bluuebunny/crossref_metadata_2025_split huggingface dataset:
An activated murine B cell lymphoma line (A‐20) produces a factor‐like activity which is functionally related to human natural killer cell stimulatory factor
Authors: Mengel José , Daré Leopoldo , Daré Gustavo Marcelo , Delgado Maristela , Nomizo Auro , Silva João S. , Campos‐Neto Antonio 
Published: March 2007

AbstractIn the present article we show that supernatants derived from lipopolysaccharide (LPS) or phorbol 12‐myristate 13‐acetate (PMA)‐stimulated A‐20 B cell lymphoma are able to induce polyclonal immunoglobulin (Ig) secretion by normal B cells in a T cell‐dependent manner. This activity could be blocked by neutralizing monoclonal antibodies against interferon‐γ, but not by monoclonal antibodies against interleukin (IL)‐2, IL‐4, IL‐5, IL‐6, IL‐10 and granulocyte macrophage colony‐stimulating factor (GM‐CSF) or even a polyclonal antibody against tumor necrosis factor (TNF)‐α. Furthermore, A‐20 supernatants induced the production of measurable amounts of interferon‐γ by normal murine spleen cells and activates natural killer (NK) cells. Fractionation of factor‐rich supernatants on a Sephacryl S‐200 column revealed that the factor activity is located in the fractions corresponding to a molecular mass of 160–150 kDa and 80–70 kDa. The biological activities found in the A‐20 supernatant are very similar to the ones described for the recently cloned human IL‐12/NK cell stimulatory factor. These results suggest the existence of a murine analogous factor for the human IL‐12 produced by A‐20 B cell lymphoma.
Inflammation activates self hsp60‐specific T cells
Authors: Anderton Stephen M. , Zee Ruurd Van Der , Goodacre John A. 
Published: March 2007

AbstractInjection of incomplete Freund's adjuvant (IFA) into the footpads of BALB/c mice induced an acute inflammation. Draining popliteal lymph nodes showed major histocompatibility complex (MHC) class II‐restricted proliferation when challenged in vitro with recombinant Mycobacterium bovis 65‐kDa heat shock protein (hsp65). αβ Tcell receptor‐positive, CD4+, hsp65‐specific T cell lines and clones were generated from these lymph nodes, and 87% of clones responded to a P galactosidase fusion protein containing residues 238–573 of human hsp60. Seventy percent of these hsp60‐responsive clones also responded to a synthetic peptide corresponding to residues 412–423 of the mouse hsp60. This peptide also induced significant responses in IFA‐primed lymph node cells but not in lymphoid cells from unimmunized mice.These results demonstrate that T cells specific for epitopes in self hsp60 are activated during inflammatory responses induced in the absence of exogenous bacterial hsp65. The findings of this study may provide a basis for understanding the often reported isolation of mycobacterial hsp65‐responsive T cells from inflammatory sites of arthritis patients, and the protective effects of preimmunization with hsp65 in experimental models of arthritis.
Antigen and helper T lymphocytes activate B lymphocytes by distinct signaling pathways
Authors: Kawakami Kazuyoshi , Parker David C. 
Published: March 2007

AbstractResting murine B lymphocytes can be induced to proliferate by cross‐linking membrane immunoglobulin, the antigen receptor, or by contact with activated helper T lymphocytes in the absence of a signal through membrane immunoglobulin. Little is known about the molecular nature of contact‐dependent T cell help. To determine whether helper T cells activate B cells through different signal transduction and second messenger pathways from those used by membrane immunoglobulin, the effects of drugs which block activation of B cells through membrane immunoglobulin were measured on B cell activation by contact with anti‐CD3‐activated and fixed T helper cells. Cyclosporin A, phorbol esters added at the time of activation, and cAMP agonists all block activation of B cells through membrane immunoglobulin at concentrations at least 100‐fold lower than those necessary to block B cell activation by contact with activated Th1 or Th2 helper T cells. Depletion of protein kinase C by pretreatment of B cells with phorbol ester inhibits the proliferative response to anti‐immunoglobulin but not the response to contact with activated T cells. The B cell response to lipopolysaccharide is intermediate in sensitivity to cyclosporin A and cAMP agonists, and resembles the response to activated T cells in resistance to phorbol esters and protein kinase C depletion. Various protein kinase inhibitors did not distinguish among these B cell activation pathways, except for the tyrosine kinase inhibitor, herbimycin A, which inhibited anti‐immunoglobulin responses at 3‐ to 5‐fold lower concentrations.
H‐2 I‐E molecules isolated from MIs1a stimulatory cells do not activate Mls1a‐responsive T cells but do present exogenous staphylococcal enterotoxins
Authors: Macphail Stuart , Stutman Osias 
Published: March 2007

AbstractThe T cell response to allogeneic murine Mls determinants is not H‐2 restricted but is dependent on H‐2 class II molecules on the Mls‐expressing stimulator cells. We have tested planar membranes containing H‐2 class II I‐E molecules alone or with I‐A molecules for their ability to activate a panel of Mls1a‐specific T hybrids. Despite the ability of the planar membranes to activate an alloreactive T hybrid and to present staphylococcal enterotoxins or an antigenic peptide to appropriately responsive T hybrids, they failed to stimulate the Mls1a‐specific T hybrids. These findings, in the light of the various controls demonstrating sufficiency of the I‐E molecules in the planar membranes, indicate that Mls1a determinants are not covalently bound to I‐E molecules; the two molecular species are thus either not physically associated or are linked by a relatively weak interaction. In addition, our experiments show that isolated I‐E molecules but not I‐A molecules present staphylococcal enterotoxins A and B to two independently derived T hybrids expressing T cell receptor Vβ1, Vβ8.2 and Vβ6 elements.
Bursa‐dependent subpopulations of peripheral B lymphocytes in chicken blood
Authors: Paramithiotis Eustache , Ratcliffe Michael J. H. 
Published: March 2007

AbstractBy selective labeling of juvenile chicken bursal cells with colloidal fluorescein isothiocyanate in situ, the emigration rate of bursal lymphocytes to the periphery was estimated at approximately 0.84% and 0.96% of the peripheral blood lymphocyte (PBL) and splenic B cell pool per hour, respectively. Emigrant bursal cells were found primarily in blood and spleen, with very small numbers migrating to thymus, bone marrow, and gut‐associated lymphoid tissues. Emigrant bursal cells expressed high levels of both major histocompatibility complex class II antigen and the Ov alloantigen, a phenotype found on a population comprising approximately 4% of bursal cells from which the bursal emigrants may be derived. Surgical bursectomy at 3 weeks of age revealed that peripheral blood B cells could be divided into three distinct populations. Specifically, 60% of the peripheral blood B cells were short lived with a half‐life of about 30 h in the blood. These cells accounted for the great majority of emigrants from the bursa to the peripheral blood. Approximately 35 % of PBL B cells had a half‐life of 12 days following bursectomy and comprised cells which did not divide in the periphery. Consequently, we propose that physiological differences between this population and the majority of bursal emigrants are established intrabursally. The remaining PBL B cells, whose relative proportion increases with age from about 5 % of PBL B cells at 2‐3 weeks of age, are short lived and are being continually produced from (a) post‐bursal site(s) of B cell production.
Epitope mapping of anti‐rat CD53 monoclonal antibodies. Implications for the membrane orientation of the Transmembrane 4 Superfamily
Authors: Tomlinson Michael G. , Williams Alan F. , Wright Mark D. 
Published: March 2007

AbstractCD53 is a pan‐leukocyte glycoprotein which is a member of the recently described Transmembrane 4 Superfamily (TM4SF) of membrane proteins that are predicted to span the lipid bilayer four times. The major hydrophilic region of murine CD53 was expressed as a glutathione‐S‐transferase fusion protein, and the epitopes of four mouse anti‐rat CD53 monoclonal antibodies (mAb) (OX‐44, 2D1, 6E2 and 7D2) were mapped to this region using mouse/rat chimeric fusion proteins. The epitopes of OX‐44,6E2 and 7D2 are restored by the substitution of a single isoleucine residue for threonine at position 154 in the mouse protein. The 2D 1 epitope is non‐linear and appears to require the juxtaposition of isoleucine at position 154 with one or more of the amino acids arginine (132), methionine (133) and serine (140). All of these epitopes are shown to be sensitive to reduction, thus indicating the importance of disulfide bonding in the correct folding of the CD53 hydrophilic domain. Moreover, as these four mAb recognize CD53 at the cell surface, the data provide direct molecular evidence for the proposed membrane orientation of the TM4SF.
Leishmania mexicana promastigotes induce cytotoxic T lymphocytes in vivo that do not recognize infected macrophages
Authors: López José Alejandro , Lebowitz Jonathan H. , Beverley Stephen M. , Rammensee Hans‐Georg , Overath Peter 
Published: March 2007

AbstractThe question is addressed whether antigens of Leishmania, a parasite residing in the endosomal compartment of macrophages, can be presented in the context of major histocompatibility complex class I molecules. We used E. coli β‐galactosidase as a model antigen which can be expressed in high levels in L. mexicana promastigotes (L. mexicana‐gal). Infection of BALB/c mice with L. mexicanagal induces β‐galactosidase‐specific cytotoxic T cells (CTL), which can be isolated using a β‐galactosidase‐expressing mastocytoma line as an antigen‐presenting cell. These CTL recognize epitopes of β‐galactosidase in the context of H‐2Kd; however, they do not recognize L. mexicanagal‐infected macrophages even after killing of the intracellular amastigotes by drug treatment or macrophage activation by lymphokines, although class I‐peptide interaction and the presentation of endogenously produced antigens is normal. It is concluded that parasite antigens can induce a CTL response in vivo but that these CTL cannot recognize infected macrophages because the relevant epitopes cannot gain access to class I molecules. The effect of priming in vivo may be explained by the well‐known but ill‐understood phenomenon of cross‐priming.
The effects of a monoclonal antibody to interferon‐γ on experimental autoimmune thyroiditis (EAT): prevention of disease and decrease of EAT‐specific T cells
Authors: Tang Haiwen , Mignon‐Godefroy Karine , Meroni Pier Luigi , Garotta Gianni , Charreire Jeannine , Nicoletti Ferdinando 
Published: March 2007

AbstractCBA/J mice immunized with thyreoglobulin (Tg) develop an experimental autoimmune thyroiditis (EAT) with lymphocytic infiltration of the thyroid glands, autoantibodies to Tg and occurrence of EAT‐specific T cells. When these mice were treated for 4 weeks after immunization with 1 mg/week of a monoclonal antibody (mAb) that neutralizes the activity of interferon‐γ (IFN) a beneficial effect on the onset of EAT was observed. Characteristic features of EAT were significantly reduced, including the lymphocytic infiltrations of the thyroid glands and the serum levels of autoantibodies to Tg. Moreover, in lymphoid organs, mAb to IFN‐γ significantly reduced the percentages of Tg‐specific CD8+ cells, labeled by the anti‐clonotypic mAb AG7. These Tg‐specific T cells seem responsible for thyroid damages and disease development, since EAT was simultaneously abrogated.These results show that IFN‐γ plays an essential role in the pathophysiology of EAT and suggest the possibility to treat autoimmune thyroid diseases with mAb to IFN‐γ or drugs able to antagonize the production and/or the action of this cytokine.
Effects of cyclosporin A, FK 506, and mycalamide A on the activation of murine CD4+ T cells by the murine B7 antigen
Authors: Galvin Frances , Freeman Gordon J. , Razi‐Wolf Ziba , Benacerraf Baruj , Nadler Lee , Reiser Hans 
Published: March 2007

AbstractThe murine B7 (mB7) protein is a potent co‐stimulatory molecule for the activation of murine CD4+ T cells. We have previously shown that stable mB7‐transfected Chinese hamster ovary (CHO) cells synergize with either anti‐CD3 monoclonal antibodies (mAb) or concanavalin A to stimulate T cell activation. In addition, mB7 can synergize with phorbol 12‐myristate 13‐acetate (PMA) to induce T cell activation in an alternative pathway. In the present report we describe the effects of three immunosuppressive drugs, cyclosporin A (CsA), FK 506, and mycalamide A on mB7‐mediated T cell activation. The immuno‐philin ligands CsA and FK 506 block activation of murine CD4+ T cells by the combination of anti‐CD3 mAb and CHO‐mB7 cells but do not affect activation by CHO‐mB7 cells and PMA. These results support the relevance of pharmacological studies of immunosuppressive compounds in the murine model prior to their application in man. In contrast to the effects of CsA and FK 506, mycalamide A blocks activation of murine CD4+ T cells by anti‐CD3 mAb and mB7 as well as activation by mB7 and PMA. On a molar basis, mycalamide A appears to be at least 10‐fold more potent than FK 506 which is 100‐fold more potent than CsA. Because of its effects on multiple activation pathways and because of its potency, mycalamide A could have considerable therapeutic potential.
Serum modulates mast cell responses to IgE antigen stimulation
Authors: Baranes Danny , Lewin Iris , Razin Ehud 
Published: March 2007

AbstractSerum induces the expression of the fos and jun gene families, which encode the transcription factor AP‐1. Since we previously found that activation of mast cells by IgE‐antigen (Ag) induces the mRNA accumulation of c‐fos, c‐jun, junB and junD proto‐oncogenes, we were prompted to investigate whether serum could affect such accumulation in these cells. In addition, we investigated whether serum could modulate inhibition of DNA synthesis in immunologically stimulated mast cells.Mast cells, which were cultured in the presence of fetal calf serum (FCS), were characterized by a high proliferation rate and high accumulation of the mRNA of c‐fos, junB and junD proto‐oncogenes. After sustained FCS deprivation both DNA synthesis and the level of c‐fos mRNA were significantly decreased, as expected, whereas the level of c‐jun, junB and junD mRNA were not affected.As opposed to mast cells which were cultured in the presence of FCS, immunological stimulation of FCS‐deprived cells resulted in DNA synthesis inhibition and an increase in c‐fos expression. The results also show that the level of c‐fos mRNA was increased by either IgE‐Ag or FCS up to a similar level, while these two triggers could not act synergistically to enhance this expression further. Thus, changes in DNA synthesis, induced by FCS, block the ability of the immunological challenge to inhibit mast cell growth and to enhance c‐fos mRNA accumulation.
T cell regulation of collagen‐induced arthritis in mice. II. Immunomodulation of arthritis by cytotoxic T cell hybridomas specific for type II collagen
Authors: Chiocchia Gilles , Boissier Marie‐Christophe , Manoury Bénédicte , Fouriner Catherine 
Published: March 2007

AbstractInjection of native type II collagen (CII) to susceptible strains of mice (H‐2q) induces a rheumatoid arthritis‐like disease. To study the role of CD8+ T cells in the collagen‐induced arthritis (CIA),we generated CII‐specific T cell hybridomas by fusion of cells from arthritic C3H.Q mice and an AKR thymoma. Two hybrid clones (P3G8 and P2D9) were selected for their ability to lyse syngeneic CH‐pulsed macrophages and recognize different antigenic epitopes in association with Kq molecules. When these T cell clones were irradiated and inoculated into (C3H.Q × AKR)F1 mice 21 days prior to priming with native CII/ complete Freund's adjuvant, the incidence and the duration of CIA were significantly reduced in comparison to groups receiving saline or control T cell hybridoma. Furthermore, both anti‐CII T cell hybridomas were able to attenuate CIA in highly susceptible inbred strains of mice and this suppression was antigen and disease specific. The protective activity seems to require intact cells as neither membrane fractions nor cytosolic preparations of the hybridoma T cells retained the vaccinating activity. Most importantly, one of the hybrid clones (P3G8) had a therapeutic effect on CIA since its administration to arthritic DBA/1 mice on day 30 after priming down‐regulated the ongoing disease. Taken together, these findings suggest that anti‐CII cytotoxic T cell clones can vaccinate against CIA and even reverse the disease.
Dissection of human Langerhans cells' allostimulatory function: The need for an activation step for full development of accessory function
Authors: Pèguet‐Navarro Josette , Dalbiez‐Gauthier Catherine , Dezutter‐Dambuyant Colette , Schmitt Daniel 
Published: March 2007

AbstractIn the present study, we analyzed the mechanism by which human Langerhans cells (LC), the dendritic cells (DC) from epidermis, support the induction of a primary allogeneic T cell response. We reported that paraformaldehyde (PF) fixation completely abrogated the stimulatory property of freshly isolated LC, although the level of major histocompatibility complex (MHC) class II antigen (Ag) expression was unaltered by the fixative. Addition of either interleukin (IL)‐ip and/or IL‐6, during the mixed epidermal cell lymphocyte reaction, failed to restore the proliferative response. By contrast, when human LC were incubated for 3 days in culture medium before fixation, they retained a low but significant allostimulatory capacity. Trypsin treatment of incubated LC before fixation did not impair their function, suggesting that stimulatory activity by fixed incubated LC did not merely reflect a repair of LC membrane after trypsin trauma suffered during epidermal cell (EC) isolation. More interestingly, we found that addition of interferon‐y during LC incubation mediated an enhanced allostimulatory activity by the PF‐fixed LC. Acquisition of allostimulatory property by in vitro activated and fixed LC did not correlate with increased MHC class II Ag expression at the cell surface. By contrast, we showed that ICAM‐1 Ag expression by human LC is involved in this maturation process. Finally, we found that once human LC have been activated, IL‐1β but not IL‐6, could serve as a costimulatory factor in the primary allogeneic T cell response. In conclusion, the data suggest that human LC accessory function is not constitutive but requires an activation step which can be provided by interferon‐y during LC‐T cell interaction.
The generation of a humanized, non‐mitogenic CD3 monoclonal antibody which retains in vitro immunosuppressive properties
Authors: Bolt Sarah , Routledge Edward , Lloyd Irene , Chatenoud Lucienne , Pope Heather , Gorman Scott D. , Clark Mike , Waldmann Herman 
Published: March 2007

AbstractCD3 antibodies are proven immunosuppressants capable of reversing transplant rejection episodes. Their general application has been limited both by their immunogenicity and, in particular, by the “first‐dose” cytokine‐release syndrome experienced by patients after the initial administration of antibody. We have produced a set of variants of the humanized YTH 12.5 CD3 monoclonal antibody (mAb) (Routledge et al., Eur. J. Immunol. 1991. 21: 2717) bearing different human heavy (H) chain constant regions, with the intention of finding a form of the antibody that is not able to activate T cells. Comparison of the variants having γl, γ2, γ3 and γ4 H chains in a competitive binding assay showed that antibody avidity was not affected by IgG subclass. Using a sensitive indicator of FcR binding activity (the capacity of the CD3 mAb to redirect cytotoxic T cells to kill the monocytic cell line U‐937) we demonstrated a functional hierarchy of γl = γ4 α2 = γ3 mb > γ2. An aglycosyl version of the γl CD3 mAb, produced by site‐directed mutagenesis (Asn297 to Ala), still had considerable activity in this assay (intermediate to the γl and α2 CD3 mAb), albeit at a level approximately 10‐fold lower than that of the parental γl form. When we tested their ablity to stimulate T cell proliferation in vitro in the presence of 5% human serum, all of the wild‐type immunoglobulin isotypes were found to be active, although there were T cell donor‐dependent variations in the extent of the responses. The aglycosyl γl mAb was, however, completely non‐mitogenic in all of ten donors tested, unless the assay was performed in IgG‐free medium. Despite being non‐stimulatory, this mAb was also able to inhibit the mixed lymphocyte reaction responses of both naive and primed T cells. Comparison of the yl and aglycosyl γ1 mAb in an experimental mouse model for CD3 mAb‐induced cytokine release indicated that removal of the carbohydrate moiety from the γl constant region reduced the in vivo tumor necrosis factor‐a response by a factor of at least 16‐fold. These data suggest that the aglycosyl γl CD3 mAb is a promising candidate for immunosuppressive therapy without “first dose” side effects.
CD2/LFA‐3 or LFA‐l/ICAM‐1 but not CD28/B7 interactions can augment cytotoxicity by virus‐specific CD8+ cytotoxic T lymphocytes
Authors: De Waal Malefyt Rene , Verma Sunita , Bejarano Maria‐Theresa , Ranes‐Goldberg Monica , Hill Marc , Spits Hergen 
Published: March 2007

AbstractIt is well established that adhesion molecules are required for interaction between cytotoxic T lymphocytes (CTL) and target cells. Two adhesion pathways, CD2/LFA‐3 and LFA‐l/ICAM‐1 can support cytotoxicity by allospecific CD8+ CTL. In this study, it was investigated whether these adhesion pathways can be utilized independently by influenza virus‐specific HLA‐A2‐restricted CTL clones. It was furthermore examined whether the CD28/B7 pathway can augment virus‐specific CTL activity. To this end, seven CD8+ CTL clones were established that were specific for a peptide encompassing positions 59 to 68 (p[59‐68]) of the influenza virus matrix protein. These seven clones apparently originated from different precursors, as they utilized different Vα and Vβ or Jα gene segments. Six of seven clones were able to lyse mouse L cells co‐transfected with HLA‐A2 and either LFA‐3 (LA2/LFA‐3) or ICAM‐1 (LA2/ICAM‐1) in the presence of p[59‐68] but did not lyse Lcells that expressed only HLA‐A2 and peptide. Three of the most cytotoxic clones were selected for further analysis. The cytotoxicity of the clones against LA2/LFA‐3 cells was blocked by anti‐LFA‐3 and anti‐CD2 monoclonal antibodies (mAb), while these antibodies did not affect cytotoxicity against LA2/ICAM‐1 cells. Likewise, the activity against LA2/ICAM‐1 was blocked only by anti‐LFA‐1 and ICAM‐1 mAb. These clones were unable to lyse Lcells co‐transfected with HLA‐A2 and B7, the counter structure of CD28, despite the fact that these clones expressed CD28. These data indicate that CD8+ virus‐specific CTL can utilize either the CD2/LFA‐3 or the LFA‐l/ICAM‐1 adhesion pathway. The CD28/B7 pathway seems not to be required for cytotoxicity mediated by activated virus‐specific CTL.