Biomedical subjects

F W Bazer

Publications and source records attributed to F W Bazer.

At least 55 records · Page 3Linked to original sources

PubMed1999

Nematode burdens and cellular responses in the abomasal mucosa and blood of Florida Native, Rambouillet and crossbreed lambs.

This experiment was carried out to compare the worm burden and cellular responses in the abomasal mucosa and blood of Florida Native and Rambouillet lambs and also in animals produced by crosses of these two breeds (generations F1 and F2). Animals were exposed to infection by gastrointestinal nematodes on three different occasions. The first infection was natural, occurring while they were suckling lambs. After weaning, they were kept indoors for 53 days and then were allowed to graze a contaminated pasture for 50 days for a second natural infection. The third infection was an artificial challenge with 6000 Haemonchus contortus infective larvae. The highest mean fecal egg counts (FEC) values were found in Rambouillet lambs followed in decreasing order by F1, F2 and Florida Native lambs. Throughout the trial, most of the high mean packed cell volumes and plasma protein levels were recorded in the F2 lambs; in contrast, most of the low values were found in the Rambouillet lambs. During the natural infection period, the highest percentages of larvae in the fecal cultures of the lambs were Haemonchus. However, high percentages of Trichostrongylus larvae were found particularly in Florida Native lambs. The mean number of blood eosinophils increased after the artificial challenge, reached a peak 21 days after infection and then declined. The highest and lowest blood eosinophil means were recorded in F2 and Florida Native lambs, respectively. The H. contortus burden was significantly higher in Rambouillet and in F1 lambs than in Florida Native and F2 lambs (p < 0.05), while no significant differences were recorded among eosinophil, mast cell and globule leucocyte counts in the abomasal mucosa (p > 0.05). The highest correlation coefficient recorded at the end of this study was between FEC and worm burden (r = 0.7). These two parameters showed a moderate negative correlation with PCV, plasma protein and mast cell counts in the abomasal mucosa. The results obtained in this study indicate that crossbreeding Florida Native and Rambouillet sheep can be a rapid way to combine and improve the characteristics of these two breeds. The parasitological results were promising, however, more studies will be necessary to verify the impact of crossbreeding in other traits.

Abomasum↗

PubMed1999

Differential effects of type I IFNs on the growth of WC1- CD8+ gamma delta T cells and WC1+ CD8- gamma delta T cells in vitro.

Type I IFNs have a broad array of immunoregulatory functions that include up-regulation of type 1 immune responses through enhancing differentiation and activation of CD8+ T cells and CD4+ Th1 cells. Ovine trophoblast IFN-tau is a recently described type I IFN with the potential for therapeutic use, based on its potent antiviral activity yet low toxicity. Studies were designed to determine the immunoregulatory effects of IFN-tau on Ag-stimulated T cells, and a novel effect of type I IFNs on gammadelta T cells was observed. In cultures of parasite Ag-stimulated bovine T cells that contained a mixture of alphabeta and gammadelta T cells, both IFN-tau and IFN-alpha suppressed the expansion of WC1+ CD2- CD6- CD8- gammadelta T cells, yet stimulated the growth of WC1- CD2+ CD6+ CD8+ gammadelta T cells and CD8+ alphabeta T cells. The CD8+ gammadelta T cell subset expressed high levels of the IL-2R alpha-chain. Furthermore, we showed that type I IFN enhanced IL-2 production by these Ag-stimulated T cell lines. In short term cultures of PBMC, IL-2 stimulated an expansion of WC1- CD6+ CD8+ gammadelta T cells, which was significantly increased by IFN-tau, even though IFN-tau alone did not support cell survival. These studies demonstrate for the first time that type I IFNs differentially modulate the proliferation of different subsets of gammadelta T cells, which appears to act in part via IL-2.

Animals↗

PubMed1999

Intrauterine infusion of bacterial lipopolysaccharide (LPS) prior to mating has no adverse effect on fertility, fetal survival and fetal development.

Lipopolysaccharide (LPS, endotoxin) is a component of the cell wall of gram-negative bacteria and a potent inducer of severe inflammatory reactions. In mice, systemically administered LPS induces fetal resorption and increases fetal mortality. However, effects of intrauterine LPS on fertility, fetal survival and development have not been reported. In the present study, pigs were used to determine the effect of intrauterine infused LPS on fertility, fetal survival and development. Prior to mating, gilts received intrauterine infusion of either a single dose of saline or increasing doses of LPS in saline using an insemination catheter. On day 30 of pregnancy, gilts were hysterectomized and litter size, fetal length, number of corpora lutea (CL), ovarian and placental weights, and allantoic and amniotic fluid volumes were recorded. Blood progesterone levels from days 10-30 of pregnancy were also determined. Results indicated that intrauterine infusion of LPS had no adverse effects on blood progesterone levels, fertility, fetal survival or fetal development. Intrauterine injection of LPS did cause an increase in fetal weight and amniotic fluid volume (P < 0.05). These results suggest that sperm, oocytes and gametes are tolerant of local LPS challenge and, to some extent, this mechanism protects gametes and conceptuses from maternal response to mating introduced bacteria and their potential endotoxins.

Amniotic Fluid↗

PubMed1999

Upregulation of interleukin-4 and IFN-gamma expression by IFN-tau, a member of the type I IFN family.

Trophoblast interferon-tau (IFN-tau) is a new member of the type I IFN family that is produced in large quantities by the ruminant conceptus. Like other type I IFN, IFN-tau inhibits viral replication and activates natural killer (NK)-mediated cytotoxicity. In mice and humans, type I IFN enhances type 1 T helper (Th) cell responses, but the effects of type I IFN, including IFN-tau, on cytokine expression by bovine Th cells have not been described. The present study determined the effects of IFN-tau on interleukin-4 (IL-4), IFN-gamma, and IL-10 expression by antigen-specific, CD4+ T cell lines derived from cattle immune to either Babesia bovis, Babesia bigemina rhoptry-associated protein-1, or Anaplasma marginale. IFN-tau upregulated IFN-gamma secretion and steady-state levels of IFN-gamma and IL-4 mRNA by cell lines cultured for 3-6 weeks. In contrast, the steady-state levels of IL-10 mRNA were either not changed or inhibited at these times. Similar effects were obtained with human IFN-alpha. Comparison of the quantities of IFN-gamma, IL-4, and IL-10 transcripts in IFN-tau-treated or IFN-alpha-treated cultures revealed that even though IFN-gamma was the predominant cytokine expressed by all T cell lines, both IFN-gamma and IL-4 steady-state transcript levels were upregulated by a comparable degree. Thus, these studies demonstrate that IFN-tau is an immunomodulatory cytokine that promotes enhanced IL-4 and IFN-gamma responses by effector T cells but not, strictly speaking, Thl-biased responses in cattle. These results indicate the potential use of this cytokine as an adjuvant in ruminants to boost cell-mediated immune responses.

Animals↗

PubMed1999

Functional characterization of monoclonal antibodies to interferon-tau.

Interferon tau (IFNtau) produces an array of biological effects, including antiluteolytic, antiviral, antiproliferative and immunomodulatory activities, without the consequent cytotoxicity associated with other type I IFNs. Four anti-IFNtau monoclonal antibodies (MAbs) have been characterized by determining regional epitopes and observation of their effects on IFNtau binding, antiviral and antiproliferative activity. Using an enzyme-linked immunoadsorbent assay (ELISA) developed against six overlapping synthetic peptides representing the entire linear sequence of IFNtau, three antibodies, HL-98, HL-100 and HL-127, were found to react with the carboxy terminal peptide, while HL-129 bound the penultimate amino terminal peptide. Binding studies indicated that MAbs directed against either region could effectively inhibit the binding of alkaline phosphatase labeled IFNtau to cells expressing type I IFN receptors. While only two of the MAbs significantly reversed IFNtau-induced growth inhibition, the antiviral activity of IFNtau was significantly inhibited by MAbs that bound the amino and carboxy termini, confirming the functional importance of these domains in the binding and subsequent activity of IFNtau.

Animals↗

PubMed1999

Amino acid composition of the fetal pig.

Amino acid composition and accretion were determined in fetal pigs obtained from gilts by hysterectomy at d 40-114 of gestation. The whole homogenate of the fetal pig was used for analysis of dry matter, nitrogen and amino acids. Uterine uptake of amino acids was estimated at d 110-114 of gestation on the basis of uterine arteriovenous concentrations. Nitrogen and amino acid accretion in fetal pigs increased more rapidly with gestation than non-nitrogen dry matter. Amino acid nitrogen represented 83-88% of total nitrogen, and arginine was the most abundant nitrogen carrier in fetal pigs at all gestational ages. Amino acid composition changed with gestation, with glycine and hydroxyproline increasing (P < 0.05) markedly and other amino acids (except ornithine and tryptophan) decreasing (P < 0.05) to a lesser extent. Amino acid concentrations in fetal pigs increased (P < 0.05) progressively from d 60 to 114 of gestation. Uterine uptake of arginine and proline plus hydroxyproline met requirements for fetal growth during late gestation only marginally, and uterine uptake of aspartate/asparagine and glutamate was only 9-29% of fetal accretion. In contrast, uterine uptake of citrulline and ornithine was 55- and 15-fold greater (P < 0.05) than fetal accretion, respectively. On the basis of hydroxyproline content, collagen was estimated to represent approximately 7, 15, 25, 28 and 29% of total body protein at d 40, 60, 90, 110 and 114 of gestation, respectively. Amino acid composition of the fetal pig is similar to that for the human fetus, indicating that the pig is an excellent model for studying amino acid nutrition and metabolism in the human preterm neonate and infant.

Amino Acids↗

PubMed1999

Identification and characterization of glycosylation-dependent cell adhesion molecule 1-like protein expression in the ovine uterus.

Glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) is an endothelial glycoprotein secreted in lymph nodes that serves as a ligand for leukocyte cell surface selectin and mediates lymphocyte extravasation. In the present studies, rabbit anti-rat GlyCAM-1 IgG was used in immunochemical analyses of GlyCAM-1-like protein in the ovine uterus. In cyclic ewes, GlyCAM-1 expression increased in the endometrial luminal epithelium (LE) and shallow glandular epithelium (cGE) between Days 1 and 5 and then decreased between Days 11 and 15. In pregnant ewes, GlyCAM-1 in the LE and cGE was low on Days 11 and 13, increased on Day 15, and was abundant on Days 17 and 19. Immunoreactive GlyCAM-1 was also detected in the conceptus trophectoderm on Days 13-19. Staining for GlyCAM-1 in the smooth muscle of the vasculature and myometrium was constitutive, and no staining was detected in the stroma. An immunoreactive protein of approximately 45 kDa was identified in endometrial extracts and uterine flushings from cyclic and pregnant ewes. In pregnant ewes, the relative amount of immunoreactive GlyCAM-1 in uterine flushings was low on Days 11 and 13 but high on Days 15 and 17. Results suggest that a GlyCAM-1-like protein may be a secretory product of the endometrial epithelium and/or conceptus trophectoderm. Patterns of distribution observed for immunoreactive GlyCAM-1-like protein in the endometrial epithelium, combined with proposed functions for lymphoid GlyCAM-1, suggest that this mucin glycoprotein may be involved in conceptus-maternal interactions during the periimplantation period of pregnancy in sheep.

Animals↗

PubMed1999

Expression of the interferon tau inducible ubiquitin cross-reactive protein in the ovine uterus.

Ubiquitin cross-reactive protein (UCRP) is a 17-kDa protein that shows cross-reactivity with ubiquitin antisera and retains the carboxyl-terminal Leu-Arg-Gly-Gly amino acid sequence of ubiquitin that ligates to, and directs degradation of, cytosolic proteins. It has been reported that bovine endometrial UCRP is synthesized and secreted in response to conceptus-derived interferon-tau (IFNtau). In the present studies, UCRP mRNA and protein were detected in ovine endometrium. Ovine UCRP mRNA was detectable on Day 13, peaked at Day 15, and remained high through Day 19 of pregnancy. The UCRP mRNA was localized to the luminal epithelium (LE), stromal cells (ST) immediately beneath the LE, and shallow glandular epithelium (GE) on Day 13, but it extended to the deep GE, deep ST, and myometrium of uterine tissues by Day 15 of pregnancy. Western blotting revealed induction of UCRP in the endometrial extracts from pregnant, but not cyclic, ewes. Ovine UCRP was also detected in uterine flushings from Days 15 and 17 of pregnancy and immunoprecipitated from Day 17 pregnant endometrial explant-conditioned medium. Treatment of immortalized ovine LE cells with recombinant ovine (ro) IFNtau induced cytosolic expression of UCRP, and intrauterine injection of roIFNtau into ovariectomized cyclic ewes induced endometrial expression of UCRP mRNA. These results are the first to describe temporal and spatial alterations in the cellular localization of UCRP in the ruminant uterus. Collectively, UCRP is synthesized and secreted by the ovine endometrium in response to IFNtau during early pregnancy. Because UCRP is present in the uterus and uterine flushings, it may regulate endometrial proteins associated with establishment and maintenance of early pregnancy in ruminants.

Animals↗

PubMed1999

Differential effects of intrauterine and subcutaneous administration of recombinant ovine interferon tau on the endometrium of cyclic ewes.

Interferon tau (IFNtau) is the antiluteolytic signal produced by the conceptus of ruminants. Intrauterine administration of recombinant ovine IFNtau suppresses expression of endometrial estrogen receptor (ER) and oxytocin receptor (OTR) in the luminal and superficial glandular epithelia to abrogate the production of luteolytic prostaglandin F(2alpha) (PGF(2alpha)) pulses. Subcutaneous (s.c.) injections of recombinant ovine (o) IFNtau appear to extend the interestrous interval by altering uterine PGF(2alpha) response to oxytocin. The present study tested the hypothesis that antiluteolytic effects of roIFNtau injected into the uterine lumen (paracrine) or s.c. (endocrine) are equivalent in suppressing expression of endometrial ER and OTR and inducing uterine expression of type I IFN-regulated Mx and ubiquitin cross-reactive proteins (UCRP). Sixteen cyclic ewes were fitted with uterine catheters on Day 5 (Day 0 = estrus), were assigned randomly to receive treatment with control proteins or roIFNtau (2 x 10(7) antiviral units/day) by either intrauterine or s.c. injections from Days 11 to 15, and were ovariohysterectomized on Day 16. Results indicated that expression of ER and OTR mRNAs in endometrial epithelium was suppressed by intrauterine but not by s.c. injections of roIFNtau. Intrauterine injections of roIFNtau increased expression of Mx and UCRP mRNA in the endometrium. Subcutaneous injections of roIFNtau increased endometrial Mx mRNA levels but not UCRP mRNA. Unexpectedly, intrauterine and s.c. injections of roIFNtau were equally effective in inducing expression of Mx and UCRP mRNA in the corpus luteum. Although s.c. injections of roIFNtau induced Mx mRNA in the endometrial epithelium, s.c. injections of roIFNtau did not abrogate activation of the uterine luteolytic mechanism by suppressing epithelial ER and OTR expression. Therefore, results of this study failed to support the assumption that endocrine roIFNtau mimics antiluteolytic effects of paracrine IFNtau to improve pregnancy rates in sheep.

Animals↗

PubMed1999

Ovine osteopontin: I. Cloning and expression of messenger ribonucleic acid in the uterus during the periimplantation period.

Trophoblast-derived interferon tau (IFNtau) acts on the endometrium to increase secretion of several proteins during the pregnancy recognition period in ruminants. One of these is a 70-kDa acidic protein that has not been identified. Our hypothesis was that the 70-kDa acidic protein is osteopontin (OPN). OPN is an acidic glycoprotein that fragments upon freezing and thawing or treatment with proteases including thrombin. OPN contains a Gly-Arg-Gly-Asp-Ser (GRGDS) sequence that binds to cell surface integrins to promote cell-cell attachment and cell spreading. Using antisera to recombinant human OPN, both 70-kDa and 45-kDa proteins were identified in uterine flushings from pregnant ewes by Western blotting. A clone containing the entire ovine OPN cDNA coding sequence was isolated by screening a Day 15 pregnant ovine endometrial cDNA library with a partial ovine OPN cDNA. In pregnant ewes, steady-state levels of OPN endometrial mRNA increased (P < 0. 01) after Day 17. In both cyclic and pregnant ewes, in situ hybridization analysis showed that OPN mRNA was localized on unidentified immune cells within the stratum compactum of the endometrium. In pregnant ewes, OPN mRNA was also expressed by the glandular epithelium. Results suggest that progesterone and/or IFNtau induce expression and secretion of OPN by uterine glands during the periimplantation period and that OPN may induce adhesion between luminal epithelium and trophectoderm to facilitate superficial implantation.

Amino Acid Sequence↗

PubMed1999

Ovine osteopontin: II. Osteopontin and alpha(v)beta(3) integrin expression in the uterus and conceptus during the periimplantation period.

Osteopontin (OPN) is an acidic 70-kDa glycoprotein that is cleaved by proteases to yield 45-kDa and 24-kDa fragments. The 70-kDa and 45-kDa proteins contain a Gly-Arg-Gly-Asp-Ser (GRGDS) sequence that binds to cell surface integrins (primarily alpha(v)beta(3) heterodimer) to promote cell-cell attachment and cell spreading. A 70-kDa acidic protein was previously detected by two-dimensional (2D) PAGE in Day 17 pregnant endometrial cytosolic extracts using Stainsall and identified as immunoreactive OPN using Western blotting. Three forms of immunoreactive OPN proteins (70, 45, and 24 kDa) were detected by 1D PAGE and Western blot analysis of endometrial extracts. OPN protein in endometrial extracts did not differ between cyclic and pregnant ewes. However, the amount of 45-kDa OPN increased in uterine flushings from pregnant ewes between Days 11 and 17. Immunoreactive OPN was localized to luminal and glandular epithelia of both cyclic and pregnant ewes, and to trophectoderm of Day 19 conceptuses. The alpha(v) and beta(3) integrins were detected on Day 19 endometrium and conceptuses by immunofluorescence. It was reported that OPN mRNA increases in the uterine glands of pregnant ewes and secretion of OPN protein into the uterine lumen increases during early pregnancy. The present results demonstrate accumulation of OPN protein on endometrial LE and conceptus trophectoderm. Therefore, it is hypothesized that progesterone and/or interferon-tau induce expression, secretion and/or proteolytic cleavage of OPN by uterine epithelium. Secreted OPN is then available as ligand for alpha(v)beta(3) integrin heterodimer on trophectoderm and uterus to 1) stimulate changes in morphology of conceptus trophectoderm and 2) induce adhesion between luminal epithelium and trophectoderm essential for implantation and placentation.

Animals↗

PubMed1999

Development and characterization of immortalized ovine endometrial cell lines.

The objective of this study was to generate immortalized endometrial epithelial and stromal cell lines from the ovine uterus. Luminal (LE) and glandular epithelial (GE) cells and stromal (ST) cells were enzymatically isolated from the uterus of a Day 5 cyclic ewe (estrus on Day 0), and primary cultures were immortalized by transduction with a retroviral vector (LXSN-16E6E7) packaged by the amphotropic fibroblast line PA-317. Cells having integrated the vector were selected by resistance to the neomycin analogue G418 (0.6-0.8 mg/ml). Surviving cells were maintained in complete culture medium containing G418 (0.1 mg/ml) and subcultured for more than 40 passages. Phase-contrast microscopy revealed that LE and GE cells exhibited a cobblestone morphology whereas immortalized ST cells were spindle shaped. The epithelial origin of LE and GE was confirmed by positive cytokeratin immunostaining, and ST cells were vimentin positive. All cell lines were negative for smooth muscle alpha-actin staining. Western blot analyses of cell extracts revealed the presence of signal transducers and activators of transcription (STAT) proteins 1, 2, and 3. In the LE cells, interferon tau (IFNtau) induced nuclear translocation of STAT proteins 1 and 2 and up-regulated several IFN-inducible genes, including STATs 1, 2, and 3 and ubiquitin cross-reactive protein (UCRP/ISG17). In the LE cell line, IFN regulatory factor one was transiently up-regulated and then down-regulated by IFNtau. Immunostaining revealed the presence of nuclear estrogen receptor and progesterone receptor in all cell lines. These ovine endometrial cell lines provide useful in vitro model systems for the study of hormone and cytokine action, signal transduction pathways, cell-cell interactions, and gene expression in specific cell types of the ovine endometrium.

Animals↗

PubMed1999

Effects of recombinant ovine interferon tau, placental lactogen, and growth hormone on the ovine uterus.

Studies were conducted to determine effects of intrauterine administration of recombinant ovine interferon tau (IFNtau), placental lactogen (PL), and growth hormone (GH) on endometrial function. In the first study, administration of IFNtau to cyclic ewes for one period (Days 11-15) resulted in an interestrous interval (IEI) of approximately 30 days, whereas administration for two periods (Days 11-15 and Days 21-25) extended the IEI to greater than 50 days. Administration of IFNtau from Days 11 to 15 and of PL or GH from Days 21 to 25 failed to extend the IEI more than for IFNtau alone. In the second study, effects of IFNtau, PL, and GH on endometrial differentiation and function were determined in ovariectomized ewes receiving ovarian steroid replacement therapy. Endometrial expression of mRNAs for estrogen receptor (ER), progesterone receptor (PR), and oxytocin receptor (OTR) were not affected by PL or GH treatment; however, uterine milk protein mRNA levels and stratum spongiosum gland density were increased by both PL and GH treatments. Collectively, results indicated that 1) PL and GH do not regulate endometrial PR, ER, and OTR expression or affect corpus luteum life span; 2) down-regulation of epithelial PR expression is requisite for progesterone induction of secretory gene expression in uterine glandular epithelium; 3) effects of PL and GH on endometrial function require IFNtau; and 4) PL and GH regulate endometrial gland proliferation and perhaps differentiated function.

Animals↗

PubMed1999

Discovery and characterization of endometrial epithelial messenger ribonucleic acids using the ovine uterine gland knockout model.

Prolonged exposure of the developing neonatal ovine uterus to a progestin from birth prevents uterine gland development and creates an adult endometrial phenotype characterized by the absence of glandular epithelium, the uterine gland knockout (UGKO) phenotype. This study used endometrium from normal and UGKO sheep to identify messenger RNAs (mRNAs) expressed differentially in the endometrial epithelium using the molecular techniques of mRNA differential display PCR (DD-PCR) and suppression subtractive complementary DNA (cDNA) hybridization (SSH). Sequence analyses of DD- and SSH-identified and cloned cDNAs indicated similarity of some to known mRNAs, including beta-lactoglobulin, alkaline phosphatase, type B and D endogenous sheep retroviruses, gp330/megalin, matrix Gla protein, and others. Other cDNAs were not similar to any known sequences and are considered novel, although some of these match human expressed sequence tags. In situ hybridization analyses of uteri from cyclic and pregnant ewes indicated that all DD-PCR- and SSH-identified mRNAs were expressed in either the endometrial lumenal and/or glandular epithelium, although some were also expressed in other uterine cell types. Northern and in situ hybridization analyses revealed that patterns of mRNA expression for most clones were affected by the day of the estrous cycle and pregnancy in a manner consistent with regulation by progesterone. Studies demonstrate the utility of the ovine UGKO model as a tool with which to identify known and novel uterine epithelial-specific genes. Cloned cDNAs identified here are expressed sequence tags useful for comparative and physical genetic mapping and may be used to reveal new factors and pathways regulating endometrial function.

Animals↗

PubMed1999

Uterine differentiation as a foundation for subsequent fertility.

Uterine differentiation in cattle and sheep begins prenatally, but is completed postnatally. Mechanisms regulating this process are not well defined. However, studies of urogenital tract development in murine systems, particularly those involving tissue recombination and targeted gene mutation, indicate that the ideal uterine organizational programme evolves epigenetically through dynamic cell-cell and cell-matrix interactions that define the microenvironmental context within which gene expression occurs and may ensure adult tissue stability. In the cow and ewe, transient postnatal exposure of the developing uterus to steroids can produce immutable changes in adult uterine tissues that may alter the embryotrophic potential of the uterine environment. Thus, success of steroid-sensitive postnatal events supporting uterine growth and development can dictate the functional potential of the adult uterus. Studies to determine effects of specific steroidal agents on patterns of uterine development during defined neonatal periods, as well as the functional consequences of targeted neonatal steroid exposure in the adult uterus, should enable identification of critical developmental mechanisms and determinants of uterine integrity and function. Extreme adult uterine phenotypes (lesion models) created in cattle and sheep by strategic postnatal steroid exposure hold promise as powerful tools for the study of factors affecting uterine function and the rapid identification of novel uterine genes.

Animals↗

PubMed1998

Endometrial connexin expression in the mare and pig: evidence for the suppression of cell-cell communication in uterine luminal epithelium.

This investigation examines the relationship between implantation strategy and gap junction protein expression in uterine endometrium. The pattern of gap junction and connexin protein expression was analyzed in porcine and equine endometrium from cycling and pregnant animals using electron microscopy and immunocytochemistry. Functional analysis of cell-cell communication was also monitored by laser cytometry in primary cultures of endometrial epithelial cells. Gap junctions were detected in endometrial stroma of cycling and pregnant animals, which was correlated with immunoreactive Cx43 within stromal fibroblasts and vascular elements. No Cx26, Cx32, or Cx43 immunostaining was detected in luminal endometrial epithelium in either the mare or the pig at any stage of the estrous cycle or pregnancy. In contrast, endometrial glands of the mare exhibited a spatiotemporal pattern of Cx43 expression in the apicolateral plasma membrane which, when present, colocalized with the tight junction-associated protein, ZO-1. Uterine glandular Cx43 expression in mares was present from day 3 postovulation through day 14 of diestrus and until day 23 of pregnancy, whereas Cx43 was absent within uterine glands during seasonal anestrus, estrus, and after day 30 of pregnancy. Primary cultures of equine endometrial epithelial cells expressed both immunoreactive Cx43 and significant gap junction-mediated intercellular communication (GJIC) which was rapidly upregulated by 1.0 mM 8-bromo-cAMP or blocked with 1.0 mM octanol. No GJIC or connexin protein was detected in cultured porcine epithelial cells despite incubation with a variety of agents, including 8-bromo-cAMP, steroid hormones, retinoic acid, and/or prolactin. Junctional communication in endometrial epithelium of domestic farm animals is different than that reported for species exhibiting invasive implantation. The absence of GJIC in uterine luminal epithelium of the gilt and mare may be involved in limiting trophoblast invasiveness.

Animals↗

PubMed1998

Structural responses of pulmonary intravascular macrophages in lentivirus-infected and/or recombinant ovine interferon-tau-treated lambs.

Ovine lentivirus (OvLV), a retrovirus, infects and disseminates to various tissue organs via monocytes. The differentiation of infected monocytes into macrophages is a prerequisite for viral replication, and the presence of infected macrophages in tissue organs induces chronic immunopathology such as lymphoid interstitial pneumonia. The pulmonary intravascular macrophage (PIM) is a recently identified mononuclear phagocyte in domestic animal species, including sheep. Recombinant ovine interferon-tau (roIFN-tau), a type I IFN originally named as the ovine trophoblast protein, has potent antiviral activity against OvLV and human immunodeficiency virus and prevents the development of OvLV-associated lung pathology. We investigated and compared the structural features of PIMs in OvLV-infected and/or roIFN-tau-treated 1-month-old lambs using transmission electron microscopy. The PIMs' numerical counts were performed in toluidine blue-stained sections of Epoxy-embedded lung tissues. A reduction in the number of PIMs was observed with OvLV infection and/or roIFN-tau treatment of lambs as compared to the control group (P < or = 0.05). The majority of the PIMs in OvLV-infected and/or roIFN-tau-treated groups were devoid of their surface coat. The PIMs of OvLV-infected lambs exhibited signs of biosynthetic activation such as expanded rough endoplasmic reticulum, prominent Golgi complexes, and accumulation of secretory vesicles. A few PIMs contained OvLV-like structures. In roIFN-tau-treated OvLV-infected lambs, the lymphocytes had ruffled plasma membranes and were in intimate contact with the PIMs, as is observed during cytotoxic cell-mediated killing of target cells. Most of the PIMs in roIFN-tau-treated OvLV-infected lambs appeared smaller in size. Ovine lentivirus and roIFN-tau, individually or in combination, alter the integrity of the surface coat of PIMs and cause their disappearance from the lungs. Ovine lentivirus infection induces morphological changes that correlate with cytotoxic cell behavior between lymphocytes and PIMs in roIFN-tau-treated or placebo-treated lambs. The loss of PIMs, probably infected with OvLV, either through direct killing by roIFN-tau or indirectly by roIFN-tau-activated cytotoxic T lymphocytes may represent different aspects of therapeutic actions of this cytokine.

Animals↗

PubMed1998

Trophoblast IFN-tau differentially induces lymphopenia and neutropenia in lambs.

Type I interferons (IFN), including IFN-alpha and IFN-beta, cause severe lymphopenia, resulting from altered lymphocyte recirculation and redistribution. IFN-tau, a product of trophectoderm of ruminant conceptuses and new member of the type I IFN family has not been examined for its effect on leukocyte recirculation. Additionally, differential effects of type I IFNs on the redistribution and recirculation of subsets of T cells have not been reported. The present study determined the effects of IFN-tau on the redistribution and recirculation of ovine leukocytes and T cell subsets. Total peripheral blood leukocytes, lymphocytes, and segmented neutrophils were reduced (p < 0.05) following treatment of lambs with IFN-tau. Furthermore, administration of IFN-tau caused an acute, differential reduction in peripheral blood CD4+ T cells (p < 0.05), CD5+ cells (p < 0.05), and gammadelta TCR+ (p < 0.01) T cells but had no effect on CD8+ T cells (p > 0.05). IFN-tau reduced the percentage of gammadelta T cells by 8-fold and that of CD4+ T cells and CD5+ cells by <2-fold in peripheral blood when compared with control lambs. The reduction in leukocytes, lymphocytes, and neutrophils was observed as early as 6-12 h after administration of IFN-tau, but levels returned to control values within 48 h. These results indicate that IFN-tau, like other members of the type I IFN family, can have immediate effects on leukocyte recirculation and redistribution. The present study is the first to demonstrate that IFN-tau differentially regulates T cell recirculation with the greatest effect on gammadelta TcR+ T cells.

Analysis of Variance↗