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B A Croy

Publications and source records attributed to B A Croy.

At least 73 records · Page 4Linked to original sources
PubMed1993

Granulated metrial gland cells: a natural killer cell subset of the pregnant murine uterus.

The metrial gland develops in the uterus of many rodent species during normal pregnancy. It is a maternally-derived tissue that contains stromal and vascular elements plus a population of large cells, striking in their light microscopic appearance due to the presence of numerous cytoplasmic granules. These cells, which have become known in mice and rats as granulated metrial gland (GMG) cells, are derived from bone marrow precursors and recent work suggests they are a subset of lymphocytes belonging to the natural killer (NK) cell lineage. The functions of GMG cells during normal gestation have not been clearly defined. In vitro, GMG cells have been shown to produce cytokines and their cytokine profile is altered upon addition of medium containing the T cell growth factor interleukin-2 (IL-2). GMG cell granules contain the cytolytic protein perforin but GMG cells have a very limited capacity to kill in vitro unless they have been stimulated by IL-2 or interferon-gamma. Histological study of GMG cells has suggested they preferentially associate with fetal trophoblast. Since trophoblast appears resistant to immune lysis, except by IL-2-activated effector lymphocytes, and because resorbing murine embryos become infiltrated by lytic cells of the NK cell lineage, it is important to establish whether GMG cells are activated by pregnancy-associated events to play a major lytic role in vivo.

Animals↗
PubMed1993

Antitumor response independent of functional B or T lymphocytes induced by the local and sustained release of interleukin-2 by the tumor cells.

Transfection of tumor cells with a vector containing the entire coding sequence of human interleukin-2 (hIL-2) was previously shown to convert the tumorigenic murine fibrosarcoma line CMS-5 into a non-tumorigenic line. The failure of the IL-2-secreting tumor to grow in conventional (immunocompetent) mice was attributed to the activation of CD8+ T cells that exhibited tumor specificity and memory. In order to determine whether or not the IL-2 produced by the tumor may be activating tumor cytotoxic effector cells other than B or T cells we have repeated this study using immunodeficient SCID and SCID-beige mice as syngeneic tumor recipients. In contrast to the rapid growth of the wild-type tumor, the hIL-2-transfected cells (N2A/IL2/CMS5) did not grow, or grew more slowly and regressed, in the mice that lack functional B and T cells. The inhibition of tumor growth associated with the local release of IL-2 was reversed in mice treated with antiasialo-GM1 antibodies specific for natural killer (NK) lineage cells. In contrast to the studies with conventional mice, the IL-2-dependent effector cells in the immunodeficient mice exhibited no evidence of memory. In vitro analysis of spleen cells from tumor-bearing mice revealed the presence of effector cells able to lyse YAC-1 target cells as well as the wild-type CMS-5 and the IL-2-transfected variant tumor lines but unable to lyse P815 cells. The pattern of selective target cell killing and the kinetics of killing were indistinguishable from those observed using tumor necrosis factor alpha (TNF alpha) the mediator associated with natural cytotoxicity cell killing of tumor cells. Histopathology of the IL-2-secreting tumors in SCID mice reveals the presence of infiltrating lymphoid cells and macrophages that were not observed in the CMS-5 tumors. Consistent with the notion that the tumor killing in the SCID mice was mediated by TNF alpha, mice bearing IL-2-secreting tumors had elevated levels of serum TNF alpha and little or no effector cell activity, or TNF alpha was found in tumor-bearing mice treated with anti-asialo-GM1 antibody. The results indicate that the cytokine-induced tumor regression observed in the IL-2-transfected tumors is a more complex phenomenon than previously recognized and one that is mediated by effector cells of the NK cell and/or monocyte/macrophage lineages, in addition to CD8+ T cells.

Animals↗
PubMed1993

Elevated endometrial natural killer cell activity during early porcine pregnancy is conceptus-mediated.

This study investigated an extended time course of endometrial NK cell activity during gestation and the mechanisms underlying changes in uterine NK cell activity in pigs. Endometrial tissues were collected from cyclic, pseudopregnant and pregnant nulliparous pigs on various days post-estrus, and from pigs 10 days after insemination with seminal plasma or killed spermatozoa. NK effector cells were isolated from each endometrial sample, size fractionated and tested for cytolytic activity against NK target cells (K562) using chromium release assays and immunocytochemically for the frequency of perforin-positive cells. Various cell fractions showed different levels of NK activity and had different proportions of cells expressing perforin. Morphologically, cells in the fraction with maximal NK activity almost all showed typical lymphocyte size and shape. Substantially elevated NK cell activity was recorded in pregnant pigs on days 10 and 20 of gestation. By day 30, the cytolytic activity declined dramatically to an almost undetectable level. Very little activity was found in uterine cells isolated from cyclic, pseudopregnant, and seminal plasma or killed spermatozoa inseminated animals, and no differences were detected either between follicular and luteal phases of the estrous cycle or between different days of pseudopregnancy. These results indicate that elevated NK cell activity during early porcine pregnancy cannot be attributed to contributions from either the maternal systemic endocrine status or from components of boar semen. The changes in NK cell activity observed in porcine endometrial tissues during early pregnancy must therefore be associated with the actual presence of conceptuses.

Animals↗
PubMed1993

An immunohistologic analysis of murine uterine T cells between birth and puberty.

Murine uterine T cells were analysed on the basis of surface phenotype expression from birth to adulthood. T cells were rare in the uterus from birth until 2 weeks of age. In genetically immunocompetent mice, mature T cells expressing either TCR alpha/beta or TCR gamma/delta were first present as a major cell population at 3 weeks of age. The ratio of TCR alpha/beta to TCR gamma/delta was 1:1 at 3 weeks of age and this ratio did not change during sexual maturation. Almost all uterine T cells were CD8+ and the majority of these cells expressed CD8 alpha/beta rather than CD8 alpha/alpha. Cells expressing Thy1.2 were less frequent than cells expressing CD3 while cells expressing CD5 were rare. No major changes in T cell subsets occurred at puberty. Further, the microbial flora of the mice did not alter the time of appearance, frequency or subset distribution of uterine TCR+ cells. In the uteri of immunodeficient mice of genotype scid/scid TCR+ cells were found in low numbers and the initial appearance of TCR+ cells was delayed until 5 weeks of age.

Animals↗
PubMed1993

Demonstration of equine immunoglobulin in sera from severe combined immunodeficiency/beige mice inoculated with equine lymphocytes.

Peripheral blood lymphocytes were isolated from four normal adult horses on Ficoll-Hypaque density gradients for intraperitoneal inoculation into 16 C.B-17 severe combined immunodeficiency/beige mice in an attempt to create a xenogeneic lymphoid chimera for modeling the equine immune system. The recipient mice had been preconditioned by prior exposure to 200 cGy of gamma irradiation. The mice were monitored for the presence of equine IgG using an ELISA technique. Equine IgG was detected in the sera of 91.7% of murine recipients and in at least one mouse inoculated from each donor horse. The levels of IgG detected in the mice ranged from 2 micrograms ml-1 to over 1000 micrograms ml-1 and showed steady decline from the time of inoculation to the end of the trial. The half-life of equine IgG in the SCID/beige mouse was determined to be 12.1 days by the intravenous injection of 9.1 mg of semi-purified equine IgG into 21 normal SCID/beige mice and taking serial blood samples to obtain the decay curve. The half-life of equine IgG was compared with the extinction curve obtained for the engrafted mice and showed that continuous production within the mice must have been occurring since the slopes of the two lines were different. These results are compared with those achieved in equine PBL-SCID/beige chimeras not preconditioned by irradiation and to those achieved in human and bovine PBL-SCID chimeras.

Animals↗
PubMed1993

A study on the engraftment and trafficking of bovine peripheral blood leukocytes in severe combined immunodeficient mice.

Bovine lymphoid cells were engrafted into untreated and into sublethally irradiated scid/scid mice, following intraperitoneal (i.p.) injection of bovine peripheral blood leukocytes (PBL). To distinguish bovine from murine cells, bovine PBL were stained prior to i.p. injection with a fluorescent cell linker compound, PKH26-GL and, after cell recovery, labelled with a monoclonal antibody (mAb) reactive with the bovine pan leukocyte cell surface marker, CD45, and analyzed by flow cytometry. This dual labelling system was used to monitor tissue localization and migration of bovine cells within PBL-SCID-bo from 30 min to 64 days after bovine PBL injection. Inoculated bovine PBL were rapidly cleared from the peritoneal cavity of PBL-SCID-bo over the first 24 h after injection, then bovine cell numbers within the peritoneal cavity increased gradually over the next 35 days. No bovine cells were observed in the peritoneal wash from either non-irradiated or irradiated mice after Day 56. Bovine cells were detected in the spleens of both non-irradiated and irradiated mice 12-14 days after inoculation, but were undetectable in non-irradiated and irradiated mice after Day 56, and in irradiated mice after Day 35. This decrease coincided with a significant reduction in both the numbers of bovine cells in the peritoneal cavity, and in the levels of bovine Ig detected in the sera. Bovine IgG and bovine IgM were detected in both normal and irradiated PBL-SCID-bo by 4 days after PBL injection, and remained detectable to 8 weeks after inoculation. T-cells appeared to be the predominant bovine cell population in the spleens. In a small proportion of both normal and irradiated PBL-SCID-bo, spleens three to 20 times the size of a normal SCID mouse spleen were observed. Relatively high levels of bovine cells were detected in the thymuses of some irradiated PBL-SCID-bo. Sporadic, low levels of bovine cells were observed in the mesenteric lymph nodes, peripheral blood, and kidneys of normal and irradiated mice, and in the lungs and livers of non-irradiated but not irradiated PBL-SCID-bo. Sublethal gamma irradiation of SCID recipients appeared to enhance engraftment of bovine cells into the murine spleen and thymus.

Animals↗
PubMed1993

Murine trophoblast failure and spontaneous abortion.

PROBLEM: Infection has been proposed to initiate abortion, and the role of viruses in spontaneous resorption in mice has not been tested. METHOD: The anti-viral drug ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) was fed to CBA/J and C3H/HeJ female mice beginning on the morning after mating with DBA/2J males. RESULTS: Ribavirin treatment increased the rate of abortion (resorption) on day 13.5, and this was associated with retardation of the rate of embryo development and hypoplasia of the trophoblast. There was a reduction in trophoblast-dependent decidua-associated soluble suppressor activity, but there was no maternal mononuclear cell infiltrate of the type reported in association with resorption of semiallogeneic and xenogeneic mouse embryos. This may be due to an immunosuppressive effect of ribavirin. Ribavirin was able to potently suppress proliferation of mouse trophoblast and mastocytoma cell lines in vitro. CONCLUSIONS: There are several drug-induced murine abortion models that provide useful insights into potential mechanisms underlying spontaneous pregnancy failure, but in the ribavirin mode, a direct impairment of trophoblast development appears to be responsible.

Abortion, Spontaneous↗
PubMed1993

Branhamella catarrhalis pathogenesis in SCID and SCID/beige mice. Brief report.

SCID and SCID/beige mice were used to study the pathogenesis of B. catarrhalis administered by intranasal, intraperitoneal or intravenous routes. Challenged adult animals did not appear overtly clinically ill. Similar symptoms were observed regardless of the challenge route, and pretreatment of mice with human transferrin did not enhance clinical virulence. Susceptibility to B. catarrhalis appeared to be age-dependent as some mice under one week of age died following challenge. Postmortem findings included circumscribed pale foci on the liver, splenomegaly and mineralization of the myocardium. Presence of lesions did not correlate with the assessment of clinical well being, and severity of the lesions was found to be challenge strain-dependent. Liver lesions and splenomegaly were not observed in animals challenged with heat-killed bacteria or placebo. SCID/beige mice were more affected than SCID mice both clinically and pathologically, suggesting that natural killer cell and polymorphonuclear cell functions may be important in resolving B. catarrhalis challenge.

Animals↗
PubMed1993

The application of scid mouse technology to questions in reproductive biology.

Mice expressing the scid gene have been used to study major questions in the field of reproductive immunology. Transfer of Mus caroli embryos to the uteri of pseudopregnant scid/scid mice disproved the hypothesis that antigen-specific immune rejection of fetuses was occurring in this model of midgestational pregnancy failure. The results of breeding studies of mice having the scid/scid.bg/bg genotype suggested that uterine lymphocytes have little or no role in promoting embryonic survival under pathogen-free conditions. Further, the results of in vitro studies using uterine lymphocytes from these immunodeficient mice suggested that the cytokines important for pregnancy success were not lymphocyte-derived. Xenogeneic engraftment of embryonic and uterine tissues into scid/scid and scid/scid.bg/bg mice is also successful and has the potential for facilitating studies of the fetomaternal interface in domestic animal species, such as cows and horses, as well as in humans.

Abortion, Veterinary↗
PubMed1993

The study of human neoplastic disease in severe combined immunodeficient mice.

Experimental models of human neoplastic diseases are used in attempts to reconstruct events that occur in patients with cancer. Although in vitro systems provide a wealth of information about the cellular and molecular biology of tumor cells, they are inadequate for studies that address the complexities of human neoplasia pertaining to metastasis, experimental therapeutics, and immunity. Since the late 1960s, athymic nude mice have provided an opportunity to study the growth and, in some cases, the metastasis of xenografted human tumors in vivo. Recently, the availability of severe combined immunodeficient (scid) mice has provided an alternative model for studying human malignancies and has led to numerous reports of its distinct advantages over nude mice. When direct comparisons have been made, it has often been apparent that human tumors grow better and are more likely to metastasize in scid mice than in nude mice. Indeed, some human tumors which have never before been propagated in vivo will engraft in scid mice. Furthermore, the unique capability of scid mice to support human immunocompetent cells offers the potential to study the human immune response to tumors. This article outlines the current progress toward defining and using scid mice in models of human neoplastic disease. Characteristics which distinguish scid mice from nude mice are emphasized and a discussion of future prospects is included.

Animals↗
PubMed1992

A study of granulated metrial gland cell differentiation in pregnant, macrophage-deficient, osteopetrotic (op/op) mice.

A population of uterine natural killer (NK) cells, commonly called granulated metrial gland (GMG) cells, differentiates in the mouse uterus during normal pregnancy. Little is known regarding the process of differentiation of GMG cells or of other NK cell subsets. It has been suggested that macrophage precursors, under the combined influences of the cytokine growth factors colony stimulating factor-1 (CSF-1) and interleukin-2, become NK-cell like in morphology, pattern of target cell lysis and surface antigen phenotype. Mice expressing the mutation osteopetrosis (op/op) are unable to produce the cytokine CSF-1. To determine whether CSF-1 is required for the successful differentiation of uterine NK cells, implantation sites in pregnant, op/op mice were studied histologically. GMG cell differentiation appeared to progress normally in op/op mice studied between days 7 and 14 of gestation. Thus, the growth factor CSF-1 is not required for differentiation of the uterine NK cell subset known as GMG cells and probably GMG cells do not differentiate from macrophage precursor cells which are deficient in op/op mice.

Animals↗
PubMed1992

Granulated metrial gland cells in the pregnant uterus of mice expressing the collagen mutation tight-skin (Tsk/+).

Influences of the extracellular matrix (ECM) on the differentiation and distribution of granulated metrial gland (GMG) cells, a uterine natural killer (NK)-like cell subset, were studied by histological examination of implantation sites in the mouse mutant Tsk/+. Tsk/+ mice overproduce collagens I and III. GMG cell differentiation appeared to progress normally in Tsk/+ mice between days 6.5 and 12.5 of gestation. The distribution of GMG cells, however, was abnormal. Significant numbers of GMG cells were found in the antimesometrial and lateral decidual regions at day 8.5 of gestation and in the regions between implantation sites until day 10.5 of gestation. Loss of GMG cells from these regions normally occurs by day 6.5 of gestation. These data suggest that alterations to the ECM change the migration properties or life span of GMG cells.

Animals↗
PubMed1992

Engraftment of severe combined immune deficient/beige mice with bovine foetal lymphoid tissues.

To develop a model of bovine thymus and lymph node growth in vivo, we have implanted bovine foetal tissues (16-23 weeks gestation) under the renal capsule of severe combined immune deficient (SCID)/beige (BG) mice and assayed for graft growth and characteristics 2-18 weeks after engraftment. Bovine foetal thymus and lymph node grew considerably following engraftment of SCID/BG mice. Growth was optimal if bovine foetal tissues were used before gestation Week 17. Bovine-mouse chimerism was confirmed using glucose phosphate isomerase analysis. Bovine thymus grew during the entire 18 weeks of study. Growth of bovine lymph node was initially rapid, reaching a maximum at 2 weeks after transplantation followed by a progressive decrease in size. Transplanted bovine lymph node and thymus were morphologically similar to age-matched bovine foetal tissue for a limited time period. Fibrosis, degeneration and depletion of lymphocytes were evident 6 weeks after engraftment; changes were more severe in lymph node than in thymus whereas increases in lymphocytes, lymphopoiesis and follicle formation were evident in age-matched bovine foetal tissue. Despite growth and morphological similarities of the transplanted tissue, blood counts suggested there was no peripheralization of bovine leucocytes. Bovine immunoglobulins (IgG1 and IgG2) were detected in serum of some SCID/BG chimeric mice for a limited time. The appearance of bovine immunoglobulins at 2 weeks in SCID/BG chimeric mice depended on the age of the foetal donor (> 18 weeks) and coincided with the appearance of morphologically mature lymphocytes in the donor foetus lymph nodes. The ability to produce bovine immunoglobulins decreased 8 weeks after engraftment, coinciding with the depletion of lymphocytes in the engrafted lymph node. Lymphocyte depletion and loss of function of engrafted tissues appear the result of a lack of lymphoid progenitors normally derived from hematopoietic stem cells in the bone marrow.

Animals↗
PubMed1992

Histological assessment of the mouse uterus from birth to puberty for the appearance of LGL-1+ natural killer cells.

The appearance of natural killer (NK) cells during growth and maturation of the murine uterus was studied by immunohistochemistry, using the monoclonal antibody LGL-1. To determine the contributions of microorganisms in the environment and of T-cell and B-cell regulation to the establishment of a uterine NK cell population, uteri from barrier-raised, flora-defined, random-bred CD-1 mice and from genetically T-cell- and B-cell-deficient SCID mice (genotype C.B-17 scid/scid) were compared to uteri from conventionally raised CD-1 mice. Uteri were studied from birth to the ages at which these mice are normally paired for mating (7-10 wk). Absolute uterine weight and the ratio of uterine weight to body weight increased remarkably between 3 and 5 wk of age in each group of animals. Growth continued beyond Week 5 of age, and in all groups the ratio of uterine weight to body weight was similar at puberty, although both the flora-defined CD-1 and SCID mice were significantly smaller than conventionally reared mice. LGL-1+ cells could not be detected in any of the neonatal uteri examined. LGL-1+ cells were first detected at 2 wk of age in uteri from the conventional and flora-defined CD-1 mice. A significant increase in the number of LGL-1+ NK cells occurred in the CD-1 uterus between Weeks 2 and 3 of age and again between Weeks 5 and 7 of age. Environmental conditions did not alter the frequency of LGL-1+ cells between the two groups of CD-1 mice at any age studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

The effect of experimental infection with Rhodococcus equi on immunodeficient mice.

To investigate the pathogenesis of respiratory lesions caused by the facultative intracellular pathogen, Rhodococcus equi, pulmonary clearance was compared in four groups of genetically defined mice, chosen for their specific deficits in immune and inflammatory responses. Complement-deficient A/J, immunodeficient nu/nu (nude), scid/scid.bg/bg (SCID/beige), C57BI/6J.bg/bg (beige) and normal Swiss mice (SW) received approximately 10(7) R. equi intranasally on day 0. Bacterial clearance was assessed in lung, liver and spleen on days 1, 4, 7 and 14. Pulmonary clearance was not significantly different between SW and A/J mice. Beige mice cleared R. equi more rapidly and completely than A/J and SW, indicating that deficits in phagocytic and NK cell function associated with the bg/bg gene did not compromise clearance. Pulmonary clearance in immunodeficient SCID/beige mice paralleled that of the SW and A/J mice initially but bacterial proliferation produced significant differences from SW mice at day 14. Nude mice were unable to clear R. equi from day 1, resulting in the death of two nude mice at day 11. Both SCID/beige and nude mice developed severe pyogranulomatous bronchopneumonia, whereas A/J and SW mice developed transient pulmonary lesions. Beige mice developed minimal lung lesions. Significant systemic bacterial proliferation occurred only in nude and SCID/beige mice. We conclude that deficiencies in complement components, phagocytic and NK cells do not impair the pulmonary clearance of R. equi but that a competent cellular immune system is required to prevent pneumonia and death. The difference in early phase pulmonary clearance in nude and SCID/beige mice indicates two phases are important for clearance. An acapsular mutant of R. equi was completely cleared from the lungs of SCID/beige mice suggesting an important role for the capsule in virulence for mice.

Actinomycetales Infections↗