Biomedical subjects

H Salmon

Publications and source records attributed to H Salmon.

At least 55 records · Page 3Linked to original sources

PubMed1990

Histocompatible miniature, boar model: selection of transformed cell lines of B and T lineages producing retrovirus.

A lymphoblastoid cell line (B1) was isolated in culture following a brief exposure to 5-azacytidine from peripheral-blood mononuclear cells of a boar previously injected with cells (Shimozuma) producing porcine retrovirus (Tsukuba-1) and suffering a severe non-neoplastic syndrome at autopsy. B1 cell line and 5 of its sublines were propagated for more than 100 generations, retaining doubling times comprised between 16.8 and 27.5 hr and growing readily in agarose or agar (plating efficiency: 5 to 50%). Karyotype analyses showed that 4 sublines were nearly diploid, except for cells of L14, which displayed a monosomy affecting chromosome 18 pair. Two sublines (L35 and L45) were considered as being of T-cell lineage, since MSA, antigen was observed on the surface of approximately 30% of cells. Three sublines (L23, L14 and L52) were considered of B-cell lineage, since membrane immunoglobulins were observed on the cell surface. In addition, sublines L23 and L52 were actively secreting immunoglobulin of mu isotype. Retrovirus particles were evidenced in gradient-purified preparation of 200-fold-concentrated cell culture supernatants of the B1 cell line, L14, L35 and L52 sublines, using both a reverse transcriptase activity assay and electron microscopic observation. These cell lines can be used to select for porcine retrovirus variants with transforming potential for lymphocytes of B and T lineages.

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PubMed1990

Kinetics of the in vitro antibody response to transmissible gastroenteritis (TGE) virus from pig mesenteric lymph node cells, using the ELISASPOT and ELISA tests.

A method is described for in vitro studies of viral humoral immune responses in the pig. After oral immunization with transmissible gastroenteritis (TGE) coronavirus, antibody production from primed mesenteric lymph node cells was revealed by an in vitro boost with viral antigen. For the latter the leukocytes were co-cultured with UV-inactivated virus using a variety of different methods of antigenic stimulation. Enumeration of specific antibody-secreting cells (ASC) and titration of secreted anti-virus antibodies were performed with ELISASPOT (using 3-amino 9-ethyl carbazole as the peroxidase chromogen) and ELISA tests respectively, according to the Ig isotype. The results showed a close relationship between ASC numbers and secreted antibody titres. The best in vitro antibody synthesis was observed when the sensitized cells were maintained in contact with virus during the whole culture period. Antibody responses were defined by a kinetic profile characterized by a narrow peak, with a maximum occurring after 4 and 6 days of culture and with the IgA response appearing earlier than the IgG. This methodology, which analyses specific antibody responses at the cellular level, may permit studies on the mechanisms of Ig isotype regulation. Extended to leukocytes from other organs of the immune system, it may also constitute an in vitro model to study antibody responses expressed in different lymphoid tissues of the pig.

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PubMed1989

Natural killer (NK) activity and interferon (IFN) production by a fraction of spleen and blood lymphocytes in swine.

After carbonyl iron treatment and gradient isolation, spleen and blood pig lymphocytes exhibited NK activity and produced IFN after viral induction. Removal of plastic-adherent cells, including the majority of B cells, did not change these activities. The plastic-non-adherent cells were further separated into two subsets of roughly similar size by panning using a monoclonal, anti-T, and anti-null cell antibodies (81 + cells). NK activity and IFN production were found in the 81 - cell fraction. A significantly higher proportion of null lymphocytes from blood and of splenic Fc-gamma receptor-bearing lymphocytes was also found among the 81 - cell fraction as compared to the 81 + fraction, without any change among other subsets. Similar proportions of helper (PT4+), cytotoxic (PT8+) and total T cells (MSA4+) were found among lymphocytes bound to target K562 cells and among the whole lymphocyte population. In contrast, lymphocytes that bound K562 cells demonstrated a striking increase in the proportion of Fc-gamma receptor-positive cells of high affinity. These results show that NK cells and IFN-producing cells are mainly included in the same blood and spleen fraction, and suggest that among 81 - cells only those expressing an Fc-gamma receptor of high affinity are active.

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PubMed1989

[Rapid collection of swine lymphocyte subpopulations in large quantity].

Lymphocyte subpopulations derived from different pig organs (blood, spleen, mesenteric lymph nodes) were separated by a simple, rapid and cheap panning technique, using either normal or ozone treated Petri dishes with bovine serum albumin. Slg+ lymphocytes could thus be obtained with a purity of up to 95% by adhesion onto Corning plastic dishes. The purified cells retained their proliferative activity with regard to lectins. The subpopulation including PT4 and PT8 was then separated by another panning on ozone-treated plastic dishes with a purity of 80-90%.

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PubMed1988

A cytotoxic murine monoclonal antibody that recognizes a porcine T cell subset involved in lectin-induced proliferation.

A panel of cytotoxic monoclonal antibodies (Moab) derived from mice immunized with porcine thymocytes has been developed which reacts with monomorphic determinants on porcine peripheral blood lymphocytes (PBL). These Moab recognized from 25% to 100% of PBL as tested by flow microfluorimetry One of the Moab (PT 81) that bound 39% of PBL, 30% of splenocytes and 65% of thymocytes as determined by flow microfluorimetry was selected for initial characterization. PT 81 specifically lysed 37% of Ficoll/Hypaque-prepared PBL depleted of monocytes by carbonyl iron ingestion. This antibody lysed 47% of T cells (PBL that formed dextran-enhanced, sheep erythrocyte rosettes; P less than 0.001) and 64% of a T cell subset (PBL that formed dextran-enhanced, porcine erythrocyte rosettes; P less than 0.001) when compared to cells treated with complement alone. Lysis of PBL with PT 81 plus complement caused a 100% enrichment in the number of surface immunoglobulin positive cells (P less than 0.01). The conclusion that PT 81 does not recognize B cells was further supported by double labelling experiments. Removal of PT 81 positive cells did not significantly affect the number of cells with C3b (zymosan-complement rosettes) or Fc gamma (erythrocyte-antibody rosettes) receptors. PBL that were treated with PT 81 plus complement were passed over Ficoll/Hypaque (density 1.09) to remove dead cells. The PT 81-depleted lymphocyte population displayed only 20%, 20%, 26% and 29% of the proliferative responses of control cells treated with complement alone (P less than 0.01) to several concentrations of the mitogens phytohemagglutinin, concanavalin A, soybean agglutinin and pokeweed mitogen, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1987

Staining of pig lymphocytes subpopulations with acid alpha-naphthyl acetate esterase.

The use of alpha-naphthyl acetate esterase (ANAE) as a T cell marker in some other species and the broad correlation of incidence of ANAE-positivity and E rosette-formation in the pig suggest that ANAE-staining may be a T-cell marker in the pig. However, by studying the staining of lymphocytes within a variety of rosettes in fixed preparations a similar incidence of pig blood lymphocytes were found to be ANAE+ among T cells (E rosettes formed in dextran), B cells (antiglobulin rosettes) and Fc-gamma receptor-bearing B and T cells (EA rosettes in saline and dextran): complement (C') receptor-bearing cells showed a higher incidence of staining than other lymphocytes. Analysis of staining morphology suggested that certain morphologies within the B and T lineages may be confined to subpopulations. Thus ANAE positivity is certainly not a marker identifying blood T lymphocytes but could be of some value indicating subpopulations of B and T lymphocytes.

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PubMed1987

The intestinal and mammary immune system in pigs.

Evidence exists from studies in other species for a link between the intestinal and mammary immune systems. This was examined in pigs by various methods including analysis of lymphocyte subsets in intestinal and mammary tissues and lymphocyte migration studies. It was concluded that in the pig both a common mucosal immune response and a genuine local immune response exist in the mammary gland.

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PubMed1985

A method of purifying sheep sIg+ lymphocytes as a tool for class II MHC antigen analysis.

A method is described for the purification of sheep lymphocytes carrying class II MHC antigens. After incubation of purified blood lymphocytes on anti-IgM-coated petri dishes, the adherent fraction contained 95% sIg-positive cells determined by immunofluorescence. When tested with cross-reacting anti-class II (bovine and human) monoclonal antibodies, more than 95% of these cells were positive either by immunofluorescence or cytotoxicity. This technique will permit studies of the polymorphism of sheep class II antigens.

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PubMed1985

Conditioned taste aversion suppresses induction of delayed-type hypersensitivity immune reactions.

Conditioned taste aversion was induced in mice by pairing saccharin drinking with an intraperitoneal injection of lithium chloride, a toxic but nonimmunosuppressive drug. Conditioned mice showed not only suppressed saccharin drinking but also a 75% reduction in the induction of delayed-type hypersensitivity immune responses to low doses of sheep erythrocytes. This effect was observed with doses of lithium chloride which had no effect of their own on immune functions. In addition, a reduction in water consumption was not responsible for the reduced immune response of conditioned mice since the immune responses of water deprived mice did not differ from those of nondeprived mice. Conditioned mice exposed to saccharin had higher plasma levels of glucocorticoids than nonconditioned mice, suggesting that the experience of being reexposed to a taste paired with lithium chloride was perceived as aversive. These data demonstrate that alterations in immune functions can be induced by a conditioned taste aversion procedure independently of any immunosuppressive drug.

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PubMed1984

[Induction of immunosuppression by dietary aversion acquired in the absence of immunosuppressive treatment].

Conditioned taste aversion induced by either an immunosuppressive (cyclophosphamide) or non immunosuppressive (lithium chloride) drug reduced expression of a T cell mediated immune response that is highly susceptible to stress hormones. These results demonstrate that the proposed concept of conditioned immunosuppression really represents another example of how stress can alter normal regulation of cell mediated immune events.

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PubMed1984

[Immunity in the fetus and the newborn infant: a swine model].

An efficient placental barrier protects the pig fetus from all exogenous antigenic stimulation. The results of studies on different subpopulations of lymphocytes, histological localization, and stimulation as well as immunization in utero with allogeneic lymphocytes have confirmed that the pig fetus becomes immunocompetent at around 80 days of fetal life (total length of gestation: 115 days). Because the newborn piglet has had no "immunological experience" in utero, it can only elaborate a primary response which is often advantageous to pathogenic microorganisms. Under natural conditions, immune protection is provided by the mother in the form of colostrum. This colostrum provides systemic immunity and is followed by milk which insures local immunity in the piglet gastrointestinal tract. However, the great disadvantage of maternal antibodies is that they suppress the active synthesis of new antibodies in young pig. Thus, the beginning of active immunity in the piglet is a function of the ratio of maternal antibody level to the level of antigenic stimulation.

Aging↗

PubMed1984

Immunity changes in confined animals: a route to disease?

An intriguing and important biological question is how the immune system is subject to regulation by exogenous factors. In the mouse system, our laboratory has demonstrated that a wide variety of environmental stimuli, such as heat, cold, short-term restraint and conditioned-taste aversions, affect cell-mediated immune events in vivo. The reduction in cell-mediated immunity that is caused by restraint can be abolished by adrenalectomy or treatment with an inhibitor of corticosterone biosynthesis. We have therefore examined the effect of a short-term restraint stressor on the immune system of pigs. Five-to-eight-week-old-pigs were restrained by placing them in an expanded-metal box for 2 h each day for 3 consecutive days. Restraint caused a significant increase in serum cortisol. Preliminary evidence indicates that restraint significantly reduced size of the thymus gland from 0.14% to 0.10% of body weight and also significantly reduced in vivo phytohemagglutinin-stimulated, cell-mediated reactions by 25%. Addition of cortisol at a concentration of 130 ng/ml to phytohemagglutinin and concanavalin A-stimulated porcine lymphocytes in vitro reduced mitogenesis of splenocytes, peripheral blood lymphocytes and thymocytes. Although these data reflect changes in immune function caused by an acute environmental stressor in vivo and by cortisol in vitro, research from another laboratory indicates that longer-term restriction of pigs with tethers and farrowing crates can also decrease immune events.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1983

Rosette-formation of pig thymic lymphocytes with sheep and pig erythrocytes. II. Markers for cortical and medullary thymocytes.

Study of the distribution of P+S+ and P-S+ cells in various lymphoid organs of pig revealed that the thymus contains the highest proportion of P+S+ cells (75.5 +/- 4.2%). In vivo treatment of neonatal piglets with cortisone: (i) Reduced both the area of the thymic cortex even more than the medulla and the P+S+ cells more than the P-S+ cells, suggesting the respective origin of these two populations in these two tissue compartments. Moreover, cortisone-resistant thymocytes responded better than the control untreated pig thymocytes to Con A and PHA stimulation. (ii) Reduced the number of P+S+ cells in peripheral organs. Separation of adult thymocytes into P+S+ and P-S+ cell fractions showed that P-S+ cells responded better than P+S+ to Con A and PHA stimulation. Cortisone-resistant thymocytes and P-S+ cells showed the same cell size distribution and both are enriched in medium sized cells. Thus, it is concluded that the property of rosette formation with pig red blood cells allows the identification of two subsets of pig thymocytes with different biological properties and thymic locations, which by analogy with other species may prove to have different patterns of emigration to peripheral organs.

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PubMed1982

Characterization of pig lymphocyte receptors for allogeneic and non-allogeneic erythrocytes. I. Apparent common identity of both receptors.

In the pig thymus, the proportion of allogeneic (or autologous) erythrocyte rosette forming cells (P-RFC) is always lower than that of sheep erythrocyte (non-allogeneic) rosette forming cells (S-RFC) even under saturated RBC/lymphocyte ratios and optimal dextran concentration. This difference accounted for lymphocytes rosetting with sheep erythrocytes and not with pig erythrocytes (P-S+ cells), as opposed to those lymphocytes which are able to bind both types of erythrocytes (P+S+ cells). Since formation of both sheep and pig erythrocyte rosettes is inhibited similarly by anti-T receptor serum, is inhibited reciprocally by sheep and pig erythrocyte membrane fragment and is similarly trypsin sensitive, it was concluded that the same receptor was responsible for both sheep and pig rosette formation. Furthermore it was found that P+S+ cells had a higher avidity for sheep erythrocytes (and lower for pig erythrocytes) than the other subset which did not bind pig erythrocytes.

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PubMed1982

[Kinetics of lymphocyte sub-populations and plasma cells in the mammary gland of primiparous sows in relation to gestation and lactation].

Qualitative and quantitative changes in pig lymphocyte sub-populations (T, B, L and nulls) were studied in the mammary gland of primiparous sows, as well as the appearance and development of plasma cells in relation to the 3 phases of mammary development: gestational, colostral and lacteal phases. Results showed: 1) An early colonisation of mammary epithelium from the beginning of the gestation phase by the three T, B and L lymphocyte subpopulations; 2) The presence of activated T lymphocytes, especially during the colostral phase; 3) The appearance of plasma cells during the colostral phase and their increase during the lacteal phase; 4) Not only the T, B and L lymphocyte subpopulations increased during the lactation but there was also a special increase in null lymphocyte subpopulation. These results give new data which are particularly important in allowing us to envisage immunization schemes for the pregnant sows, with the aim of enhancing local mammary or lactogenic immunity by transfer of antibodies and lymphocytes to the newborns.

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PubMed1980

Lysis of antibody coated chicken erythrocytes by a non-lymphocyte pig blood leukocyte.

Antibody-dependent cellular-cytotoxicity (ADCC) was studied by the 51chromium release test after a 18 h incubation of non-immune porcine blood leukocytes with labelled chicken erythrocytes sensitized with pig antibodies. It was shown that ADCC was inhibited by incubation of leukocytes with aggregated immunoglobulins. In our assay, pig lymphocytes were shown to be inactive whereas non-lymphocyte pig leukocytes are effector cells even at low effector:target ratios.

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PubMed1979

Surface markers of porcine lymphocytes and distribution in various lymphoid organs.

Three rosette test systems were developed for the classification of subpopulations of porcine lymphocytes and correlated with the presence or the absence of membrane immunoglobulins, as well as agg-P-IgG receptors, by means of various RFC depletion experiments. Among the ED-RFC negative cells, PBL with surface immunoglobulins (SIg), at 4 degrees C, can be subdivided into two about equal populations: (1) One half of these cells have surface stable SIg (B cells) and mu determinants; they possess C3b receptors leading to the formation of rosettes with complement-coated zymosan particles (ZC). (2) The other half have surface labile Ig when the cells are washed at 37 degrees C (L-cells); they possess Fc receptors as detected by EA-RFC, i. e. pig-IgG-coated ox RBC. Receptors for Fc-agg, as detected by agg-P-IgG, were primarily shown on B cells. ZC and EA-RFC are in the highest tissue concentration, in bone marrow and spleen, respectively, and more numerous in adults than in newborns. Moreover, the number of EA-RFC was twofold higher than that of ZC-RFC in spleen, mesenteric lymph node and cisterna chyli. This latter organ was the only one without null cell.

Aging↗

PubMed1979

Influence of a mycoplasma respiratory tract infection on sheep erythrocyte and complement receptor-bearing cell composition in the respiratory tract of swine.

Pulmonic and peripheral blood lymphocyte subpopulations in healthy and Mycoplasma suipneumoniae-infected pigs were compared. The T- and the B-lymphocyte populations were counted, the B cells by the complement receptor (zymosan-complement rosettes) technique and the T cells by the ED-rosette technique (sheep RBC-dextran rosettes). The T cells were found to predominate among pulmonic, as well as blood, lymphocytes. Pulmonic B-cell and blood T-cell percentages were increased after mycoplasma respiratory tract infection. However, blood B-cell and pulmonic T-cell percentages were not significantly affected. A significant (P less than 0.001) correlation between pulmonic and blood T-lymphocyte compositions was found; conversely, no correlation was observed between blood and pulmonic B-cell percentages. These data could imply that pulmonic B cells are predominantly involved in local immune reactions after a mycoplasma respiratory tract infection.

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