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H del Favero

Publications and source records attributed to H del Favero.

3 recordsLinked to original sources
PubMed1997

Specific uptake of tumor necrosis factor-alpha is involved in growth control of Trypanosoma brucei.

Trypanosoma brucei is lysed by tumor necrosis factor-alpha (TNF-alpha) in a dose-dependent way, involving specific binding of the cytokine to a trypanosomal glycoprotein present in the flagellar pocket of the parasite. TNF-alpha-gold particles are endocytosed via coated pits and vesicles and are directed towards lysosome-like digestive organelles. The specific uptake of the cytokine by the parasite results in a developmentally regulated loss of osmoregulatory capacity. TNF-alpha specific lysis is prevented when lysis assays are performed at a temperature <26 degrees C, despite uptake of the cytokine. Inhibition of lysis is also observed when a lysosomotropic agent is added during the first 2 h of incubation. Both monomorphic and pleomorphic trypanosomes are lysed but only when isolated during the peak of parasitaemia. Lysis is not observed with early infection stage parasites or procyclic (insect-specific) forms. Anti-TNF-alpha treatment of T. brucei-infected mice reveals a dramatic increase in parasitaemia in the blood circulation, the spleen, the lymph nodes, and the peritoneal cavity. These data suggest that in the mammalian host, TNF-alpha is involved in the growth control of T. brucei.

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PubMed1994

Production of fibronectin and adherence to fibronectin by human myeloma cell lines.

In the present study we examined the production of fibronectin (FN) in 10 human myeloma cell lines (HMCL). By Northern blot analysis we could detect the presence of FN-mRNA in most of these lines. A majority of the cell lines (LP-1, OPM1, SKMM-2, EJM, JJN3 and ARH-77) hybridized with two probes recognizing total FN while the mRNA of one cell line (LB84-1) was shown to hybridize also with a probe recognizing the EDA segment of cellular FN. In one cell line (L363) FN-mRnA could only be detected after PCR amplification. Using an enzyme-linked immunosorbent assay, we could also demonstrate that HMCL secrete FN in their culture medium. Seven myeloma cell lines that produce FN showed a significant adherence to soluble FN. By blocking experiments, this adhesion was found to be mediated by the VLA-4 (alpha 4 beta 1) receptor. The production of fibronectin and the expression of a functional receptor for this protein may represent independent features of myeloma cells but may also be functionally linked. Since fibronectin has recently been identified as a crucial co-factor of IL6 in the regulation of the terminal B cell differentiation, the endogenous FN production may be part of an autocrine-line process mediating the autonomous growth of these cell lines. Alternatively, the FN production may also reflect a mechanism that myeloma cells use to communicate with their natural environment, i.e. the bone marrow stroma.(ABSTRACT TRUNCATED AT 250 WORDS)

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