bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distinct epitopes on Ik gene products identified by monoclonal antibodies
Authors: Pierres Michel , Kourilsky François M. , Rebouah Jean‐Paul , Dosseto Magali , Caillol Danielle 
Published: February 2007

AbstractAnalysis of reactivity of monoclonal anti‐Iak alloantibodies, obtained by fusion between NS 1 myeloma and spleen cells from alloimmune A.TH mice, permitted the identification of 9 distinct determinants of the Ik gene products. Competitive binding experiments indicated that 2 private epitopes (defined by H 8–109.13 and H 8–138.4 antibodies) of the I‐Ak product could be separated, thereby apparently splitting the Ia.2 specificity. A public determinant of the I‐Ak molecule (identified by H 8–15.9 antibody) was found expressed not only on the 1‐A products of the H‐2b, H‐2d, H‐2ja, H‐2P and H‐2q murine haplotypes, but also on human HLA‐DR antigens. Four determinants of the I‐E/Ck antigen (defined by H 7–8.26, H 10–81.10, H 10–93.2 and H 8–86.2 antibodies) had a strain distribution analogous to the Ia.7 specificity. However, competitive binding experiments, and the cross‐reactivity pattern with la‐like antigens from other species (e.g. human HLA‐DR antigens) indicated that these antibodies detected distinct determinants on the I‐E/Ck molecule, thereby subdividing the broad Ia.7 specificity. Two other determinants (defined by H9–14.8 and H9–15.4 antibodies) had a strain distribution that did not permit a precise assignment to a given Ia antigen, even though preliminary data suggested that they could detect separate determinants on the I‐E/Ck product. All these monoclonal antibodies identified membrane antigens with the expected Ia tissue distribution pattern, and most of them could precipitate a molecule containing two chains of 28 kD and 35 kD, from mouse spleen cell lysates.
The rapid isolation of clonable antigen‐specific T lymphocyte lines capable of mediating autoimmune encephalomyelitis
Authors: Ben‐Nun Avraham , Wekerle Hartmut , Cohen Irun R. 
Published: February 2007

AbstractThe isolation and propagation of functional antigen‐specific lines of T lymphoblasts is described. These lines were found to recognize foreign or self antigens in association with accessory cells of syngeneic major histocompatibility complex genotype. Intravenous inoculation of a T cell reactive only against myelin basic protein led to development of clinical paralysis in syngeneic rats. Thus, it is possible to study biological function as well as antigen specificity using T cell lines.
Immunofluorescence studies on the expression of VHa allotypes by pre‐B and B cells of homozygous and heterozygous rabbits
Authors: Gathings William E. , Mage Rose G. , Cooper Max D. , Lawton Alexander R. , Young‐Cooper Glendowlyn O. 
Published: February 2007

AbstractFluorochrome‐conjugated antibodies specific for Cμ determinants and VH a allotypes were used to examine pre‐B cells and B lymphocytes for expression of these markers. The majority of μ+ bone marrow pre‐B cells were shown to express a allotypic determinants in conjunction with Cμ. Both pre‐B and B cells from a2a3 heterozygous rabbits showed allelic exclusion of these allotypes. Pre‐B cells expressing the a2 or a3 specificities appeared to be generated in approximately equal numbers in heterozygotes, while B lymphocytes expressing a3 appeared to undergo preferential clonal expansion very early in development. It was also observed that rabbit bone marrow and blood contained a population of myeloid cells which, in a2a3 heterozygotes, stained for both a2 and a3 determinants. The frequencies of this cell type, which exhibited bright immunofluorescence staining for a allotypes, could not be reduced by prolonged incubation at 37°C but were readily reduced after cell suspensions were treated with low pH buffer. It is concluded that these myeloid cells bear high avidity Fc receptors for serum immunoglobulin and may be the culprits in studies which have found production of two a or b allotypes by individual B lymphocytes.
Genetic control of autoimmune encephalomyelitis and recognition of the critical nonapeptide moiety of myelin basic protein in guinea pigs are exerted through interaction of lymphocytes and macrophages
Authors: Ben‐Nun Avraham , Otmy Hanoch , Cohen Irun R. 
Published: February 2007

AbstractGenetic control has been studied of the response to the encephalitogenic nonapeptide (NP) determinant of myelin basic protein (BP) in inbred guinea pigs of strains resistant or susceptible to induction of experimental autoimmune encephalomyelitis (EAE). By studying bone marrow‐reconstituted animals, we found that susceptibility to induction of EAE was a function of the genotype of the cells of the lymphohematopoietic system and not of the physiological environment or target organ. Analysis of the T cell response showed that susceptible strain 13 or (2 × 13)F1 hybrid guinea pigs recognized the NP determinant when injected with whole BP in adjuvant. Resistant strain 2 guinea pigs responded to undefined determinants on BP, but not to the NP moiety. We investigated the cells involved in regulating the response to the NP determinant by injecting susceptible F1 hybrids with BP‐pulsed macrophages of either parental strain. Susceptible strain 13 macrophages triggered a response to the NP determinant and induced clinical EAE. In contrast, F1 animals injected with resistant strain 2 macrophages failed to respond to the NP determinant, although the macrophages were capable of presenting other undefined determinants present on whole BP. Therefore, genetic control of the immune response to the NP determinant appears to be exerted at the level of antigen presentation by macrophages to T lymphocytes.
Distinctive functional characteristics of human „T”︁ lymphocytes defined by E rosetting or a monoclonal anti‐T cell antibody
Authors: Beverley Peter C. L. , Callard Robin E. 
Published: February 2007

AbstractThe properties of human lymphocyte fractions isolated either by sheep red cell (E) rosetting or by fluorescence‐activated cell sorting after staining with UCHT1 monoclonal anti‐T cell antibody have been compared. Two populations of E+ cells with very different phenotype and function have been identified. E+/UCHT1+ cells respond well to the T cell mitogens phytohemagglutinin and concanavalin A and provide help for an in vitro specific antibody response. They can also suppress the antibody response of allogeneic peripheral blood mononuclear cells. In contrast, the E+/UCHT1− population, which has no other markers characteristic of T cells, fails to respond to mitogens or to provide help or suppression for an antibody response. These cells, however, are highly active natural killers. They possess Fcγ receptors and have a characteristic staining pattern of nonspecific esterase enzyme activity.
Membrane immunoglobulins of spontaneous B lymphomas of aged BALB/c mice
Authors: Laskov Reuven , Kim Jin K. , Woods Virgil L. , McKeever Paul E. , Asofsky Richard 
Published: February 2007

AbstractFour cell lines derived from spontaneous BALB/c B lymphoma tumors were analyzed with regared to the type of their membrane immunoglobulins (Ig). Using lactoperoxidase iodination of membrane proteins combined with immunoprecipitation and electrophoresis on polyacrylamide gel, three of these cell lines (X16c, L10A and K46) were found to express the monomeric form of IgM and IgD as well as half molecules. One cell line (M12) lacked both IgM and IgD. The apparent mol. wt. of the lymphoma μ chain was about 80000 and exceeded the mol. wt. of 75 000 determined for μ chains secreted by myeloma cells. The mol. wt. of the δ heavy chain was found to be 66000. Immunofluorescence showed that the L10A and X16c lines expressed λ light chains on their cell surface. Another Ig‐bearing cell line (K46) expressed both λ and χ chains. Thus, three out of the four B lymphomas examined expressed both IgM and IgD with light chains of the δ type. These results, together with our previous findings which demonstrate the presence of Ia and Fc receptors on the same cells, indicate that spontaneous B lymphomas in BALB/c mice are the malignant counterpart of mature B lymphocytes.
Activation of T lymphocytes by lectins and carbohydrate‐oxidizing reagents viewed as an immunological recognition of cell‐surface modifications seen in the context of “self” major histocompatibility complex antigens
Authors: Kimura Arthur , Ersson Bo 
Published: February 2007

AbstractThe experiments reported here were directed at the question of whether polyclonal activation of T cells by mitogenic substances results as a consequence of (a) a truly antigen‐independent stimulation of T cells through mitogen receptors, bypassing requirements for T cell‐specific recognition or (b) an immunological reaction, similar in principle and requirements to T cell activation induced by antigen. Several lines of evidence have provided strong support for the latter interpretation. First, the ability of several mitogenic substances to induce polyclonal T cell activation was found to be crucially dependent upon cell surface expression of major histocompatibility complex (MHC) products. Thus, the presence of alloantisera or monoclonal antibodies directed against either class I (SD) determinants or class II (Ia) products on the responding cell population resulted in a sizeable dose‐dependent inhibition of the mitogenic response. Additional studies using spleen cells from normal F1 mice or F1→parent bone marrow chimeras provided the most direct and convincing evidence for a specific immunological role of MHC products in mitogenic T cell activation. Here, the concanavalin A response of normal F1 T cells was found to be inhibited by alloantisera against either parental haplotype, while the H‐2‐heterozygous F1→parent chimeras were only inhibited by antisera against the H‐2 of the parent in which they matured and possessed functional, MHC‐restricted helper T cells.The inherent characteristics and reactivities which endow only certain lectins to exert a mitogenic effect were specifically examined in light of the observed dependence for MHC expression in these mitogenic reactions. Using a panel of 20 different lectins as affinity absorbents for cell surface glycoproteins, it was found that only mitogenic lectins were capable of binding to cell surface‐expressed H‐2 products (both K/D and la). The results obtained here are discussed in support of the concept that mitogeninduced T cell responses involve an immunological recognition of cell surface modifications seen in the context of self H‐2 antigens.
Cytotoxic T cell recognition of Epstein‐Barr virus‐infected B cells. I. Specificity and HLA restriction of effector cells reactivated in vitro
Authors: Moss Denis J. , Wallace Lesley E. , Rickinson Alan B. , Epstein M. Anthony 
Published: February 2007

AbstractThe experiments show that the phenomenon of regression, seen exclusively in Epstein‐Barr (EB) virus‐infected cultures of mononuclear cells from EB virus antibody‐positive donors, is mediated by cytotoxic T cells reactivated in vitro and specifically recognizing an EB virus‐induced lymphocyte‐detected membrane antigen LYDMA. Thus, effector T cells from regressing cultures kill autologous EB virus‐transformed cells but not autologous pokeweed mitogen‐stimulated lymphoblasts nor any of a range of EB virus genome‐negative human hemopoietic cell lines (K562, HSB2, BJAB, EB4) particularly sensitive to nonspecific natural killer‐like activities. Moreover, these reactivated effector cells exhibit classical HLA restriction of target cell recognition; in a survey of 14 effector cell donors, preferential lysis of the autologous virus‐transformed line was a consistent feature, while the relative degree of lysis of allogeneic lines was in general directly related to the number of HLA‐A and B antigens shared between effector and target cells. The pattern of reactivity shown by effector T cell preparations from any one donor was strikingly reproducible, and the results from a number of donors revealed differences between particular HLA‐A and B antigens with respect to the level of EB virus‐specific killing which was associated with sharing through these determinants.
Suppression of lymphocyte reactivity in vitro by a soluble factor secreted by explants of human decidua
Authors: Golander Avraham , Zakuth Vera , Shechter Yoram , Spirer Zvi 
Published: February 2007

AbstractThe immunologic mechanisms that protect the fetus from rejection were the subject of numerous investigations. Reports showing the uterus as a favorable site of implantation focused our attention to the decidua which is the maternal tissue intimately attached to fetal structures.Explants of human decidua were cultured for periods of 24 h and incubation media tested for their immunosuppressive activity. The incubation medium of human decidua when added to cultures of human lymphocytes suppressed both their reactivity to lectins and their activity in the mixed lymphocyte reaction. The results of these experiments suggest that decidual tissue releases a soluble factor which is a potent inhibitor of cell‐mediated immunity.
I region‐restricted T cell line stimulated with haptentreated syngeneic cells: Selection of clones with reactivity for both allogeneic Ia determinants and self‐I‐A plus hapten
Authors: Guimezanes Annick , Albert Françoise , Schmitt‐Verhulst Anne‐Marie 
Published: February 2007

AbstractThe apparent switch in proliferative T cell reactivity which occurred in a B10 T cell line (B10(T4)) repeatedly stimulated with trinitrobenzene sulfonic acid (hapten)‐treated syngeneic cells is described. This functionally heterogenous T cell population, apparently depleted of alloreactivity and strictly dependent on cells expressing syngeneic I‐A and the hapten for its propagation, lost, after its 10th restimulation, the previously detected T cell functions, and expressed a new pattern of proliferative reactivity; this pattern included reactivity to self‐I‐A plus hapten as well as to untreated stimulating cells expressing certain allogeneic determinants. Analysis of reactivity of B10(T4) cells grown under limiting dilution conditions and of five clones of cells derived from B10(T4) indicated that the same T cells were reactive to both self‐I‐A plus hapten, and to a public I‐A‐mapped alloantigen possibly related to the serologically defined Ia.5 specificity.
Autoimmune effector cells. II. Transfer of experimental allergic encephalomyelitis with a subset of T lymphocytes
Authors: Holda James H. , Swanborg Robert H. 
Published: February 2007

AbstractThis study was conducted to further characterize the effector cells of experimental allergic encephalomyelitis (EAE) which are activated in vitro when spleen cells from Lewis rats previously immunized with myelin basic protein and adjuvant are cultured with antigen prior to transfer to syngeneic recipients. The effector cells were isolated on discontinuous Percoll gradients in the cell fraction that floated on Percoll with a buoyant density of 1.067 kg/l. These cells (designated fraction 1) transferred EAE and incorporated [3H]dThd in culture. Fraction 1 was enriched for T cells when evaluated with monoclonal anti‐rat T cell serum W3/13 and deficient in Ig+ cells; approximately 33% were positive with monoclonal anti‐rat T cell serum W3/25. In contrast, the small, nonproliferating cells found in higher density Percoll fractions did not transfer EAE.When fraction 1 was recultured in the presence of basic protein and interleukin 2 for 72 h, these cells retained the ability to transfer EAE. Moreover, these recultured cells exhibited an increase in the W3/25 antigen and a decrease in the W3/13 marker. It was concluded that a subset of T cells which bear the W3/25 marker is involved in the transfer of EAE.
Analysis of Fcγ receptors on human peripheral blood leukocytes by flow microfluorometry. I. Receptor distributions on monocytes, Tγ cells and cells labeled with the 3A1 anti‐T cell monoclonal antibody
Authors: Titus Julie A. , Haynes Barton F. , Thomas Charles A. , Fauci Anthony S. , Segal David M. 
Published: February 2007

AbstractA dual parameter flow microfluorometric technique for accurately measuring Fcγ receptor (FcR) expression on defined subsets of cells within a heterogeneous cell sample was developed. The FcR distribution of human peripheral blood mononuclear cells consists of three distinct peaks. By analyzing cells fluorescently labeled with the 3A1, an anti‐T cell hybridoma antibody (using a green‐emitting fluorophore) and for FcR (with a red‐emitting fluorophore), and by using cell isolation procedures, it was shown that the cells lying within the peak with intermediate FcR density are mainly monocytes, while cells lying within the peaks with highest and lowest (i.e. negative) FcR densities are predominantly T cells. The FcR+ T cells (Tγ cells) express higher levels of the 3A1 antigen than other T cells, thus demonstrating the utility of the 3A1 hybridoma antibody as a marker for Tγ cells.
Immunoglobulin C‐gene expression. III. Possible induction of specific genetic events in activated B lymphocytes by the polyclonal stimuli driving clonal expansion
Authors: Martinez‐Alonso Carlos , Coutinho Antonio 
Published: February 2007

AbstractPolyclonal activation of resting B lymphocytes by either lipopolysaccharide or specific helper cells recognizing antigens on B cell membranes results in selective patterns of IgG subclass expression among plaque‐forming cells. We have studied the IgG subclasses of plaque‐forming cells generated in cultures of purified B cell blasts selected for reactivity to either LPS or helper cells, and restimulated by either lipopolysaccharide, specific helper cells, or as “bystanders”, by nonspecific B cell growth factors. Development of IgG1 plaque‐forming cells is observed only when clonal expansion is maintained by specific helper cells, whereas IgG3 secretion specifically requires stimulation by lipopolysaccharide and the absence of helper cell activity. Furthermore, exposure of resting B lymphocytes to specific helper cells induces, in 48 h, an irreversible loss of the potential to produce IgG3. Other than showing that helper cell‐dependent B cell growth and maturation is more complex than previously suspected, these results suggest that differentiation signals or factors induce specific DNA recombination and deletion events.
Immunological focusing by the mouse major histocompatibility complex: Mouse strains confronted with distantly related lysozymes confine their attention to very few epitopes
Authors: Katz Michael E. , Maizels Richard M. , Wicker Linda , Miller Alexander , Sercarz Eli E. 
Published: February 2007

AbstractThe gallinaceous lysozymes are a family of antigens that are distantly related to mouse lysozyme. A T cell‐dependent proliferation assay was used to characterize the spectrum of reactivities to lysozyme determinants in B10‐congenic mice. Cross‐reactivity studies using a panel of species variant lysozymes to stimulate lymph node cells from chicken egg white lysozyme‐ and ring‐necked pheasant egg white lysozyme‐primed B10.D2 mice indicated a preferential focusing of T cell reactivity onto a single determinant containing amino acids 113‐114. These data, in conjunction with results obtained by priming with cyanogen bromide cleavage fragments of lysozymes, suggested that a site common to the L3 region (amino acids 106‐129) of all the lysozymes tested was a preferential anchorage site for I region‐encoded la molecules on H‐2d antigen‐presenting cells, leading to the limited display of a determinant containing residues 113‐114.Priming with L2H (amino acids 13‐105), a peptide containing the major epitopes recognized by B10.A and B10 mice, failed to stimulate any T cell proliferation by B10.D2 lymph node cells. Thus, it appears the la molecules in any one mouse strain attach to very few sites on lysozyme to effectively display antigenic determinants for T cell activation. This result points to a model of limited determinant selection even on a very “foreign” antigen based upon a shortage of appropriate amino acid residues usable by la antigen‐presenting structures of a strain.
Human cytotoxic T cell structures associated with expression of cytolysis. I. Analysis at the clonal cell level of the cytolysis‐inhibiting effect of 7 monoclonal antibodies
Authors: Malissen Bernard , Rebai Najet , Liabeuf André , Mawas Claude 
Published: February 2007

AbstractMonoclonal antibodies (mAb) derived from BALB/c mice immunized with human anti‐HLA‐A2 cloned cytotoxic T lymphocytes (CTL) were screened for their ability to block, in the absence of complement, the cytolytic activity of the immunizing CTL clone. Eight cytolysis‐inhibiting mAb have been derived. One of these was directed against a monomorphic determinant expressed on HLA‐class I molecules and thus probably inhibited cytolysis via a target cell antigen‐masking effect. The 7 other mAb recognized “CTL function‐associated structures” and did not have to interfere with target cell antigens in order to inhibit cytolysis. F(ab')2 and Fab fragments of these 7 mAb were also inhibitory. Competitive inhibition of binding and preliminary biochemical analysis suggested that these 7 mAb defined on cloned CTL various epitopes of a structure of 30 kDa disulfide‐bonded into several multimeric forms when analyzed without reduction. The inhibitory effect of these 7 mAb has been investigated on a series of short‐term (1 month) and long‐term (> 10 months) expanded cloned CTL lines derived in vitro from an in vivo allosensitized individual exhibiting various specificities. Unexpectedly, only 10% of these CTL clones were inhibited. Flow cytofluorimetric analysis further revealed that noninhibited and inhibited CTL clones expressed similar amounts of the 30‐kDa structure. Consequently, the inhibition of CTL was heterogeneous when analyzed at the clonal level and not simply related to the presence or absence of this structure. Furthermore, the ability of CTL clones to be inhibited appeared to be unrelated to their HLA‐A, B or C specificity or to their lytic activity. The connections between this mAb‐defined structure and CTL function are discussed.
Suppression of cell‐mediated lymphocytotoxicity against minor histocompatibility antigens mediated by Lyt‐1+Lyt−2+ T cells of stimulator‐strain origin
Authors: Rammensee Hans‐Georg , Nagy Zoltan A. , Klein Jan 
Published: February 2007

AbstractCultured, unprimed spleen cells suppress the generation of cytolytic T lymphocytes when added to mixed lymphocyte culture of cells disparate at minor histocompatibility (H) loci. Cells cultured for 2 to 3 days inhibit cell‐mediated lympholysis specifically in that they suppress only when they carry the same H antigen by which the stimulators activate the responding cells. However, culturing of cells for more than 3 days results also in the generation of nonspecific suppressor cells which inhibit the cell‐mediated lympholysis regardless whether they carry the stimulating antigens. The specific suppressor cells are T lymphocytes of the Lyt‐l+Lyt−2+ type. Fresh, uncultured spleen cells, although ineffective in vitro, can prevent the in vivo priming of minor H‐specific cytotoxic T lymphocyte precursors when injected i.v. into mice incompatible at minor H loci. This suppressive effect of the immunizing inoculum is abolished by irradiation (3300 rds) or by treatment with a monoclonal Thy‐1‐specific antibody and complement. Thus the suppressor T cell demonstrated here is of the “veto” cell type; that is, it probably suppresses minor H‐specific cells when the latter recognize the stimulating antigen on the surface of the suppressor cell itself.