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S T Licence

Publications and source records attributed to S T Licence.

At least 37 records · Page 2Linked to original sources
PubMed1992

Homing of blood, splenic, and lung emigrant lymphoblasts: comparison with the behaviour of lymphocytes from these sources.

The distinctive homing patterns of [125I]deoxyuridine-labelled lymphoblasts and 51Cr-labelled lymphocytes from the three sites--splenic and pulmonary venous emigrants, and peripheral blood--were demonstrated by study of their entry into a large number of tissues. These included the major organs such as the lung, liver, bone marrow, spleen, skin, and muscle, and several lymph nodes (LNs), Peyer's patches (PPs), tonsils and thymus, portions throughout the gastrointestinal tract and immunologically-stimulated sites. Major differences in homing of blood blasts (up to 4-fold) were found in particular tissue types, such as the different LNs, three PP types, and the three tonsils, and their distribution was quite different from lymphocytes. While splenic blasts behaved like blood blasts, lung blasts showed even more distinctive homing, e.g. to tissues with particular blast uptake, including spleen, stomach, bladder, portal and stimulated LNs, and liver and lung. While blast recovery data showed that all types homed well to bone marrow (about 25%) and the gastrointestinal wall (about 15%), the roughly 50% found in blood, muscle, skin, lung, and liver showed some homing preferences: blood blasts tended to stay more in blood, splenic blasts to home to muscle, and lung blasts to liver and lung. These studies have demonstrated that physiologically-derived lymphoblasts are not predominantly mucosal-homing but distribute through several non-lymphoid organs and that, even considering only those in the blood compartments, they show differences in homing preference.

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PubMed1990

Exit of recirculating lymphocytes from lymph nodes is directed by specific exit signals.

During recirculation, lymphocytes leave the peculiar structurally inverted lymph nodes (LN) of pigs via blood vessels instead of via efferent lymphatics, as in sheep and other mammals. This functional difference provided an opportunity to show the existence of signals directing lymphocyte exit from LN. The recirculation of pig peripheral blood lymphocytes was traced through fetal sheep LN and of sheep PBL into and out of unsuckled newborn piglet LN, using the lack of natural antibody or natural killer cell function in these immunologically mature young to compare foreign and homologous lymphocyte behavior. In spite of some 50 million years of evolutionary divergence, the detailed kinetics and route of recirculation of the xenogeneic PBL were essentially the same as those of the host species. Thus determinants guiding the anomalous blood exit from pig LN must involve conserved "exit" signals in a new site and not changes in pig lymphocyte homing receptors.

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PubMed1990

Phytohemagglutinin induces major short-term protease-sensitive lymphocyte traffic involving high endothelium venule-like blood vessels in acute delayed-type hypersensitivity-like reactions in skin and other tissues.

Injection of phytohemagglutinin induces dose-dependent acute delayed-type hypersensitivity-like reactions in young pig skin which attract large numbers of labeled peripheral blood lymphocytes and lymphoblasts but not red cells. Similar reactions are induced in the gut wall, joints, and draining lymph nodes, and also in the skin of sheep and cattle, and by concanavalin A. Labeled peripheral blood lymphocyte entry starts within 2 h, is maximal at 6-18 h and is effectively over by 48 h and, both early and late, is markedly inhibited in a selective way by trypsinization, like high endothelium venule-mediated entry to lymphoid tissues. Electron microscopy showed development of high endothelium venule-like blood vessels with intramural lymphoid cells in mononuclear infiltrates. Inductive processes in this model short-term peripheral defense mechanism are being investigated.

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PubMed1988

Subpopulations of T lymphocytes emigrating in venous blood draining pig thymus labelled in vivo with fluorochrome.

The emigration of labelled thymus cells in the pig was studied directly in blood draining the large right distal cervical lobe of the thymus after controlled labelling with FITC delivered through cannulated branches of a main thymic artery and vein by temporary ex vivo perfusion at body temperature. Roughly 1% of thymic cells emigrated per day. Unlike most thymocytes, which are small, the size spectrum of thymic emigrants is slightly larger than that of typical blood lymphocytes. Surface-marker studies show that the surface phenotypes of the emigrants differ from both typical thymus and peripheral blood lymphocytes. Although the emigrants resemble thymocytes in the high proportion of strong rosettes formed with sheep red blood cells (RBC), they rosette poorly with pig red cells, particularly in the unenhanced saline test, in this respect behaving like blood lymphocytes. The peripheral T-cell subset bearing a Fc receptor is almost absent in thymus, but is well represented among the emigrants which thus resemble corticosteroid-resistant thymocytes in the pig. The large population of thymus-dependent Null lymphocytes in young pig blood apparently arise in thymus since they constitute 1/3 of emigrants, although only forming less than 10% of thymus cells. This emigration of thymic cells is discussed in relation to its implications for the turnover of known functional peripheral T-cell populations.

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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

Evidence of a selective major vascular marginal pool of lymphocytes in the lung.

The size and mobilization of the pulmonary vascular pool of lymphocytes was studied in young pigs. Blood lymphocytes, labeled in vitro with a fluorescent dye, were injected either intravenously or into the left heart. Comparable high numbers of lymphocytes were found in the lung after 30 min, demonstrating a specific homing of lymphocytes to the lung vascular bed. When the left lung was perfused with a cell-free medium for as long as 4 h in vitro, a continuous venous release of lymphocytes was found that resulted in about 1.5 x 10(9) lymphocytes and 5.7 x 10(6)/min leukocytes. Peripheral blood lymphocytes were labeled with 51Cr in vitro and injected intravenously. Fifteen minutes or 1 day later the lungs were perfused, and the release of cell-bound radioactivity was measured. The data indicate the existence of a large intravascular pulmonary lymphocyte pool. The sequestration of lymphocytes in the lung in many lymphocyte migration studies is not a removal of effete cells but a physiologic phenomenon.

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PubMed1985

Characterization of pig T cell growth factor and its species-restricted activity on human, mouse and sheep cells.

Crude T cell growth factor was prepared from pig blood cells in mixed lymphocyte culture together with Concanavalin A. The TCGF was recovered from the crude supernatant by ammonium sulphate precipitation and fractionated by gel exclusion chromatography to yield active fractions corresponding to an apparent molecular weight of 23,000d. The TCGF was further purified by isoelectric focussing and was found to migrate as a single peak of pI 5 - 5.5. The crude preparation was found to support the growth of mouse and sheep activated cells but had no effect on human activated cells. Human TCGF supported the continued growth of activated pig cells whereas mouse and sheep TCGF had no such effect.

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PubMed1985

Surface markers on lymphocytes leaving pig lymph nodes.

Mesenteric lymph nodes of normal young pigs were perfused in vitro at physiological temperature. Cell-free perfusion medium was pumped into the artery for more than 2.5 hr, and lymphocytes were continuously released into the venous effluent. Recirculating lymphocytes emigrate from pig lymph nodes by entering the blood vasculature directly and not via efferent lymphatics. The presence of lymphocytes in paracortical venular walls after 2 hr of perfusion with new medium suggests that these are the sites of emigration. The rate of emigration of lymphocytes from mesenteric lymph nodes was estimated to be 6 X 10(7)/hr. Study of the lymphocyte populations emerging from the perfused lymph nodes showed that B lymphocytes and E-rosette forming T lymphocytes, but almost no Null lymphocytes, are involved. While the proportion of B lymphocytes remained constant during the perfusion period, E-rosette forming lymphocytes increased significantly. Lymphocyte subpopulations differ profoundly in their capacity to migrate through lymph nodes.

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PubMed1985

Lymphocyte emigration from lymph nodes by blood in the pig and efferent lymph in the sheep.

Two types of experiment using local labeling of lymph nodes with FITC showed that lymphocytes emigrate from lymph nodes, predominantly in blood in the pig and in efferent lymph in the sheep. In the first type of experiment with the pig, few cells emigrated via the lymph, while the number of labelled cells in the blood increased progressively and the indices in mesenteric blood were always higher than in jugular blood in simultaneously-drawn samples. However, in the sheep, when efferent lymph flowed freely, very low numbers emerged in blood and continuing large numbers of lymphocytes emerged in efferent lymph. In the second type of experiment carried out wholely under anaesthetic on mesenteric lymph nodes in pigs and sheep, and on superficial inguinal lymph nodes in pigs, the lymph node was isolated, the lymph and venous drainage collected and only the arterial supply maintained. Large numbers of FITC+ lymphocytes emigrated via the vein in pigs with either node cannulation (i.e. up to 7% blood lymphocytes were labelled with an emigration rate of approximately 10(8) cells/hr) but in sheep, while lymph contained approximately 30-80% labelled cells and the emigration rate was also approximately 10(8) cells/hr, the mesenteric blood contained very few labelled cells (approximately 0.2%, giving a mean venous emigration rate of 2.7 X 10(6)/hr). Study of the type of lymphocytes emerging from labelled pig lymph nodes and spleen during the phase of major emigration showed that sIg+ B and E rosette-forming T cells, but almost no Null cells, are involved.

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PubMed1984

Analysis of a sheep anti-pig T lymphoblast serum with specificity for E rosette-forming lymphocytes.

Sheep antibodies against a pig E-rosette-forming lymphoblastic T lymphoma raised by two intravenous injections of 10(10) cells showed little lymphocytotoxic activity which could be absorbed with red cells, alveolar macrophages or kidney or liver cell homogenates. Bone marrow absorption yielded subpopulation specific antibody which binds to E rosette-forming cells (E.RFC) using either complement-mediated cytotoxicity or indirect antiglobulin rosette formation. In 30 blood lymphocyte preparations from 20 pigs with a range of approximately 20-85% E rosettes the mean E% 43.5 +/- 2.7 agreed with the % antigen+ cells by cytotoxicity mean = 42.6 +/- 2.7 and in each individual sample these figures also agreed closely. In samples of blood lymphocytes enriched and depleted for E rosettes, results of %E+ also agreed closely with % antigen+ cells. This relationship also held for thymocytes and the specific antibodies could be completely absorbed with thymocytes. These data show that the antibody identified peripheral and thymic E.RFC. Bound to lymphocytes the antibody inhibited E rosette-formation with sheep red blood cells (SRBC) in saline (S) and dextran (DS) and with pig RBC in dextran and in Ficoll, but did not affect B cells shown by immunofluorescence, direct antiglobulin rosette formation or Fc rosette-formation, either in saline or dextran, (which include T gamma cells). E rosette inhibition was dependent on antibody concentration, showing single and double sigmoid curves for S and DS rosettes respectively, consistent with differing ease of inhibition of the strong and weak rosette formation. The same spectrum of inhibition of rosette formation by antibody binding followed subsequent incubation with C'6-deficient rabbit serum, but with C'-sufficient serum resulted in loss of cells which require dextran for Fc rosette-formation (T gamma). Thus the serum reveals E rosette-forming T cells and their subpopulations, perhaps by binding to the SRBC receptor.

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PubMed1983

The demonstration of sIg, MHC and T cell antigens and Fc receptors on the lymphocyte surface by anti-globulin rosetting reactions: some technical considerations.

The previously shown marked difference in sensitivity of antiglobulin rosette formation and immunofluorescence was confirmed in detection of varying amounts of anti-Ig bound to B cells. The direct and indirect rosette method revealed twice the number of sIg+ cells shown by direct immunofluorescence (DIF), and at least an order of magnitude more antibody on the cell surface is necessary to detect the conventional B cells (shown by DIF) by indirect immunofluorescence compared with indirect antiglobulin (IARR) rosette formation. Variants of the sensitive IARR test were developed to reveal general lymphocyte, MHC class I and class II and T cell-specific antigens and Fc receptors using xenogeneic or allogeneic reagents. Sensitive indicator cells were used which form almost no rosettes with unsensitized lymphocytes although coated with IgG which would otherwise bind to the Fc receptor. The suggestion that chromic chloride treatment inactivates the relevant Fc determinants was supported by experiments showing the failure of IgG antibody-sensitized bovine RBC (standard Fc indicator cells) to form rosettes after treatment with chromic chloride.

Animals↗
PubMed1983

Long-term survival of MHC-compatible lymphocytes and two-phase clearance of allogeneic incompatible lymphocytes in the young pig.

Major histocompatibility complex (MHC)-compatible pig lymphocytes survive in vivo for well over a week. In the first day, they show a rapid reduction in numbers followed by reappearance in the blood consistent with equilibration with the lymphoreticular tissue populations, where they are found. By contrast, allogeneic lymphocytes show an early partial clearance and late (40-50 hr) exponential immune clearance.

Animals↗
PubMed1983

Classification of newly formed and migrating splenic lymphocytes.

Newly formed lymphoid cells in the spleens of normal young pigs were selectively labelled with 3H-TdR, using an extracorporeal perfusion system. One day later splenic and blood lymphocytes were separated by rosetting with sheep red blood cells for classical T cells and by a direct anti-globulin rosetting reaction for B cells. The proportion of newly formed lymphocytes in these subsets was determined by autoradiography. In this study we show that while both B and T lymphocytes are produced, B cells show a much higher incidence of newly formed cells. Labelled populations of spleen derived T and B lymphocytes were also found in the blood, but the B cells showed a lower labelling incidence than in the spleen.

Animals↗
PubMed1982

Subpopulations of pig blood E-rosette-forming lymphocytes and thymus-dependent null cells: separation by nylon wool columns, rosette formation and macrophage-dependent mitogen and antigen responsiveness.

Pig peripheral blood lymphocyte subpopulations were characterized by their adherence to nylon wool. Thus whilst B cells, defined by surface Ig and Fc receptor, were predominantly adherent, thymus-dependent Null cells and the T cells forming rosettes with sheep red blood cells in dextran (DS+) were predominantly non-adherent. There was a direct relationship between the size of the non-adherent fraction and the proportion of the total DS+ cells which were in the non-adherent fraction. Using nylon wool and/or DS rosette separation, lymphocytes from normal and BCG sensitized animals were stimulated in vitro with phytohemagglutinin (PHA), concanavalin A (Con A) and tuberculin (PPD). The cells responding to PHA and Con A (T cell mitogens in other species) were DS+ lymphocytes. Non-rosetting, adherent (B cells) and non-adherent (thymus dependent Null cells) lymphocytes were unresponsive, even in the presence of homologous alveolar macrophages at levels which greatly enhanced the PPD response. Cells responding to PPD were present in the DS+ and DS-, adherent and non-adherent fractions but their response was apparently controlled by macrophage dependence and suppression. Techniques are described for the preparation and storage in liquid nitrogen of alveolar macrophages resulting in high numbers of viable cells, capable of helping in vitro responses, even after 3 years of storage.

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