Diphtheria toxin inhibits protein synthesis in eukaryotic cells by catalyzing inactivation of elongation factor 2. The 10,000-fold greater sensitivity in vitro to diphtheria toxin of human cells as compared to mouse cells seems to be attributable to a difference at the level of the cell membrane. Mouse-human cell hybrids are as sensitive to diphtheria toxin as human cells. We have shown that th...

INTRODUCTION It is known that cells from different animal species show marked differences in their susceptibility to the destructive action of diphtheria toxin (Lennox & Kaplan, 1957). It therefore seemed possible that diphtheria toxin might be used as a speciesspecific marker in the study of interspecific hybrid cells and perhaps also as a selective agent to facilitate the isolation of such hy...

New neurons are continuously generated in the subgranular zone of the adult hippocampus and, once sufficiently mature, are thought to integrate into hippocampal memory circuits. However, whether they play an essential role in subsequent memory expression is not known. Previous studies have shown that suppression of adult neurogenesis often (but not always) impairs subsequent hippocampus-depende...

1. The metamorphosis of the Cecropia silkworm is accompanied by large and systematic changes in the insect's sensitivity to diphtheria toxin. 2. Injection of less than 1 gamma of toxin into mature caterpillars, prepupae, or developing adults causes cessation of development followed by delayed death 1 to 5 weeks later. 3. Dormant pupae, on the contrary, are resistant to 70 gamma of toxin and may...

Routine immunologic screening of four patients with chronic mucocutaneous candi­ diasis (CMC) revealed that they manifested positive Schick tests in ·ui;,o despite adequate diphtheria toxoid immunization and the presence of circulating hemaggluti­ nating antibody to diphtheria. Plasma from these individuals was found to neutralize Schick toxin in rabbits. Unlike normal individuals who preferent...

The T domain of diphtheria toxin is known to participate in the pH-dependent translocation of the catalytic C domain of the toxin across the endosomal membrane, but how it does so, and whether cellular proteins are also required for this process, remain unknown. Here, we report results showing that the T domain alone is capable of translocating the entire C domain across model, planar phospholi...

Phage beta 197tox-, which codes for CRM197, a nontoxic protein immunochemically indistinguishable from diphtheria toxin, was UV induced from a culture of the C7(beta 197)tox- strain. A total of 191 C7(beta 197)tox- lysogens were isolated and selected according to the halo produced on TYE agar containing antidiphtheria toxin serum and were further characterized by Southern blots of their chromos...

Lysosomotropic amines, such as ammonium chloride, are known to protect cells from the cytotoxic effects of diphtheria toxin. These drugs are believed to inhibit the transport of the toxin from a receptor at the cell exterior into the cytoplasm where a fragment of the toxin arrests protein synthesis. We studied the effects of lysosomotropic agents on the cytotoxic process to better understand ho...

Warren, Leonard (National Institute of Arthritis and Metabolic Diseases, Bethesda, Md.) and C. W. Spearing. Sialidase (neuraminidase) of Corynebacterium diphtheriae. J. Bacteriol. 86:950-955. 1963.-The characteristics of a sialidase produced by Corynebacterium diphtheriae were studied. The enzyme was partially purified from preparations of diphtheria toxin on a column of Sephadex G-75. By this ...

The IL-2 toxin-mediated inhibition of protein synthesis in high affinity IL-2-R-positive murine and human T cell lines has been examined. Both excess free IL-2 and mAb to the Tac epitope of the p55 subunit of IL-2-R are shown to block the action of IL-2 toxin; whereas, agents that interact with other receptors or antigens on the T cell surface have no effect. We show that IL-2 toxin, like dipht...