bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immature thymocytes isolated using a sialic acidspecific lectin are unresponsive to concanavalin A
Authors: Herron Lynne R. , Abel Carlos A. , Wall Jennifer Vander , Campbell Priscilla A. 
Published: February 2007

AbstractMouse thymocytes, which are approximately 90% immature cortical cells, are low in surface sialic acid when compared with more mature cortisone‐resistant, presumably medullary, thymocytes and peripheral T lymphocytes. Thus, medullary thymocytes bind and are agglutinated by the N‐acetylneuraminic acid‐specific lectin, lobster agglutinin 1 (LAg1), whereas cortical thymocytes are not agglutinated by this lectin. It is demonstrated herein that mouse cortical thymocytes, purified using LAg1, do not respond to the mitogenic effects of concanavalin A (Con A). The lack of response to this lectin is not due to depletion of macrophages, since addition of macrophages does not restore the response. Populations of LAg1‐negative thymocytes can be made to respond weakly to Con A by the addition of interleukin 2, but this response appears to be due to the presence of a few contaminating LAg1‐binding thymocytes since it is abolished by treatment of the cells with rabbit anti‐LAg1 serum plus complement. Therefore highly purified cortical thymocytes not only cannot respond to Con A, but also they cannot be induced to respond by the addition of the T cell growth factor, interleukin 2. Thymocytes isolated by a single criterion, that is by virtue of their low amount of surface sialic acid, appear to be a truly immature population of thymocytes.
Distinct HLA‐DR epitopes and distinct families of HLA‐DR molecules defined by 15 monoclonal antibodies (mAb) either anti‐DR or allo‐anti‐Iak crossreacting with human DR molecule. I. Cross‐inhibition studies of mAb cell surface fixation and differential binding of mAb to detergent‐solubilized HLA molecules immobilized to a solid phase by a first mAb
Authors: Rebai Najet , Malissen Bernard , Pierres Michel , Accolla Roberto S. , Corte Giorgio , Mawas Claude 
Published: February 2007

AbstractA series of HLA‐DR‐reactive mouse anti‐human B cell or anti‐Ia monoclonal antibodies (mAb) have been used to explore the serological complexity of human class II antigens at the determinant level, using two techniques: (a) cross antibody‐binding competitor assays using 125I‐labeled and ‐unlabeled mAb were performed to study the topological organization of the corresponding determinants to determine epitopic clusters recognized by this collection of mAb and (b) differential reactivity of mAb to detergent‐solobilized solid‐phase‐immobilized HLA‐DR molecules to determine epitopes expressed on identical DR isotypes. The fifteen mAb could be classified according to the first technique as falling into three different epitopic clusters. Using the second technique, we were able to define at least two independent molecular subsets, one co‐expressing two of the three epitopic clusters and the second expressing only the third one. We could not formally identify molecular subsets expressing only one of the first two clusters, using the second technique.The precise serological mapping of the determinants recognized by various anticlass II mAb should prove very useful if such mAb were to be introduced in anticlass II‐specific T cell clone blocking experiments. We anticipate that some of them should facilitate the correlation at the clonal level between the T cell repertoire and the epitopes or molecular subsets defined by these mAb. However, within mAb belonging apparently to a same cluster, some could mediate different biological effects.
Autonomously proliferating K/D‐restricted cytolytic T cell clones
Authors: Von Boehmer Harald , Turton Katrin 
Published: February 2007

AbstractK/D‐restricted male‐specific cytolytic T lymphocytes (CTL) have been cloned and assayed for male‐specific proliferation in the absence of exogenous interleukin 2 (T cell growth factor). The majority of freshly cloned CTL proliferate in response to cell‐bound antigen. The clones lose their proliferative potential after growing for three weeks in media containing IL2.
Simultaneous absence of the human IgG1, IgG2, IgG4 and IgA1 subclasses: Immunological and immunogenetical considerations
Authors: Lefranc Gérard , Chaabani Hassen , Van Loghem Erna , Lefranc Marie‐Paule , De Lange Gerda , Helal Ahmed‐Noureddine 
Published: February 2007

AbstractSimultaneous absence of the IgG1, IgG2, IgG4 and IgA1 immunoglobulins has been unambiguously demonstrated in a healthy 75‐year‐old woman by testing for allotypes, isoallotypes and for isotypes of these four subclasses. Only IgM, IgD, IgG3, IgA2 and IgE were present. The IgG3 levels were significantly increased. Family investigation showed inheritance of a haplotype Gm−;−;b A2m2. This person is homozygous for an extensive DNA deletion including the Cγ1, Cγ2, Cγ4 and Cα1 genes.
A cross‐reacting human idiotype (B17) associated with antibodies to N‐acetyl‐D‐glucosamine Specificity, immunoglobulin class association, and distribution in the population
Authors: Emmrich Frank , Greger Bernd , Eichmann Klaus 
Published: February 2007

AbstractThis report describes the study of the expression of an idiotype in the human population which is associated with antibodies to N‐acetyl‐D‐glucosamine (GlcNAc) present in most human sera presumably due to streptococcal infections. The idiotype is identified with antisera and monoclonal antibodies prepared against the IgM (χ) antibody secreted by the Epstein‐Barr virus‐transformed human B cell line B17.At least 90% of 207 individuals tested had immunoglobulin with B17 idiotypic determinants in their sera, as demonstrated with conventional and one monoclonal anti‐idiotypic antibody. Another monoclonal anti‐idiotypic antibody reacted with antibodies in only a few of the sera. No correlation was found between the level of expression of different idiotopes in individual human sera, suggesting molecular heterogeneity of the B17‐positive antibody population.B17‐positive immunoglobulins are to a large extent specific for GlcNAc but represent only a minor population of all GlcNAc‐specific antibodies in human sera. B17 determinants are on IgM (χ) in all human sera and on IgG and IgA in some. In addition, some λ‐bearing Ig was found to react with anti‐B17 antisera, suggesting the detection of VH‐associated idiotypic determinants in this experimental system.
Complement inhibits immune responses: C3 preparations inhibit the generation of human cytotoxic T lymphocytes
Authors: Ballas Zuhair K. , Feldbush Thomas L. , Needleman Barbara W. , Weiler John M. 
Published: February 2007

AbstractC3 fragments have been shown to inhibit mitogen‐ and antigen‐induced human lymphocyte blastogenesis. In this study, C3 preparations and a small fragment of C3 (contained in a preparation called Fraction 2) were examined for their capacity to regulate cytotoxic T lymphocytes (CTL) and proliferative mixed lymphocyte responses (MLR). We found that both preparations inhibited the generation of allogeneic human CTL as well as MLR in a dose‐related manner. In contrast, Fraction 1, which contained native C3 and C3b, did not inhibit the generation of CTL nor did it inhibit the MLR. The kinetics of inhibition of proliferation were divergent from the kinetics of inhibition of CTL generation; the active preparations inhibited proliferation significantly when added as late as day 5 of a 6‐day culture, whereas no inhibition of CTL generation was seen when these preparations were added after day 3 of culture.Cultures in which C3 preparations caused complete inhibition of CTL generation had normal levels of the nonspecific, anomalous killer cell activity, as assayed on K 562 target cells. Furthermore, C3 preparations and Fraction 2 had no effect on the lytic function of differentiated CTL, on “spontaneous” natural killer cell activity or on interferon‐induced augmentation of natural killer cell activity. These findings indicate that C3 fragments may play a negative role in the regulation of CTL responses.
Strong histocompatibility and cell‐mediated cytotoxic effects of a single Mls difference demonstrated using a new congenic mouse strain
Authors: Berumen Luis , Halle‐Pannenko Olga , Festenstein Hilliard 
Published: February 2007

AbstractIn vivo and in vitro effects of incompatibility at the Mls locus have been studied utilizing a recently created congenic mouse strain. Results obtained with skin grafts were compared to those obtained in the mixed lymphocyte reaction (MLR) and cell‐mediated cytotoxicity assays. The in vitro responsiveness of cells from skin‐grafted mice was compared to that of cells from corresponding ungrafted mice. The results showed that: (a) Mlsa, strongly stimulatory in primary MLR, has a weak effect on skin graft rejection; specific in vivo preimmunization against Mlsa increases and accelerates the rejection of skin grafts, but abrogates the responsiveness in MLR; and (b) incompatibility for Mlsb, nonstimulatory in primary MLR, induces relatively rapid rejection of 100% of skin grafts; this rejection is dramatically accelerated by specific in vivo preimmunization and is followed by activation of helper and cytotoxic cells. Results obtained in the cell‐mediated cytotoxicity assay suggest that the recognition of Mlsb determinants is H‐2‐restricted. Finally, the rejection of skin grafts incompatible for numerous non‐H‐2 loci is delayed by an additional incompatibility for Mlsb, suggesting that Mlsb decreases the response to other non‐H‐2 antigens, thus acting as a suppressor and/or competitor antigen. We conclude that, in contrast with previous findings, Mls incompatibility may have a strong effect on skin graft rejection, depending on the allelic combination involved, and, after in vivo immunization, Mlsb activates cell‐mediated proliferative and cytotoxic responses and definitely is not “silent”. The importance of the histocompatibility effects of Mls determinants and the variety of its biological functions are much in favor of the existence of a polymorphic and complex system capable of activating different cell subsets.
Genetic polymorphism of λ1 and λ3 immunoglobulin light chains in the Mus subgenus
Authors: Amor Mounira , Guenet Jean‐Louis , Bonhomme François , Cazenave Pierre‐André 
Published: February 2007

AbstractSeveral inbred or partially inbred mouse strains derived from wild mice of different Mus subgroups were surveyed for expression of λ1 light chain. One strain, SPE, expressed little or no λ1 chains. Two populations of antibodies were obtained by immunization of SPE mice with λ1 light chain isolated from the BALB/c J558 (α,λ1) myeloma protein. One population of antibodies recognized λ1 allotypic determinants located on the C terminal fragment beginning at the residue 176. A second population was directed against epitopes present on both λ1 and λ3 chains. These determinants, which were detected in all strains tested with the exception of SPE, were located in the V region. This result is in concordance with recent DNA studies showing that the λ1 and λ3 isotype use the same Vλ1 genes (Blomberg, B. et al., Proc. Natl. Acad. Sci. USA 1981. 78: 3765). Whether the V epitopes recognized by SPE antibodies are allotypic or isotypic in nature is not certain.
The selection and maintenance of the V region determinant repertoire is germ‐line encoded and T cell‐independent
Authors: Juy Dominique , Primi Daniélé , Sanchez Pierre , Cazenave Pierre‐André 
Published: February 2007

AbstractThe number of lipopolysaccharide‐sensitive precursor cells synthesizing immunoglobulin (Ig) which reacts with the monoclonal anti‐M460 antibody F6(51) has been determined in the spleen and in the bone marrow of different strains of mice. These precursor frequencies fall into two quantitatively different groups. The first group includes mice with the same Igh haplotype as BALB/c animals (Igh3). In this group, spleen cells contained between 1:104 to 1:5 × 104 B cell precursors secreting Ig which bound F6(51). The second level of precursor was obtained with animals with allotypic haplotypes other than Igh3. These values were too low to allow accurate frequency determinations. The frequency of these cells in mice of the latter group, however, increased dramatically when these animals were hyperimmunized with the monoclonal anti‐M460 antibody. Similar results were obtained when the frequencies were determined using the Ig− fraction of bone marrow cells.Surprisingly, the numbers of lipopolysaccharide‐sensitive B cell precursors secreting F6(51)‐binding Ig in spleen cells of nude mice was found to be similar to the one in splenocytes of normal mice, and even in this case, the frequencies reflected the genetic background of the animals tested. Taken together these data support the notion that the establishment and the maintenance of the M460 idiotypic repertoire is germ‐line encoded and independent of regulatory T cells.
The mechanism of SiO2 (Aerosil)‐mediated enhancement of the proliferative response of mouse spleen lymphocytes to antigen and mitogens in a serum‐free system
Authors: Burger Mikulas , Hess Max W. , Cottier Hans 
Published: February 2007

AbstractSiO2 particles enhanced the in vitro proliferation of splenic B cells obtained from BALB/c mice immunized with sheep erythrocytes. T cells from immunized animals were capable of replacing SiO2 with regard to the enhancement of both in vitro proliferation and the primary immune response. In addition, the stimulating effect of IgG, phytohemagglutinin (PHA) and concanavalin A (Con A) on spleen lymphocytes was also augmented by SiO2. The enhancing effect of SiO2 was higher at suboptimal than at supraoptimal concentrations of Con A. SiO2 is capable of binding Con A. The SiO2‐bound lectin retained its mitogenic effect on spleen cells and, under certain conditions, SiO2‐bound Con A was considerably more active in this respect than the free substance.
Prevention of complement activation on the homologous cell membrane of nucleated cells as well as erythrocytes
Authors: Okada Hidechika , Tanaka Hiroko , Okada Noriko 
Published: February 2007

AbstractA C3b receptor, a glycoprotein with a molecular weight of 205 kDa (gp205) on human erythrocytes (Ehu), has been claimed to restrict the activation of human complement via the alternative complement pathway (ACP), thereby inhibiting the activation of the ACP even on neuraminidase (Nase)‐treated Ehu. However, the Nase‐treated Ehu were sensitive to hemolysis by guinea pig complement via ACP activation, although the C3b receptors on Ehu can react with guinea pig C3b. Furthermore, HeLa cells which had no detectable C3b receptor did not became reactive with guinea pig ACP. On the contrary, Nase treatment of guinea pig erythrocytes (Egp) as well as guinea pig line 10 tumor cells, which have no detectable C3b receptor, could not make those cells reactive with the homologous guinea pig ACP although they became reactive with human and rabbit ACP. Similarly, rabbit E did not become reactive with the homologous rabbit ACP following Nase treatment. Nase‐treated Egp preincubated with human serum in the presence of EDTA were also not lysed by guinea pig serum. Therefore the unreactiveness of Nase‐treated cell membrane with homologous ACP was not merely due to the absence of antibody to cell membrane in the homologous serum. There may be a membrane inhibitor which preferentially interacts with homologous complement to circumvent undesirable complement activation on the homologous cell membrane.
T lymphocyte surface antigens in primates
Authors: Letvin Norman L. , King Norval W. , Reinherz Ellis L. , Hunt Ronald D. , Lane Heather , Schlossman Stuart F. 
Published: February 2007

AbstractWe examined the binding of peripheral blood mononuclear cells from various primate species to a panel of monoclonal antibodies with specificity for human T lymphocytes. A remarkable structural conservation of the erythrocyte rosette receptor on T cells between such phylogenetically distant primates as lemurs and man was found. Furthermore, it was demonstrated that the degree of sharing of other T cell‐specific surface determinants between man and other primates reflects the phylogenetic distance between them. Moreover, these studies suggest the potential use of monoclonal antibodies for further structural and functional elucidation of T lymphocyte‐specific surface structures.
The origin of human B and T cells from multipotent stem cells: a study of the Tn syndrome
Authors: Brouet Jean‐Claude , Vainchenker William , Blanchard Dominique , Testa Ugo , Cartron Jean‐Pierre 
Published: February 2007

AbstractThe Tn (or polyagglutinability) syndrome corresponds to a human nonmalignant acquired condition which results from a somatic mutation occurring at the level of bone marrow stem cells. This model offers therefore a unique opportunity to study the contribution of multipotential stem cells to the maintenance of cells from the lymphoid lineage. We found that the Tn mutation is expressed by both myeloid and lymphoid mature blood cells. Whereas a large proportion of surface IgM‐bearing B cells carry the Tn mutation, only a small percentage of T cells and IgA‐ or IgG‐bearing B cells are defective, showing that under physiological conditions the penetration of stem cells into the various myeloid and lymphoid compartments is variable.
Recognition of λ1 and λ2 murine light chains by carrierspecific isologous T helper cells; effect of L‐H chain assembly
Authors: Bogen Bjarne , Jørgensen Trond , Hannestad Kristian 
Published: February 2007

AbstractPrevious studies from this laboratory have revealed an antigenic site located on the variable domain of the λ2 light chain of BALB/c myeloma protein 315 (the Vλ2315 site). This site is recognized by conventional carrier‐specific T helper cells (Th) of BALB/c mice and is expressed on both the free and assembled Vλ2315 domain. The present work defines two new antigenic sites associated with murine λ chains. The first site was associated with free λ1‐chain of myeloma protein J558. It was recognized by splenic Th from animals that had been primed with free λ1J558 in complete Freund's adjuvant; when transferred to irradiated animals the primed Th responded to a boost with (4‐hydroxy‐5‐iodo‐3‐nitro‐phenyl)acetate (NIP)‐free λ1J558 in saline, but did not respond to NIP‐complete J558 or NIP‐free λ2315. Priming with complete J558 failed to elicit Th that responded to NIP‐free λ1J558. This determinant was therefore only expressed on the free (as opposed to the assembled) form of λ1J558, and it was not shared with free λ2315. The second antigenic site was shared between free λ1J558 and free λ2315. It was defined by free λ2315‐primed Th which responded to a boost with NIP‐free λ1J558. Since priming with free λ1J558 did not elicit Th that recognized NIP‐free λ2315, the cross‐reaction was undirectional. The free λ2315‐primed Th failed to respond to the complete J558, and M315‐primed Th failed to respond to NIP‐free λ1J558, indicating that the second (cross‐reactive) antigenic site, like the first, was only expressed on free λ chains. Completely reduced and alkylated (unfolded) free λ1J558 and free λ2315 chains elicited Th that recognized native (folded) free chains.Thus, free λ1J558 bears two antigenic determinants recognized by Th, one private and a second shared with free λ2315. λ2315 also bears two determinants, a cross‐reactive one on free λ2315 shared with free λ1J558, and a private one located on the Vλ2315 domain of the complete M315.The discussion is focused on possible explanations for the quenching of the two new λ chain determinants upon light‐heavy chain assembly and why, by contrast, the private Vλ2315 site is maintained in the complete M315.
Inhibition of lymphocyte proliferation and antibody production in vitro by silica, talc, bentonite or Corynebacterium parvum: involvement of peroxidative processes
Authors: Hoffeld J. Terrell 
Published: February 2007

AbstractThis study was undertaken to determine whether and by what means particles which induce granulomata in vivo can affect murine spleen lymphoproliferative and antibody responses in vitro. Particles of silica, talc, Bentonite or C. parvum cells inhibited lipopolysaccharide‐ or concanavalin A‐stimulated proliferation and sheep red blood cell‐induced antibody response in vitro. The inhibition required at least 48 hours exposure of the cells to the particles. The late onset of inhibition and its reproducibility at different cell or mitogen concentrations implicated particle‐induced injury to both phagocytes and lymphocytes. Either α‐tocopherol or 2‐mercaptoethanol prevented the particle‐induced inhibition of spleen cell responses. α‐Tocopherol and 2‐mercaptoethanol have in common the capacity to protect cells against membrane lipid peroxidation. The inhibitory peroxidative process(es) implicated by these studies are most likely attributable to: (a) stimulation of oxidative metabolism of phagocytic cells by particles; and (b) iron‐catalyzed peroxidation directly by the particles. These data may be relevant in understanding the pathogenesis of and devising therapeutic approaches toward various granulomatous conditions.
Antigen‐binding human T suppressor cells and their association with the HLA‐DR locus
Authors: Lehner Thomas 
Published: February 2007

AbstractThe ability of human lymphocytes to bind antigen was studied by direct binding of 125I‐labeled streptococcal protein antigen, followed by autoradiography. T‐enriched lymphocytes depleted of adherent cells and B cells showed specific binding of 125I‐labeled streptococcal antigen (SA) at 4°C and in the presence of sodium azide. Further depletions of the T‐enriched population by the monoclonal T4 or T8 antiserum and complement revealed that the antigen‐binding T cell is T4−, T8+. This was confirmed by positive selection of T8 cells, by rosetting with ox red blood cells and by the binding of SA by in vitro induced suppressor but not helper cells. Antigen specificity of binding to the suppressor cells was established by complete inhibition with the SA but no inhibition with keyhole limpet hemocyanin. A characteristic dose‐response of binding 1 or 10 ng SA to HLA‐DRw6 lymphocytes and 1000 ng SA to DR4,1,2,3 or 5 lymphocytes was found. A comparison of the dose‐responses of antigen‐binding T+ suppressor cells with those of helper and suppressor functions showed that the dose of SA which binds to suppressor cells is similar to the dose required to induce helper but not suppressor function. A plausible interpretation of these observations is that the T8+ antigen‐binding suppressor cells might function as “contrasuppressor cells” which compete successfully for the membrane receptors of helper cells, thereby preventing suppression by the major subset of suppressor cells.