bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loss of serological determinants does not affect recognition of H‐2Kk target cells by an influenza‐specific cytotoxic T cell clone
Authors: Wraith David C. , Holtkamp Bodo , Askonas Brigitte A. 
Published: February 2007

AbstractThe recognition of “self determinants” by an H‐2Kk‐restricted cytotoxic T (Tc) cell clone (K5) has been investigated as follows: (a) differential inhibition of cytotoxicity by several monoclonal antibodies directed to determinants on the H‐2Kk molecule of the target cells and (b) recognition and lysis of target cell variants of cell line LDHB, which have lost the majority or all of the serological determinants defined by the inhibiting antibodies while still expressing an H‐2Kk molecule. Such variant cells infected with influenza virus were effectively recognized by Tc cell clone K5, whereas a target cell line, which lacks the Kk molecule, was not lysed. The results suggest; (a) that virus‐specific Tc cell see “self” in a manner distinct from the recognition of serological determinants by B cell and (b) that antibody inhibition indicates conformational closeness, but not identity, of the class I determinant seen by T cells.
Immune capacity of the chicken bursectomized at 60 hours of incubation: transplantation of bone marrow cells of the bursectomized chickens into cyclophosphamide‐treated newly hatched recipients
Authors: Jalkanen Sirpa 
Published: February 2007

AbstractChickens bursectomized at 60 h of incubation are known to be able to produce immunoglobulins (Ig) but not specific antibodies. In the present work bone marrow (BM) cells of 2‐ and 10‐week‐old embryonically bursectomized (Bx) chickens were transferred to newly hatched cyclophosphamide‐treated chickens for the purpose of studying whether the transplanted cells home into the bursa and gain a capacity to produce specific antibodies. BM cells of normal 2‐ and 10‐week‐old chickens were transferred as controls. Cells of 2‐week‐old control (Co) and of 2‐ and 10‐week‐old Bx chickens could to some extent reconstitute serum Ig of the recipients, but were totally incapable of homing into the bursa and of restoring the specific antibody production. Only BM cells of 10‐week‐old Co chickens could restore the production of specific antibodies without homing into the bursa, indicating their postbursal nature. These findings indicate (a) that 2‐ and 10‐week Bx BM cells have irreversibly bypassed the bursal phase of education, (b) that also the normal BM at the age of 2 weeks contains cells that are capable of Ig but not of specific antibody synthesis and (c) that bursal microenvironment is not necessary for isotype switch, but is essential for creation and expansion of the antibody repertoire.
Opposite effects of the synthetic immunodulator, muramyl dipeptide, on rejection of mouse skin allografts
Authors: Zídek Zdeněk , Čapková Jana , Boubelík Michal , Mašek Karel 
Published: February 2007

AbstractThe influence of muramyl dipeptide (N‐acetylmuramyl‐L‐alanyl‐D‐isoglutamine) on the rejection of mouse skin allografts was investigated. While the 0.1‐mg dose administered on days 7, 6, 5 prior to transplantation caused significant prolongation of the graft survival, the 0.5‐mg dose administered on days 3,2,1 prior to transplantation resulted in remarkable augmentation of the graft rejection. The present results support the view that muramyl dipeptide can induce both stimulatory and suppressive immune mechanisms, depending on the treatment regimen.
The specificity of H‐2‐restricted cytotoxic T lymphocytes directed to AKR/Gross leukemia virus‐induced tumors I. Isolation of a selectively resistant variant tumor subclone
Authors: Green William R. 
Published: February 2007

AbstractThe AKR.H‐2bSL1 tumor cell line is susceptible to H‐2Kb‐restricted cytotoxic T lymphocytes (CTL) directed against the subclass of AKR endogenous leukemia virus‐induced tumors that express the Gross cell surface antigen (anti‐AKR/Gross virus CTL). A variant subclone (cl.18‐5) of AKR.H‐2bSL1 was isolated, whose susceptibility to lysis by conventional or cloned lines of anti‐AKR/Gross virus CTL was approximately 5% or less than that of the parental tumor. The cl.18‐5 variant was also ineffective when used as an in vivo priming cell or an in vitro stimulator cell in the generation of anti‐AKR/Gross virus CTL or as an unlabeled target cell in competitive inhibition assays. These results implied that the failure of cl.18‐5 to be lysed was due to a lack of recognition by the CTL.In contrast, cl.18‐5 was able to be lysed by and stimulate the generation of predominantly H‐2Db‐restricted CTL with apparent specificity for AKR minor histocompatibility antigens. The variant line was also about as susceptible as the parental AKR.H‐2bSL1 line to both allogeneic CTL and to H‐2Kb‐restricted, TNP‐specific CTL. Thus, the lack of recognition of cl.18‐5 by anti‐AKR/Gross virus CTL did not appear to be due to a failure to express functional H‐2 products or to a generalized insusceptibility to H‐2‐restricted CTL. Rather, cl.18‐5 appeared to be a selective variant and a useful probe for studying the specificity of anti‐AKR/Gross virus CTL.
Natural killer activity in (C57BL/6 × DBA/2)F1 hybrids undergoing acute and chronic graft‐vs.‐host reaction
Authors: Pattengale Paul K. , Ramstedt Urban , Gidlund Magnus , Örn Anders , Axberg Inger , Wigzell Hans 
Published: February 2007

AbstractThe present findings demonstrate that a total i. v. transfer of 100 × 106 C57BL/6 (B6) parental spleen cells into untreated (C57BL/6 × DBA/2)F1 hybrids (B6D2F1) resulted in acute runting, which was associated with a significantly elevated graft‐vs.‐host (GVH) index over a one‐month period following GVH induction. Furthermore, this B6‐induced acute GVH disease was associated with a marked depression of natural killer (NK) cell activity (spleen and peripheral blood) (with or without addition of mouse fibroblast interferon), which correlated with lymphoid cell hypocellularity, prominent splenic extramedullary hematopoiesis (EMH), and parallel depressions of both concanavalin A‐ and lipopolysaccharide‐induced mitogenesis. Significantly increased killing by antibody‐dependent cellular cytotoxicity of antibody‐coated chicken red blood cells, as well as increased T cell killing of the NK‐insensitive cell line P815 (as compared to the significantly decreased killing of the NK‐sensitive cell line YAC‐1) was also observed in the spleens of this 100 × 106 B6‐injected F1 group.In marked contrast to this 100 × 106 B6‐injected acute GVH group, untreated mice injected i. v. with the same or greater numbers of parental DBA/2 spleen cells (100 × 106‐150 × 106 DBA/2 spleen cells) exhibited a milder and more chronic form of GVH disease, which was not associated with a significant decrease of NK activity. It was of considerable interest that a total i. v. transfer of 50 × 106 B6 spleen cells (i.e. one‐half of that required to produce acute GVH, markedly depressed NK, and prominent splenic EMH) into B6D2F1 hybrids also resulted in a more chronic form of GVH disease, but was associated with significantly increased levels of NK activity at two weeks post GVH induction.
Tolerance induction during ontogeny II. Distinct unresponsive states in immature mice question the generality of clonal abortion
Authors: Waters Cory A. , Diener Erwin 
Published: February 2007

AbstractMultivalent trinitrophenyl (TNP) conjugates of both human γ‐globulin (HGG) and bovine serum albumin (BSA) are capable of inducing hapten‐specific unresponsiveness in neonatal mice, as assessed by challenge with TNP on thymus‐dependent carriers. When such mice are challenged with TNP on thymus‐independent carriers, however, only TNP‐HGG‐ but not TNP‐BSA‐treated mice are found to be substantially unresponsive to the hapten. Moreover, unresponsiveness induced by BSA, but not HGG, as a carrier was associated with the presence of antigen‐specific suppressor cells. Thus, contrary to predictions made by defendants of the classical clonal abortion hypothesis, functional deletion of hapten‐specific B cells appears to depend on the nature of the hapten‐carrier complex. This conclusion is supported by B cell‐precursor frequency estimates indicating that the number of hapten‐specific precursor cells is significantly lower in TNP‐HGG‐treated mice, but remains unaltered in TNP‐BSA‐treated mice relative to the precursor frequency in untreated animals. While it remains a formal possibility that the differences in tolerogenicity seen between the two carriers can be interpreted in terms of a difference in serum half‐life, we favor the interpretation that the distinction lies in molecular aspects of the carrier, which allow for differences in antigen handling by sets of interacting cells.
The emigration of lymphocytes from Peyer's patches in sheep
Authors: Reynolds John D. , Pabst Reinhard 
Published: February 2007

AbstractThe magnitude of the output of lymphocytes from Peyer's patches (PP), the morphology of the lymphocytes and their route of exit from PP has been examined in sheep. An extracorporeal perfusion system was used to selectively label a 3–4 m length of the terminal ileum of lambs at 6–10 weeks of age (the mesenteric lymph nodes had previously been excised from most lambs). This part of the intestine contains about 80% of the total PP tissue in a lamb and most of the lymphoid cells in the perfused tissue were within the PP. During a 10 min labeling period, fluorescein isothiocyanate (FITC) was added to the perfusate to label all the cells in the perfused tissues and [3H]thymidine ([3H] dThd) was added at the same time to label only those cells in the S‐phase of the cell cycle. The unincorporated label was then washed from the perfused tissues, the normal blood circulation was reestablished and the lamb allowed to recover from anesthesia. It was established that the labeling was restricted to the perfused tissue and therefore that any labeled cells subsequently found elsewhere in the animal must have emigrated from the terminal ileum. During the 24 h after perfusion 1.4 × 109−3.9 × 109 lymphoid cells (i.e. FITC labeled) left the perfused tissues via the lymph; 12–19% of these cells were either in the process of dividing or less than 24 h old (i.e. [3H] dThd labeled). The majority of the labeled cells probably came from the PP and most were classified as small lymphocytes although the [3H] dThd labeled population included a high proportion of large lymphocyte and lymphoblasts especially during the early hours after the perfusion. The labeled lymphocytes entered the blood in substantial numbers which increased linearly with time so that by 24 h about 7% of the lymphocytes in the blood were fluorescent. The numbers of newly produced cells began to increase rapidly in the blood only during the 12 h to 24 h period. The number of labeled cells in the blood was reduced by about 95% when the lymph from the perfused tissues was drained from the lamb during the experiment. This result provides clear evidence that the vast majority of all of the cells that leave the PP do so via the lymph and not via the blood.
Different mechanisms of release of vasoactive amines by mast cells occur in T cell‐dependent compared to IgE‐dependent cutaneous hypersensitivity responses
Authors: van Loveren Henk , Kraeuter‐Kops Sandra , Askenase Philip W. 
Published: February 2007

AbstractIt has recently been shown that the classical 24–48‐h component of delayed‐type hypersensitivity (DTH) in mice is preceded by an early 2‐h component. This early component of DTH resembles IgE‐dependent hypersensitivity reactions, but is mediated by an antigen‐specific T cell factor that activates cutaneous mast cells (MC). In the current study of cutaneous hypersensitivity reactions, evidence is presented that serotonin and histamine are released from the granules of MC in IgE‐dependent responses, but that T cell activation of MC induces preferential release of serotonin. In T cell‐dependent reactions, it was found that serotonin was released under experimental conditions in which MC granules were depleted of serotonin, but catabolism of serotonin in the cytosol was prevented. This suggests that T cells induce differential release of serotonin from nongranule storage sites in MC, such as transport vesicles in the cytoplasm. Morphological observations of MC in IgE‐dependent compared to T cell‐dependent cutaneous reactions were consistent with this hypothesis. Exocytosis of granules characterized IgE activation and was not found in MC that were activated by T cells, which instead showed mild degranulation accompanied by numerous cyto‐plasmic vesicles.
Pure interferon gamma enhances class II HLA antigens on human monocyte cell lines
Authors: Virelizier Jean‐Louis , Perez Nestor , Arenzana‐Seisdedos Fernando , Devos René 
Published: February 2007

AbstractHuman recombinant interferon gamma (IFN‐γ) with a chemical purity of over 90% was shown to enhance membrane expression of HLA‐DR antigens on cells from 3 human myelomonocytic lines (HL‐60, U‐937 and THP‐1). Immunofluorescence techniques using a series of anti‐HLA‐DR monoclonal antibodies showed that the low, although variable, levels of DR‐positive cells were clearly enhanced as soon as 24 h after incubation with IFN‐γ. Only IFN‐γ was able to exert this effect, since incubation with high concentrations of IFN‐α or ‐β did not induce any significant modification of the percentage of HLA‐DR‐positive cells. In contrast, doses of IFN‐γ as low as 2 units were effective, indicating a highly preferential, apparently selective effect of IFN‐γ for enhancement of HLA‐DR expression. Private class II antigen expression was also enhanced by IFN‐γ on the U‐937 cell line. Through its enhancing effect on class II public and private HLA antigens on the membrane of human monocytes, the IFN‐γ lymphokine may have a critical role in the modulation of antigen presentation by monocytes and on the regulation of HLA‐DR‐restricted cell cooperation.
Human B cell activation and cell cycle progression: stimulation with anti‐μ and Staphylococcus aureus Cowan strain I
Authors: Kehrl John H. , Muraguchi Atsushi , Fauci Anthony S. 
Published: February 2007

AbstractThe responses of resting human B lymphocytes to a variety of activation signals were studied. Human tonsillar B lymphocytes were separated according to size by countercurrent elutriation. The small B lymphocytes were then stimulated in vitro with various concentrations of anti‐μ antibody in the presence or absence of B cell growth factor (BCGF) or with Staphylococcus aureus Cowan strain I (SAC). Cellular volume changes and RNA synthesis were measured over the first 24 h of stimulation and were similar with either 15 μg/ml of anti‐μ, 100 μg/ml of anti‐μ, or SAC. In the subsequent 24 h, however, substantial increases occurred in the amount of RNA synthesis and cell enlargement only in those cultures stimulated with 100 μg/ml of anti‐μ or SAC, but not in the cultures stimulated with 15 μg/ml of anti‐μ. The addition of BCGF to those cultures stimulated with 15 μg/ml of anti‐μ did not alter the increases in cellular volume and RNA synthesis found 24 h after stimulation with anti‐μ alone. However, over the subsequent 24 h, the presence of BCGF in culture enhanced both B cell volume changes and RNA synthesis, when compared to cultures stimulated with 15 μg/ml of anti‐μ alone. In addition, BCGF enhanced DNA synthesis in cultures stimulated with low and high concentrations of anti‐μ. DNA content changes following stimulation with anti‐μ, anti‐μ plus BCGF, and SAC were also measured using propidium iodide staining and flow cytometry. Optimal concentrations of anti‐μ induced 20% of the resting B cells to enter S phase, while optimal concentrations of anti‐μ plus BCGF or SAC induced approximately 40%. Finally, prestimulation of resting B cells for 24 h with a low concentration of anti‐μ, sufficient for cell enlargement but not S phase progression, allowed for rapid entrance of the prestimulated B cells into S phase when a high concentration of anti‐μ or SAC was added. These findings suggest the existence of a control point in the progression of human B cells through the cell cycle. This control point is located in the G1 phase of the cycle and is reached 24 to 36 h after a surface immunoglobulin‐mediated stimulus.
Activation and proliferation signals in mouse B cells II. Evidence for activation (G0 to G1) signals differing in sensitivity to cyclosporine
Authors: Klaus Gerry G. B. , Hawrylowicz Catherine M. 
Published: February 2007

AbstractWe have previously shown that cyclosporine (CS) selectively inhibits polyclonal activation of B cells by anti‐Ig antibodies but not by lipopolysaccharide (LPS). Here we extend these results using a two‐stage B cell culture system in which cells from either CBA/N or normal mice are activated to enter G1 by anti‐Ig, and are then stimulated to proliferate by LPS. In this system CS blocks an event that occurs within 4 h after initial activation, i.e. prevents entry of B cells into G1. Phorbol myristic acetate also induces some CBA/N B cells to enter G1. However, activation of B cells by this agent is resistant to inhibition by CS. These data suggest that there are two biochemically distinct mechanisms for driving resting B cells into G1. A hypothesis to explain these results is presented.
T‐dependent activation of resting B cells mediated by concanavalin A
Authors: Ratcliffe Michael J. H. , Julius Michael H. 
Published: February 2007

AbstractIn cultures containing long‐term cultured lines of antigen‐specific helper T (Th) cells, normal unprimed B cells and concanavalin A (Con A), induction of B cells to immunoglobulin secretion and DNA synthesis was observed. The plaque‐forming cell (PFC) response was large (frequently > 75000 PFC/106 input B cells) demonstrating the polyspecific nature of the response. Con A‐mediated maturation and induction to DNA synthesis of responding B cells was completely Th cell dependent and inhibited with methyl‐α‐D‐mannoside. Both resting and blasted B cells, separated by Percoll density centrifugation were induced to DNA synthesis and immunoglobulin secretion. Responses were completely unrestricted by the B cell major histocompatibility complex, even at the level of the resting B cell. The polyclonal nature of the response taken together with the Con A‐mediated bypassing of T cell specificity and restricting haptotype indicates that this response is analogous to lectin‐mediated cytotoxicity.
A monoclonal antibody which differentiates between bound and free human secretory component
Authors: Gore Martin E. , Bunnage Hilary J. , McIlhinney Robert A. J. 
Published: February 2007

AbstractIn this study a mouse monoclonal antibody (LICR‐LON‐LC28) to human secretory component (SC) is reported. This antibody binds to free SC or to SC associated with IgA or IgM. It exhibits a 10‐fold higher affinity for SC bound to IgA than for free SC. The affinity of the antibody for SC associated with IgM is equivalent to that seen for free SC.LICR‐LON‐LC28 appears to be species specific and does not cross‐react with other human milk proteins.
Clonal expression of differentiation and Ia‐like antigens on alloreactive human T lymphocytes
Authors: Schendel Dolores J. , Johnson Judith P. , Evans Robert L. , Wank Rudolf 
Published: February 2007

AbstractA series of human T lymphocyte clones showing specific responses for major histocompatibility complex‐encoded alloantigens were isolated from a single culture. They were classified into distinct functional groups based on measurement of alloantigen‐specific proliferation and cytotoxicity. Surface antigen expression on these clones was analyzed using a panel of monoclonal antibodies specific for T cell differentiation antigens and for Ia‐like antigens. Four distinct groups were identified based on the Leu series of differentiation antigens: (a) Leu1+,2+,3+,4+; (b) Leu1+,3+,4+; (c) Leu1+,2+,4+; and (d) Leu2+,4+. Functionally distinct clones showed not only differential expression of Leu2 and Leu3, antigens which had previously been shown to distinguish helper/inducer and cytotoxic/suppressor cells, but also of Leu1, an antigen classified as a common T cell marker. All of the clones were found to express Ia antigens as detected by three framework monoclonal antibodies, but none were found to express a determinant associated with the DR3 allospecificity, although it was found on normal B lymphocytes and a B cell line established from the HLA‐DR3 individual from whom these clones were derived.
Frequency and activity of immune interferon (IFN‐γ)‐and colony‐stimulating factor‐producing human peripheral blood T lymphocytes
Authors: Kees Ursula , Kaltmann Brigitte , Marcucci Fabrizio , Hültner Lothar , Staber Fritz , Krammer Peter H. 
Published: February 2007

AbstractThis report describes the first frequency estimate of immune interferon (IFN‐γ)‐ and colony‐stimulating factor (CSF)‐producing human peripheral blood T lymphocytes. Human peripheral blood lymphocytes (HPBL) were activated with T cell mitogens [concanavalin A (Con A) or phytohemagglutinin (PHA)] in bulk culture and subsequently plated in limiting dilution (LD) microcultures in the presence of irradiated allogeneic HPBL filler cells and culture medium supplemented with human inter‐leukin 2 and T cell mitogen (Con A or PHA). HPBL growing in these cultures were T cells as determined by E‐rosetting (> 85%) and were positive for the OKT8 marker. The growth frequency (f) of HPBL in LD was f = 1/20‐1/100. Such cells were induced with T cell mitogens (Con A or PHA) to release lymphokines into the supernatant. Statistical analysis of the data from the LD experiments showed that (a) the precursor cell frequency for IFN‐γ‐ and CSF‐producing T cells was f = 1/63‐1/151 and 1/89‐1/217, respectively, and (b) most T cell clones released IFN‐γ and CSF simultaneously. In addition, individual T cell clones were shown to be capable of releasing different CSF types. In principle, this experimental system can be used to evaluate the precursor frequency, relationship and activity of normal or pathological human T cells performing any in vitro T cell function.
Antigenic polymorphism of Trypanosoma cruzi: clonal analysis of trypomastigote surface antigens
Authors: Plata Fernando , Pons Francisco Garcia , Eisen Harvey 
Published: February 2007

AbstractThe surface membrane antigens of infectious Trypanosoma cruzi trypomastigotes were studied at the levels of the strain and of individual trypomastigote clones. Blood trypomastigotes from three T. cruzi strains, Y, CL and Tehuantepec (“Teh”), were grown in vitro by weekly infection of J774 mouse macrophage tumor cells. Each T. cruzi strain was subsequently cloned by infection of J774 cells at limited trypomastigote dilution, and antisera were produced in mice against a selection of trypomastigote clones. Criss‐cross panel analyses indicated the existence of a large degree of polymorphism among trypomastigote surface antigens. Various trypomastigote surface antigens were cross‐reactive, appeared to be highly conserved, and were common to the three strains considered and to all the clones derived from each strain. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that numerous trypomastigote antigenic proteins were precipitated by mouse antisera generated against cloned trypomastigotes. Some of these proteins were commonly distributed, while others were polymorphic. Finally, a state of cross‐reactive immunity could be induced in C3H/He mice by infection with a cloned T. cruzi trypomastigote population. Immune mice resisted subsequent infections with lethal doses of wild‐type bloodstream trypomastigotes from any one of the three T. cruzi strains.