coding the major histocompatibility antigens HLA-a2 and HLA-B7 by DNA-mediated gene transfer. 695 20