bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biochemical characterization and purification of human B cell stimulatory factor (BSF)
Authors: Schwarting Roland , Welte Karl , Chiorazzi Nicholas , Ralph Peter , Lane Caryl L. , Long Cedric , Wang Chang Yi 
Published: February 2007

AbstractB cell stimulatory factor (BSF)B cell growth factor (BCGF) was renamed B cell stimulatory factor (BSF) on the proposal of a group of scientists that met on the 5th International Congress of Immunology in Kyoto, Japan 1983.
activity was generated over a period of five days by phytohemagglutinin ‐ stimulated E rosette ‐ positive peripheral blood lymphocytes. This activity was subjected to a multistep purification procedure including ammonium sulfate precipitation, anion‐exchange chromatography, gel filtration, procion redagarose chromatography and reverse phase high performance liquid chromatography (RP‐HPLC). The last purification step dissected BSF activity into two active fractions, one corresponded to the interleukin 2 (IL2) activity whereas the other active fraction was free of IL2 activity. Preparative isoelectric focusing analysis defined isoelectric points of pH 7.2 for both BSF and IL2. Molecular weight analysis of BSF was carried out by preparative sodium dodecyl sulfate ‐ polyacrylamide gel elec‐ trophoresis analysis. BSF activity was eluted from gel strips corresponding to a molecular mass of 16 and 17 kDa. The 16‐kDa fraction was free of IL2 activity wher eas the 17‐kDa fraction overlapped with IL2. Since recombinant IL2 was capable of exhibiting significant BSF activity in anti‐IgM or Staphylococcus aureus Cowan strain I‐dependent assay systems, it cannot be excluded that IL2 itself is a BSF. Nevertheless these studies demonstrate the existence of a BSF free of IL 2 activity.
Anti‐IgM treatment influences immunoglobulin heavy and light chain mRNA levels in mitogen‐stimulated B lymphocytes
Authors: Leanderson Tomas , Hsu Ellen 
Published: February 2007

AbstractThe mechanism by which soluble anti‐IgM inhibits plaque formation by lipopolysac‐charide‐stimulated B cells was investigated. Since lower amounts of immunoprecipitable μ heavy and ϰ light chains were found in cell lysates, this indicated that soluble anti‐IgM was inhibiting not only secretion. Subsequently, Northern blot analysis of poly(A+) RNA showed that the steady state levels of mRNA for immunoglobulin heavy and light chain from B cells stimulated with lipopolysaccharide were reduced if the cultures were treated with soluble anti‐IgM. The steady‐state levels of class I major histocompatibility complex antigen RNA were unaffected by anti‐IgM treatment. Addition of supernatants from mouse spleen cells stimulated with concanavalin A at day 2 of culture partially reversed the effect of soluble anti‐IgM on immunoglobulin expression.
T cell triggering by lectins II. Stimuly for induction of interleukin 2 responsiveness and interleukin 2 production differ only in quantitative aspects
Authors: Roosnek Eddy E. , Brouwer Mieke C. , Aarden Lucien A. 
Published: February 2007

AbstractWe have investigated the requirements for lectin‐induced proliferation of highly purified human T cells. To study activation, independent of growth factor production, we cultured the cells in the presence of an excess of interleukin 2 (IL2), which was a product of cDNA cloned in E. coli. In the presence of IL2, the same cooperative effect of lectin and accessory cells was found that we have previously described for IL2 production. Thus, analogous to induction of IL2 production, the acquisition of responsiveness to IL2 can be completely monocyte dependent, but a 10‐fold increase in lectin concentration completely abolishes the requirement for accessory cells. Furthermore, two stimuli (IL1 and phorbol myristate acetate), which are able to replace monocytes at the level of IL2 production, also induce responsiveness to IL2 under accessory cell‐dependent conditions. Thus, very similar conditions are required for proliferation and for the induction of IL2 production. There is only a quantitative difference: proliferation of cells in the presence of exogenous IL2 occurs already at low lectin concentrations, whereas IL2 production and consequently proliferation in the absence of exogenous IL2 requires higher lectin concentrations.At high lectin concentrations, when IL2 production has become the only limiting factor, purified T cells cannot be induced to proliferate in the absence of exogenous IL2 because the lectin concentration that induces IL2 production independent of accessory cells inhibits mitogenesis. However, after addition of thiols to the medium, which enhances the IL2 production, a very narrow range of lectin concentration can be found which is just below toxic values and still high enough to induce IL 2 production in the absence of accessory cells. Under these conditions, accessory cells are no longer a prerequisite for lectin‐induced T cell proliferation.
Activation/suppression of the immune response in vitro by antigen and dextran sulfate I. Analysis by limiting dilution methods
Authors: Kettman John R. , Soederberg Anita , Lefkovits Ivan 
Published: February 2007

AbstractSpleen cells of normal mice which were stimulated with either T‐dependent or T‐ independent antigens and dextran sulfate (DxS) in microcultures at limiting dilution show at low cell densities an increased frequency of responding units (B cells) with both types of antigens. At higher cell densities, DxS induces a suppression of the immune response as assessed by a declining frequency of expressed B cells. When T cells were decreased in number, the stimulating effect of DxS on T‐independent responses remained unaltered while the suppressive effect (dependent on cell density) was eliminated.It is suggested that DxS lowers the threshold of activation for regulatory T cells, i.e. of cells which under standard in vitro conditions remain unactivated, and which in the presence of DxS become activated. We conclude that the regulatory cells are rare and that they are not present in most low cell density cultures. The net effect is a potent activation in dilute cultures and lack of response in dense cultures.
pl50/95, Third member of the LFA‐1/CR3 polypeptide family identified by anti‐Leu M5 monoclonal antibody
Authors: Lanier Lewis L. , Amin Arnaout M. , Schwarting Roland , Warner Noel L. , Ross Gordon D. 
Published: February 2007

AbstractMonoclonal antibody (mAb) anti‐Leu M5 reacts with a two‐chain molecule composed of a 150‐kDa α subunit noncovalently associated with a 95‐kDa β subunit and probably is specific for an epitope on the 150‐kDa β chain. This pl50/95 antigen is the third member of a family of polypeptides sharing a common 95‐kDa β chain, which includes the lymphocyte function‐associated antigen LFA‐1 (p177/95) and complement receptor CR3 (Mo1/MAC‐1/OKM1; p165/95) antigens. Sequential immunoprecipitation with anti‐p95 β chain mAb specifically removed the antigens detected by anti‐LFA‐1, anti‐CR3 and anti‐Leu M5 mAb. Certain patients with recurrent bacterial infections are genetically deficient in expression of the LFA‐1 and Mo1 antigens, and have impaired granulocyte function. Granulocytes from a patient with this disease also failed to react with anti‐Leu M5. Stimulation of normal granulocytes with f‐Met‐Leu‐Phe, C5a‐desArg, or calcium ionophore resulted in increased expression of Mo1 and Leu M5 antigens on the cell surface, but did not significantly increase expression of LFA‐1 antigen. In functional assays, anti‐Leu M5 did not inhibit T cell‐mediated or natural killer cell‐mediated cytotoxicity. In addition, anti‐Leu M5 neither inhibited the binding of complement‐coated particles to CR1 or CR3 nor did it affect the binding of EC3dg to neutrophils (CR4). These studies clearly indicate that the p150/95 antigen recognized by the anti‐Leu M5 antibody is a structurally distinct member of the LFA‐ 1/CR3 family.
The lymphoproliferating cells of MRL‐lpr/lpr mice are a polyclonal population that bear the T lymphocyte receptor for antigen
Authors: Nemazee David A. , Studer Suzanne , Steinmetz Michael , Dembić Zlatko , Kiefer Michael 
Published: February 2007

AbstractMice bearing the recessive gene Ipr develop an age‐dependent, massive lymphoproliferation, primarily in the lymph nodes (LN), with associated autoimmunity. LN cells from these mice express T cell receptor protein on the cell surface at 50–70% of normal levels. Normal levels of T cell receptor α, β and γ mRNA were found in these cells as compared to normal LN cells. Southern blot analysis of MRL‐lpr/lpr LN DNA showed rearrangements in 80–90% of the chromosomes at the β gene loci. The pattern of rearrangement indicated that a polyclonal rather than monoclonal expansion of T cells occurred. These data support a lymphokine‐induction model of lymphoproliferation in MRL‐lpr mice.
Vλ2 rearranges with all functional Jλ segments in the mouse
Authors: Weiss Siegfried , Meyer Jutta , Wabl Matthias R. 
Published: February 2007

AbstractWe have analyzed 210 λ‐producing hybridomas derived from lipopolysaccharidestimulated spleen cells from a single x‐suppressed mouse. All were classified as λ1, λ2 or λ3 with the exception of four unusual lines. Two of these were due to Vλ2 Jλ1 and the other two to Vλ2 Jλ3 rearrangements. The lines were clonally independent since the point of VJ recombination in each one was different. Southern blot analysis of the Vλ2 Cλ1‐producing lines showed no evidence for an inversion. Under the assumption of a simple deletion model of rearrangement these findings place the Vλ2 cluster upstream of the Vλ1 cluster oriented in the same direction.
Immunoregulation by mouse T cell clones III. Cloned H‐Y‐specific cytotoxic T cells secrete a soluble mediator(s) that inhibits cytotoxic responses by acting on both Lyt‐2− and L3T4− lymphocytes
Authors: Simon Markus M. , Nerz Gaby , Prester Marlot , Moll Heidrun 
Published: February 2007

AbstractIn this study we report that cloned Thy‐1+, L3T4−, Lyt‐1−, Lyt‐2+, H‐Y‐specific and H‐2Db‐restricted cytotoxic T cell lines (CTLL) when induced by lectin or antigen secrete a soluble mediator(s) (SF) that inhibits proliferation and generation of cytotoxic lymphocytes (CTL) in mixed lymphocyte cultures (MLC). The biological activity was separable by gel filtration and appeared as a broad peak in the molecular mass range between 10 000 and 50 000 kDa. It was found that the suppressive activity released by CTLL neither strictly correlates with their cytotoxic potential nor with their ability to produce immune interferon or lymphotoxin. SF was shown to elicit its activity in an antigen‐nonspecific manner in that it suppressed the maturation of T lymphocytes responding to both, the appropriate H‐Y antigen as well as to unrelated H‐2d alloantigens or to the hapten 2,4,6‐trinitrophenyl (TNP). The effect of SF on CTL responses was most pronounced in early phases of primary or secondary MLC. When analyzed for its inhibitory activity on precursor cells in populations selected for either Lyt‐2− or L3T4− lymphocytes, it was found that SF interfered with the maturation of both subsets. The inhibition of CTL responses elicited by SF could not be reversed by the addition of exogenous interleukin 2. The finding that SF also inhibited the proliferation of some but not all antigen‐dependent cloned T cells with helper or cytotoxic potential provides evidence that the factor also may regulate effector lymplrc∼cytes. In addition, the results support the assumption that SF exerts its effect directly on the responder rather than the stimulator population, and demonstrate that the development of CTL from their precursor cells is controlled at least in part by the cytotoxic effector cells themselves via a soluble factor(s) that interferes with distinct stages of T cell maturation. These findings again emphasize the expression of multiple functions by CTL and indicate their possible role during the course of an immune response by their capability to eliminate target cells and to secrete a soluble product(s) that mediates feedback control.
A rapid isolation technique of unmodified human T cells on a polystyrene resin column
Authors: Noma Takeshi , Kawano Yutaka , Yoshimura Naoko , Abe Tsutomu , Inagaki Kenji , Yata Junichi 
Published: February 2007

AbstractAn easy and rapid isolation technique of human T cells on a polystyrene resin particle column has been developed. The cells of the effluent fraction contained more than 90% sheep erythrocyte (SRBC) rosette‐forming cells and less than 1% of cells bearing surface immunoglobulin (Ig) or peroxidase. The T cell (SRBC rosette‐forming cells) recovery rate was 80%. The distribution of OKT antigen T cell subsets was essentially the same as that of T cells separated by rosette sedimentation. Cell functions such as tritiated thymidine uptake by T cells and helper activity in Ig production were also the same as that of T cells separated by SRBC rosette sedimentation. Natural killer‐like activity of the T cells isolated by the present method increased more than that of T cells obtained by the conventional method. Moreover, it was free from functional modification which tends to result from stimulation such as by the SRBC antigen in the SRBC centrifugation method. The combination of a T cell population offered by the present method and B cells depleted of SRBC‐binding B cells minimized background plaque formation and enabled us to quantify the plaque‐forming cell number in an antigen‐specific plaque‐forming assay. Furthermore, these populations produced relatively pure interleukin 2 (IL2) by stimulation of an autologous mixed lymphocyte reaction without any absorption of IL2 produced in the same culture. It seemed to be useful to evaluate the ability of lymphocytes from normal individuals and patients to produce IL2.
Measurement of parasite‐specific immune responses in vitro: evidence for suppression of the antibody response to Trypanosoma cruzi
Authors: Tarleton Rick L. , Kuhn Raymond E. 
Published: February 2007

AbstractUsing the Mishell and Dutton culture system, we have developed an assay for eliciting and quantifying parasite‐specific immune responses in vitro. The ability of spleen cells from noninfected and Trypanosoma cruzi‐infected mice to respond to parasite‐associated antigens was assessed by examining the primary plaque‐forming cell response to trinitrophenylated T. cruzi (TNP‐TC). The response to TNP‐TC of both normal, noninfected, unprimed mice and mice infected with T. cruzi is T cell dependent and appeared to involve recognition of parasite antigens by T. cruzi‐specific T cells. In most experiments, spleen cells from infected mice respond to TNP‐TC at levels equal to, or below, that of spleen cells from normal mice. This near “normal” response is in apparent contrast to the suppressed response of spleen cells from infected mice to another antigen (sheep red blood cells) or TNP on a different carrier (TNP‐chicken erythrocytes). Demonstration that the response of spleen cells from infected mice to TNP‐TC can be potentiated by addition of interleukin 2‐containing supernatants or by depletion of plastic and Sephadex G‐10‐adherent cells suggests that the mechanisms which control the response of infected mice to nonparasite antigens may also limit parasite‐specific immune responses.
Disulfide‐linked surface molecules of monoclonal antigen‐specific suppressor T cells: evidence for T cell receptor structures
Authors: Ballinari Dario , Castelli Chiara , Traversari Catia , Pierotti Marco A. , Parmiani Giorgio , Palmieri Gabriella , Ricciardi‐Castagnoli Paola , Adorini Luciano 
Published: February 2007

AbstractBy two‐dimensional polyacrylamide gel electrophoresis analysis under nonreducing/reducing conditions, five proteins with interchain disulfide bridges are revealed on the surface of the suppressor T cell lymphoma line LH8‐105 obtained by radiation leukemia virus‐induced transformation of hen egg‐white lysozyme‐specific suppressor T lymphocytes. Two disulfide‐linked surface proteins expressed by LH8‐105 cells have been positively identified by immunoprecipitation with specific antisera. The major labeled membrane protein of LH8‐105 cells is the murine leukemia virus env glycoprotein gp70. The second disulfide‐linked molecule identified on LH8‐105 cells has a molecular mass of 84 kDa under nonreducing conditions and 42 kDa after reduction, and is immunoprecipitated by an antiserum which recognizes the T cell receptor for antigen. A disulfide‐linked molecule of a similar molecular mass is also immunoprecipitated from surface‐labeled LH8‐105 cells by a rabbit antiserum directed against a synthetic peptide predicted from the nucleotide sequence of a cDNA clone encoding the β chain constant region of a helper T cell hybridoma. Therefore, a dimeric structure comparable to the T cell receptor expressed by cytotoxic and helper T cells is present on the cell surface of these monoclonal antigenspecific suppressor T cells.
I‐J expression is not associated with murine chromosome 4
Authors: Waltenbaugh Carl , Sun Lizhe , Lei Huan‐Yao 
Published: February 2007

AbstractI‐J originally mapped within the murine major histocompatibility complex (H‐2) between the EB and Ea, loci using intra‐H‐2 recombinants. Cloning of this segment of H‐2 shows no DNA that can be ascribed to I‐J. Various hypotheses have attempted to explain this dilemma. One hypothesis attributes a chromosome 4 locus with I‐Jk expression. This hypothesis requires the AKR/J and A/WySn mouse strains to be I‐Jk negative. In the present report we show that AKR/J spleen cells express I‐Jk surface molecules and that both the AKR/J and A/WySn mouse strains produce functional I‐Jk‐bearing suppressor factors to poly(Glu50Tyr50). Our data imply that mapping of I‐J‐determining genes to chromosome 4 may be premature.
Cytolytic T cell hybridomas: III. The antigen specificity and the restriction specificity of cytolytic T cells do not phenotypically mix
Authors: Haas Werner , Mathur‐Rochat Jacqueline , Kisielow Pawel , Boehmer Harald Yon 
Published: February 2007

AbstractWe have obtained cytolytic T‐T hybrids by fusing an H‐2Kk restricted clone specific for the hapten 3‐(p‐sulfophenyldiazo)‐4‐hydroxyphenyl acetic acid (SP) with an H‐2Dd‐restricted clone specific for the hapten fluorescein (FL). Several hybrid clones express both parental specificities but fail to lyse SP‐coupled H‐2Dd and FL‐coupled H‐2Kk target cells. We also fused the H‐2Kk‐restricted, SP‐specific clone with a clone which recognizes FL in the context of any class I major histocompatibility complex antigen. Again several hybrids show both parental specificities but fail to recognize SP coupled to target cells which are not recognized by the parental SP‐specific clone. These findings indicate that the observed cytotoxic T lymphocyte specificities for haptens on the one hand and polymorphic as well as nonpolymorphic class I major histocompatibility complex antigenic determinants on the other hand are not carried by independent proteins.
Inhibition of mast cell sensitization in vitro by a human immunoglobulin ϵ‐chain fragment synthesized in Escherichia coli
Authors: Coleman John W. , Helm Birgit A. , Stanworth Denis R. , Gould Hannah J. 
Published: February 2007

AbstractAn immunoglobulin ϵ‐chain fragment was synthesized in E. coli by cloning and expression of the gene coding for the second, third and fourth constant domains of the human IgE heavy chain. The bacterial CH2–4 polypeptide product was assembled by oxidation into a covalently linked dimeric E‐chain molecule presumably analogous to the Fc region of native IgE. This bacterial Fc, preparation, within the concentration range 0.01–10 μglml, inhibited sensitization of human lung mast cells, determined as histamine released upon challenge with specific antigen. Monomer CH2–4 ϵ‐chain polypeptide, prepared by reduction and alkylation of the active bacterial Fcϵ, fragment, was inactive as an inhibitor of sensitization. The molar potency of the active bacterial Fcϵ, product was approximately one fourth of that of native IgE. Since the bacterial Fcϵ, is nonglycosylated, carbohydrate does not make an essential contribution to the Fc receptor binding activity of IgE. These results show that a functionally active immunoglobulin molecule can be synthesized by gene cloning and expression in E. coli.
Activation of Lyt‐2+ T cells by antibodies towards brain‐associated antigens: II. Antibody‐dependent induction of “nonspecific” cell‐mediated cytotoxicity
Authors: Gullberg Martin , Coutinho Antonio 
Published: February 2007

AbstractPurified IgG from a rabbit anti‐mouse brain antiserum (RaMB), previously shown to activate most Lyt‐2+ T cells, was probed for lectin‐like effects on cell‐mediated cytolysis (CML) and found to induce “nonspecific” killing of syngeneic B cell targets by allospecific cytotoxic T lymphocytes (CTL) as effectively as concanavalin A, and at levels comparable to antigen‐specific cytolysis of target cells. Interestingly, RaMB‐mediated “nonspecific” CML of syngeneic targets, by polyclonally or specifically activated CTL, was restricted to B cell targets and cold target inhibition experiments indicated that syngeneic target cell blasts do not functionally interact with effector CTL in the presence of RaMB. The role of target cell Fc receptors was demonstrated by the competitive inhibition of RaMB‐dependent CML by normal rabbit IgG. We conclude that RaMB both activates and bridges the effector CTL to target cells, RaMB‐mediated “nonspecific” CML being a similar phenomenon to lectin‐facilitated “nonspecific” cytolysis, and the mirror image of classical ADCC.These observations allowed us to interprete the effects of RaMB on allo‐major histocompatibility complex‐specific CML. Since RaMB stimulates specific CML of B cell targets while selectively blocking that of T cell targets, we conclude that RaMB antibodies interact with structures associated with the CTL antigen receptor, explaining the contradictory effects previously reported with monoclonal antibodies against the CTL receptor complex, which can both stimulate and inhibit T cell functions.
Use of a P815‐derived line with an amplified adenosine deaminase gene: an improved target for cellular cytotoxicity
Authors: Vielh Philippe , Castellazzi Marc 
Published: February 2007

AbstractWe describe a cytotoxic T lymphocyte‐mediated cytotoxicity assay in which the release of a cytoplasmic enzyme, adenosine deaminase (ADA), instead of the widely used radioactive chromium is a measure of target lysis. In this enzyme‐release assay the target is a mastocytoma P815‐derived cell line, noted P815 ADA++, isolated by applying a selection procedure devised to specifically amplify the ADA gene. Gene amplification in P815 ADA++ was indeed demonstrated. Routine measurement of ADA activity from numerous supernatants is performed using a specific and sensitive colorimetric assay. The use of 96‐well microtiter plates as well as of an automatic Multiscan spectrophotometer makes this measurement rapid and convenient.We show that this ADA‐release assay is significantly more sensitive than the classical chromium‐release test because of its consistently lower (5 to 10‐fold) spontaneous release in 4 h, short‐term cytotoxicity experiments. We also found that it is especially suited for the rapid detection, by visual screening, of rare, active killer clones among large, heterogeneous cytotoxic T lymphocyte populations.The assay could easily be adapted to other tumor targets (EL4, YAC‐1, K562) of common use in studies involving immune lysis; indeed, the procedure of amplifying the ADA gene used in the isolation of the P815 ADA++ hyperactive line may be generally applied to these targets.