bluuebunny/crossref_metadata_2025_split huggingface dataset:
The evolution and involution of Peyer's patches in fetal and postnatal sheep
Authors: Reynolds John D. , Morris Bede 
Published: February 2007

AbstractThe Peyer's patches (PP) of sheep have a number of important anatomical features and functional characteristics which are similar to tissues that have been classified as primary lymphoid organs. The prenatal maturation of PP occurs in the absence of any antigenic stimulus as immunogenic molecules are not normally encountered by the sheep fetus. Primordial PP were first detected in the small intestine of fetal sheep at about 60‐days gestation; lymphoid follicles were present by 75‐days gestation and vigorous lymphopoiesis was occurring in these follicles by 100 days. From 120‐days gestation until birth, at about 150 days, the PP follicles were histologically mature and they had the greatest density of proliferating lymphoid cells found anywhere in the body. The total number of PP and their constituent follicles had developed before birth when there were 25–40 discrete PP in the jejunum and proximal ileum and one single continuous PP in the terminal ileum. There was no evidence of any change in the rate of growth of the PP follicles at birth which could be related to the advent of the first antigens in the gut.The total weight of PP tissue was greater than any other single lymphoid tissue by about 6 weeks after birth weighing around 120 g or about 1.2% of the body weight; about 50–60 g of the PP tissue was calculated to be lymphoid tissue. At this time the ileocecal PP (IPP) extended 2.5 m along the terminal ileum and accounted for about 90% of the total mass of PP.From about 12 weeks after birth the IPP began to involute and only a few PP follicles remained in this region of the intestine by 18 months of age. Follicles in PP in other parts of the small intestine remained and continued to produce lymphocytes throughout the life of the animal.PP contain a number of anatomically and functionally distinct lymphoid compartments that could play different roles in the body's immune defense. Explicit in most theories on the function of PP is the notion that antigenic stimulation is the cause of the lymphopoiesis in the follicles; our results do not support this view. Instead they suggest that the follicles in the PP of sheep may play a role similar to that played by the bursa of Fabricius in birds.
Disappearance and reappearance of high endothelial venules and immigrating lymphocytes in lymph nodes deprived of afferent lymphatic vessels: a possible regulatory role of macrophages in lymphocyte migration
Authors: Hendriks Hans R. , Eestermans Inge L. 
Published: February 2007

AbstractInterruption of the afferent lymphatic vessels of the popliteal lymph node resulted in the disappearance of high endothelial venules (HEV) and immigrating lymphocytes within 3 weeks. HEV showed several characteristic morphological changes: the endothelial cells became flattened and less pyroninophilic, the chromatine became condensed and protein synthetizing and secretory cell organelles became scarce. At the same time the number of macrophages in the lymph node was severely reduced. Injection of sheep red blood cells into such lymph nodes, 6 weeks after operation, resulted in reappearance of HEV and immigrating lymphocytes, and development of many plasma cells and some germinal centres. Injection of lipopolysaccharide into the operated lymph nodes resulted in the appearance of many plasma cells and a few poorly developed germinal centres; HEV and immigrating lymphocytes, however, remained almost absent.The results show a relationship between the immigration of lymphocytes and the activity of the endothelial cells in the HEV. The activation of the latter may occur by mediators released by antigen‐stimulated macrophages and T cells. Moreover, the morphological features of the HEV are independent of the presence of recirculating lymphocytes.
Ultrastructural characteristics of human T cell clones with various cytolytic activities
Authors: Grossi Carlo E. , Zicca Antonio , Cadoni Angela , Mingari Maria C. , Moretta Alessandro , Moretta Lorenzo 
Published: February 2007

AbstractFifteen T cell clones with different (specific, antibody‐dependent or natural killer‐like) cytolytic activity were derived from mixed lymphocyte culture activated T cells and analyzed for their morphological characteristics and, in some instances, for their surface markers.All of the five cytolytic clones analyzed by electron microscopy possessed numerous electron‐dense granules and in some instances multivesicular bodies, with or without an electron‐dense matrix, that are the putative precursors of the granules. In addition, light microscopy examination of semithin sections of other ten cytolytic clones showed that the large majority of the cells in each clone had numerous toluidine blue‐stained cytoplasmic granules. It is of note that nine clones without detectable cytolytic activity analyzed by electron microscopy did not possess granules and presented the features of large agranular blasts. Ten cytolytic clones were analyzed for different surface markers including rosette formation with sheep erythrocytes (E rosettes), receptors for the Fc portion of IgG or IgM (FcγR and FcμR) and a group of antigens recognized by monoclonal antibodies including Ia, 4F2, OKT8 or OKT4. All the clones were Erosette+, Ia+ and 4F2+. Expression of FcγR was restricted to the clones active in antibody‐dependent cell‐mediated cytotoxicity. Expression of OKT8 and OKT4 antigens was variable; in particular, five clones were OKT8+/OKT4−, whereas the other five expressed the OKT8−/OKT4+ phenotype. It is noteworthy that the ultrastructural features of cytolytic T cell clones are similar to those of large granular lymphocytes, known to be the only lymphoid cells in normal peripheral blood which possess cytolytic activity. Thus, it is possible that the presence of electron‐dense granules may represent a morphological marker for all human cytolytic lymphocytes.
Thymic reticulum in mice III. Phagocytic cells of the thymic reticulum in culture secrete both prostaglandin E2 and interleukin 1 which regulate thymocyte proliferation
Authors: Papiernik Martine , Homo‐Delarche Françoise 
Published: February 2007

AbstractA phagocytic cell of the thymic reticulum in culture (P‐TR‐C) has recently been isolated whose characteristics closely resemble those of the thymic interdigitating cell despite the modifications induced by culture conditions.In the present report it is demonstrated that this cell population is able to produce both interleukin 1 (IL1) and prostaglandin E2 (PGE2). IL1 has no direct mitogenic effect on thymocytes but is comitogenic with concanavalin A. PGE2 has no direct effect on the secretion of IL1 by P‐TR‐C, but has an effect antagonistic to IL1, inhibiting thymocyte proliferation. P‐TR‐C are thus able to modulate thymocyte proliferation in vitro.
Synthesis of λ light chain subtypes by stimulated and unstimulated mouse B cells
Authors: Onodera Yoshimitsu , Reilly Edward B. , Eisen Herman N. 
Published: February 2007

AbstractInbred mouse make 3 λ chain subtypes. The λ1 and λ3 chains have similar variable (V) regions (in both the same V gene segment [Vλ1] is used), whereas λ2 and λ3 have similar constant (C) regions. Despite the λ1 and λ3 V region similarity, λ1 occurs much more frequently than λ3 (and λ2) in the serum immunoglobulins and antibody responses of most inbred strains of mice. To explore the basis for the λ1 predominance, we compared the rates of synthesis of the 3 subtypes and the frequencies of the B cells that synthesize them, focussing on “resting” (i.e., unstimulated) and on polyclonally stimulated B cells from spleens of unimmunized BALB/c mice.In resting cells the relative rates of synthesis and the relative frequencies of the respective B cells were in accord, indicating that the rate of λ chain synthesis is approximately the same per resting B cell, regardless of the λ subtype it produces. However, in the polyclonally stimulated cells, λ1 was made 7 times faster than λ2 and 10 times faster than λ3; normalizing these rates by the frequencies of the respective stimulated cells suggests that in stimulated B cells λ1 chains are made 5 times faster per cell than λ2 or λ3, while the latter are made at about the same rate per cell. In view of the marked structural homology between λ2 and λ3 genes in segments other than the V‐gene segment, we suggest that the pronounced differences among polyclonally stimulated B cells in expression of the genes for the various λ subtypes may be due to the presence of less potent enhancer‐like sequences in the λ2 and λ3 genes than in the λ1 gene.
Epitope specificity and Ia restriction of T cell responses to insulin in a system of complementing Ir genes: analysis with primed lymph node T cells and a long‐term cultured T cell line
Authors: Spaeth Eberhard , Rüde Erwin 
Published: February 2007

AbstractThe antibody response of (H‐2b × H‐2k)F1 mice to pig insulin (PI) has previously been shown to be under the control of H‐2‐linked, complementing Ir genes. In addition, this response was reported to depend on the genetic background of the parental strains (Keck, K., Eur. J. Immunol. 1977. 7: 811). Here it is demonstrated that the secondary in vitro response of proliferating T cells shows the same dependence on H‐2‐linked Ir genes yet an influence of the background genes could not be detected. The complementing genes were mapped to the Kb, I‐Ab and Kk, I‐Ak regions. For restimulation of F1 T cells by PI, the Ir genes of both parental chromosomes have to be expressed in the same antigen‐presenting cell, suggesting complementation at the molecular rather than at a cell interaction level. With a long‐term cultured, PI‐specific T cell line (ST2) of (B10 × B10.BR)F1 origin the complementation data could be confirmed by mapping the Ia restriction elements to Kb, I‐Ab and I‐Ak. The reactivity pattern of this line towards species variants of insulin and the isolated A and B polypeptide chains in the presence of syngeneic accessory cells suggests that the glutamic acid residue in position 4 of the A polypeptide chain (Asp in mouse insulin) is essential for recognition in conjunction with an (I‐Ab × Ak)F1 hybrid Ia complex. I‐Ab‐encoded molecules carrying specificity Ia. W39 which, according to Rosenwasser, L. J. and Huber, B. T. are essential for the presentation of BI to (CBA/N × C57BL/6)F1 T cells, are not required as components of the F1‐unique restriction element recognized by the F1 T cells of the ST2 line in conjunction with PI. This is indicated by the fact that accessory cells of (CBA/N × B10)F1 hybrids, regardless of their sex, could present PI as well as beef, sheep and horse insulin to the F1‐restricted ST2 cells.
Antibodies specific for different T15 idiotopes induce neonatal suppression of the T15 idiotype
Authors: Berek Claudia 
Published: February 2007

AbstractThe response of BALB/c mice to Pneumococcus pneumoniae is dominated by a single idiotype defined by the phosphorylcholine‐binding myeloma protein TEPC15 (T15). Injection of newborn BALB/c mice with antibodies to the T15 idiotype will lead to suppression of this idiotype. Such mice will respond to the antigen Pneumococcus, but with idiotypically different anti‐phosphorylcholine antibodies. In an attempt to further characterize the effect of anti‐idiotypic antibodies on induction of tolerance, three monoclonal antibodies specific for different T15 idiotopes were used. Although these antibodies belonged to the mouse immunoglobulin classes, IgG1 or IgG2a, and were derived from different mouse strains, in all cases, a long lasting suppression could be induced. The data show that injection of idiotope‐specific antibodies will suppress the T15 idiotype, but not necessarily the idiotope itself. The results are discussed in terms of the mechanism which will lead to the suppression of a dominating idiotype in the newborn mouse.
The immunomodulatory effect of anti‐Micrococcus luteus antibodies I. Effect on in vitro rabbit T cell functions
Authors: Vaeck Mark , Grooten Johan , Hamers Raymond , De Baetselier Patrick 
Published: February 2007

AbstractA range of purified rabbit anti‐Micrococcus luteus antibodies (anti‐MCAb) were tested for their ability to interfere with a variety of in vitro immune responses. Such antibodies strongly inhibited the secondary IgG antibody response to sheep red blood cells without affecting the IgM response or the proliferative responses to mitogens and antigens. By exposing lymphocyte populations to anti‐MCAb, it was found that such reagents exerted a strong mitogenic effect on rabbit T lymphocytes, provided these cells were derived from antigen‐activated lymph nodes. This mitogenic effect was also obtained with F(ab')2 fragments of anti‐MCAb and with hybridoma‐derived anti‐MCAb. Collectively, these data indicate that anti‐MCAb inhibit the initiation of IgG synthesis possibly through the expansion of immunoregulatory T cell subsets.
Detection in vivo 6 hours after immunization of a mediator with possible antisuppressor activity
Authors: Al‐Maghazachi Azzam , Lee Sho‐Tone , Paraskevas Frixos 
Published: February 2007

AbstractImmunization of mice with foreign proteins or particulate antigen induces the formation of immunoglobulin (Ig)‐antigen complexes which are strongly cytophilic for T cells and have been shown recently to markedly enhance the 7 S antibody response. In this report we demonstrate that pretreatment of the animals with cyclophosphamide or anti‐I‐J antiserum eliminates the difference in the antibody response between the mice injected with the complexes and the controls, in other words, the enhancement. Six hours after allogeneic stimulation the serum of mice contains also a cytophilic (for T cells) Ig which most likely represents, as in the case of the foreign antigens, complexes of Ig with alloantigens. The allogeneically induced 6‐h serum (6HS) contains a factor which enhances the cytotoxic T lymphocyte(s) (CTL) response in vivo. As with the 7 S antibody response, pretreatment of mice with cyclophosphamide, in doses known to eliminate suppressor cell expression, “masks” the CTL enhancement of the allogeneically induced 6HS. The same result was also observed with the anti‐I‐J antiserum.In conclusion, the 6‐h complexes in cyclophosphamide‐ and anti‐I‐J‐treated mice do not produce a 7 S antibody or CTL response above that produced by the control group (no complexes).Using heat‐treated allogeneic tumor cells, known to induce suppressor cells in vivo, we have shown that for a low dose of tumor cells, the allogeneically induced 6HS did not block the induction of suppressor cells, but completely blocked their function. These results suggest that the enhancement of both humoral and cell‐mediated immunity by the 6HS (complexes) is likely to be due to interference with normal suppressor cell function, that is, an antisuppressor mechanism.
Regeneration and the immune system II. Suppressor activities of lymphocytes activated in vivo by liver regeneration and their genetic control
Authors: Yokomuro Kozo , Miyahara Seiko , Takahashi Hidemi , Kimura Yoshitami 
Published: February 2007

AbstractThe lymph node cells (LNC) activated in vivo by liver regeneration following partial hepatectomy of mice (primed lymph node cells) respond to regenerating liver cells in vitro with typical secondary immune response characteristics (Miyahara, S. et al., Eur. J. Immunol. 1983. 13: 878). These LNC activated in vivo suppress the proliferation of responder lymphocytes cultured with mitomycin C‐treated regenerating syngeneic liver cells (sMLHLR). The suppressive activity was already present in LNC 4 days after partial hepatectomy and remained unchanged for at least 16 days. These primed LNC were effective not only on sMLHLR but also on syngeneic mixed lymphocyte culture (sMLR) and allogeneic mixed lymphocyte culture, of which responder cells share the I‐A (I‐B) subregions of the major histocompatibility complex (MHC) with primed LNC. At least one cell in the suppressor circuit is a T cell. The primed LNC restimulates in vitro with regenerating liver cells (in vitro reactivated primed LNC) suppressed the proliferation of syngeneic responder cells in sMLR, but not of cells from congeneic mice differing from the in vitro reactivated primed LNC at a cluster of genes linked to the Ig locus. Thus the suppressive activity of primed LNC is controlled by the I‐A (I‐B) subregions of the MHC and that of in vitro reactivated primed LNC by genes in the Ig region. The role of these suppressive cells in liver regeneration is discussed.
Rabbit leukocyte surface antigens defined by monoclonal antibodies
Authors: De Smet Walter , Vaeck Mark , Smet Erik , Brys Lea , Hamers Raymond 
Published: February 2007

AbstractSeveral monoclonal antibodies (mAb) against rabbit leukocytes were characterized in binding and functional studies. mAb 1.24 stains thymocytes, bone marrow cells, peripheral T and B cells and blood monocytes. T cells express more 1.24 antigen than B cells. In the absence of added complement (C), mAb 1.24 inhibits alloantigen‐, concanavalin A (Con A)‐, and phytohemagglutinin (PHA)‐, but not pokeweed mitogen (PWM)‐ or anti‐immunoglobulin (Ig)‐induced cell proliferation. It also strongly blocks anti‐sheep erythrocyte plaque‐forming cell responses. A second mAb, designated 4.B9, binds to 20% of thymocytes and to most, if not all, peripheral T cells and in vitro‐activated T cell blasts. A third one, 10.B3, is reactive with the nearly entire thymocyte and a major peripheral T cell population. Two‐color membrane immunofluorescence reveals the presence of a small population of peripheral blood leukocytes which bear surface Ig and are weakly stained by mAb 4.B9 and 10.B3. Without C, both 4.B9 and 10.B3 inhibit Con A‐ and PHA‐induced mitogenesis, but have no effect on PWM‐, antigen‐, or alloantigen‐induced cell proliferation. Depletion of 4.B9+ cells by panning or complement lysis completely abrogates proliferative responsiveness to antigen and alloantigen, significantly reduces responsiveness to the T cell mitogens Con A and PHA, but enhances that to the B cell mitogen anti‐Ig. A fourth mAb, 12.C7, binds to 60% of thymocytes and to 10–30% of peripheral T lymphocytes at high‐level fluorescence. T cell blasts obtained in mixed leukocyte reactions are partially stained by mAb 12.C7, while those obtained after Con A or PHA activation are not. In addition, mAb 12.C7 is completely unreactive with B cells or monocytes. Without complement, it does not seem to interfere with any of the in vitro functions tested. All antigens studied here do not appear to be expressed in nonleukon tissues, as they do not bind to erythrocytes and are absent from brain, heart, liver and kidney as shown by quantitative absorption analysis.
Analysis by limiting dilution of interleukin 2‐producing T cells in murine ontogeny
Authors: Ishizaka Sally T. , Stutman Osias 
Published: February 2007

AbstractThe ontogeny of interleukin 2 (IL2) production in young CBA/HT6T6J mice was studied using both bulk culture and limiting dilution methods. The ability of spleen cells in bulk culture to produce IL2 in response to concanavalin A (Con A) was found to rise through the first 2 weeks of life, from no production at day 1, through 20 units/ml at day 6, to 80–100 units/ml in adults. No evidence for suppression of IL2 production by young spleen was found. Limiting dilution analysis of both young spleen and young lymph node (LN) shows that young spleen has a much lower complement of cells producing IL2 in response to Con A or allogeneic stimulation than does adult spleen. The frequency of 6‐day spleen cells producing IL2 in response to Con A is 1/1000, while the adult frequency is approximately 1/50. Young LN, in contrast, has levels of IL2‐producing cells close to those of adult LN, with a frequency of responders to Con A of 1/20. No evidence was found for a deficiency in IL2 production on a per cell basis, in either 6‐day spleen or LN. In examining allogeneic reactivity, a high frequency of cells reacting to strong Mls stimulation was found in both young and adult spleen and LN.
Induction of natural killer‐like cytotoxicity in cultured human thymocytes
Authors: Toribio María Luisa , De Landázuri Manuel O. , López‐Botet Miguel 
Published: February 2007

AbstractSupernatants containing interleukin 2 (IL2) induce strong proliferation and expression of natural killer (NK)‐like activity in human thymocytes. Different supernatants were compared for: (a) IL2 activity, (b) thymocyte proliferation capacity and (c) induction of NK‐like cytotoxicity. All these activities were present in a partially purified IL2 preparation obtained by gel filtration chromatography (Mr 15000–20000). However, in supernatants from different sources and in the 15000–20000‐Mr semipurified fractions, we observed that the NK‐like cytotoxicity inducer effect did not correlate with either the mitogenicity or the IL2 activity.The presence in the supernatants of interleukin 1 (IL1), interferon (IFN) or phytohemagglutinin (PHA) does not seem to be a prerequisite for the induction of NK‐like cytotoxicity, since this activity was (a) fully present in supernatants devoid of IL1, IFN and PHA, (b) absent in preparations of IL1 and (c) not augmented after supplementation of the supernatants with IFN‐γ.We also investigated the cellular characteristics of the precursor thymocytes responsive to IL2 supernatants. Removal of the T3+ cells at the initiation of the culture abrogated the proliferative response and eliminated the generation of NK‐like cytotoxicity. Under the same conditions, removal of the HTA1+ population increased the proliferation and did not affect the NK‐like activity.Our results suggest that: (a) either IL2 is not responsible for the induction of NK‐like cytotoxicity or its action is modulated by other molecules, and (b) the precursor‐responder population is preferentially included in the mature T3+ subset.
Immune elimination of aging platelets by autologous monocytes: role of membrane‐specific autoantibody
Authors: Khansari Nemat , Fudenberg H. Hugh 
Published: February 2007

AbstractMembrane‐bound IgG was found only on old populations of platelets from normal individuals. This IgG could be dissociated from senescent cells by repeatedly heating the cells. Heat‐eluted IgG (He‐IgG) prepared from senescent red blood cells was capable of binding to either heat‐treated old platelets or Vibrio choleare neuraminidase (VCN)‐treated young platelets, suggesting expression of a common age‐dependent antigen on the senescent red blood cells and old platelets. We analyzed the role of membrane‐bound IgG in the immune elimination of aging platelets by direct phagocytosis of different platelet subpopulations by autologous monocytes in vitro. While removal of He‐IgG from old platelets inhibited their phagocytosis, preincubation of either heat‐treated old or VCN‐treated young platelets promoted phagocytosis of these cells by autologous monocytes. The phagocytosis of senescent cells required intact IgG on these cells. Either removal of Fc fragments from He‐IgG or treatment of autologous monocytes with Fc fragments prior to the phagocytosis assay resulted in a marked reduction of phagocytosis (> 75%). We conclude that Fc receptors on the monocytes and the presence of membrane‐specific IgG are crucial elements for immune elimination of senescent platelets.