bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of pre‐B cell proliferation in bone marrow: immunofluorescence stathmokinetic studies of cytoplasmic p chain‐bearing cells in anti‐IgM‐treated mice, hematologically deficient mutant mice and mice given sheep red blood cells
Authors: Opstelten Davine , Osmond Dennis G. 
Published: February 2007

AbstractTo identify factors influencing the in vivo proliferate activity of bone marrow pre‐B cells, the metaphase‐blocking drug, vincristine sulfate, was injected into (a) mice depleted of B lymphocytes by treatment with anti‐mouse IgM antibodies from birth; (b) hematologically deficient WWv and SI/SId mutants, and (c) mice injected with a foreign agent, sheep red blood cells (SRBC). Subsequently, a quantitative measure of pre‐B cell proliferation was provided by examining marrow cells by immunofluorescence labeling for the absolute number of pre‐B cells, identified by the presence of cytoplasmic μ chains (cμ) without surface μ (sμ), which had been arrested in meta‐phase. In anti‐IgM‐treated mice, some changes were observed in the size of the large pre‐B cell population and in the incidence of mitotic cells after vincristine administration, but the overall production rate of pre‐B cells did not differ from that in controls given normal rabbit serum. Pre‐B cell kinetics in WW and SI/SId mice also generally resembled those in homozygous controls. In contrast, after SRBC injection, there was an increase in the rate at which large pre‐B cells entered mitosis. Thus, the proliferation of cμ+sμ‐ bone marrow pre‐B cells shows no evidence of feedback control from the mature B lymphocyte pool, as indicated by lack of stimulation of pre‐B cell production in anti‐IgM‐treated mice, and is independent of the hemopoietic defects of WW or SI/SId mutants. On the other hand, the increased bone marrow pre‐B cell proliferation after SRBC injection demonstrates that the magnitude of B cell genesis in the bone marrow can be influenced by extrinsic agents and thus may be influenced by environmental stimuli.
Purine nucleotide metabolism in resident and activated rat macrophages in vitro
Authors: Barankiewicz Jerzy , Cohen Amos 
Published: February 2007

AbstractThe overall purine metabolism was studied in detail in resident peritoneal macrophages (MO) and in thioglycolate elicited peritoneal Mϕ in vitro. The salvage of purine bases (adenine, hypoxanthine and guanine) was active in both Mϕ populations, whereas purine biosynthesis de novo was low. Purine nucleosides (inosine, guanosine and adenosine) were efficiently degraded to uric acid and only adenosine was directly salvaged into nucleotides. Purine salvage was markedly increased in elicited Mϕ as compared to resident Mϕ whereas purine degradation pathways were enhanced only slightly. These results clearly indicate that salvage of purine bases is the main source for purine nucleotide biosynthesis in Mϕ, but nucleotide catabolism is the predominant pathway.
Receptors for immunoglobulin isotypes (FcR) on murine T cells: II. Multiple FcR induction on hybridoma T cell clones
Authors: Daeron Marc , Neauport‐Sautès Catherine , Yodoi Junji , Moncuit Janine , Fridman Wolf H. 
Published: February 2007

AbstractIn the preceding report (Eur. J. Immunol.1985. 75: 662), we described a variety of receptors for the Fc portion of the different isotypes of mouse immunoglobulins (FcR), that were found to be expressed on hybridoma T cell clones. In the present work, we wondered whether the expression of these T cell FcR would be regulated by environmental influences such as the presence of corresponding ligands. We found that exposing the cells to the bulk of serum immunoglobulins in vivo, or to purified monoclonal immunoglobulins in vitroboth resulted in FcR induction. The expression of all constitutive receptors, i.e.Fcγ1/2bR, Fcγ3R, FcαR and FcϵR, could be increased upon incubation with IgG1, IgG2b, IgG3, IgA and IgE, respectively. After induction, the specificity of FcR was not modified. Two FcR were detectable only upon induction. These were Fcγ2a/2b/1R, induced by IgG2a and FcμR, induced by IgM. Interestingly, FcR detectable after induction only were short‐lived at the membrane. Ten to 15 h after induction they were not detected any more, whereas the expression of constitutive FcR remained elevated for at least 24 h following induction.Therefore, depending on the concentration of immunoglobulins in the environment, and depending on whether they are short lived or long lived, FcR can modulate their expression on the membrane of T cells. Such a versatility might be an efficient means to contribute to isotypic regulation through the release of regulatory immunoglobulin‐ binding factors.
A high incidence of cross‐reactive idiotypes among murine natural autoantibodies
Authors: Lymberi Peggy , Dighiero Guillaume , Ternynck Thérèse , Avrameas Stratis 
Published: February 2007

AbstractAnti‐idiotypic (anti‐Id) antibodies were produced in rabbits against two natural monoclonal IgM autoantibodies (NmAb), D23 and E7, which exhibited a broad reactivity and were derived from fusions of spleen cells from adult unprimed B ALB/c mice and nonsecreting myeloma cell lines. They were used to test the reactivities of 12 NmAb obtained from adult and newborn unprimed mice. Both anti‐Id recognized cross‐reactive idiotopes frequently shared by NmAb; 8 out of the 12 NmAb reacted with anti‐IdD23, while 5 of them also reacted with anti‐IdE7. All of the Id‐bearing antibodies possessed widespread reactivity with structurally dissimilar self and non‐ self antigens. In most cases, their cross‐reactive Id determinants seemed to be located outside of their antigen‐binding sites. Furthermore, the presence in normal mouse sera of significant levels of D23 and E7 idiotopes correlated with the presence of natural antibody activity and was mainly associated with IgM and IgG2b fractions. Finally, D23 idiotope(s) were also found on induced murine anti‐myosin antibodies. The high incidence of cross‐reactive idiotopes found among NmAb produced by clones derived from different mice and their presence in normal BALB/c mouse serum Ig fractions suggest that families of germ‐line genes may encode for at least a part of them.
Growth of normal human T lymphocytes induced by monoclonal antibody to the T cell antigen receptor
Authors: Boylston Arthur W. , Cosford Paul 
Published: February 2007

AbstractA monoclonal antibody (mAb) called 30‐3D6 has been raised against the T cell antigen receptor analogue on a human T cell leukemia cell line HPB‐ALL. This mAb comodulates the T3 molecule on HPB‐ALL and precipitates the heterodimeric structure previously described as a T cell idiotypic receptor analogue on this cell line. 30‐3D6 reacts with a variable percentage of normal T cells (up to 6%) depending on the donor and this number is stable on repeated sampling and is not affected by the temperature of the reaction. When normal T cells from a high frequency donor are stimulated with 30‐3D6 and interleukin 2 in vitro the idiotype‐positive (Id+) population can be expanded. Large numbers of > 90% Id+ T cells can be generated. Id cells are present in both the helper and cytotoxic suppressor subsets.
Senescence of a human lymphoblastoid clone producing anti‐Rhesus(D)
Authors: Melamed Mark D. , Gordono John , Ley Steven J. , Edgar David , Hughes‐Jones Nevin C. 
Published: February 2007

AbstractThe exploitation of Epstein‐Barr virus transformation to generate human lymphoblastoid clones (LCL) producing antibody of predefined specificity has proved highly inefficient, Observations reported here on a cloned LCL producing anti‐Rhesus(D) may provide an explanation for the low success rate. Over a few months this clone manifested a progressive loss of capacity to maintain growth in culture. Evidence consistent with terminal differentiation to a cell with the properties of a nonproliferating plasma cell was obtained. These late cells differed from those in the earlier actively cycling phase in that they were no longer able to respond to autostimulatory growth factors although they continued to produce them. This irreversible senescence leading to the death of the clone may be a common feature of virally transformed B cells and this would explain many of the difficulties encountered on this route to the production of human monoclonal antibodies.
Major surface protein of Toxoplasma gondii (p30) contains an immunodominant region with repetitive epitopes
Authors: Rodriguez Céste , Afchain Daniel , Capron André , Dissous Colette , Santoro Ferrucio 
Published: February 2007

AbstractFour monoclonal antibodies (mAb) against surface antigens of tachyzoites of Toxoplasma gondii were produced. Immunoprecipitation of extracts of 125I‐labeled tachyzoites identified the same polypeptide with apparent molecular weight of 30 000 (p30). A competition binding assay indicated that a single region of p30 was recognized by all 4 of the mAb. Furthermore, we found that single mAb inhibited 25–50% of the specific binding of antibodies of patients with toxoplasmosis to the antigenic extract of tachyzoites. It appears, therefore, that p30 is the most immunogenic constituent of tachyzoites, and that a single region of this molecule contains most of the immunogenic activity. Finally, a two‐site/one‐antibody immunoradiometric assay with the same mAb indicated that the p30 molecule is multivalent with respect to the expression of a single epitope.
A monoclonal λ1‐bearing anti‐dextran antibody from a λ‐defective mouse strain
Authors: Weissn Siegfried , Lehmann Kathrin , Cohn Melvin 
Published: February 2007

AbstractA hybridoma from the λ‐defective mouse strain SJA has been established. It produces a λ1‐bearing IgG2b, dextran B 1355‐binding antibody. The DNA sequence of the VJ and C gene segment was in complete accordance with the published germ‐line sequence. The rate of secretion and the steady state level of cytoplasmic RNA of this line was comparable to that of cell lines from normal mice. The idiotype was closely related to that of MOPC 104E indicating that the λ1 light chain is associated with the same VH region and in a similar fashion as in BALB/c mice. This antibody should be useful for further experiments on the λ defect of SJL or SJA mice.
Antigen stimulation of cytolytic T lymphocyte precursors: minimal requirements for growth and acquisition of cytolytic activity
Authors: Erard François , Nabholz Markus , Robson MacDonald H. 
Published: February 2007

AbstractMinimal requirements for growth and acquisition of cytolytic activity by alloantigenstimulated cytolytic T lymphocyte precursors (CTL‐P) have been investigated. CTL‐P from C57BL/6 spleen were purified by staining with monoclonal anti‐Lyt‐2 antibodies followed by positive selection on a fluorescence‐activated cell sorter. Microcultures containing 2000 purified Lyt‐2+ cells were set up with irradiated P815 (DBA/2 mastocytoma) stimulating cells and pure interleukin 2 obtained by recombinant DNA technology (rIL 2). Proliferation and generation of antigen‐specific cytolytic activity were observed to be both antigen and IL2‐dependent in such microcultures. Furthermore, P815 stimulating cells could be replaced by 5 other H‐2d cell lines of differing tissue origin. In limiting dilution studies, 1–2% of Lyt‐2+ CTL‐P (contaminated by < 0.2% macrophages) could be induced to grow and express cytolytic activity in the presence of irradiated P81S and rIL 2. Taken together, these data indicate that neither accessory cells nor differentiation factors (other than IL 2) are absolutely required for alloantigen‐induced growth and differentiation of CTL‐P.
A cell surface marker of thymus‐dependent lymphocytes in Xenopus laevis is identifiable by mouse monoclonal antibody
Authors: Nagata Saburo 
Published: February 2007

AbstractA mouse monoclonal antibody (mAb), named XT‐1 (IgG2b,λ), was prepared against J strain Xenopus laevis thymocytes. The determinant recognized by this mAb (XT‐1 determinant) was expressed by 92–98% thymocytes and 22–37% splenic lymphocytes from intact J strain frogs and larvae, as analyzed by flow cytofluorometry. The XT‐1 determinant was also expressed by 20–30% peripheral blood lymphocytes and 5–11% bone marrow lymphocytes from adult, and 11–17% liver lymphocytes from larval J strain Xenopus. Early larval thymectomy depleted XT‐1‐positive cells in the spleen to less than 2% of the total lymphocyte population. Double immunofluorescence experiments revealed that XT‐1+ lymphocytes in the spleen are surface IgM−. The strain distribution study on the expression of XT‐1 determinant suggests the allelic polymorphism of the XT‐1 determinant. The surface antigen identified by the present XT‐1 mAb may provide an important marker for lymphocytes in thymus‐dependent lineage in Xenopus.
Antigen‐specific T cell suppressor factor (TsF): isolation of a cDNA clone encoding for a functional polypeptide chain of phosphorylcholine‐specific TsF
Authors: Sugimura Kazuhisa , Yamasaki Noriyuki , Matsuura Makiko , Watanabe Takeshi 
Published: February 2007

AbstractA cDNA library of phosphorylcholine (PC)‐specific suppressor T hybridoma, 29‐C‐6, was constructed. By differential colony hybridization, 68 colonies were selected which hybridized with mRNA probes of two PC‐specific suppressor T hybridomas, 29‐C‐6 and 09‐M‐24–8, but not with those of BW5147. A hybridization translation assay revealed that only one combination of translation products of cDNA clones, p6–1 and p6–5, showed strong PC‐T cell suppressor factor (TsF) activity. Sequence analysis showed that p6–5 contained a specific cDNA sequence of about 800 base pairs (bp) while p6–1 had a 190 bp poly(A) sequence insert.When total poly(A)+RNA of 29‐C‐6 was hybridized with a p6–1 filter alone the recovered mRNA was capable of producing PC‐TsF. However, when the total poly‐(A)+RNA was hybridized with a p6–1 filter combined with a p6–5 filter, the mRNA eluted from the p6–1 filter was not able to produce PC‐TsF, suggesting that the depletion of p6–5 specific mRNA from p6–1‐binding poly(A)+RNA led to a complete abolishment of the capability to produce PC‐TsF.Furthermore, p6–5 hybridizing mRNA could successfully restore the p6–1‐binding poly(A)+RNA depleted of p6–5‐specific mRNA, and translation products of both RNA mixtures showed strong PC‐TsF activity. These results suggest that PC‐TsF is not a single polypeptide chain, but is composed of at least two distinct polypeptide chains, and also that p6–5 contains a cDNA sequence encoding for one of the polypeptide chains composing the PC‐TsF molecule.
Hepatobiliary transport of plasma IgA in the mouse: contribution to clearance of intravascular IgA
Authors: Delacroix Dominique Léon , Malburny Geneviève Nicole , Vaerman Jean‐Pierre 
Published: February 2007

AbstractLabeled monomeric and polymeric (pIgA) mouse monoclonal IgA were injected intravenously into mice which were either sequentially bled for plasma turnover studies of IgA, or cannulated at their common bile duct, with excluded gallbladder, for quantitation of plasma‐to‐bile transport of pIgA. Our data show that mice do display a relatively high rate of biliary transport of plasma pIgA (22–28% of the injected 125I‐labeled pIgA over 3 h), which accounts for ∼90% of the total amount of pIg A (8.8 mg/kg/day) daily delivered by hepatic bile into the duodenal fluid of this species. However, in mice the absolute biliary output of pIgA does not exceed that of IgG (9.5 mg/kg/day) and the kinetics of the hepatobiliary transport of plasma PIgA appear to be slower than in the rat. Furthermore, as plasma survival studies of 125I‐labeled pIg A yielded a plasma turnover of pIgA averaging 20.6 mg/kg/day, it can be approximated that the hepatobiliary pathway contributes for only 38% to the elimination of intravascular pIgA from mouse plasma, a figure to be compared to 89.8% in the rat and ∼ 8.9% in man. We conclude that internal catabolism plays a dominant role in the clearance of intravascular pIgA in the mouse which appears as a model intermediate between rats and humans. Supporting this conclusion, serum pIgA two days after common bile duct ligation in 6 mice was increased by 2.5‐fold vs. > 14‐fold in ligated rats and 1.1‐fold in humans with complete biliary obstruction.
Antigens apparently nonimmunogenic for xid/Y mice cause the development of specific splenic plasmablasts and of fusion partners for SP2 cells giving hybridomas that secrete antibodies
Authors: Ohriner William D. , Cebra John J. 
Published: February 2007

AbstractAlthough xid/Y mice fail to make a detectable primary antibody response to a variety of antigens such as Type III pneumococcal capsular polysaccharide (SIII), 2,4,6‐trinitrophenyl (TNP)‐Ficoll, pneumococcal C carbohydrate, group A streptococcal vaccine and several kinds of related antigenic determinants such as phosphorylcholine (PC) and N‐acetyl‐glucosaminyl (GlcNAc), even when the latter are coupled to hemocyanin (Hy), they do show: (a) an antigen‐dependent development of splenic B cells which can act as successful, productive fusion partners for SP2 cells giving hybridomas making monoclonal anti‐SIII, anti‐PC, anti‐GlcNAc, anti‐TNP, etc., and (b) an antigen‐dependent appearance of antigen‐binding plasmablasts in their spleens. The frequencies of specific B cells arising in xid/Y males with either of these properties are of the same order of magnitude as those found in immunocompetent xid/Y female littermates. Further, both PC‐Hy and GlcNAc‐Hy prime xid/Y and xid/X mice for quantitatively and qualitatively similar secondary responses. All three of these expressions of a specific, primary response occur in xid/Y mice in the absence of any rise in circulating antibodies.The properties of successful, productive normal fusion partners leading to secretory hybridoma lines are unknown. Thus we cannot decide whether the antigen‐binding plasmablasts that arise in xid/Y mice can also play the role of productive fusion partners. Neither do we know whether the development of specific IgM and IgG3 plasmablasts in xid/Y mice after antigen stimulation is an abnormality reflecting the xid mutation. It cannot be excluded that the development of productive fusion partners, of nonsecretory plasmablasts and of memory cells are all interrelated and reflect a process that also normally occurs in xid/Y, X/X and X/Y mice following similar immunization regimens. It is tempting to speculate that such cells initially responding may lag in the development of normal secretory mechanisms and that the “transformed” fusion partner may complement this deficiency.
Ultrastructure of human C4‐binding protein: proposition for a new model
Authors: Villiers Marie‐Bernadette , Thielens Nicole M. , Villiers Christian L. , Colomb Maurice G. 
Published: February 2007

AbstractThe structure of human C4‐binding protein (C4bp), a regulatory factor of the classical C3 convertase of complement, has been under investigation for several years, but remains poorly understood. For example, the number of subunits in the C4bp molecule has not been established. In this report, we use two different techniques (partial reduction and electron microscopy) to clarify the structure of the C4bp. Our results lead us to propose a structural model which is quite different to that suggested before, i.e. the C4bp molecule appears to be a decamer. In addition to the disulfide bonds which link each subunit to another, a second disulfide interaction leads to the association of the subunits in pairs. Each pair of subunits appears as a filament ending in a globular head at the N‐terminal extremity. The pairs of subunits join to form a conical central domain (at the C‐terminal extremity) linked by disulfide bonds. The proposed pentameric shape of the C4bp is consistent with the stoichiometry of the C4b‐C4bp interactions. The proposed model indicates an overall structural homology between C4bp and other binding proteins.
Antibody density on rat red cells determines the rate of activation of the complement component Cl
Authors: Hughes‐Jones Nevin C. , Gorick Barbara D. , Howard Jonathan C. , Feinstein Arnold 
Published: February 2007

AbstractIt is a common observation that there is variability in the rate of activation of C1, the first component of complement, when bound to immune complexes. The cause of this variation has been investigated with experiments designed to assess separately the effect of antibody, antigen and C1 density. Using 125I‐labeled C1 and a rat monoclonal antibody specific for the class I antigen, it has been found that the rate of activation is primarily dependent on antibody density on the cell surface and not on antigen or C1 density. This finding supports the suggestion that direct contact between the Clr2Cls2subcomponent of C1 and antibody may be required for potentiation of C1 activation.
Modulation of complement receptors of a human monocyte cell line, U‐937, during incubation with phorbol myristate acetate: expression of an iC3b‐specific receptor (CR3)
Authors: Gilbert Danièle , Peulve Pascal , Daveau Maryvonne , Ripoche Jean , Fontaine Marc 
Published: February 2007

AbstractThe human monocyte line, U‐937, derived from an individual with histiocytic lymphoma was studied for the expression of surface C3 receptors, after cultivation in the presence of phorbol myristate acetate (PMA) or T lymphocyte‐conditioned medium. Receptors were detected by using EAC4b, EAC3b, EC3b, EAC3bi and EAC3d intermediates. U‐937 cells, in exponential growth phase, poorly bound the intermediates; after exposure to PMA or T lymphocyte‐conditioned medium, U‐937 cells strongly bound both EAC3b and EAC3bi since about 50% of cells rosetted with these intermediates. This binding was totally inhibited by EDTA and by Mac‐1 monoclonal antibody, suggesting the presence of only CR3 receptor types on these cells. Although U‐937 cells formed rosettes with EACSb, there was no evidence for the presence of CR1 receptors since no rosette was observed either with EAC4b or with EC3b intermediates (EC3b were prepared by coupling purified C3b to erythrocytes with N‐succinimidyl 3‐(2‐pyridyldithio)propionate. As small amounts of factor H were present on EAC3b intermediates, incubation of EAC3b with U‐937 cells induced their transformation into EAC3bi and their binding to CR3. Moreover, U‐937 cells did not promote the cleavage of C3b in the presence of factor I alone, suggesting that these cells did not bear a sufficient amount of functionally active CR1. These results demonstrated that U‐937 cells predominantly expressed CR3. The study of the kinetics of EAC3bi rosette formation demonstrated that CR3 expression is closely related to PMA activation. We suggest that CR3 activity could result from a phosphorylation of existing receptors.