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Biomedical subjects

C Baglioni

Publications and source records attributed to C Baglioni.

212 records · Page 12Linked to original sources
PubMed1966

Allelic antigenic factor Inv(a) of the light chains of human immunoglobulins: chemical basis.

Twenty-seven Bence Jones proteins of immunological type K show a common set of peptides. One 6f the commnon peptides differs in three of the proteins which are the only ones classified by a serological test as Iav(a+). The difference in the peptide analyzed is caused by a valine-leucine interchange; Inv(a+) proteins have leucine, whereas Inv(a-) proteins have valine in position 189.

Amino Acid Sequence↗
PubMedDate not supplied

Expression of interleukin-1 alpha and beta in early passage fibroblasts from aging individuals.

Human diploid fibroblasts (HDFs) from newborn foreskin constitutively express interleukin-1 (IL-1) mRNA and protein after completing at least 70% (approximately 40 population doublings) of their in vitro life span. This IL-1 in turn induces the synthesis of specific proteins in aging HDFs. To determine whether IL-1 expression may be promoted by in vivo aging, we analyzed the expression of IL-1 and of inducible mRNAs in HDFs from two normal individuals 55 and 92 years old and in HDFs from a patient with premature aging caused by Werner's syndrome. By reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), we detected expression of IL-1 alpha and beta mRNA and protein in early passage HDFs from both normal individuals and the Werner's syndrome patient. These HDFs also expressed the IL-1-inducible mRNAs for stromelysin, plasminogen activator inhibitor type 2, manganous superoxide dismutase, and collagenase. These results suggest that an age-dependent expression of IL-1 occurs either in vivo or after a few cell divisions in vitro. Therefore, the fibroblast phenotype is modified by the expression of IL-1-inducible genes during aging.

Aged↗
PubMedDate not supplied

Inhibition of mRNA binding to ribosomes by localized activation of dsRNA-dependent protein kinase.

The initiation of protein synthesis can be regulated in mammalian cells by protein kinases which phosphorylate the alpha subunit of initiation factor eIF-2. This phosphorylation results in a block in the recycling of eIF-2 and in the inhibition of messenger RNA binding to 80S initiation complexes. After eIF-2 alpha is phosphorylated, the mRNA becomes associated with 48S complexes consisting of a 40S ribosomal subunit, eIF-2 (alpha P), GDP and Met-tRNAf. One of the eIF-2 alpha kinases is activated by low concentrations of double-stranded RNA (dsRNA). This kinase (PKds) is present at a basal level in all mammalian cells investigated and its synthesis is induced in cells treated with interferon. The PKds may be involved in the inhibition of translation of viral mRNA in interferon-treated cells infected with RNA viruses, as it is activated by viral replicative complexes. It is not known, however, if the activated PKds preferentially inhibits the translation of viral mRNA when cellular protein synthesis proceeds at a normal rate in infected cells. We now report that mRNA covalently linked to dsRNA is preferentially inhibited from binding to 80S complexes by a localized activation of PKds. This suggests that in interferon-treated cells the binding of some nascent viral mRNAs to functional initiation complexes may be preferentially inhibited by a similar mechanism.

Enzyme Activation↗
PubMedDate not supplied

Downregulation of tumor necrosis factor receptors of macrophages by interferons and interleukin-1. Role of protein kinase C activation.

Freshly harvested murine peritoneal macrophages and a line of transformed murine macrophages (RAW) were used in experiments designed to investigate the effect of different interferons (IFN) and interleukin-1 (IL-1) on tumor necrosis factor (TNF) receptors. Low concentrations of IFN-gamma or somewhat higher concentrations of IFN-alpha drastically downregulated the TNF receptors of RAW cells. A similar, but less pronounced, downregulation of TNF receptors was observed in peritoneal macrophages treated with these IFNs. This downregulation could not be accounted for by an induction of TNF secretion. Furthermore, IFN-alpha and gamma interacted synergistically in downregulating TNF receptors of RAW cells. IL-1 also downregulated TNF receptors. When RAW cells were treated with inhibitors of protein kinase C, the downregulation of TNF receptors by IFNs or IL-1 was reversed, and TNF binding increased up to 2-fold over that of untreated cells. Such increase was also observed in RAW cells treated only with the inhibitor of protein kinase C, staurosporine. However, TNF receptors decreased in peritoneal macrophages treated with staurosporine. This finding was explained by activation of macrophages by staurosporine, which induced secretion of TNF. These findings indicate that protein kinase C activity regulates TNF receptors in macrophages.

Alkaloids↗
PubMedDate not supplied

The antiviral activity of tumor necrosis factor in HeLa cells is not mediated by interferons. Studies with TNF-resistant variants.

Tumor necrosis factor (TNF) has a relatively modest antiviral activity in HeLa cells, when compared to that of interferon (IFN). Addition of antisera neutralizing IFN-alpha or beta did not reduce the antiviral activity of TNF. Furthermore, we determined with a sensitive hybridization assay that less than one molecule of IFN-beta 1 mRNA could be present per TNF-treated cell. HeLa cell variants resistant to the TNF cytocidal activity were selected. These variants had TNF receptors with a dissociation constant similar to that of parental cells. Three cloned variants tested did not respond to the antiviral activity of TNF, but responded to IFN-alpha. Surprisingly, two of the variants did not respond to IFN-gamma. This suggests that the pathways mediating the cytocidal activity of TNF and the response to IFN-gamma share some common step. TNF induced transcription of IFN-beta 2 in resistant variants, indicating that this cytokine does not contribute to the antiviral activity of TNF.

Antiviral Agents↗