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At least 991 records · Page 55Linked to original sources
PubMed1982

Differences in spleen suppressor cell content in rats with progressing and regressing tumors.

Young New Zealand Black rats (less than 35 wk old) developed progressively growing tumors when given injections of cells from a syngeneic 3-methylcholanthrene (MCA)-induced fibrosarcoma. Spontaneous tumor regression occurred in animals more than 10 months of age. Compared to the responses of spleen cells from age-matched controls, spleen cells from rats in which tumor progression was present progressor rats) showed decreased proliferative responses to concanavalin (Con A), phytohemagglutinin (PHA), and syngeneic MCA tumor cells. Spleen cells from rats in which the tumors had regressed (regressor rats), however, produced significant increases in proliferative responses when compared with the responses of spleen cells from age-matched controls and from progressor rats. Cell-mixing experiments implicated the presence of two spleen suppressor cell populations in progressor rats, one of which was not present in regressor rats. The unique suppressor cell found in progressor rats appeared to be specific for tumor cell-induced proliferative responses. Spleen cells from both progressor and regressor rats produced similar suppressive effects in the PHA and Con A responses of normal cells.

Animals↗
PubMed1984

Immunoregulation in experimental filariasis. IV. Induction of non-specific suppression following in vitro exposure of spleen cells from infected jirds to Brugia pahangi antigen.

Studies with inbred jirds chronically infected (greater than 5 months) with Brugia pahangi have demonstrated splenic suppressor cells which modulate in vitro responsiveness to mitogens and parasite antigens. The stimuli which induce suppression were characterized by analysing the effect of activated cells from inbred normal or B. pahangi-infected jirds on the PHA and PWM responsiveness of cultures on normal cells. Regulatory cells were stimulated in vitro with concanavalin A (Con A; 5 micrograms/ml) or an extract of adult B. pahangi (20 micrograms/ml) for 72 hr and irradiated (1500 rads) prior to cocultivation with normal cells. Addition of Con A-activated normal spleen cells to normal cells produced moderate suppression of PHA and enhancement of PWM responsiveness. However, Con A-stimulated spleen cells from infected animals consistently suppressed both the PHA and PWM responsiveness of normal cells by 80-90%. Spleen cells from chronically infected jirds were also induced by B. pahangi antigen to suppress both the PHA and PWM responsiveness of normal lymphocytes. In contrast, spleen cells from animals 3-15 weeks after infection and lymph node cells from all time points were capable of suppressing only PWM responses when stimulated by antigen. Normal spleen cells were not induced by B. pahangi antigens to exhibit immunoregulatory activity. The suppression mediated by antigen-induced spleen cells from chronically infected jirds was partially or totally alleviated by removal of non-specific suppressor cells which are plastic adherent and cyclophosphamide-sensitive, or by removal of antigen-specific suppressor cells which bear receptors for histamine. the results suggest the involvement of regulatory cell circuits in experimental filarial infections.

Animals↗
PubMed1982

Spleen weight distribution in Ibadan and its relationship to disease.

The 5407 autopsies performed during an 8-year period formed the basis of the study; 2444 were infants and children, while 2963 were adults. The histogram of the spleen weight distribution has a fairly smooth contour with a positive skew towards the heavier spleens. The mean adult spleen weight was 271 g, and this was heavier than that of subjects in temperate climates, but comparable to the mean spleen weight of other localities in a holoendemic belt of malaria. The most frequent diagnosis at autopsy were diseases of the respiratory system, infective and parasitic diseases of which malaria is the most common, diseases of the digestive system and neoplasms. In those subjects with spleens weighing more than 500 g, neoplasms, diseases of the haematopoietic system and infectious and parasitic diseases were the most prominent. The role of environmental stimuli in a tropical environment in the hyperplasia of the reticuloendothelial system is discussed. The findings would prove useful in the differential diagnosis of large spleens found in this locality.

Adolescent↗
PubMed1978

Generation of anti-MOPC-315 cytotoxicity in uneducated or in vitro educated spleen cells from normal or MOPC-315 tumor-bearing mice pretreated in vivo with Bacillus Calmette-Guérin.

Cultured spleen cells from normal or MOPC-315 tumor-bearing BALB/c mice that were pretreated in vivo with Bacillus Calmette-Guérin (BCG) exhibited in vitro cytotoxicity against MOPC-315 plasmacytoma. In vitro education of BALB/c spleen cells from normal or tumor-bearing mice by cocultivation with mitomycin C-treated MOPC-315 stimulator cells also resulted in antitumor cytotoxicity. The combination of BCG pretreatment of donor mice with the in vitro education of their spleen cells resulted in a level of anti-MOPC-315 cytotoxicity that was greater than the sum of the levels of cytotoxicity exhibited by spleen cells subjected to either process alone. The levels of cytotoxicity exhibited by educated or uneducated spleen cells from BCG-pretreated mice were dependent on the dose of BCG used and on the time interval between in vivo pretreatment and the initiation of in vitro culture. Thus, our findings suggest that educated spleen cells from tumor-bearing hosts that were pretreated with BCG might be useful in immunotherapeutic regimens requiring histocompatible cells with augmented antitumor cytotoxicity.

Animals↗
PubMed1978

Suppression of mitogen-induced proliferation of normal spleen cells by macrophages from chickens inoculated with Marek's disease virus.

Spleen cells from chickens 7 days after inoculation with Marek's disease virus (MDV) responded poorly to stimulation by phytohemagglutinin (PHA). Addition of these cells to syngeneic normal spleen cells caused of marked suppression of the PHA response of the normal cells. The MDV spleen cells also inhibited the DNA synthesis of MSB-1 lymphoblastoid cells in vitro. The suppressive activity is attributed to the presence in MDV spleen cells of a population of suppressor cells with characteristics typical of macrophages. The suppressor cell activity was not removable by treatment with anti-T or anti-B serum with C, but it was reversible by treatment with carrageenan or carbonyl iron/magnet, by passage through glass wool column, and by adherence to plastic Petri dishes. The adherent MDV spleen cells also showed strong suppressor cell activity against syngeneic normal spleen cells.

Animals↗
PubMed1983

The origin of cytotoxic T lymphocyte precursors (CTL-P): MHC-restricted and alloreactive CTL-P in the spleen during regeneration after a sublethal dose of cyclophosphamide (Cy).

The regenerating spleen 8 days after an injection of a sublethal dose (300 mg/kg) of cyclophosphamide (Cy) had a defective capacity to give rise to cytotoxic T lymphocytes (CTL) in response against allogeneic cells, whereas the cytotoxicity against 2,4,6-trinitrophenyl-(TNP) modified syngeneic cells was at the normal level. Alloresponse was first obtained 2 wk after the Cy treatment. The limiting dilution analysis showed this at the clonal level: the frequency of anti-TNP-specific CTL precursors (CTL-P) in the spleen treated with Cy 8 days previously was the same as the frequency in the normal spleen. The defective alloresponse was due to a decreased number of allospecific CTL-P that was later increasing. The regenerative capacity was not abolished by adult thymectomy or treatment of the mice with a bone marrow-seeking isotope, 89Sr, suggesting that these CTL-P are derived from Cy-resistant splenic precursors rather than from the thymus or bone marrow. These precursors have probably been under thymic education: the dominance of H-2k-restricted CTL over H-2d-restricted CTL in the response of (H-2k X H-2d)F1 mice to TNP-self is known to be influenced by the H-2 genotype of the thymus, and this dominance was also demonstrated with anti-TNP CTL derived from these F1 mice pretreated with Cy. The CTL-P in the regenerating spleen (day 8) were not hydrocortisone sensitive, and nylon wool-purified T cells from this stage had a lactate dehydrogenase (LDH) isoenzyme pattern of the mature T cell type (rather than of the thymocyte type). Thus, in these aspects the T cells of the regenerating spleen resembled normal splenic cells. These data suggest that the Cy-resistant spleen population contains cells that can give rise to CTL-P that have a defective specificity repertoire at the beginning of the regeneration, but later mature to a normally alloreactive population.

Animals↗
PubMed1984

Suppression of Con A mitogen-induced proliferation of normal spleen cells by macrophages from chickens with hereditary muscular dystrophy.

Spleen cells from chickens with hereditary muscular dystrophy (MD) give low blastogenic responses to the T cell mitogen concanavalin A (Con A) while exhibiting normal mitogen stimulated blastogenic responses to the T cell mitogen phytohemagglutinin (PHA). The addition of MD spleen cells to normal spleen cells caused a marked suppression of the Con A response of the normal cells while not affecting the PHA response of the normal cells. The suppressive activity by the MD spleen cells requires viable cells and is contact mediated. The suppressive activity is attributed to the presence in MD spleens of a population of suppressor cells with characteristics typical of macrophages. The suppressor cell activity was not removable by complement-mediated lysis using anti-T or anti-B sera, but it was reversible by treatment with carrageenan or carbonyl iron magnet, by passage through a Sephadex G-10 column, and by adherence to plastic petri dishes or glass beads. MD spleen cells depleted of the suppressor cell population remained unable to respond to Con A.

Animals↗
PubMed1981

Enhancement by immunostimulants of the production by mouse spleen cells of factor(s) stimulating differentiation of mouse myeloid leukemic cells.

Mouse myeloid leukemic Ml cells can be induced to differentiate into macrophages and granulocytes in vitro by a factor(s) stimulating differentiation of the cells (D-factor) or by various chemical compounds. Spleen lymphocytes and spleen macrophages have been shown to produce D-factor when treated with various mitogens including lipopolysaccharide or synthetic double-stranded polyribonucleotide, poly(I) . poly(C). Several immunostimulants from microorganisms were tested for ability to induce differentiation of Ml cells and to stimulate production of D-factor by spleen cells. Mycobacterium bovis BCG (500 micrograms/ml) and the cell wall skeleton of Nocardia rubra (50 micrograms/ml) induced differentiation of Ml cells; but Corynebacterium parvum CN6134 and the cell wall skeleton of Propionibacterium acnes C7 had no effect on Ml cells. On the other hand, all immunostimulants tested at concentrations of more than 10 micrograms/ml were found to stimulate production of D-factor by both spleen lymphocytes and spleen macrophages. Synthetic derivatives of N-acetylmuramyl dipeptide(MDP), the minimal adjuvant-active subunit of the bacterial cell wall, had no direct effect on the differentiation of Ml cells and only slightly stimulated the production of D-factor by spleen cells. Therefore, the structure of microorganisms required for induction of differentiation of Ml cells and for stimulation of production of D-factor are suggested to be different from that of MDP.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1982

Ontogeny of 'macrophage' function. III. Manifestation of high accessory cell activity for primary antibody response by Ia+ functional cells in newborn mouse spleen in collaboration with Ia- macrophages.

The ontogenesis of the responsiveness of murine whole spleen cells in the in vitro primary antibody response paralleled not only the development of competent lymphoid cells but also that of the accessory cell (A-cell) activity of spleen adherent cells (SAC). The Ia+ cell content of SAC (and also peritoneal exudate cells) was very low until 2 weeks of age. The phagocytic activity of macrophages in SAC was higher in newborns than in adults, though no significant difference was observed between Ia- and Ia+ macrophages in phagocytic activity. We attempted to reveal a high A-cell activity using cells in newborn spleen by means of our experimental strategy documented previously in adult mice (Inaba, Nakano & Muramatsu, 1981): though neither Ia- macrophage population (Ia- SAC) nor a temporarily adherent spleen cell population containing few phagocytic macrophages (crude non-macrophage cell fraction, CF) serves as an autonomous A-cell source, the collaboration of Ia+ non-macrophage cells in CF with Ia- SAC causes the manifestation of A-cell activity. Adult CF collaborated as well with newborn SAC as with adult Ia- SAC, indicating that newborn Ia- macrophages are functionally comparable with adult Ia- macrophages in the ability to collaborate with Ia+ non-macrophage cells. On the other hand, a high A-cell activity was generated by the combination of adult Ia- SAC with a large number of newborn CF cells, indicating that there exist competent Ia+ cells in newborn spleen, though much fewer than in adult spleen.

Animals↗
PubMedDate not supplied

Residual immunogenicity of irradiated spleen cell suspensions after a single intravenous injection of sheep red blood cells in mice.

Studies were carried out to characterize the residual immunogenicity located in spleen cells of mice after one single intravenous injection of SRBC. An in vivo system was applied for initiation and expression of the immune response consisting of one intraperitoneally injection of spleen cell suspension from SRBC-injected mice in separate groups of recipients in which DTH and secondary humoral response were measured, respectively: six days or four days after the transfer of irradiated spleen cell suspension, the separate groups of recipients being either pretreated with cyclophosphamide (200 mg/kg) or primed with 5 X 10(5) SRBC. The residual immunogenicity was found to be located in a population of radio-resistant (10,000 rads) adherent spleen cells. The same population derived from naive mice injected together with the native antigen did not modify the immune response as compared with those induced by the antigen alone. Furthermore, irradiated spleen cell suspensions from SRBC-injected mice were not able to transfer adoptively DTH sensitivity in naive recipients. Accordingly to the test used to evaluate the residual immunogenicity, it was found that the kinetics of residual immunogenicity able to induce DTH was different from those which stimulate the secondary humoral response. Furthermore, it was found that distinct variations of residual immunogenicity for DTH and antibody formation were induced by varying host manipulations, such as non-specific stimulation of the reticulo-endothelial system, specific activation of T cells involved in DTH or helper function or induction of a state of anergy. It appears, therefore, that the same population of radio-resistant adherent spleen cells are able to induce an immune response and to dispatch information to cells involved in DTH or those involved in antibody synthesis. Moreover, depending upon conditions of immunization, varying subsets of T cells are able to modify the dispatching function of these cells in the processing or presentation of antigen to committed or non-committed lymphocytes.

Animals↗
PubMed1981

Murine T cells that lyse antibody-sensitized target cells. III. Contribution of Thy 1-Bearing cells to the lytic activity of normal spleen.

Murine spleen cells were analysed for their capacity to lyse 51Cr-labelled antibody-sensitized erythrocytes and a human lymphoma cell line. Incubation of spleen cells with iron powder followed by removal of iron-containing cells with a magnet significantly decreased the lytic capacity of the remaining cells against erythrocyte target cells. However, substantial cytotoxicity remained in the relatively phagocyte-depleted population. Both antibody-sensitized erythrocytes and tumour cells were lysed by phagocyte-depleted effector cells. However, more spleen cells were required to lyse nucleated target cells than were required to produce comparable lysis of the erythrocytes. Such phagocyte-depleted spleen cells were subsequently treated with three different antisera containing specificities for thymus-dependent antigens and a monoclonal IgM anti-Thy 1.2 in the presence of complement. The remaining viable cells were recovered and tested as effector cells. All four reagents in the presence of complement caused an inhibition of antibody-dependent cell-mediated cytotoxicity (ADCC) that was proportional to the percentage of T cells eliminated. However, the antisera also inhibited ADCC in the absence of complement, even when the cells were trypsinized following the antiserum treatment to remove attached antibodies. On the other hand, treatment of spleen cells with the monoclonal IgM anti-Thy 1.2 followed by trypsin treatment did not inhibit ADCC unless complement was added. Thus, with the latter reagent, decreased ADCC could be ascribed to elimination of T cells and not immune complex inhibition. Cells bearing Thy 1.2 accounted for approximately half of the lytic activity of phagocyte-depleted spleen cells against antibody-sensitized target cells.

Animals↗
PubMed1982

Formation of IgE-binding factors by rat T lymphocytes. VI. Cellular mechanisms for the formation of IgE-potentiating factor and IgE-suppressive factor by antigenic stimulation of antigen-primed spleen cells.

Analysis of cellular mechanisms of formation of IgE-binding factors by KLH-primed spleen cells revealed that the presentation of KLH to KLH-primed T cells by adherent cells resulted in the formation of lymphokines that in turn stimulated unprimed lymphocytes to form IgE-binding factors. Lymphokines released from KLH-alum-primed spleen cells induced normal lymphocytes to form IgE-potentiating factors, whereas those released from KLH-CFA-primed spleen cells induced the formation of IgE-suppressive factors. Fractionation of the lymphokines from KLH-primed spleen cells and analysis of cell sources of the lymphokines revealed that multiple factors are involved in the selective formation of one or the other IgE-binding factors. Thus, KLH-alum primed splenic T cells from "inducers" of IgE-binding factors and glycosylation-enhancing factors upon antigenic stimulation, and these factors in combination stimulate unprimed W 3/25+ Fc gamma R+ T cells to form IgE-potentiating factors. Antigenic stimulation of KLH-CFA-primed T cells results in the formation of the "inducers" and glycosylation-inhibiting factors, and these two lymphokines collectively stimulate unprimed W 3/25+ Fc gamma R+ T cells to form IgE-suppressive factors. Cell sources of "inducers" are W 3/25+ Fc gamma R- T cells, cells different from the source of IgE-binding factors. The glycosylation-enhancing factor is derived from W 3/25+ F gamma R+ T cells in KLH-alum-primed spleen; the glycosylation-inhibiting factor is derived from OX 8+ T cells in KLH-CFA-primed spleen. Evidence was obtained that these lymphokines, which modulate the protein glycosylation of IgE-binding factors during their biosynthesis, are derived from antigen-primed T cells and determine the nature of IgE-binding factors formed.

Animals↗
PubMed1981

Ontogeny of humoral immune function in normal chickens: a comparison of immunoglobulin-secreting cells in bone marrow, spleen, lungs and intestine.

A reverse haemolytic plaque was employed to study the ontogeny of immunoglobulin (Ig) secreting cells of either IgG, IgA, or IgM class in normal chickens. After hatching, IgM-secreting cells were detectable in the spleen by 3 days of age whereas IgG- and IgA-secreting cells were first noted at 6 days. Adult levels of Ig-secreting cells of all three classes were attained by 31 days of age in bone marrow and two separate lymphoid populations (lamina propria and intraepithelial lymphocytes). By contrast, adult levels of Ig-secreting cells were not obtained in either the spleen or the lungs until after 50 days of age. In the case of the spleen, the delay in attainment of adult levels of total Ig-secreting cells reflected the smaller spleen size in immature birds, whereas the percentages of cells secreting Ig of each class were in the adult range by 31 days. By contrast, the numbers of cells recovered from the lungs of 50-day-old chickens were near the adult range, while the percentages of cells secreting either IgG, IgA, or IgM were much fewer than those seen in the lungs of adult chickens. These data indicate that the lungs of normal chickens are populated more slowly with Ig-secreting cells than either the bone marrow, spleen, or intestine. At all ages studied, greater numbers of Ig-secreting cells, particularly of the IgG and IgM classes, were recovered from the bone marrow and spleen as compared to the lungs and intestine. Since only a portion of the total bone marrow population was studied, these data include that the bone marrow may be a major site of Ig-secreting cells in chickens beginning shortly after hatching.

Aging↗
PubMed1982

Hydrocortisone reverses the suppression of immunoglobulin synthesis by concanavalin A-activated spleen cell supernatants.

Supernatants of concanavalin A (Con A)-activated human spleen cells have been previously shown to inhibit polyclonal immunoglobulin (Ig) biosynthesis by pokeweed mitogen (PWM)-stimulated human spleen and peripheral blood mononuclear cells. In the present study, hydrocortisone was added at the beginning of in vitro culture to determine whether it might influence the immunoregulation of polyclonal IgG, IgA and IgM biosynthesis by PWM-stimulated human spleen and peripheral blood mononuclear cells. Hydrocortisone (10(-5) m) mildly increased (15 +/- 9%; mean +/- s.e.m.) polyclonal Ig biosynthesis when added to PWM-stimulated human mononuclear cells. The addition of supernatants from Con A-activated human spleen cells to PWM-stimulated human spleen and peripheral blood mononuclear cells significantly (P less than 0 . 001) suppressed (94 +/- 2%) polyclonal Ig biosynthesis. In contrast, when hydrocortisone (10(-5) m) was added together with Con A supernatants to PWM-stimulated cells, there was no significant suppression (6 +/- 13%) of polyclonal Ig synthesis. Thus, one mechanism by which hydrocortisone can influence Ig biosynthesis is by blocking the suppressive effect of a soluble suppressor factor secreted by Con A-activated human spleen cells.

Antibody-Producing Cells↗
PubMed1980

Blood flow distribution within the spleen distended by perfusion at high venous pressure.

Red cell washout from the isolated, Ringer-perfused cat spleen, dilated by perfusion at elevated venous pressure (25 cm H2O), was compared with that from the relaxed spleen perfused under normal venous pressure (6 to 8 cm H2O). Cell concentrations in the outflow were measured by a Celloscope counter and plotted on semi-logarithmic paper as a function of the volume of Ringer solution perfused. Washout kinetics from relaxed spleens yielded three exponential components, the V 1/2's being 3.1, 121, and 585 ml, respectively. In the case of dilated spleens, however, only two components were found. For spleens dilated, before washout, with blood in vivo the V 1/2 value were 50 and 415 ml; for normal spleens dilated in vitro, before washout, by Ringer perfusion at high venous pressure the V 1/2 values were 60 and 439 ml. The results indicate a greatly altered intrasplenic blood flow distribution in the presence of a high splenic venous pressure; the customary fast cmponent of flow is absent, and the blood appears to be directed entirely through the pulp. This must be the situation, presumably, in congestive splenomegaly arising from portal hypertension.

Animals↗
PubMed1994

[The possibilities for organ-preserving operations on the spleen].

Experience had with application of spleen salvaging operations in adult patients is shared. They are used traumatic lesions of the spleen in eleven patients, employing the method of Delany, as modified with the Bulgarian polyamide meshwork Ampoxen. In two of them the hemostasis fails, and splenectomy is resorted to. Preservation of the spleen is accomplished in one patient with chronic pancreatitis where left pancreatectomy with spleen preservation according to the technique of Pradere et al is done. In another female patient, presenting echinococcus of the spleen, echinococcectomy with preservation of the organ is performed. Based on updated knowledge of the role played by the spleen in promoting protection against infection, the strive for its salvage whenever possible is fully justified.

Caprolactam↗
PubMed1995

Murine spleen stromal cell line SPY3-2 maintains long-term hematopoiesis in vitro.

The hematopoietic microenvironment (HIM) of mouse spleen predominantly induces the differentiation of hematopoietic progenitors into erythroid lineage in vivo. However, the mechanisms of this phenomenon have not been fully explored because of the lack of an adequate in vitro system mimicking the spleen hematopoiesis. To reconstruct the HIM of mouse spleen in vitro, we established spleen stromal cell lines from a three-dimensional (3D) spleen primary culture in collagen gel matrix. Of these, SPY3-2 cells were negative for preadipocytic and endothelial markers, had a fibroblastoid morphology, and were not converted to adipocytes in the presence of 1 mumol/L hydrocortisone. They supported the maintenance and multilineal differentiation of hematopoietic progenitor cells for more than 8 weeks in vitro. The differentiated hematopoietic cells in the coculture medium were predominantly monocytes rather than granulocytes. Furthermore, erythropoiesis was predominantly induced in the presence of 2 U/mL erythropoietin and continued for more than 12 weeks. The number of burst-forming units-erythroid (BFU-E) was increased 10 times after 3 weeks of coculture, which was followed by pronounced production of erythroid cells in the coculture after week 4. SPY3-2 expressed high levels of c-kit ligand and low levels of granulocyte macrophage colony-stimulating factor and interleukin-3, and these molecules were all involved in this long-term erythropoiesis. Thus, the clonal SPY3-2 cell line will provide a novel HIM in vitro analogous to that of mouse spleen in vivo. These results suggest that 3D collagen gel culture may facilitate the establishment of functioning stromal cell lines of hematopoietic organ.

Adipose Tissue↗
PubMed1995

Immunohistochemical study of the spleen in chronic immune thrombocytopenic purpura. With special reference to hyperplastic follicles and foamy macrophages.

OBJECTIVE: To better understand immunologic and pathophysiologic changes in the spleen in chronic immune thrombocytopenic purpura. DESIGN: We performed immunohistochemical studies on 12 spleens of patients with immune thrombocytopenic purpura. RESULTS: Four spleens had prominent hyperplastic secondary follicles in the white pulp and trapping of platelet antigen (GPIIb/IIIa) in the germinal center. Four other spleens had hyperplastic follicles and foamy macrophages but no platelet antigen trapping in the germinal centers. Another four spleens had predominantly foamy macrophages but no hyperplastic follicles. Foamy macrophages were found mainly in the marginal zone; abundant platelet antigen (CD41) was present in their cytoplasm. CONCLUSIONS: Hyperplastic follicles in the white pulp or foamy macrophages in the marginal zone (or both) are major pathologic features in most spleens in immune thrombocytopenic purpura. The presence of platelet antigen (CD41) in the germinal centers and foamy macrophages may reflect the sites of immune reaction and platelet destruction in immune thrombocytopenic purpura.

Adolescent↗