Treatment Of Beta Research Articles

Anti-tumor effects of interleukin-2 and interleukin-1 in mice transplanted with different syngeneic tumors.

We have studied the anti-tumor effects of human recombinant IL-2, alone or in association with LAK cells, in mice transplanted subcutaneously (s.c.) with the following syngeneic tumors: highly metastatic Friend leukemia cells (FLC), nonmetastatic FLC, lymphoma RBL-5 cells and HeJ16 fibrosarcoma cells. In these tumor models, peri-tumoral injections of IL-2 were more effective in inhibiting tumor growth than a systemic treatment. Although s.c. IL-2 treatment resulted in marked inhibition of tumor growth in mice injected s.c. with highly metastatic FLC, it was not effective in inhibiting growth of FLC in the liver and spleen. IL-2 therapy was more effective at increasing survival time in mice transplanted with non-metastatic FLC or with RBL-5 cells. In mice transplanted with HeJ16 fibrosarcomas, s.c. IL-2 treatment resulted in highly significant anti-tumor effect and survival of 70% of tumor-injected mice. No general correlation was found between in vitro sensitivity or resistance to the cytolytic activity of LAK cells and the anti-tumor effects observed in vivo. Subcutaneous injection of IL-1 beta in mice transplanted with highly metastatic FLC resulted in a marked increase in survival time and inhibition of metastatic tumor growth in liver and spleen. Combined treatment of IL-1 beta and IL-2 produced a synergistic anti-tumor effect: 60% of mice injected with highly metastatic FLC survived. Combined IL-1/IL-2 treatments exerted no anti-tumor activity either in DBA/2 mice injected with antibody to Thy 1.2 antigen or in nude mice, indicating that T cells play important roles during IL-1/IL-2 therapy. In vitro treatment of FLC with IL-1 beta resulted in a slight inhibition of cell multiplication, whereas even high doses of IL-2 did not affect FLC multiplication. Our results indicate that local combined treatments with IL-1 and IL-2 can induce potent, host-dependent (T cell-mediated) anti-tumor effects against highly malignant tumors.

Abnormal minor human erythrocyte membrane sialoglycoprotein (beta) in association with the rare blood-group antigen Webb (Wb).

Individuals whose erythrocytes are positive for the rare blood-group antigen Webb (Wb) have an altered form of the minor sialoglycoprotein beta (synonyms glycophorin C and glycoconnectin). This altered sialoglycoprotein beta (beta Wb) has an Mr about 2700 lower than that of normal sialoglycoprotein beta. Treatment of normal sialoglycoprotein beta with endo-beta-N-acetylglucosaminidase F decreased its Mr by about 3600, but similar treatment of sialoglycoprotein beta Wb had no effect. These results suggest the possibility that sialoglycoprotein beta Wb lacks the N-glycosidically linked oligosaccharide found on normal sialoglycoprotein beta.

Conformational and ligand binding properties of the isolated domains from the beta 2 subunit of Escherichia coli tryptophan synthetase investigated by the reactivity of their cysteines.

A mild proteolytic treatment of the dimeric beta 2 subunit of Escherichia coli tryptophan synthetase (L-serine hydrolase (adding indole) EC 4.2.1.20) is known to nick each polypeptide chain into two complementary fragments, F1 and F2 (Högberg-Railbaud, A., and Goldberg, M.E. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 442-446). The reactivity of the cysteines in the isolated or associated fragments is studied and used to characterize the structural and functional properties of these fragments. It is shown that the total number of cysteines, their reactivity to dithiobisnitrobenzoate, and their protection by various ligands are the same in the nicked and intact enzyme, thus demonstrating the close structural analogy between these two proteins. In the isolated F1 fragments two cysteines are reactive and two are buried, thus confirming that this fragments has a compact, globular structure. Various ligands tested fail to produce any modification of the cysteines in the isolated fragments, thus suggesting that none of the fragments alone carries a binding site for the substrates and coenzyme.