Escherichia coli administered into pig amniotic cavity appear in fetal airways and attract macrophages into fetal lungs.

Escherichia coli (2 x 10(4) bacteria) of the non-pathogenic O86 strain or enteropathogenic O55 strain were administered into the pig amniotic cavity at 79 to 86 days of gestation for six or ten hours. Translocation of bacteria into fetal lungs was confirmed by cultivation as well as by light and electron microscopy. Infection caused an influx of macrophages that were immunostained in cryostat sections by monoclonal antibody recognizing calprotectin.

Nitric oxide metabolites in gnotobiotic piglets orally infected with Salmonella enterica serovar typhimurium.

Reactive NO metabolites play a distinct role in the control of Salmonella enterica serovar Typhimurium (ST; a facultative intracellular pathogen) in susceptible host. A significant increase of nitrite and/or nitrate plasma levels, 3-nitro-tyrosine expression and pathological changes in mesenteric lymph nodes have been observed in gnotobiotic piglets orally infected for 1 d with a virulent strain of ST but not in piglets infected with a rough mutant of ST.

Cellular changes and cytokine expression in the ilea of gnotobiotic piglets resulting from peroral Salmonella typhimurium challenge.

Two stable rough mutants of Salmonella spp. were studied as live peroral vaccines. The SF1591 mutant of S. typhimurium (Ra chemotype) protected germ-free piglets against subsequent infection with virulent smooth S. typhimurium LT2, whereas a deep-rough mutant of S. minnesota mR595 (Re chemotype) did not. We investigated cytokine and leukocyte profiles in the ilea of gnotobiotic piglets colonized for 1 week either with rough mutants alone or with rough mutants followed by S. typhimurium LT2. The ileal mucosae of piglets associated with strain SF1591 alone were not inflamed. Villi contained activated macrophages, and enterocytes expressed transforming growth factor beta (TGF-beta). Subsequent infection of piglets with S. typhimurium LT2 resulted in immigration of alphabeta T cells and immunoglobulin A (IgA) response. In contrast, the ileal mucosae of piglets associated with strain mR595 alone expressed heat shock proteins and inflammatory cytokines but not TGF-beta. Acellular villi contained numerous gammadelta T cells but no alphabeta T cells. After subsequent challenge with the LT2 strain, most piglets died of sepsis. Intestinal mucosae contained IgG but no IgA. These findings suggest the importance of cytokine signals in the regulation of intestinal responses against Salmonella infection.

Ontogeny of MHC class II antigens in pigs.

Cells constitutively expressing MHC class II antigens have been studied in the course of prenatal development in the Minnesota miniature pig. Frozen sections, cell suspensions and peripheral blood mononuclear cells were examined by using the HL-40 monoclonal antibody cross-reactive with a light chain determinant of the SLA-D molecule (MHC class II porcine antigen). It could be demonstrated that the yolk sac contained cells expressing SLA-D antigens as early as the 24th day, the liver and the spleen on the 39th day of gestation. Splenic cells bearing SLA-D molecules formed periarteriolar structures. Except the spleen, peripheral blood, lymph nodes, bone marrow and intestinal wall were the main sites of SLA-D expression in the perinatal period of the pig.

[Immune cells on the IUD]. / Immunní bunky na IUD.

Cells isolated on the surface of just removed IUD "DANA" were characterized by means of monoclonal antibodies and the avidin-biotin method. Activated macrophages with the membrane sign CD 14 and transferrin receptors (25-72%) and B lymphocytes producing IgA and IgG (14-56%) contained strong transplantation antigens class II. By these glycoproteins macrophages and B cells are able to differentiate alie and thus also paternal antigens. The presence of these cells in the uterus may be the stimulus for triggering an aggressive cytotoxic reaction against the blastocyst and explains the contraceptive action of intrauterine devices.

Expression of MHC class II antigens is modulated by ouabain.

Ouabain enhances a modulation effect of lipopolysaccharide (LPS) on the expression of MHC class II antigens. A similar but lesser effect than that of ouabain, which increases intracellular concentration of sodium ions, has been observed when treating cells with ionophores quercetin which increases [Ca2+]i or valinomycin which increases [K+]i. These findings confirm the role of ion flux in cellular activation and differentiation. Optimal concentration of ouabain is 10(-7) M with 10 micrograms of LPS/ml for human and pig peripheral blood cells. The increase in radioactivity of mononuclear human blood cells after the binding of 125I-anti-MHC class II monoclonal antibody is at the fourth hour of cultivation with LPS and ouabain, the number of immunofluorescently positive cells rises at the twelfth hour. A similar modulation has been observed on pig kidney cell line. It can be concluded that the expression of class II antigens on the plasma membrane can be induced by cumulative effect of LPS and agents alterating ion transport.

Ontogeny of T lymphocytes in the pig.

Mononuclear cells isolated from pig fetal thymus (and thymus region), spleen and cord blood were examined for their reactivity with polyclonal sheep anti-pig T cell antiserum. First immunofluorescence-positive cells were detected after 28 d of gestation in the thymus region, cord blood and the liver.