bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytotoxic T cell recognition of Epstein‐Barr virus‐infected B cells. II. Blocking studies with monoclonal antibodies to HLA determinants
Authors: Wallace Lesley E. , Moss Denis J. , Rickinson Alan B. , McMichael Andrew J. , Epstein M. Anthony 
Published: February 2007

AbstractMonoclonal antibodies specifically binding common determinants on all HLA‐A, B and C antigen molecules blocked the lysis of EB virus‐transformed target cells by EB virus‐specific cytotoxic T cells reactivated in vitro. Blocking was mediated through binding of the antibodies to the target rather than to the effector cells and was maximal (75 to 85% inhibition of lysis) at saturating antibody concentrations. A similar blocking effect was also shown by a monoclonal antibody binding to β2‐microglobulin, a molecule physically associated with HLA‐A, B and C antigens on the target cell surface, but not by a monoclonal antibody binding to the non‐HLA‐associated leukocyte‐common antigen. Saturating concentrations of monoclonal antibodies specific for common determinants on all HLA‐DRw antigen molecules either had no effect at all upon EB virus‐specific T cell cytotoxicity or caused a slight, but nonspecific, inhibition. The results demonstrate unequivocally that HLA‐A, B and C antigens on the target cell surface are indeed the polymorphic elements which impose genetic restriction upon EB virus‐specific cytotoxic T cell function.
T cell regulation of isotype expression The requirement for a second Ig‐specific helper T cell population for the induction of IgG responses
Authors: Rosenberg Yvonne J. , Asofsky Richard 
Published: February 2007

AbstractA characteristic of the in vivo responses to T‐dependent antigens is the highly restricted expression of Ig heavy chain classes of both the antibody and nonspecific Ig produced. To investigate the cellular interactions which regulate expression of Ig class, sheep red blood cell‐ and keyhole limpet hemocyanin‐primed BALB/c T cells were tested in vitro for their ability to induce normal BALB/c B cells to selective Ig secretion. The results, based initially on linear regression analysis, indicate that while the production of IgM required help from a single antigen‐specific helper cell, additional signals from a second pool of helper cells were necessary for the expression of IgG isotypes. The greatly diminished ability of primed T cells from mice suppressed from birth for IgM production to induce IgG responses indicated that the generation of this second class‐regulating T cell pool requires the presence of Ig, probably B cell‐presented, during the period of priming.Based on the present data, secretion of IgG by normal B cells can be explained by invoking the requirement for a second pool of helper T cells which recognize Ig determinants, in contrast to the I region recognition known to exist for effective help by the first helper cell. In addition, it is proposed that in the absence of such a second signal only IgM secretion will occur.
Regulation of antibody synthesis in the X‐irradiated Mexican axolotl
Authors: Charlemagne Jacques 
Published: February 2007

AbstractThe effects of X‐irradiation were studied on the Mexican axolotl antibody synthesis. To reduce the anti‐horse red blood cell (HRBC) antibody titers, 150 rd and smaller doses are ineffective, 200–450 rd are increasingly effective, and 700 rd are maximally effective (and lethal). A significant enhancement of the anti‐HRBC titers was observed in low doses (50–150 rd X‐irradiated animals). This enhancement was also observed when a low X‐ray dose was applied only on the thymic areas. In whole body, but thymus area‐shielded, 100 rd X‐irradiated animals, the anti‐HRBC titers were similar to those of the nonirradiated, HRBC‐immunized control group. To explain these phenomena, it is suggested that a radiosensitive, adult thymectomy‐sensitive and hydrocortisone‐sensitive suppressor T cell subpopulation regulates the antibody synthesis in the axolotl.
Binding of one monoclonal antibody to human Ia molecules can be enhanced by a second monoclonal antibody
Authors: Tosi Roberto , Tanigaki Nobuyuki , Sorrentino Rosa , Accolla Roberto , Corte Giorgio 
Published: February 2007

AbstractA monoclonal anti‐human Ia antibody, PTF 29, was tested for its ability to bind purified, 125I‐labeled human Ia preparations. It was found that the binding level increases considerably in the presence of a second monoclonal antibody.Experimental conditions were selected under which only the binding of PTF 29 and not the binding of the second antibody could be determined. Under these conditions, it was found that “helped” PTF 29 binding has higher affinity and is exerted on a molecular subset different from that bound by PTF 29 alone.This phenomenon, while not easily accommodated in the present conceptual framework of the human Ia system, appears in itself interesting and may have more general implications.
Nomarski differential interference contrast studies of murine lymphocytes
Authors: Khalaf Ragaa M. F. , Bainbridge Douglas R. 
Published: February 2007

AbstractNomarski differential interference contrast microscopy (DIC) of lymphocyte surface morphology was combined with immunofluorescence studies of T and B cell markers on the thymus, lymph nodes, spleen, peripheral blood lymphocytes and thoracic duct lymph of female CBA mice. DIC identified smooth cells and several categories of villous cells; more extreme forms were present in lymph. Most B cells seemed to belong to the smooth group and most peripheral T cells to the villous group. Thymus cells were almost entirely smooth, but treatment with cortisone increased the proportion of villous cells to 50%.The surface morphology of lymphocytes was highly labile preventing direct identification or separation of T and B cells. In vivo removal of T cells by adult thymectomy, lethal irradiation and bone marrow reconstitution caused the villous cells to decrease. During recovery from irradiation, T lymphocytes tended to parallel villous cells, B lymphocytes smooth cells, but there were differences between the spleen and lymph nodes.Mice deprived of T1 cells by adult thymectomy showed a modest decrease of smooth cells in the spleen and blood; mice depleted of T2 cells by anti‐lymphocyte serum, or which were naturally deficient in T2 cells, were markedly lacking in villous cells. Thoracic duct lymph, which is rich in T2 cells, had a high proportion of extremely villous lymphocytes.Exposure to lymph induced extreme villous features in lymph node cells, and it was found that the thoracic duct lymph was markedly hypertonic to serum, although varying in osmolarity throughout the day. It is suggested that the villous shape of T2 cells is a circulatory adaptation, necessitated by the peculiar character of the lymphatic system in mice.
The role of monovalent cations in the interaction between the cytotoxic T lymphocyte and its target
Authors: Russell John H. , Dobos Claraine B. 
Published: February 2007

AbstractEvidence is provided for the participation of monovalent cations in both the binding and lytic phases of the lytic cycle. There appears to be one sodium requirement in the cytotoxic T lymphocyte‐target binding event (effective dose50 ∼ 35 mM) and possibly another sodium requirement in the delivery of the lethal hit (ED50 <7 mM). Potassium can replace sodium in the binding event but antagonizes the lethal hit phase (inhibitory dose50 ∼ 110 mM). Lithium antagonizes the binding event (ID50 ∼ 15 mM).
Antigen‐specific antibody response induced in cultures of human blood lymphocytes in presence of polyethylene glycol
Authors: Luzzati Alma L. , Ramoni Carlo , Ferrara Giovanni B. 
Published: February 2007

AbstractHuman peripheral blood lymphocytes respond in vitro to sheep red blood cells (SRBC) with the appearance of numerous specific plaque‐forming cells, if the Epstein‐Barr virus (EBV) is added to the cultures together with the antigen. However, it was found that when polyethylene glycol (mol. wt. 6000) is included in the culture medium at a final concentration of 4%, antigen alone is able to induce an anti‐SRBC response, with clear hemolytic plaques of regular size. Addition of EBV causes a further increase in the antigen‐specific antibody response.
Countercurrent distribution of human peripheral blood lymphocytes: isolation of a subpopulation enriched with natural killer and K cells
Authors: Levy Elinor M. , Zanki Steve , Walter Harry 
Published: February 2007

AbstractAqueous solutions of dextran and of poly(ethylene glycol) when mixed give rise to two‐phase systems suitable for the separation by partitioning of cells based on subtle differences in their membrane surface properties. Human peripheral blood mononuclear cells were obtained by centrifuging blood over Hypaque‐Ficoll and removing the cells from the cushion. Clean lymphocytes were then isolated by velocity sedimentation of the mononuclear cells. Lymphocytes were subjected to countercurrent distribution (i.e., a multiple extraction procedure) in a two‐polymer aqueous phase system which separates cells primarily on the basis of surface charge‐associated properties. It was found that a small subpopulation of cells with highest partition coefficient (presumably highest surface charge‐associated properties) contain virtually all of the natural killer (NK) and K cell activities.
Immunoregulatory circuits which modulate responsiveness to suppressor cell signals: contrasuppressor cells can convert an in vivo tolerogenic signal into an immunogenic one
Authors: Ptak Wlodzimierz , Green Douglas R. , Durum Scott K. , Kimura Art , Murphy Donal B. , Gershon Richard K. 
Published: February 2007

AbstractThe intravenous injection of 2,4,6‐trinitrophenyl (TNP)‐labeled peritoneal exudate cells (TNP‐PEC) into CBA mice fails to produce a state of hypersensitivity; rather, it renders recipient mice incapable of mounting a contact hypersensitivity response when they are subsequently immunized with a reactive form of the specific hapten. However, if precultured neonatal spleen cells are injected along with the cells that induce tolerance (TNP‐PEC), not only is the development of tolerance inhibited but sensitization to TNP develops. The neonatal spleen cell responsible for turning the tolerogenic signal into an immunogenic one is I‐J+ and adheres to the Vicia villosa lectin. Thus, it expresses markers that distinguish contrasuppressor effector cells from helper cells (D. R. Green et al., Eur. J. Immunol. 1981. 11: 973), indicating that activated contrasuppressor cells can act as potent, helpful regulatory cells in vivo.
Heterogeneity of stimulator cells in the murine mixed leukocyte response
Authors: Sunshine Geoffrey H. , Katz David R. , Czitrom Andrei A. 
Published: February 2007

AbstractMouse spleen cells were fractionated and tested for their ability to stimulate a primary mixed leukocyte response (MLR). Several nonlymphoid populations were stimulatory, purified dendritic cells and 18‐h adherent macrophages being the most effective. B and T lymphocytes and peritoneal washout cells were almost ineffective by comparison. This hierarchy of stimulator potential was observed whether the genetic difference between stimulator and responder was whole H‐2 or H‐2 subregion (K. D. I. I‐J). Allostimulatory populations contained a high proportion of cells expressing I region determinants. The functional importance of these antigens was confirmed using specific anti‐I region antisera. Thus, it appears that stimulator cells in the MLR are heterogeneous, Ia‐bearing, and of “accessory” rather than lymphoid type.
Expression of Qat‐4 and Qat‐5 alloantigens on cytotoxic precursor and effector cells: different surface phenotypes of alloreactive and H‐2‐restricted cytotoxic T Cells
Authors: Zahn Gabriele , Hämmerling Günther J. , And Klaus Eichmann , Simon Markus M. 
Published: February 2007

AbstractMonoclonal anti‐Qat‐4 and anti‐Qat‐5 antibodies, which define antigens expressed on peripheral T cell subsets, have been used to study the phenotypes of alloreactive and H‐2‐restricted cytotoxic effector cells and their precursors. Depletion of Qat‐4+ or Qat‐5+ cells from the T cell pool prior to their sensitization in bulk cultures prevented the development of alloreactive and H‐2‐restricted cytotoxic activities in the selected populations. No reconstitution of cytolytic activities to normal levels was obtained when mixtures of Qat‐4+ and Oat‐5+ cells were sensitized in bulk cultures to H‐2 or non‐H‐2 antigens. Sensitization of limiting numbers of Qat‐4− or Qat‐5− lymphocytes under optimal conditions for help (interleukin 2), with the appropriate antigens (H‐2, H‐Y) did not result in the generation of cytotoxic T cells, indicating that the majority of all cytotoxic T lymphocyte (CTL) precursors are Qat‐4+, Qat‐5+.When CTL effector populations were treated with the antisera and complement (C) at their maximum CTL activity, it was found that H‐2‐restricted CTL were totally eliminated by anti‐Qat‐4 and considerably reduced by anti‐Qat‐5 antisera and C. In contrast, alloreactive CTL effector cells were insensitive to anti‐Qat‐4 and to anti‐Qat‐5 plus c. Although alloreactive CTL effector populations regained some Qat‐4 antigens during further in vitro culture, it was shown that H‐2‐restricted CTL were at all times more sensitive to anti‐Qat‐4 than were alloreactive CTL. The findings suggest that during maturation of alloreactive and H‐2‐restricted CTL from their precursors, both alloantigens undergo differential quantitative variations in their expression that lead to different Qat‐4,5 phenotypes of alloreactive and H‐2‐restricted CTL.
Monoclonal antibodies OKT 11 and OKT 11A have pan‐T reactivity and block sheep erythrocyte “receptors”
Authors: Verbi Winston , Greaves Melvyn F. , Schneider Claudio , Koubek Kristian , Janossy George , Stein Harald , Kung Patrick , Goldstein Gideon 
Published: February 2007

AbstractMonoclonal antibodies OKT11 (γ1) and OKT11A (γ2) are described and appear to have similar binding specificities. They bind, in immunofluorescence, with >95% of infant thymocytes, staining both cortical and medullary cells, 65‐80% of blood lymphocytes and selectively stain the T cell‐dependent paracortical areas of tonsil. A small proportion (9‐12%) of bone marrow lymphocytes stain, but this population excludes the terminal transferase‐positive cells.Both the γ1 and γ2 antibodies stain the surface membrane Ig‐negative lymphocytes in blood and tonsil and are able to block sheep E rosette formation (to normal or leukemic T cells). In contrast, other monoclonal anti‐T reagents tested (OKT1, OKT3, OKT4, OKT6, OKT8, OKT9, OKT10) did not block E rosette formation. E rosette formation and OKT11 binding are coincident on T‐ALL cell lines and both are trypsin‐sensitive. In a series of 145 leukemias and 26 leukemic cell lines investigated, only leukemias with a T cell phenotype including E rosette positivity were reactive with OKT11 and OKT11A.OKT11A binds to a polypeptide of approximately 50000 molecular weight on thymic lymphocytes. This structure may carry the recognition site for sheep erythrocytes. These antibodies provide additional useful markers for T cell analysis and are of potential therapeutic value.
T suppressor cells activated by anti‐Tsud serum are Igh‐V‐restricted
Authors: Owen Frances L. , Riblet Roy , Gottlieb Paul D. 
Published: February 2007

AbstractT suppressor (Ts) cells can be activated by alloantiserum directed against Tsud, a cell surface marker associated with the Ts cell receptor for antigen. These cells are restricted in their ability to transfer suppression in allotype‐congenic mice. Transfer of suppression requires matching of donor and recipient mice at Igh‐V loci, but recipient mice need not share the Tsud allele nor the same allotype as the activated Ts cells. Genes linked to the kappa light chain locus apparently do not affect this transfer.
Human monoclonal autoimmune antibody produced in Vitro: rheumatoid factor generated by Epstein‐Barr virus‐transformed cell line
Authors: Steinitz Michael , Tamir Sara 
Published: February 2007

AbstractThe infection of selected lymphocytes from a rheumatoid arthritis patient with Epstein‐Barr virus resulted in an immortalized cell line that secretes a monoclonal rheumatoid factor (RF). The cloned line has been growing for more than 24 months, and constantly produces a monoclonal IgM, λ, 19 S, RF (1‐2 μg/ml/l06 cells).The RF agglutinates human and rabbit IgG (but not IgM) and also protein A‐coated erythrocytes, but fails to do so to mouse, goat and swine IgG‐coated erythrocytes. When bound to immune complexes, this monoclonal RF does not bind complement. In the cell supernatant RF is the only immunoglobulin and it comprises approximately 5% of the total proteins. The affinity of RF to aggregated human IgG, as detected in inhibition experiments, is higher than that of Fe receptors found on human non‐T lymphocytes, K562 and Daudi cell lines.
Antigen‐independent, IgM‐induced antibody responses: requirement for “recurrent” idiotypes
Authors: Ivars Fredrik , Holmberg Dan , Forni Luciana , Pierre‐André  , Cazenave  , Coutinho Antonio 
Published: February 2007

AbstractAnti‐idiotypic antibodies (a‐Id) were produced in syngeneic mice against two monoclonal IgM antibodies of BALB/c origin, TNP.11 and SP/603. In plaque inhibition tests, using IgM‐secreting hybridoma cells and anti‐idiotypic antibodies, these two IgM proteins, as well as the anti‐TNP myeloma protein MOPC 460 (IgA) were found to carry non‐cross‐reactive idiotypes.Analysis of the anti‐trinitrophenyl (TNP) plaque‐forming cells (PFC) in BALB/c mice, either normal or immunized with TNP‐horse red blood cells, revealed that in addition to the MOPC 460 Id, also the SP/603 Id is recurrent and expressed by a fraction of the anti‐TNP antibody‐secreting cells in all individuals tested. In contrast, the TNP.11 Id could not be detected in any BALB/c mouse studied.TNP.11 and SP/603 antibodies were then characterized by their ability to induce an antigen‐independent anti‐TNP response in normal BALB/c mice. While TNP.11 was found to be inactive, the same titers of SP/603 IgM induced antigen‐specific PFC all of which expressed the SPi603 Id, and increased titers of circulating IgM molecules carrying the same Id, suggesting that “recurrent” but not “nonrecurrent” Id are competent in this respect. A fraction of these SP/603‐induced, SP/603‐positive anti‐TNP antibodies also carried MOPC 460 Id, suggesting expression on the same molecule of idiotypic determinants found on independent non‐cross‐reactive “recurrent” idiotypes.
Demonstration at the single‐cell level of the existence of distinct clusters of epitopes in two predefined human Ia molecular subsets
Authors: Accolla Roberto S. , Sekaly Rafick P. , McDonald Audrey P. , Corte Giorgio , Gross Nicole , Carrel Stefan 
Published: February 2007

AbstractThe expression at the cell surface level of two previously defined human Ia antigen subsets, NG1 and NG2, was studied. Two monoclonal hybridoma antibodies, D1‐12 (anti‐NG1) and D4‐22 (anti‐NG2), labeled with distinct fluorochromes, were used as probes.The results indicate that NG1 and NG2 molecules are simultaneously expressed on the same cell, and moreover, that they are identifiable as spatially separate structures. In addition, when a series of 6 other anti‐Ia monoclonal antibodies previously described were analyzed in a checkerboard test of binding inhibition at the cell surface level, they were found to closely mimic the reactivity pattern of either D1‐12 or D4‐22 antibody, suggesting that NG1 and NG2 Ia subsets express independent clusters of highly immunogenic epitopes.
Allotypes in Basilea rabbits
Authors: Weiss Siegfried , Garcia Irène , Jaton Jean‐Claude , Kelus Andrew S. 
Published: February 2007

AbstractBasilea rabbits produce immunoglobulin molecules, practically all of which have λ light chains rather than x chains. This variant strain was derived from a homozygous (b9/b9) male. Sensitive serological methods revealed that at least some homozygous bas/bas individuals possess traces (about 100 ng/ml) of b9 molecules. This level usually increases to almost 1 μg/ml upon hyperimmunization with pneumococcal or streptococcal vaccines. One exceptional rabbit, with 50 μg/ml of b9 molecules, was found. In spite of the presence of b9 molecules in early pre‐immune bleeds, homozygous bas/bas rabbits produce strong anti‐b9 antibodies; i.e., they are capable of making autoantibodies. These anti‐b9 allotypic antisera were not distinguishable by our methods from routinely produced anti‐b9.
The effects of a monoclonal anti‐μ chain antiserum on the in vitro growth of normal B cells
Authors: Boyd Andrew W. , Pike Beverley L. 
Published: February 2007

AbstractMembrane immunoglobulin (Ig) on B cells plays a role in specifically focusing antigen onto the cell surface. An unresolved question is whether the Ig receptor itself has the capacity to deliver a signal to the B cell, and if so what is the mechanism of that signal. To explore these questions we have developed a monoclonal rat anti‐mouse μ chain antibody (E4). In this study it is shown that protein A‐Sepharose‐purified monoclonal anti‐μ chain antibody inhibits proliferation of normal B cells in vitro even at the single cell level. This effect was independent of Fc receptor interactions. Furthermore, E4 was shown to inhibit lipopolysaccharide‐induced mitogenesis. These results provide evidence that interaction of antibody with only a single determinant on the Ig receptor can deliver a negative signal to the B cell.
Demonstration of two distinct light chains in HLA‐DR‐associated antigens by two‐dimensional gel electrophoresis
Authors: De Kretser Theonne A. , Crumpton Michael J. , Bodmer Julia G. , Bodmer Walter F. 
Published: February 2007

AbstractThe polypeptide composition of HLA‐DR‐associated antigens was analyzed by two‐dimensional nonequilibrium pH gradient electrophoresis (NEPHGE)/sodium dodecyl sulfate (SDS)‐polyacrylamide gel electrophoresis (PAGE). Glycoprotein fractions from B lymphoblastoid cell lines homozygous for the DR antigen were used as antigen source. The HLA‐DR‐associated antigens were isolated by immunoprecipitation using a monoclonal anti‐DR antibody, TDR31.1. Two polypeptides corresponding in molecular weight to the HLA‐DR‐associated antigen β chain were detected. These polypeptides were shown to be different molecules on the basis of their separation on NEPHGE/SDS‐PAGE analysis, their rates of turnover relative to the other polypeptides of the HLA‐DR‐associated antigens, and their noncoordinate alteration in position on NEPHGE/SDS‐PAGE two‐dimensional analysis of different cell lines. Of the two β polypeptides, only one was invariant in position on NEPHGE/SDS‐FAGE analyses of cell lines homozygous for the same DR specificity. It appears therefore that the position of one of these β polypeptides correlates with DR specificity, while the other β polypeptide exhibits positional variation on NEPHGE/SDS‐PAGE analysis, indicative of polymorphism at a second HLA‐DR‐associated locus.
T‐T cell interactions during cytotoxic T cell responses IV. Murine lymphoid dendritic cells are powerful stimulators for helper T lymphocytes
Authors: Röllinghoff Martin , Pfizenmaler Klaus , Wagner Hermann 
Published: February 2007

AbstractEnriched populations of Ia+ Fc receptor‐negative dendritic cells were compared to other cell types for their stimulatory activity in primary mixed lymphocyte reactions to alloantigens and 2,4,6‐trinitrophenylated syngeneic cells. Dendritic cells were 20‐100 times more effective than unfrationated splenocytes. A second cell type exhibiting strong stimulatory activity was an Ia+ Fc receptor‐positive transiently adherent cell. Both types of stimulatory cells were only effective when able to produce the monokine interleukin 1. Thus glutaraldehyde‐fixed cells were not stimulatory unless extraneous interleukin 1 was added. Stimulation of helper cells by either dendritic cells or Ia+ Fc receptor‐positive cells resulted in the production of interleukin 2. The data are discussed in view of the recently formulated interleukin model as a minimal scheme to explain T‐T cell interactions during the in vitro induction of cytotoxic T lymphocytes.