Product Information

As described in the preceding paper,monoclonal antibodies have been raised by immunization of rats with mouse hematopoietic cells which detect a major cell-surface glycoprotein (Mr = 95 000) of mouse bone-marrow cells of the granulocytic series. While most of the monoclonal antibodies detect this molecule one bone-marrow and spleen cells of all mouse strains,two antibodies recognize alternative allelic forms of the molecule. One alloantigen is expressed in all the remaining inbred strains examined. The alloantigens are codominantly expressed on the cells of F1 mice. Backcrosses of DBA/2 and C57BL/6 with F1 mice (B6D2F1) confirmed that a single genetic locus is involved in the expression of the two antigenic forms and demonstrated linkage to Ly-m11 which has previously been mapped to mouse chromosome 2. These genetic mapping experiments and the biochemical properties of the glycoprotein suggested that it might be identical to a glycoprotein first identified on murine fibroblasts by Hughes and August and designated Pgp-1. This has been firmly established by exchange of monoclonal antibody reagents and sequential immunoprecipitations. View Publication

A murine leukocyte surface glycoprotein (Mr = 95 000) has been defined by means of xenogeneic monoclonal antibodies. In normal hematopoietic tissues,the glycoprotein is found in highest amounts in the bone marrow. Flow cytometric analysis shows that essentially all bone-marrow cells express the glycoprotein and that it is a major component of a subpopulation of cells containing predominantly granulocytic precursors. In contrast,only about 5 percent of thymocytes express sufficient glycoprotein to be detected by flow cytometric analysis,although under stringent conditions up to 20 percent of thymocytes are susceptible to complement-mediated cytotoxicity using a monoclonal antibody against the glycoprotein. Functional assays showed that both prothymocytes and colony forming unit-spleen express the glycoprotein which is broadly distributed on murine hematopoietic tumor cell lines. However,although some Thy-1+ (T) cell lymphomas express large amounts of the glycoprotein,others do not express detectable quantities of the molecule. The glycoprotein is not restricted to hematopoietic cells and can be detected on lung,kidney,brain,and liver as well as cultured fibroblasts. Monoclonal antibodies against the glycoprotein cross-react with an antigen present on human cells. As described in the accompanying paper,the glycoprotein exists in two antithetical allelic forms and we show that it is identical to a polymorphic surface molecule independently characterized by Colombatti and co-workers. View Publication

By using immunoelectron microscopy,we have localized the binding site on 50S Escherichia coli ribosomal subunits for puromycin,an antibiotic that interacts with the ribosomal peptidyltransferase center. This was achieved by affinity-labeling 50S subunits with N-bromoacetyl puromycin and treating the labeled subunits with an antibody specific for the N6,N6-dimethyladenosine moiety of puromycin. The position of the puromycin binding site was then revealed by localizing the attachment sites of the IgG molecules on the surfaces of the 50S subunits under the electron microscope: it was located at the interface between the subunits,on and around the wider lateral protuberance of the 50S subunit. This localizes directly the peptidyl transferase center on the surface of the large ribosomal subunit. View Publication

View Publication

Lymphoblasts from 93 children with acute lymphoblastic leukemia (ALL) were characterized by immunologic cell surface markers. These patients were treated on a single protocol,featuring adriamycin therapy during remission,and have been followed from 2 to 6.5 yr (median 4 yr). Three classes of patients were defined serologically: HTA+ Ia- CALLA-,Ia+ CALLA+ HTA-,and Ia+ CALLA- HTA-. Disease-free survival and sites of relapse were assessed within immunologic subsets. Similar to the findings of others,T-cell (HTA+ Ia-) patients fared poorly as compared to non-T-cell (Ia+ HTA-) patients (median disease-free survival was 12 and 47 mo. respectively; p = 0.0004). The majority of relapses in the HTA+ patients occurred at extramedullary sites. Late testicular relapse was rare among Ia+ patients. In addition,the common ALL antigen" (CALLA) may identify a relatively favorable subset within the Ia+ population. The prognostic value of the immunologic markers was compared with traditional clinical factors. There was much overlap between HTA+� View Publication

This report describes the establishment directly from normal preimplantation mouse embryos of a cell line that forms teratocarcinomas when injected into mice. The pluripotency of these embryonic stem cells was demonstrated conclusively by the observation that subclonal cultures,derived from isolated single cells,can differentiate into a wide variety of cell types. Such embryonic stem cells were isolated from inner cell masses of late blastocysts cultured in medium conditioned by an established teratocarcinoma stem cell line. This suggests that such conditioned medium might contain a growth factor that stimulates the proliferation or inhibits the differentiation of normal pluripotent embryonic cells,or both. This method of obtaining embryonic stem cells makes feasible the isolation of pluripotent cells lines from various types of noninbred embryo,including those carrying mutant genes. The availability of such cell lines should made possible new approaches to the study of early mammalian development. View Publication

A method has been described for the long-term culture of human bone marrow cells in liquid medium. Hematopoiesis,as measured by the production of granulocytic-macrophage progenitor cells (CFUc),continued for at least 20 weeks and was dependent upon the presence of a marrow-derived adherent layer of cells. As in the case of murine marrow liquid cultures,the adherent layer consisted of mononuclear phagocytic cells,endothelial cells,and lipid-laden adipocytes,the latter being essential for long-term hematopoiesis. Optimal growth conditions included McCoy's medium supplemented with fetal bovine serum,horse serum,and hydrocortisone and incubation at 33 degrees C. Horse serum in conjunction with hydrocortisone appeared essential for the growth of adipocytes. View Publication

Serotonin receptor affinity and photelectron spectral data were obtained on a number of substituted N,N-dimethyltryptamines. Evidence is presented that electron-donating substituents in the 5-position lead to enhanced behavioral disruption activity and serotonin receptor affinity as compared to unsubstituted N,N-dimethyltryptamine and analogues substituted in the 4- or 6-position. Some correlation was found between ionization potentials and behavioral activity,which may have implications concerning the mechanism of receptor binding. View Publication

View Publication

Sinefungin (A9145) and a related metabolite,A9145C,were found to be potent inhibitors of Newcastle disease virion and vaccinia virion mRNA(guanine-7-)-methyltransferase and vaccinia virion mRNA(nucleoside-2'-)-methyltransferase. Both Sinefungin and A9145C were competitive inhibitors of these S-adenosyl-L-methionine-dependent enzymes having inhibition constants substantially less than S-adenosyl-L-homocysteine. These compounds also inhibited plaque formation by vaccinia virus in mouse L-cells. View Publication