bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD3 antigen‐mediated calcium signals and protein kinase C activation are higher in CD45R0+ than in CD45RA+ human T lymphocyte subsets
Authors: Robinson Anne T. , Miller Nigel , Alexander Denis R. 
Published: March 2007

AbstractT lymphocytes may be separated into subsets according to their expression of CD45 isoforms. The CD45R0+ T cell subset has been reported to proliferate in response to recall antigen and to mitogenic mAb to a much greater extent than the CD45RA+ subset. This difference could be due to more efficient coupling of the T cell antigen receptor complex to mitogenic signaling pathways. To investigate this possibility, CD3 antigen‐induced calcium signals, diacylglycerol (DAG) production and protein kinase C (PKC) activation levels were compared in CD45RA+ and CD45R0+ human T lymphocyte subsets derived from peripheral blood. The mean CD3‐induced rise in intracellular calcium was 80% greater in CD45R0+ than in CD45RA+ cells. Basal DAG levels in CD45R0+ cells were found to be, on average, 60% higher than in CD45RA+ cells (p = 0.002), but the CD3‐induced production of DAG over background was not different in the two subsets (p = 0.4). Basal PKC activity, and CD3‐induced PKC activation levels over background, were found to be 50% and 140% higher, respectively, in CD45R0+ cells than in CD45RA+ cells (p = 0.015 and 0.023). The CD45R0+ subset contained a higher proportion of cells expressing activation markers, such as CD25, CD71 and major histocompatibility complex class II, when compared to the CD45RA+ subset. Our results suggest that the elevated basal DAG levels observed in the CD45R0+ subset may reflect the recent activation of these cells. Both the higher basal DAG and CD3‐induced elevation in intracellular calcium observed in the CD45R0+ cells may contribute to the greater PKC activation signals triggered by CD3 mAb in this subset. These findings elucidate the greater response of CD45R0+ T cells to mitogenic stimuli compared to CD45RA+ cells.
Recognition of shared melanoma antigen by HLA‐A2‐restricted cytolytic T cell clones derived from human tumor‐infiltrating lymphocytes
Authors: Viret Christophe , Davodeau Francois , Guilloux Yannick , Bignon Jean‐Denis , Semana Gilbert , Breathnach Richard , Jotereau Francine 
Published: March 2007

AbstractThree melanoma‐specific cytotoxic T lymphocytes (CTL) clones were derived from the tumor‐infiltrating lymphocyte (TIL) of human melanoma M17, and were used to study the expression of immunogenic melanoma peptides on allogeneic tumors. Antibody inhibition studies showed that two of these TIL clones were restricted by an HLA‐A2 molecule which was identified as A2.1 by gene sequencing. The third CTL clone was not restricted by HLA‐A2, but by a B or C HLA antigen. HLA‐A2‐restricted CTL clones M17‐1 and M17‐2 lysed 5 and 12 out of 15 HLA‐A2+ allogeneic melanomas, respectively. Since they did not lyse autologous Epstein‐Barr virus B cells, HLA‐A2.1‐transfected P815 cells,13 HLA‐A2+ non‐melanoma tumor cell lines and 10 HLA‐A2− melanomas, these clones appeared specific for melanoma‐restricted epitopes presented by the HLA‐A2.1 molecule. We then tried to determine why a few HLA‐A2+ melanomas were refractory to TIL lysis. By using a combination of flow cytometry analysis, partial cloning and sequencing of their HLA‐A2 genes, we show that failure to lyse did not result from low expression or polymoprhism of the HLA‐A2 molecule, or from deficient expression of the adhesion molecules ICAM‐1 and LFA‐3 by these melanomas. Taken together, our data confirm at the clonal level the existence of shared melanoma antigens recognized by TIL in the HLA‐A2.1 context. They further show that individual peptides derived from these antigens are expressed by a large majority of HLA‐A2+ melanomas. Identification of such peptides appears crucial for the future of vaccination therapies.
A role for immunoglobulin D: interference with tolerance induction
Authors: Carsetti Rita , Köhler Georges , Lamers Marinus C. 
Published: March 2007

AbstractWe have studied the induction and maintenance of tolerance in the B lymphocyte compartment. Neonatal and adult transgenic mice which expressed either surface IgM (sIgM) or sIgM and sIgD anti‐2,4,6‐trinitrophenyl (TNP) were treated with soluble mono‐ and multivalent forms of TNP‐modified carriers. We compared the B cell compartment of mice treated with antigen and of littermates injected with phosphate‐buffered saline. Antigen‐mediated cross‐linking of membrane‐bound IgM (sIgM) caused deletion of B cells both in neonatal and adult mice with μ and χ transgenes. Deletion was the result of apoptosis. In mice that carried an additional δ transgene sIgD interfered with tolerance induction. The stage in which the cells were sensitive to deletion was characterized as a transitional stage between immature (sIgMdull, heat‐stable antigenbright, B220dull, sIgD−) and more mature (IgMbright, heat‐stable antigendull, B220bright, slgD−) B cells. Surviving cells were functional as measured by receptor‐mediated changes in the intracellular free Ca2+ concentration. We propose that when the immature B cells have reached the final stages of maturation IgM always transmits negative signals in the absence of T cell help. When B cells need to be screened against self reactivity IgM is the only antigen receptor expressed. The presence of sIgD protects resting B cells from deletion and allows them to initiate an effective immune response.
Macrophage colony‐stimulating factor gene transfer into tumor cells induces macrophage infiltration but not tumor suppression
Authors: Dorsch Marion , Hock Hanno , Kunzendorf Ulrich , Diamantstein Tibor , Blankenstein Thomas 
Published: March 2007

AbstractIn order to analyze the effect of a high local concentration of macrophage colony‐stimulating factor (M‐CSF; CSF‐1) on tumor growth, the plasmacytoma cell line J558L was transfected with the human M‐CSF gene and injected into syngeneic BALB/c mice. In contrast to the parental tumors, M‐CSF transfectants were heavily infiltrated by macrophages as evidenced by immunohistochemistry with antibodies to Mac‐1 and Mac‐3 and by isolation of the macrophages from the tumor. Nevertheless, tumor growth was only slightly affected by M‐CSF and M‐CSF‐producing cells grew as tumor in all cases. The growth retardation of M‐CSF‐producing cells varied depending on the experiment and seemed to be due to an indirect effect because the growth rate of the cells in vitro had not changed upon gene transfer. Attempts to activate the tumor‐infiltrating macrophages for tumor suppression by systemic application of interferon‐γ and/or lipopolysaccharide were not successful. Altogether, our results suggest that M‐CSF is a potent chemoattractant for macrophages in vivo but alone is not sufficient to activate these macrophages for tumoricidal activity.
CD8 is needed for positive selection but differentially required for negative selection of T cells during thymic ontogeny
Authors: Fung‐Leung Wai‐Ping , Wallace Valerie A. , Gray Dawn , Sha William C. , Pircher Hanspeter , Teh Hung‐Sia , Loh Dennis Y. , Mak Tak W. 
Published: March 2007

AbstractDuring thymic development, immature thymocytes expressing major histocompatibility complex (MHC) class I‐restricted T cell receptors (TcR) differentiate into CD8+ T cells with cytolytic functions. To evaluate the role of CD8 in positive and negative selection during thymic ontogeny, mice rendered CD8‐null by gene targeting were bred with three lines of transgenic mice expressing unique MHC class I‐restricted TcR. In all three instances CD8 was required for positive selection of MHC class I‐restricted transgenic T cells. The efficiency of positive selection decreased in accordance with a reduced level of CD8 expression on thymocytes. Surprisingly, there was a differential requirement for CD8 expression in negative selection of MHC class I‐restricted thymocytes, depending on the antigen specificity of TcR. These observations show that CD8 is essential for positive selection but is differentially required for negative selection of MHC class I‐restricted T cells. Thus thymic selection, at least for negative selection, can occur in the absence of the CD8 accessory molecule.
Microheterogeneity in the recognition of a HLA‐DR2‐restricted T cell epitope from a meningococcal outer membrane protein
Authors: Wiertz Emmanuel , van Gaans‐van den Brink Jacqueline , Hoogerhout Peter , Poolman Jan 
Published: March 2007

AbstractThe trimolecular interaction of T cell receptor (TcR), antigen and major histocompatibility complex (MHC) class II was analyzed using a panel of HLA‐DR2‐restricted T cell clones recognizing the 49‐61 region of a meningococcal class I outer membrane protein (OMP). The clones, all CD3+CD4+CD8−TcRct/β+, were selected by restimulation with the synthetic peptide OMP(49‐61), which contains an immunodominant T helper determinant. Using a series of peptides that were sequentially truncated from the N or C terminus, four different epitope fine‐specificity patterns were identified. Furthermore, each clone was found to exhibit a distinct recognition pattern for a panel of 20 single‐residue substitution analogues of the minimal epitope OMP(50‐58). Most substitutions that were not tolerated in the nonamer were allowed when the analogues were prepared departing from the native peptide OMP(49‐61). Obviously, the residues outside the minimal epitope contribute to stabilization of the trimolecular complex. These findings suggest that defining the minimal size of T cell determinants may be of limited value. By performing proliferation competition assays putative MHC and TcR contact residues were identified in the peptide. Most likely, He 51 and Phe 54 act as MHC‐anchoring residues, whereas Asp 53 represents a critical TcR contact residue for all of the clones. MHC anchoring may be provided by other residues as well, since He 51 and Phe 54 can be substituted by conservative residues [as OMP(50‐58) and OMP(49‐61) analogues] and with Ala [as OMP(49‐61) analogues only]. Some evidence was found for interaction of particular side chains at other positions with TcR molecules, but this contribution was not equally important for all clones. Apparently, the clonotypic TcR can see a single epitope in different ways in the context of the same MHC restriction element. Since most clones use different Vα and Vβ genes (which encompass the putative MHC‐binding regions first and second complementarity‐determining regions, CDR1 and CDR2) different modes of interaction with the HLA‐DR2 molecule indeed are likely to occur.
Signal joint of immunoglobulin Vλ1‐Jλ and novel joints of chimeric V pseudogenes on extrachromosomal circular DNA from chicken bursa
Authors: Kondo Tokukazu , Arakawa Hiroshi , Kitao Hiroyuki , Hirota Yoshikazu , Yamagishi Hideo 
Published: March 2007

AbstractWe isolated extrachromsomal circular DNA from the bursa of 18‐day chick embryos and cloned their BamHI fragments into a phage vector. We found examples of the signal joint fused by Vλ1‐Jλ, rearrangement and the sequences homologous to Vλ1 segments that showed: (1) clustered V pseudogene (ΨV) germ‐line segments containing new ΨV26, (2) a head‐to‐tail duplication of ΨV13‐ΨV12 region and (3) chimeric structures composed of 5′‐Vλ1 and 3′‐ΨV segments. Both intrachromosomal tandem duplications and extrachromosomal circles may be generated by unscheduled DNA synthesis and recombination. The chimeric structure of Vλ1 joined with upstream ΨV segments suggests the involvement of V gene replacement for somatic diversification of the immunoglobulin genes in addition to a mechanism of segmental gene conversion.
Reconstitution of C.B‐17 scid mice with BALB/c T cells initiates a T helper type‐1 response and renders them capable of healing Leishmania major infection
Authors: Varkila Kari , Chatelain René , Leal Ludmila M. C. C. , Coffman Robert L. 
Published: March 2007

AbstractC.B‐17 scid mice, which were found to be very susceptible to infection with Leishmania major, were reconstituted with various doses of T cells, T plus B cells or unfractionated spleen cells from nonhealer BALB/c mice. All reconstitution protocols, except for the transfer of very high numbers of BALB/c spleen cells, led to a spontaneously healing infection and resistance to reinfection, rather than the lethal, nonhealing infection typical of BALB/c mice. These healing responses were associated with a strong T helper 1 (Th1)‐like response characterized by delayed‐type hypersensitivity (DTH) responsiveness, but no elevation of serum IgE, and by the production of high levels of interferon‐γ (IFN‐γ), but no interleukin‐4 (IL‐4) by lymph node and spleen cells after restimulation with antigen in vitro. The development of this Th1 response from BALB/c Th cells requires IFN‐γ during the initial infection period. Treatment of scid mice with a single injection of neutralizing anti‐IFN‐γ antibody prior to infection and reconstitution prevented healing and permitted the development of a Th‐2 like response as indicated by elevated serum IgE, but no DTH, and by the production of IL‐4, but very little IFN‐γ, after antigen stimulation in vitro. As few as 104 transferred T cells led to a Th1‐like response, suggesting that the IFN‐γ is of host rather than donor origin. The transfer of very high numbers (7.5 x 107) of BALB/c spleen cells overcame the effects of the IFN‐y and led to the nonhealing infection and cytokine pattern characteristic of BALB/c mice. The enrichment or depletion of B cells from the transferred T cells had no measureable effect upon the development of a healing response in reconstituted scid mice.
Position 71 in the α helix of the DRβ domain is predicted to influence peptide binding and plays a central role in allorecognition
Authors: Coppin Hélène L. , Carmichael Paul , Lombardi Giovanna , L'Faqihi Fatima E. , Salter Russell , Parham Peter , Lechler Robert I. , De Preval Claude 
Published: March 2007

AbstractDespite all the structural and functional data that have been accumulated regarding major histocompatibility complex (MHC) class II molecules during recent years, the relative contribution of putative T cell receptor (TcR)‐contacting residues and peptide‐binding MHC polymorphisms to MHC‐restricted and allospecific T cell responses remains a point of contention. Some authors emphasize the importance of direct interaction between the allospecific TcR and polymorphic MHC residues whereas other emphasize the role of naturally processed MHC‐bound peptides.We have previously described a new HLA‐DRB1 allele: DR BON (DRB1*0103). This gene differs from DRB1*0101 by six base pairs clustered in the third variable region of the second exon leading to three amino acid changes at positions 67, 70 and 71 of the β chain of the HLA‐DR molecule. To define the respective role of these residues in allorecognition, we have performed site‐directed mutagenesis on the DRB1*0103 allele to create six mutants which are intermediary between the DR BON and the DR1 alleles. These mutant cDNA were expressed in mouse fibroblasts and the transfectants with the highest expression of class II molecules were used as stimulators for a panel of ten anti‐DR BON and five anti‐DR1 alloreactive T cell clones. We demonstrate that the residue at the peptide‐binding position 71 is of paramount importance in the alloresponse of these clones. In addition some clones were sensitive to amino acid substitution at the TcR‐contacting position 70, while substitution at position 67 affects very few clones. The dominance of residue 71 was also observed with an influenza hemagglutinin‐specific HLA‐DR BON‐restricted T cell line.
Limiting dilution analysis of interleukin‐2‐producing T cells responsive to recall and alloantigens in human immunodeficiency virus‐infected and uninfected individuals
Authors: Schulick Richard D. , Clerici Mario , Dolan Matthew J. , Shearer Gene M. 
Published: March 2007

AbstractPeripheral blood mononuclear cells (PBMC) from individuals who were seropositive for the human immunodeficiency virus type 1 (HIV), and most without symptoms (HIV+) were compared with PBMC from healthy HIV‐seronegative (HIV−) individuals for in vitro generated T helper cell (Th) responses. Th function in bulk culture and limiting dilution analysis was assessed by IL‐2 production following stimulation with influenza A virus (FLU) or irradiated allogeneic PBMC (ALLO). We observed that the frequencies of FLU‐ and ALLO‐stimulated Th cells were not appreciably different in the PBMC of those HIV‐ individuals, and that they were also not different in the PBMC of those HIV+ individuals who responded to both FLU and ALLO in bulk culture. However, there was a severe drop in the Th frequency to FLU in HIV+ individuals who were unresponsive to FLU but responsive to ALLO by bulk culture. The PBMC of HIV+ individuals who were unresponsive by bulk culture to both FLU and ALLO exhibited a drastic reduction in the Th frequencies for both stimuli. These results demonstrate a concordance between Th functional analysis performed by limiting dilution and bulk culture. The results also indicate that the early selective loss in Th function to recall antigens is not likely to be due simply to a difference in frequencies of FLU‐ and ALLO‐stimulated Th cells present prior to the onset of Th dysfunction.
Activation of CD44 induces ICAM‐1/LFA‐1‐independent, Ca2+, Mg2+, —independent adhesion pathway in lymphocyte‐endothelial cell interaction
Authors: Toyama‐Sorimachi Noriko , Miyake Kensuke , Miyasaka Masayuki 
Published: March 2007

AbstractWe have established an endothelial cell line KOP2.16 from pooled mouse lymph nodes. Resting lymphocytes avidly bound to KOP2.16 and migrated underneath the cytoplasm. The binding was partly mediated by VLA‐4 and VCAM‐1, but apparently independent of CD44 since anti‐CD44 antibody examined failed to inhibit the binding. However, pretreatment of lymphocytes with anti‐CD44 resulted in the rapid appearance of Ca2+‐, Mg2+‐independent, LFA‐1/ICAM‐1‐, CD2/LFA‐3,VLA‐4/VCAM‐l‐independent lymphocyte binding, indicating that a novel adhesion pathway was induced by the anti‐CD44 treatment. Interestingly, the elicited adhesion was observed only when anti‐CD44 that block hyaluronate recognition of CD44 were used for lymphocyte pretreatment. Neither hyaluronate itself nor non‐blocking anti‐CD44 up‐regulated the adhesion. Fab fragment of the blocking anti‐CD44 did not induce the up‐regulation unless cross‐linked with a second antibody, indicating that cross‐linking of surface CD44 is necessary for induction of a novel adhesion pathway. We propose that the agonistic anti‐CD44 antibodies induce a novel adhesion pathway by mimicking ligand binding to CD44 on the lymphocyte surface and that non‐hyaluronate ligand(s) is involved in regulation of adhesive function of CD44. Potential involvement of such a regulatory mechanism in lymphocyte homing is discussed.
Expression of human minor histocompatibility antigen on cultured kidney cells
Authors: Beck Yoshifumi , Sekimata Masayuki , Nakayama Setsuko , Müller Gerhard A. , Müller Claudia A. , Yamamoto Junji , Nagao Takeshi , Uchida Hisanori , Akiyama Nobuo , Kariyone Ai , Takiguchi Masafumi 
Published: March 2007

AbstractIncompatibility of human minor histocompatibility (hmH) antigens can induce rejection of grafts in organ transplantation and graft‐versus‐host reactions in bone marrow transplantation. In spite of their importance in clinical transplantation, hmH antigens are not well studied. Previous studies have demonstrated the expression of hmH antigens on Tand B cells, hematopoietic progenitor cells and keratinocytes. We have for the first time demonstrated the expression of hmH antigens on cultured kidney cells using HLA‐B35‐restricted, hmH antigen‐specific cytotoxic T lymphocyte (CTL) clones, which were previously established from a patient who rejected two kidneys from HLA‐identical sisters. The CTL clones could not kill cultured kidney cells. Since cultured kidney cells expressed very low levels of HLA class I antigens it was thought that their failure to be killed by the CTL clones was due to lack of expression of HLA‐B35 antigens. After induction of class I antigens on cultured kidney cells by interferon‐y (IFN‐γ), the IFN‐γ‐treated cultured kidney cells were killed by the CTL clones. Furthermore, we isolated hmH antigens as peptides from cultured kidney cells after treatment with IFN‐γ. These results indicate that cultured kidney cells express hmH antigens when HLA class I antigen is induced by IFN‐γ and hmH antigens on cultured kidney cells are recognized by T cells as peptides presented by HLA‐B35 molecules.
Manipulation of the superantigen‐induced lymphokine response. Selective induction of interleukin‐10 or interferon‐γ synthesis in small resting CD4+ T cells
Authors: Cardell Susanna , Höidén Ingmarie , Möller Göran 
Published: March 2007

AbstractThe production of several lymphokines by freshly isolated CD4+ T cells has been analyzed at the single‐cell level, after stimulation with staphylococcal enterotoxin B (SEB). High frequencies of cells producing interleukin‐2 (IL‐2) and interferon‐γ (IFN‐γ) were induced, but very low frequencies of CD4+ T cells produced IL‐4, IL‐5 or IL‐10 in response to SEB. Exogenously added IL‐4 markedly altered the lymphokine profile induced during primary SEB stimulation. IFN‐γ production was reduced, while a high fraction of cells contained IL‐10 and IL‐4 after activation in the presence of IL‐4. We further demonstrate that IL‐4 and IL‐10 or IFN‐y production was selectively induced in resting, high‐density CD4+ T cells during primary stimulation, by SEB + IL‐4 or SEB. Under conditions where both IL‐10 and IFN‐γ were produced, most cells contained only one of the two lymphokines.
Interferon‐γ arrests proliferation and causes apoptosis in stromal cell/interleukin‐7‐dependent normal murine pre‐B cell lines and clones in vitro, but does not induce differentiation to surface immunoglobulin‐positive B cells
Authors: Grawunder Ulf , Melchers Fritz , Rolink Antonius 
Published: March 2007

AbstractNormal pre‐B cells from fetal liver or bone marrow of the mouse proliferate for long periods of time in tissue culture on stromal cells in the presence of interleukin‐7 (IL‐7). Their IgH loci are partly in germ‐line, partly in DHJH‐rearranged configuration, while their light chain loci are in germ‐line configuration. They express the pre‐B cell‐specific genes VpreB and λ5. Proliferation of these pre‐B cells is inhibited by interferon (IFN)‐γ, with half‐maximal inhibition at concentrations between 0.1 and 1 unit/ml. Normal pre‐B cells exposed to IFN‐γ die by apoptosis, as is evidenced by the disintegration of pre‐B cell DNA into oligonucleosomal multimers of 180‐200 bp. While the proliferation of pre‐B cells from Eμ‐bcl‐2 transgenic (tg) mice is inhibited by IFN‐γ, these cells do not die by apoptosis. IFN‐γ does not induce differentiation to more mature B lineage cells. In the absence of IL‐7 normal pre‐B cells differentiate to VHDHJH/VLJL‐rearranged, surface immunoglobulin‐positive B cells expressing the a chain of the IL‐2 receptor. They also down‐regulate the expression of VpreB and X.5, and lose the capacity to proliferate on stromal cells in the presence of IL‐7. In contrast, both normal and Eμ‐bcl‐2 tg pre‐B cells exposed to IFN‐γ in the presence of stromal cells and IL‐7 fail to differentiate, i.e. do not express surface immunoglobulin, retain expression of VpreB and λ5, do not express the α chain of the IL‐2 receptor, and retain the capacity to proliferate on stromal cells in the presence of IL‐7, once IFN‐γ is removed. The potential usefulness of a treatment of acute lymphocytic leukemia of the B cell lineage (pre B‐ALL) with IFN‐γ is discussed.