Biomedical subjects

F Bernadotte

Publications and source records attributed to F Bernadotte.

6 recordsLinked to original sources

PubMed1992

A fraction of murine placental extract enhances IgA production in cultured splenocytes.

During the second half of murine pregnancy there is a characteristic increase in the number of spontaneous immunoglobulin-secreting cells in the maternal spleen (IgM, IgG and IgA), the uterus-draining lymph nodes (IgG) and Peyer's patches (IgA). There are indications that signals originating from the feto-placental unit are of importance for the generation of at least some of these changes. To evaluate further the role of placental factors as regulators of maternal Ig-secretion, placental extract (PE) was separated into eight fractions by gel-chromatography and each fraction was screened for its effect on splenic (1) background DNA-synthesis, (2) background Ig-secretion and (3) Ig-secretion in lipopolysaccharide (LPS) activated B-cells (anti-Thy1.2 + complement-treated splenocytes). Similarly prepared extracts of fetuses, maternal spleen and maternal liver served as controls. All tissue extracts and splenocytes were syngeneic to avoid reaction to allogeneic determinants. Placental extract fractions did not differ significantly from the other tissue extracts in affecting background lymphocyte activity. However, fraction number 3 from placental extract (PE3, corresponding to an approximate molecular weight of 18-70 kDa) was found strongly to increase the number of IgA-secreting cells (P less than or equal to 0.001) in LPS-activated B-cells. This effect was absent or much less pronounced in the corresponding controls. Blocking of PE3-activity by antibodies against rat prolactin indicated that the enhancing activity may be attributed to proteins of the prolactin/placental lactogen/growth hormone family. This assumption was further strengthened by experiments demonstrating that prolactin exerted preferential enhancement of IgA secretion when added to LPS-activated B-cell cultures in vitro. The possible role of placental prolactin-like molecules as regulators of maternal IgA secretion is discussed.

Animals↗

PubMed1991

Placental MHC class I antigen expression is induced in mice following in vivo treatment with recombinant interferon-gamma.

Allogeneically pregnant mice (NFR/N (Swiss-derived) H2q x 57/B1 H2b) were injected daily from day 11 to 18 of gestation with recombinant rat interferon-gamma (IFN-gamma) and the effects on placental MHC antigen expression were evaluated by immunohistochemistry. The results demonstrated that a daily dose of 200,000 U/mouse induces a significant increase in placental MHC class I expression in the decidua and the basal zone spongiotrophoblast as well as the fetal mesenchyme, while the labyrinthine trophoblast was almost completely MHC negative. No significant induction of MHC class II antigen expression was observed in the placental tissue, with the exception of a few scattered cells. The MHC class II-inducing efficiency of the treatment protocol used was ascertained by staining maternal skin (ear), which proved to contain considerably elevated numbers of MHC class II-positive cells (mainly keratinocytes). The IFN-gamma treated group showed a higher incidence of fetal resorptions than the corresponding controls, but this was probably due to a non-specific toxic effect of the treatment as none of the sera analysed contained detectable amounts of anti-paternal antibodies, no infiltrating lymphocytes were detectable on histological examination of placental sections, and most of the IFN-gamma treated animals successfully completed their pregnancy.

Animals↗

PubMed1989

Expression of a cell surface antigen with potential Ca2+-sensor/receptor function in rat placenta and uterus.

The reactivities of monoclonal anti-parathyroid antibodies identifying a cell surface 'calcium sensing' mechanism were investigated in the placenta and uterus of the pregnant rat. The rat placenta showed positively stained cells at the end of pregnancy. Staining was confined exclusively to the columnar epithelial cells lining the sinuses of Duval. In the uterus, positive staining of the epithelium lining the uterine lumen was obtained exclusively prior to and during implantation.

Animals↗

PubMed1988

Allopregnancy in B-cell deprived C57/BL mice--an investigation focusing on the relationship between survival of the fetuses and anti-paternal immune activity of the mothers.

C57/B1 female mice (haplotype H2-b) were treated throughout their life cycles with rabbit anti-mouse IgM antibodies in order to remove all maturing B-lymphocytes. At an age of 40 days the B-cell-deprived mice and the corresponding controls were allowed to mate with CBA/Ca males (haplotype H2-k). Four groups of allopregnant animals were investigated: (A) mice not subjected to further treatment, which were allowed to pass through a first pregnancy, (B) mice not subjected to further treatment, which were allowed to pass through a first and second pregnancy, (C) mice immunized with paternal cells prior to mating and then allowed to pass through a first pregnancy, (D) mice which during their first pregnancy were given transfusions of anti-paternal lymphocytes obtained from hyperimmune virgin donors. All animals were dissected on the calculated day for parturition (or the first day that abortions or resorptions were detected). On conclusion of the experiments, the efficiency of the anti-IgM treatment was defined for each mouse, using three different methods (ELISA for detection of serum IgG, immune staining for detection of surface Ig-carrying cells, and the protein A plaque assay for detection of Ig-secreting cells). The T-cell function was recorded in vitro by ConA responsiveness. In addition, control animals were assayed for anti-paternal serum antibodies. In experiments (A), (B) and (C), B-cell-deprived mice and corresponding controls were equally successful in passing through pregnancy, having fairly similar litter sizes and resorption frequency. In group (D), however, some of the anti-IgM-treated mice resorbed all her fetuses. Those that gave birth at on schedule had a resorption frequency and litter size fairly similar to those of the controls.

Animals↗

PubMed1988

Enhancement of murine splenic immunoglobulin secretion in vitro by supernatants from fetal and placental cell cultures.

Supernatants from short-term cell cultures of fetal and placental tissues of mid-term allogeneically (CBA/Ca x C57/Bl) and syngeneically (CBA/Ca x CBA/Ca) pregnant mice were tested for B-cell enhancing activity in vitro. Immunoglobulin (Ig) secreting cells were detected by the protein-A-plaque assay and DNA synthesis was measured by the incorporation of [3H]thymidine. Supernatants from placental and fetal liver cell cultures (but not fetal fibroblasts) were significantly stimulatory to spontaneous IgM (and to some extent IgG) production in a system using adult untreated spleen cells as target cells. Conditioned media were also added to LPS- and PHA-activated spleen cell cultures. In this system none of the supernatants affected the development of Ig secretors. The DNA synthesis of the target cells was slightly depressed by the addition of conditioned medium from fetal and placental cells. The results indicate that the typical increase in the number of maternal splenic Ig secretors observed in vivo during murine pregnancy could be the result of enhancing factors deriving from the placenta and the fetus (e.g. fetal liver).

Animals↗

PubMed1988

An investigation of allogeneic pregnancy in multiparous mice subjected to in vivo depletion of CD8 (Ly2)-positive lymphocytes by monoclonal antibody treatment.

Adult thymectomized C57/Bl (H-2b) and DBA/1 (H-2q) female mice were subjected to treatment with rat anti-mouse CD8 and mouse anti-rat Ig (kappa) prior to entering their third pregnancy with CBA/Ca (H-2k) males. The treatment protocol drastically reduced the number of CD8 (Ly2)-carrying lymphocytes (T-cytotoxic/suppressor phenotype) in the spleen and para-aortic lymph nodes, as assessed by immuno-staining. All mice were investigated on day 18 of their third gestation. The following data were collected from experimental and control groups: (1) resorption frequency, (2) weight of the placenta, fetuses, spleen and para-aortic lymph nodes, (3) immunohistochemical analysis of maternal lymphoid tissues, (4) level of anti-paternal IgG serum antibodies, (5) content of "background" IgM and IgG-secreting cells in spleen and para-aortic lymph nodes. Neither the resorption frequency nor placental/fetal weight was affected by anti-CD8 treatment. However, the formation of anti-paternal antibodies was enhanced in anti-CD8 treated C57/Bl mice.

Animals↗