bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitogenic and polyclonal B cell activation activities of synthetic lipid A analogues
Authors: Kumazawa Yoshio , Matsuura Motohiro , Nakatsuru‐Watanabe Yoko , Fukumoto Mitsuru , Nishimura Chiaki , Homma J. Yuzuru , Inage Masaru , Kusumoto Shoichi , Shiba Tetsuo 
Published: February 2007

AbstractThe activation of murine B cells and macrophages by synthetic lipid A analogues, solubilized with triethylamine and complexed with bovine serum albumin, were investigated in vitro. The analogues used are nonphosphorylated, C‐1 or C‐4′ monophos‐phorylated and C‐1,4′ diphosphorylated derivatives of β‐1,6‐linked D‐glucosamine disaccharide possessing both ester‐ and amide‐bound fatty acid substituents. They were divided into 4 groups, A, B, C and D in terms of the fatty acid substitution. Ester‐ and amine‐bound fatty acids of the analogues are both tetradecanoic acids (C14) in group A, C14 and (R)‐3‐hydroxytetradecanoic acids (C14‐OH) in group B, both C14‐OH in group C and C14‐OH and (R)‐3‐tetradecanoyloxytetradecanoic acids in group D.Mitogenic activity was exhibited in spleen cells from C3H/HeN mice by the C‐1 monophosphorylated analogues in groups A and B, and by the C‐4′ monophosphorylated analogues in groups B, C and D, but not in cells from C3H/HeJ mice. Nonphosphorylated analogues in groups A, B and C, and C‐4′ monophosphorylated analogue in group A showed negative mitogenic activity. Only the nonphosphorylated analogue in group D exhibited mitogenic activity in spleen cells from C3H/HeJ mice as well as those from C3H/HeN mice. None of the other analogues exhibited the activity in C3H/HeJ spleen cells.Polyclonal B cell activation activity was exhibited by the C‐1 monophosphorylated analogues in groups A and B, and by the C‐4′ monophosphorylated analogues in groups C and D. Nonphosphorylated analogues in all groups and C‐4′ monophosphorylated analogues in groups A and B showed negative PBA activity.None of the analogues tested could induce any cytostatic macrophages from thioglycollate‐elicited peritoneal macrophages.
Assignment of human natural killer (NK)‐like cells to the T cell lineage. Single allospecific T cell clones lyse specific or NK‐sensitive target cells via distinct recognition structures
Authors: Moretta Alessandro , Pantaleo Giuseppe , Mingari Maria Cristina , Melioli Giovanni , Moretta Lorenzo , Cerottini Jean‐Charles 
Published: February 2007

AbstractThe aim of the present study was to define the cell lineage of mixed lymphocyte culture (MLC)‐induced natural killer (NK) effector cells. Human MLC cells were plated under limiting microculture conditions in the presence of irradiated spleen cells and interleukin 2‐containing supernatant. After 18 days, microcultures were scored for proliferation and for cytolytic activity against specific lymphoblasts and NK‐sensitive K562 target cells. About 1 in 7 and 1 in 5 proliferating microcultures had specific or NK‐like cytolytic activity, respectively. Moreover, several microcultures exhibited dual (specific and NK‐like) cytolytic activity, even when they had been established at relatively low numbers of responding cells/well (0.5–0.25) to ensure a high probability of monoclonality. Direct evidence for the existence of cytolytic effector cells with dual activity was achieved by using clones derived from single MLC T cells by micromanipulation. Out of 26 cytolytic clones so derived, 16 exhibited specific cytolytic activity, whereas 22 lysed K562 target cells. More interestingly, 12 of these 26 clones were active against both types of target cells. Only one of these clones was able to lyse autologous or unrelated target cells. In contrast, all such clones lysed the NK‐sensitive cell lines G11, MOLT‐4, Raji, Daudi, Chang and T‐24. Addition of saturating amounts of B9‐4 monoclonal antibody in the lytic assays resulted in the inhibition of the specific cytolysis, but not the NK‐like activity of clones with dual cytolytic activity. It thus appears that (a) alloreactive cytotoxic T lymphocytes can mediate both specific and NK‐like cytolysis and (b) two independent recognition structures are involved in this dual activity.
Functional significance of the regulation of macrophage Ia expression
Authors: Beller David I. 
Published: February 2007

AbstractThe relationship of la expression and antigen‐presenting function by macrophages has been evaluated. When macrophages are maintained in standard culture media, both Ia antigens and accessory cell function are lost. The reacquisition of these properties follows exposure to an Ia‐inducing lymphokine, for which cDNA‐derived interferon‐γ may substitute. The induction of function is related quantitatively to the level of Ia expression. Moreover, both properties reflect newly expressed Ia determinants, since treatment with anti‐I‐A plus complement at the beginning of culture diminishes neither the subsequent level of Ia expression nor function. Treatment with anti‐Mac‐1 plus complement, however, reduces function commensurate with the effectiveness of macrophage depletion. Finally, we find that fixation of macrophages after exposure to antigen does not inhibit antigen presentation, indicating that metabolic activity, while required for antigen processing, is not necessary for presentation.
Characterization of a major human antibody clonotype (1A) by monoclonal antibodies to combining siteassociated idiotopes
Authors: Zenke Gerhard , Eichmann Klaus , Emmrich Frank 
Published: February 2007

AbstractTo identify major human antibody clonotypes with specificity to N‐acetyl‐D‐glucosamine (GlcNAc), affinity‐purified antibody preparations of different human individuals were analyzed by isoelectric focusing (IEF). A major clonotype (1A) was identified representing 7% of all anti‐GlcNAc antibodies of one donor (no. 371). Anti‐GlcNAc antibodies of donor 371 were used as immunogen to prepare monoclonal anti‐idiotopic antibodies (mAb). Two anti‐idiotopic mAb were specific for the major clonotype 1A, as shown by blotting of the anti‐GlcNAc antibodies after IEF in thin‐layer agarose to nitrocellulose filters and staining with either iodinated antigen or iodinated anti‐idiotopic mAb. The two anti‐idiotopic mAb 13F15 and 10F59 were further analyzed with respect to the antigenic determinant which they recognize. Both were directed to combining site‐related determinants as shown by inhibition studies. Although 13F15 has a 500‐fold higher binding capacity (relative affinity) equal amounts do not inhibit more than 50% of 10F59 binding, suggesting that the two mAb detect two closely related, but not identical, idiotopes in the antigen combining site of clone 1A. Although clonotype 1A is a unique antibody exclusively found in IEF of donor 371, the idiotope 1A.1, defined by mAb 13F15, is a recurrent determinant detectable on different anti‐GlcNAc spectrotypes in various human sera.
T‐T cell interactions during in vitro cytotoxic T cell responses. VI. The role of T cell‐derived colony‐stimulating factor in helper T cell activation
Authors: Krönke Martin , Scheurich Peter , Pfizenmaier Klaus , Heeg Klaus , Wagner Hermann 
Published: February 2007

AbstractA limiting dilution culture system has been used to analyze the role of T cell‐derived colony stimulating factor (CSF) during the activation of IL2‐producing helper T lymphocytes (HTL). EL4 thymoma‐derived supernatant (EL4‐SN) increased about 4‐fold the frequency of HTL precursors responding to metabolically active allogeneic stimulator cells. Upon biochemical separation this biological activity within the EL4‐SN segregated from interleukin 2 (IL2) and gamma interferon but was associated with or identical to CSF. Further, a comparable rise in HTL precursor frequencies was observed when semipurified interleukin 1 (IL1) derived from the P388 D1 cell line was added to limiting dilution cultures. In contrast to IL1, semipurified CSF failed to facilitate the activation of HTL precursors when heat‐treated allogeneic spleen cells were used as stimulator cells. Because EL4‐derived CSF was found to induce IL1 production by macrophages we conclude that T cell‐derived CSF amplifies, via stimulation of antigen‐presenting cells the number of inducible HTL precursors. Therefore, the CSF/IL 1‐dependent increase in HTL precursor frequencies reported here may reflect the differential activation threshold of HTL precursors, most of which will not be activated by antigen per se but only in presence of additional cytokines.
Heterogeneous and monoclonal helper T cells induce similar anti‐(4‐hydroxy‐3‐nitrophenyl)acetyl (NP) antibody populations in the primary adoptive response I. Isotype distribution
Authors: Tesch Hans , Smith Frances I. , Müller‐Hermes Werner J. P. , Rajewsky Klaus 
Published: February 2007

AbstractIn the response to NP‐lipopolysaccharide or NP‐Ficoll predominantly anti‐NP antibodies of the IgM class are produced in mice with lower amounts of IgG3 and IgG2b but little or no IgG1 and IgG2a. In contrast, in the primary T‐dependent response to NP‐keyhole limpet hemocyanin (KLH) or NP‐chicken gamma globulin high amounts of all IgG isotypes are induced. To investigate whether isotype‐specific T cells are responsible for these differences we carried out cell transfer experiments using carrier‐specific T cell lines. Two such lines were established and one of the two could be cloned. Upon activation by antigen the T cell lines induced unprimed syngeneic splenic B cells to proliferate and differentiate into antibody‐secreting cells in vitro in an antigen‐nonspecific way. Antigen‐specific activation of unprimed B cells in a cell transfer system in vivo showed that high concentrations of hapten‐specific antibodies of all IgG isotypes are induced through both carrier‐specific T helper lines. The isotypic pattern of these antibodies is similar to that produced via heterogeneous splenic T cells in the cell transfer system, or in normal animals on immunization with the same antigen. These results suggest that isotype‐specific T cells are not required for the production of IgG isotypes in a primary anti‐NP response and thus not responsible for the differences seen in isotypic patterns between T‐dependent and T‐independent responses.
Antibody‐free target cells stimulate chemiluminescence in polymorphonuclear leukocytes: an artifact due to mycoplasma contamination
Authors: Peterhans Ernst , Bertoni Giuseppe , Köppel Peter , Wyler Robert , Keller Robert 
Published: February 2007

AbstractThe generation of toxic oxygen species represents a significant mechanism in the killing of microorganisms and antibody‐coated cells by phagocytic cells. We have investigated the possibility that antibody‐free target cells stimulate reactive oxygen generation in polymorphonuclear leukocytes (PMNL) using the measurement of luminol‐dependent chemiluminescence (CL). It was found that the induction of CL consistently correlated with a mycoplasma contamination of the target cells. Free mycoplasma organisms of two species found frequently as contaminants in cell culture also stimulated CL. Upon artificial infection with mycoplasma, cultured cells acquired the capacity to evoke CL generation in PMNL. Our experiments strongly suggest that the induction of reactive oxygen generation by antibody‐free target cells is an artifact due to mycoplasma contamination of the target cell cultures.
Suppression of the cytotoxic T cell response to minor alloantigens in vivo Linked recognition by suppressor T cells
Authors: Gascoigne Nicholas R. J. , Crispe I. Nicholas 
Published: February 2007

AbstractThis report describes the activity of transferable suppressor T cells (Ts) generated in vivo in response to minor alloantigens. These Ts cells are antigen specific in both primary and secondary in vivo cytotoxic T lymphocyte responses to minor alloantigens and are the result of a host response rather than of a graft‐vs.‐host reaction. The Ts cells are produced soon after immunization and their activity is transient. They act via “linked recognition”, since they can suppress the cytotoxic T lymphocyte response to noncross‐reactive minor antigens, but only if these are presented on the same antigenic cell. A model for dominant low responsiveness in (high × low responder)F1 animals is proposed, whereby Ts cells, activated via the low responder allele, work by linked recognition to suppress helper cells activated via the high responder allele.
The surface expression of a tumor‐associated antigen on human kappa myeloma cells
Authors: Boux Heather A. , Raison Robert L. , Walker Karen Z. , Musgrove Elizabeth , Basten Antony 
Published: February 2007

AbstractThe monoclonal antibody K‐1‐21 defines an antigen, KMA (kappa myeloma antigen) on the surface of human χ myeloma cells. K‐1‐21 also recognizes human χ light chains in free form but not when covalently bonded to heavy chains. To examine the relationship between KMA and this determinant on free χ chains, the surface expression of KMA was examined on the IgG,χ myeloma line LICR LON/HMy2 (HMy2). No patching or capping was observed in the presence of K‐1‐21 alone, but KMA could be capped if the cells were incubated with K‐1‐21 followed by fluorescein isothiocyanate‐conjugated sheep F(ab′)2 anti‐mouse immunoglobulin. Capping was not affected by the inhibitors calcium ionophore or dibucaine. When IgG molecules were removed from the cell surface by capping with anti‐IgG antiserum both KMA and free χ light chains could still be detected with K‐1‐21 and a polyvalent anti‐χ antiserum, respectively. By contrast, after removal of all surface χ chains with the polyvalent anti‐χ serum, no staining was observed with K‐1‐21 indicating that KMA may be an epitope on free χ chains inserted in the membrane of χ myeloma cells but absent from normal cells. KMA cell surface expression varied with the stage of the cell cycle. Flow cytometric analysis of K‐1‐21‐stained HMy2 cells from either continuous cultures or from elutriated fractions enriched for various cell cycle phases showed that, within the cycling population, cells in G2 + M expressed KMA at a higher frequency and density than did cells in G1.
Analysis of antigen uptake and presentation by Epstein‐Barr virus‐transformed human lymphoblastoid B cells
Authors: Chu Edward , Umetsu Dale , Lareau Marianne , Schneeberger Evelyn , Geha Raif S. 
Published: February 2007

AbstractEpstein‐Barr virus‐transformed human B cells (EBV‐B cells), but not resting B cells or B cells activated by T cell‐derived factors, have been shown to support the proliferation of tetanus toxoid (TT)‐specific autologous T cell clones in response to TT antigen. The accessory cell function of EBV‐B cells was compared to that of monocytes with regard to antigen uptake and processing.After an 18‐h incubation period with 125I‐labeled TT, the amount of radioactivity associated with the cells (∼ 50 ng/107 cells) and the percentage of cells containing radiolabeled material (∼ 50%) were equivalent for EBV‐B cells and monocytes. Like with monocytes, EBV‐B cells pulsed with TT for 18 h or more were equivalent in their capacity to induce T cell proliferation to EBV‐B cells to which soluble TT was added for the duration of the culture period.The requirements for antigen uptake and presentation to T cells were similar for both EBV‐B cells and monocytes. Both processes were energy dependent, inhibited by cold (4 °C), 2‐deoxyglucose, and azide, and both required no de novo protein synthesis as they were not affected by pretreatment of the cells with the irreversible protein inhibitor pactamycin. Trypsin treatment of antigen‐pulsed EBV‐B cells and monocytes followed by fixation for 1 min in 0.03% paraformaldehyde completely abolished the capacity of both cell types to induce T cell proliferation.In both EBV‐B cells and monocytes, antigen presentation, but not antigen uptake, was inhibited by the addition of the lysosomotropic agent chloroquine during the antigen‐pulse period suggesting that the mechanisms of antigen processing are similar for both cell types. Vacuoles positive for acid phosphatase with an electron microscopic structure similar to that of lysosomes were found in EBV‐B cells but not in resting B cells or B cells activated by T cell‐derived factors.The present observations indicate that EBV‐B cells take up antigen and process it in a fashion similar to monocytes. The presence of lysosomes appears to correlate with the capacity of B cells to present antigen.
HLA‐DC antigens can serve as recognition elements for human cytotoxic T lymphocytes
Authors: Spits Hergen , Borst Jannie , Giphart Marius , Coligan John , Terhorst Cox , de Vries Jan E. 
Published: February 2007

AbstractThe specificity of four cytotoxic T lymphocyte (CTL) clones which recognize class II major histocompatibility complex (MHC) antigens was analyzed. All clones recognized antigens associated with the serologically defined HLA‐DRw6 specificity. The activity of two of these clones, JR‐2‐2 and JR‐2‐10, could be inhibited by a monoclonal antibody Q 5/13 specific for a monomorphic determinant present on HLA‐DR. In contrast, the activity of the two other CTL clones, JR‐2‐19 and JR‐2‐26, was not blocked by Q 5/13, but by a new monoclonal reagent, SPV‐L3. This latter monoclonal antibody precipitated a two‐chain structure of 28 kDa and 33 kDa and reacts with a monomorphic determinant. The molecular weight of the polypeptides precipitated with SPV‐L3 was slightly less than those precipitated with a HLA‐DR‐specific monoclonal reagent. In addition two‐dimensional gel electrophoresis showed that the antigen precipitated by SPV‐L3 differed in charge from those precipitated with the anti‐HLA‐DR antibody. These results indicate that SPV‐L3 recognizes a class II MHC product different from HLA‐DR. This observation was confirmed by partial amino acid sequence analysis of the two chains which revealed that the molecule precipitated by SPV‐L3 is homologous to HLA‐DC/DS molecules. Therefore this report provides the first evidence that human cytotoxic T cells can recognize HLA‐DC/DS antigens.
Independent inhibition of IL 2 synthesis and cell proliferation by anti‐Ia antibodies in mixed lymphocyte responses to Mls
Authors: Macphail Stuart , Stutman Osias 
Published: February 2007

AbstractWhole anti‐I region antisera and monoclonal anti‐Ia antibodies are capable of totally inhibiting the response of murine spleen cells to the non‐H‐2 Mls alloantigens. This inhibition was shown to be highly specific for the appropriate Ia and operative at the level of the stimulator cell. Both cell proliferation and interleukin (IL 2) production were inhibited; however, the inhibition of cell proliferation was not due only to the inhibition of IL 2 production and the inhibition of IL 2 production was not solely due to the inhibition of IL1 production. We propose that both the IL 2‐producing cell and the proliferating cell need to “see” an intact Ia+ cell and perhaps Ia antigens in association with Mls determinants to respond.
Surface immunoglobulin phenotype of complement receptor‐positive and complement receptor‐negative B cells of normal and xid immunodeficient mice
Authors: Lindsten Tullia , Finkelman Fred D. , Thompson Craig B. , Andersson Birger , Scher Irwin 
Published: February 2007

AbstractSingle‐ and dual‐parameter fluorescence‐activated cell sorter analyses of complement receptor‐positive and ‐negative (CR+ and CR−) splenic B cells of normal and xid immunodeficient mice were performed to determine the frequencies of surface (s) IgM+ and sIgD+ cells, as well as the quantities of sIgM and sIgD on these cells. Single parameter analysis revealed identical frequencies of sIgM+ and sIgD+ cells in the CR+ B cell population of normal mice. In contrast, the percentage of sIgM+ cells exceeded that of sIgD+ cells in the CR− normal and CR+ xid B cell population to a similar extent. CR− xid B cells showed an even greater discrepancy between sIgM+ and sIgD+ cells.Dual‐parameter analysis of CR+ normal B cells showed the typical sIg phenotype of mature B cells, i.e. an intermediate density of sIgM and a high density of sIgD. The CR+ xid B cell population displayed an increase in cells with high sIgM and no‐to‐low sIgD and a decrease in cells with intermediate sIgM and high sIgD when compared to CR+ normal cells. CR− B cells from normal and xid immunodeficient mice were similar in that both consisted largely of a cell population with low sIgM and no‐to‐low sIgD. However, the CR− normal B cell population also contained cells with intermediate sIgM and high sIgD, which were lacking in the CR− xid cell population. Similar results were obtained when CR+ and CR− B cells from normal and xid mice were purified from a small resting B cell population, isolated by elutriation. This indicates that the sIg phenotype of CR− cells is not due to the presence of large cells which have lost sIgD during activation.
Polyclonal B cell responses in the presence of defined filler cells: complementary effects of lipopolysaccharide and anti‐immunoglobulin antibodies
Authors: Zubler Rudolf H. 
Published: February 2007

AbstractThe signal requirement for polyclonal B cell responses in the presence of T helper (Th) cells, lipopolysaccharide (LPS), anti‐Ig antibodies coupled to Sepharose beads (anti‐Ig) and/or T cell supernatants (SN) was studied in a murine system using (a) low numbers of B cells/culture in order to reduce the effects of contaminating Th cells and (b) defined sources of irradiated filler cells in the form of EL4 thymoma cells or cloned male H‐Y antigen‐specific Th cells. The results demonstrate that for optimal proliferation as well as (protein A) plaque‐forming cell (PFC) generation B cells required at least two activation signals in addition to factor(s) present in Th or EL4 SN, i.e. either a specific (or concanavalin A‐dependent nonspecific) Th signal and anti‐Ig or (in cultures with EL4 filler cells) LPS and anti‐Ig. While confirming several previous studies, including our own, which showed a requirement for two activation signals in conjunction with T cell factors in antigen‐specific B cell responses, the present system differs from previous polyclonal systems by showing nonoverlapping effects of LPS or a specific Th signal on the one hand and anti‐Ig on the other in the induction of growth factor responsiveness of B cells. In addition, limiting dilution analysis showed that in cultures with EL4 filler cells, LPS, anti‐Ig and EL4 SN 1/8 surface Ig‐positive cells generated > 10 PFC with a mean clone size of 70 PFC and indicated that only the B cells were limiting. This system using defined thymoma filler cells should be useful for assaying factors potentially replacing the LPS or anti‐Ig signals.
Chicken thymocyte‐specific antigen identified by monoclonal antibodies: ontogeny, tissue distribution and biochemical characterization
Authors: Chen Chen‐lo H. , Chanh Tran C. , Cooper Max D. 
Published: February 2007

AbstractTwo monoclonal antibodies, CT‐1 (IgG1,χ) and CT‐1a (IgG3,χ), were prepared against chicken thymocytes. The antigen identified by these antibodies was found to be a glycoprotein with a major polypeptide component having an apparent molecular weight of 63000 and a minor polypeptide component of approximately 103000. Immunoprecipitation and blocking experiments revealed that the two antibodies react with different antigenic determinants of the molecule. Ontogenic studies employing immunofluorescence failed to reveal the antigenic determinants on cells from the embryo or embryonic yolk sac on days 3 and 6 of incubation. The number of embryonic thymocytes bearing the molecules detected by these antibodies increased from 6% on day 12 to 54% on day 13; the frequency of thymocytes expressing this glycoprotein reached adult levels (> 90%) by the 15th day of embryonic age. In contrast, the CT‐1 and CT‐1a antibodies reacted with only 2‐5% of blood and splenic cells and less than 0.05% of cells from bursa or bone marrow of young adult chickens. In the quail CT‐1 reacted with cortical, but not medullary, thymocytes, while the CT‐1a antibody was unreactive with quail thymocytes. The surface glycoproteins detected by these discriminating monoclonal antibodies may provide an important discriminating marker for thymic lymphocytes in the chicken and the quail.