Antigenic characterization of human interferon derived from amniotic membranes induced by virus.
ABSTRACT The presence of protein(s) with interferon (IFN)-like activity in culture fluid from human amniotic membranes induced by viruses has been described by different groups. However, the antigenic structure of this protein is controversial. Here we report the presence of IFN activity in supernatants of human amniotic membranes induced by Sendai virus. The major component responsible for this antiviral activity seems to be the classical IFN-beta. However, we were able to demonstrate the presence of a protein fraction with antiviral activity that does not bind to an affinity column for IFN-beta. The antiviral activity of this unbound fraction cannot be neutralized by antibodies to IFN-alpha, -beta, gamma, or by a mixture of them. We called this unbound fraction IFN-AM. We also report the development of a monoclonal antibody that does not neutralize the antiviral activity of IFN-alpha or IFN-beta but reduces the antiviral activity of a partially purified preparation of Sendai virus-induced amniotic membrane supernatant. These observations suggest that the IFN-AM (the unbound fraction that lacks reactivity with antibodies against known IFNs) contains a unique antigenic determinant that is not present, or, if so, is not located at the functional domain of IFN-alpha, -beta, or -gamma.
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ABSTRACT: The human placenta has been demonstrated to be a site of interferon (IFN) production. We report here that early human placental explants in vitro release both type I (IFN-alpha and -beta) and type II (IFN-gamma) immunoreactive IFN. The mitogen concanavalin A (Con A) stimulated immunoreactive (ir-) IFN-gamma secretion in both a dose- and time-dependent manner, but had no significant effect on either ir-IFN-alpha or -beta release. The enhancement of ir-IFN-gamma secretion by Con A, at 2-20 micrograms/ml, was significant at 1 h and persisted until 24 h, but was not significant at 48 h. A high dose of recombinant human interleukin-2 (IL-2) stimulates the release of all three types of ir-IFNs, suggesting that interaction of IL-2 with its receptor might be one cause of the constitutive production of placental IFNs. The patterns of response to Con A and IL-2 were different from those of lymphocytes, providing indirect evidence suggesting that the source of these IFNs might not be lymphocytic. Taken together, these results indicate that first trimester human placental explants in vitro produce both type I and type II IFNs, the major IFN produced depending on the inducer. IL-2 may be one of the physiological inducers of placental IFNs.Journal of Reproductive Immunology 09/1993; 24(3):201-12. DOI:10.1016/0165-0378(93)90075-S · 2.37 Impact Factor
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ABSTRACT: Primary cultures of human amniotic membrane (PCHAM) cells display very low proliferation rates while their doubling times vary between 150 h and 210 h even after mitogenic stimuli. However, the pattern of proto-oncogenes (c-fos, c-myc and c-jun) expression in these cells, upon serum restimulation, resembled that of cell lines that display shorter population doubling times. Serum stimulation of quiescent PCHAM cells promoted a rapid and transient c-fos mRNA expression, which was detected within 10 min, reached maximal levels at 30 min and decreased to undetectable levels 2-3 h later. The levels of c-myc or c-jun mRNA increased within 10 min after serum restimulation, peaked at 3 h and decreased to intermediate levels thereafter. We also present evidence showing that IFN alpha 2 treatment of PCHAM cells had no effect on their population doubling times nor in c-fas, c-myc, or c-jun mRNA expression, under conditions in which induction of IFN-stimulated genes, such as 2'-5' oligo-adenylate synthetase (OAS) and 6-16 was observed. We conclude that the growth constraints observed with this cells are not directly associated with a negative cellular growth regulation exerted by IFN alpha 2, nor due to a deregulated proto-oncogenes' expression.Placenta 03/1997; 18(2-3):163-8. DOI:10.1016/S0143-4004(97)90088-6 · 3.29 Impact Factor
- Placenta 01/1992; 13:55-72. DOI:10.1016/S0143-4004(05)80308-X · 3.29 Impact Factor