Phytohemagglutinin is a glycoprotein that accumulates in the protein storage vacuoles of bean seeds. The mature glycoprotein has a high-mannose and a complex glycan. We describe here the use of site-directed mutagenesis and expression of the mutated genes in transgenic tobacco to study the role of glycans in intracellular targeting. The reading frame for phytohemagglutinin-L was mutated so that...

The carboxyl-terminal one-third of human topoisomerase II polypeptide expressed in Escherichia coli was used as antigen to generate polyclonal antibodies in rabbits. With the use of antiserum, DNA topoi somerase II levels of phytohemagglutinin-stimulated human lymphocytes were measured by immunoblotting. Our results showed that the increase in intracellular topoisomerase II level paralleled the...

By B .iw ui BAIN, MAGDALENE R. VAS AND LoUIS LOWENSTEIN W HEN human peripheral blood leukocytes are cultured in vitro in the presence of phytohemagglutinin, some of the cells transform into immature forms that are capable of mitotic division.’ An incidental observation by Schrek and Donnelly2 indicated that, under certain conditions, a similar reaction might occur without phytohemagglutinin. Th...

The capacity of retinole acid to modulate human T-lymphocyte and B-lymphocyte activation by mitogens was examined. Tlymphocyte proliferation stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA) or phytohemagglutinin was enhanced by 5 nw to 5 U.Mretinoic acid in a dose-dependent manner with a 65 ± 35% (SD) increase (n = 6, P < 0.01) in TPA-stimulated proliferation induced by 5 U.Mretinoic a...

The interleukin 2-diphtheria toxin-related fusion protein (IL-2-toxin) rapidly inhibits protein synthesis in IL-2 receptor (IL-2R)-bearing phytohemagglutinin-activated T cells but transiently stimulates DNA synthesis. At 7 hr after interaction with IL-2R+ phytohemagglutinin-activated T cells, IL-2-toxin-treated cells bear augmented steady-state levels of c-myc, interferon gamma, and IL-2R mRNA;...

An assay has been developed to measure the ability of human lymphocytes to repair damage to DNA. In this assay, purified human lymphocytes are exposed to graded doses of radiation and then stimulated with phytohemagglutinin to undergo DNA replication. The rate of incorporation of thymidine in irradiated lymphocytes during the second and subsequent rounds of DNA replication is taken to be indica...

6/94 virus, a parainfluenza type 1 virus recovered by lysolecithin fusion of multiple sclerosis brain cell cultures with CV-1 cells, replicated in monocyte macrophages and lymphocytes from normal human donors and from a patient with multiple sclerosis. In macrophage cultures, hemadsorption-positive cells and high levels of infectious virus became apparent within 24 to 48 h after infection, pers...

The effects of the interleukins IL-7 and IL-9 on cell cycle progression were investigated by conventional [3H]thymidine incorporation and by the bivariate BrdU/Hoechst technique. Both IL-7 and IL-9 drive phytohemagglutinin-activated T cells through more than one cell cycle, but IL-7 was more potent on cell cycle progression than IL-9. Neither synergistic nor inhibitory effects were seen between...