Immunoglobulin heavy chain genes in humans are located on chromosome.

The human immunoglobulin heavy chain gene complex has been assigned to chromosome 14 by filter hybridization of restriction digests of mouse-human somatic cell hybrids. Cloned DNA probes for both variable and constant regions were used.

Human--rat muscle somatic cell hybrids form myotubes and express human muscle gene products.

Somatic cell hybrids have been prepared at high frequency between the rat muscle cell line L6 and human fetal muscle cells. The hybrid cells express several human gene products including an antigen, 12E7, controlled by the human X chromosome, Thy-1, and several human isoenzymes. In addition, one clone (37-11) expresses a human muscle-specific surface antigen (5.

Deficiency of malic enzyme: a possible marker for malignancy in lymphoid cells.

Soluble malic enzyme (MEs) has been examined in long-term human lymphoid cell lines cultured from 101 individuals. In 65 out of 66 lines derived from people without lymphoreticular malignancy the enzyme was very active. Lines established from 35 individuals with various forms of lymphoreticular malignancy were also examined, including in some cases more than 1 line derived from the same patient.

A human cell-surface antigen defined by a monoclonal antibody and controlled by a gene on chromosome 12.

A murine monoclonal antibody 602-29, subclass IgG1, that recognizes an antigenic determinant expressed by most human cells is described. Immunoprecipitation and sodium dodecyl sulfate-gel electrophoresis analysis indicate that the antigenic determinant is carried by a protein with an apparent molecular weight of 21,000. The antigen is expressed by human-mouse somatic cell hybrids, and analysis of segregants that have lost human chromosomes indicates that the gene controlling expression of the 602-29 antigen is on chromosome 12.

The expression of MHC antigens by human teratocarcinoma derived cell lines.

We have used flow microfluorimetry to investigate quantitatively the expression of HLA-A, B and C antigens, and beta 2 microglobulin, by cell lines derived from human teratocarcinomas, Although low levels of these cell surface molecules were expressed by all the lines examined, there was no evidence of discrete HLA-A, B, C/beta 2-microglobulin positive and negative subpopulations in any cultures. In contrast, using similar techniques, no murine embryonal carcinoma cell line was found to express the homologous H-2 antigens, It is suggested that human embryonal carcinoma cells may differ from their mouse counterparts by expressing low levels of major histocompatibility antigens

A human quantitative polymorphism related to Xg blood groups.

A monoclonal antibody, 12E7, raised against lymphocytes from a patient with a T-cell acute lymphocytic leukaemia reacts strongly with cortical thymocytes and, to a lesser extent, with other human cells. The antigen defined by 12E7 is not expressed on mouse or hamster cells; this species specificity allowed us to investigate the genetics of the expression of the 12E7 antigen using human--rodent somatic-cell hybrids. Hybrid cells which contain the human X chromosome as the only human genetic contribution react with 12E7.

Detection of a common feature in several human tumor cell lines--a 53,000-dalton protein.

Human cell lines, whether derived from spontaneous tumors or transformed in vitro with simian virus 40, were found to contain a 53,000-dalton phosphoprotein (pp53) in contrast to normal human cells in which this protein was not detected. Isoelectric focusing showed that pp53 comprised several species in both simian virus 40-transformed and tumor cells. Comparison of the pp53 species from the various cell lines by partial proteolysis showed that they were similar but not identical.

A human X-linked antigen defined by a monoclonal antibody.

We have constructed hybrids between human thymocytes and the mouse thymoma BW5147. These hybrids, and others, have been used to show that the expression of a thymocyte antigen is controlled by an X-lined gene.

Antigen expression by somatic cell hybrids of a murine embryonal carcinoma cell with thymocytes and L cells.

Thymocyte x PCC4azaR (a murine embryonal carcinoma cell) hybrid cells resembled PCC4azaR. They continued to express two embryonic antigens (SSEA-1 and 3C4-10) found on PCC4azaR, but did not express the thymocyte antigens Thy-1 and Ly-2. However, H-2Kk of thymocyte origin continued to be expressed, while H-2Db of PCC4azaR origin was not reexpressed.

Assay for antibody mediated cytotoxicity of mouse spermatozoa by 86rubidium release.

The analysis of the antigenic structure of murine spermatozoa has been hampered by the lack of a convenient objective serological assay. Spermatozoa, in common with other cells, are capable of concentrating 86rubidium. Antibody mediated complement dependent cytotoxicity of murine spermatozoa has been quantitated by measuring release of 86rubidium from pre-labeled spermatozoa.

Monoclonal antibodies reacting with murine teratocarcinoma cells.

Monoclonal antibodies were produced in vitro by fusing mouse myeloma cells with spleen cells from a rat immunized with the C3H mouse teratocarcinoma C86-S1. After the fusion two clones were chosen for further analysis. The first clone, 3C4-10, produced an antibody recognizing an antigen with a distribution restricted to teratocarcinoma cell lines, an endoderm cell line, and a neuroblastoma.

Analysis of anti-sperm sera for T/t locus-specific antibody.

An objective antiglobulin radioimmunoassay for the analysis of anti-spermatozoa antisera has been used to characterize more than 30 alloantisera. Each of these antisera was raised against spermatozoa from mice carrying T/t regin mutations. Whilst all of the antisera had considerable activity for mouse spermatozoa, none of them was found to contain antibodies specific for T/t region gene products.

Identification of stage-specific polypeptides synthesized during murine preimplantation development.

[35S]Methionine-labeled extracts of mouse ova and preimplantation embryos were analyzed by two dimensional polyacrylamide gel electrophoresis. Of the 400-600 molecular species that have been resolved as distinct spots on autoradiograms of gels for every stage of development from unfertilized eggs to early blastocysts, particular attention has been paid to the identification of 36 of these proteins, each of which is expressed only for a portion of the period under investigation. These molecules are referred to as stage-specific polypeptides and they are biochemical markers of early embryonic development and differentiation.

Serological studies of Cw1 and Cw3 expressed on the same haplotype.

A serological comparison has been made between individuals who are phenotypically Cw1 and Cw3. The first individual is Oriental and carries Cw1 and Cw3 on the same haplotype, the other individuals are Caucasian and carry either Cw1, Cw3 or Cw1 and Cw3 on different haplotypes. No unique specificities could be found on the Oriental Cw1, Cw3 haplotype by reciprocal absorption experiments, inhibition of complement dependent microcytotoxicity by F(ab') 2 fragments prepared from Cw1 and Cw3 antisera or by lysostrip experiments.

Bw21 partition and crossreactivity of the components.

Available lymphocytotoxic antisera permitted the clear partition of the Bw21 antigen into two distinct components, Bw21.1 and Bw21.2.

Cellular distrubtion, purification, and molecular nature of human Ia antigens.

Human Ia antigens were extensively purified (1390-fold increase in specific activity) in 32% yield from BRI 8 cells, a lymphoblastoid B-cell line. Purification was monitored by using allogeneic antisera arising by foetal-maternal stimulation. The product, a glycoprotein fraction, contained the Ia antigens, the HLA-A and -B antigens, and a glycoprotein of unknown function.

Expression of HLA system antigens on placenta.

The levels of HLA-A and -B antigens expressed by placenta have been assessed relative to parental and other A and B antigen types that were not shared by the foetus. A purified preparation of placenta plasma membrane was used to estimate the antigen activities. The results indicate that maternally and paternally inherited A and B antigen activities and beta2-microglobulin are expressed to similar extents but at much lower levels than in spleen lymphocytes (less than 5%).

Human gene mapping using an X/autosome translocation.

Human fibroblasts containing a translocation between the X chromosome and chromosome 15 were fused with the 6-thioguanine-resistant mouse cell line, IR. Resulting hybrids, selected in HAT medium, retained the X/15 chromosome. Hybrids which were counterselected in 6-thioguanine lost this chromosome.

Production of specific antisera to human B lymphocytes.

Antisera have been prepared, in mice and rabbits, to membrane and sub-membrane fractions of human B lymphocyte derived lymphoid lines. Antisera to a protein subfraction were, after only minimal absorption, specific for human peripheral B lymphocytes, monocytes and B cell derived lymphoid lines. The antigen(s) recognised by these antisera were not the same as the previously described B-cell markers; immunoglobulin, Fc receptor, complement receptor and Ia antigens.