Biomedical subjects

F D Toth

Publications and source records attributed to F D Toth.

7 recordsLinked to original sources

PubMed1993

Human trophoblast interferons.

The human placental trophoblasts which constitute the first fetal cells and form the major cell layer of the feto-maternal interface are potent producers of interferons (IFNs). The IFN production is dependent on the gestational age of the trophoblast, type of inducer and the stage of differentiation of the trophoblasts. First trimester trophoblast populations produce higher levels (5-6 times) of IFN than the third trimester trophoblasts when stimulated with viruses. Non-viral inducers, such as poly(rl).poly(rC), induce exclusively IFN-beta whereas viruses such as Sendai and Newcastle Disease Virus (NDV) induce mixtures of IFN-alpha subtypes and IFN-beta. Differentiation of mononuclear cytotrophoblasts into syncytiotrophoblasts in vitro increase the IFN production. High-performance and immunoaffinity chromatography of the virus-induced trophoblast IFN preparations resulted in the isolation of three antigenically distinct IFNs, namely, alpha I, alpha II1 (omega 1), and beta with molecular masses of 16, 22 and 24 kDa, respectively, on SDS-PAGE. The human trophoblast IFNs have physical and antiviral activities characteristic of the Type 1 IFNs. The possible roles of the trophoblast IFNs in human placental and fetal development are also discussed in this review.

Female↗

PubMed1991

Human trophoblast interferon: pattern of response to priming and superinduction of purified term trophoblast and choriocarcinoma cells.

We recently described a beta interferon response of primary cultures of term human trophoblast exposed to poly(I:C). The response pattern has now been studied further with priming and superinduction both of normal placental cell types and JAR, JEG-3 and BeWo choriocarcinoma cells. Pre-treating placental trophoblast cells, fibroblasts and macrophages with human interferon generally led to increased yields of interferon after poly(I:C) induction, whereas choriocarcinoma cells did not respond to priming. All the cells showed the superinduction phenomenon although to varying degrees. The combination of priming and superinduction conditions led to the production of very high yields of interferon in placental fibroblast cultures. The combined procedure also produced more interferon in macrophage cultures than priming or superinduction alone. Combined superinduction and priming of normal trophoblast did not produce higher yields than those obtainable by superinduction alone. These data might help to provide additional insight into the cellular control mechanisms of sensitivity of normal and malignantly transformed cells to interferon. Furthermore, the large quantity of trophoblast interferon produced by superinduction could be used for studies of its anti-viral and immunomodulatory effects.

Cells, Cultured↗

PubMed1991

Purification of human placental trophoblast interferon by two-dimensional high performance liquid chromatography.

Human placental trophoblast challenged with Sendai virus induced IFNs mainly of the beta-type (75%) and relatively low levels of the alpha-type (25%). A two-step high performance liquid chromatographic procedure ("two-dimensional HPLC") has been developed for the complete purification of the placental trophoblast interferon beta (tro-IFN-beta) from serum-containing culture supernatant. The method involved a combination of high performance liquid affinity chromatography (HPLAC) on Cibacron Blue 3GA immobilized on an activated pressure stable macroporous synthetic polymer, 2-hydroxyethyl methacrylate vinyl sulphone (HEMA-BIO 1000 VS), as the first dimension and reversed-phase high performance liquid chromatography (RP-HPLC) on Separon SGX C-18 as the second. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot experiments showed that the tro-IFN-beta was present as a 24 kDa protein. Densitometric scanning analysis of Coomassie-stained gel revealed the purity of the final preparation to be greater than 99%. The purified tro-IFN-beta had a specific activity of 1.03 x 10(8) IU/mg of protein and the overall recovery was 81% of the total IFN-beta activity in the crude preparation and 61% of the total IFN activity.

Cells, Cultured↗

PubMed1990

Interferon production by cultured human trophoblast induced with double stranded polyribonucleotide.

Human trophoblast cultures were established from term placentae. Upon exposure to polyriboinosinic-polyribocytidylic acid (poly(I:C] the cultures produced interferon. Results of neutralization experiments and indirect immunofluorescence studies indicated that the trophoblast produces beta-interferon. The fusion of trophoblast cells into syncytia was accompanied by a restriction in interferon release after stimulation with poly(I:C). It was also demonstrated that the malignant choriocarcinoma cell line JAR produced less interferon than the non-transformed cytoorsyncytiotrophoblast.

Cell Separation↗

PubMed1989

Different types of false positive anti-HIV reactions in patients on haemodialysis.

Serum samples of 589 haemodialysis patients were screened for HIV antibody by ELISA methods. Of these, 36 samples were found to be repeatedly reactive. None of the 36, however, could be confirmed by competitive enzyme immunoassays and Western blot; therefore, they were considered to be false positive. The sera could be divided in two groups. The sera of Group 1 were designated as the usual type of false positivity, caused most probably by anti-lymphocyte antibodies. In 19 sera, however, a special type of false positivity was found. These sera reacted strongly with the plates coated with the supernatants of HIV-infected cells but not with those of uninfected H9 cells. Three and two sera showed, respectively, positive immunofluorescence reaction with the HIV-infected, but not with the uninfected, H9 and CEM cells. Reactivity to HIV-infected H9 cells could be adsorbed from a part of these samples with lesser amounts of HIV-infected than uninfected H9 cells. This special type of false positivity was observed frequently (7/65) in patients who rejected a kidney graft. These findings suggest that this type of anti-HIV false positivity is due to antibodies reacting with cellular antigens present in HIV-infected but not in uninfected lymphocytes. Their appearance seems to be associated with the immunological activation occurring at graft rejection.

Blotting, Western↗

PubMedDate not supplied

Differential HIV replication and HIV-induced interferon production in mononuclear phagocytes: relationship to cell maturation.

We have investigated the replication of human immunodeficiency virus (HIV) and HIV-induced interferon (IFN) production in human mononuclear phagocytes at 2 different stages of in vitro maturation. Blood monocytes and monocyte-derived macrophages from 6 healthy, HIV-seronegative donors were challenged with HIV1IIIB and HIV2ROD. Freshly separated monocytes produced IFN when inoculated with both HIV types. In these cultures, an inverse correlation was observed between the amount of IFN production and the rate of HIV replication. In contrast to the monocytes, 5-day-old monocyte-derived macrophages did not produce IFN when challenged with HIV, but a significant replication of HIV1IIIB and HIV2ROD was found in all cultures.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

In vitro interferon and virus production at in vivo physiologic oxygen tensions.

Rhabdomyosarcoma (TE) and cervical carcinoma (MS) cells 24 h previously brought from medium with a PO2 of 18 kilo Pascal (kPa) (ambient air) to PO2 of 6 or 3 Kpa (in vivo physiologic values) were infected with Sendai virus, and the interferon (IFN) and virus production was followed in the ensuing 24 h period. With TE cells the IFN production decreased when moving from 18 to 6 Kpa and ceased completely at 3 Kpa, while the virus production responded inversely. MS cells produced most IFN at the lowest oxygen tension, and virus production was only moderately affected. Growth for three months at the three different oxygen tensions prior to infection reduced the difference in IFN production at the different oxygen tensions. On the same target cells different human virus responded in different ways to the tested oxygen tensions. It is concluded that mimicking the in vivo situations might require primary cultures of virus and cells to be started and passaged at in vivo physiological oxygen tensions.

Carcinoma↗