bluuebunny/crossref_metadata_2025 huggingface dataset:
Differentiation antigens in rat lymphocyte subpopulations recognized by rabbit antisera against electrophoretically separated cells
Authors: Zeiller K. , Pascher Gertrud
Published: February 2007

Rat lymphocytes of high (H cells) and low (L cells) electrophoretic mobility (EPM) from lymph node (LN), spleen (Spl) and thymus (Thy) were separated by free flow electrophoresis and antisera against these cells raised in rabbits. Eight distinct lymphocyte‐specific xenoantigens could be characterized by appropriate cross‐absorption of three antisera: anti‐Thy‐L cell IgG, anti‐LN/‐Spl‐H cell IgG and anti‐LN/Spl‐L cell IgG. Cross‐absorption of anti‐Thy‐L cell IgG with unseparated LN or Spl cells revealed a thymus‐specific antigen complex which was absent from peripheral rat lymphocytes but present on mouse thymocytes and peripheral T cells. This complex could be further separated into brain‐associated and nonassociated antigens. The brain‐associated antigens consisted of a rat‐specific component, a component shared by the rat and all mice which carry the Thy‐1.1 and Thy‐1.2 allogenic specificity, and a third component shared by rat and Thy‐1.1 mice. This Thy‐1 antigen complex showed a 26‐fold larger antibody‐binding capacity to thymocytes of low EPM than to those of high EPM. The thymic antigens which were not absorbed by brain tissue showed similar antibody‐binding capacity to all thymocytes whether of low or high EPM. Anti‐LN/Spl‐H cell IgG cross‐absorbed with LN/Spl‐L cells detected antigens which were localized on all rat peripheral H cells and thymocytes but which were absent from peripheral L cells. Further absorption with Thy‐L cells revealed a distinct subclass of antigens present on peripheral H cells and Thy‐H cells but absent from Thy‐L cells. On the other hand, cross‐absorption of anti‐LN/Spl‐L cell IgG with peripheral H cells provided specificities which were directed against all peripheral L cells but which did not react with peripheral H cells and thymocytes. The relationship of these different xenoantigens to known lymphocyte subpopulations is discussed.
Clearance and re‐expression of a myeloma cell's antigenbinding receptors induced by ligands known to be immunogenic or tolerogenic for normal B lymphocytes: a model to study membrane events associated with B cell tolerance
Authors: Bankert R. B. , Mayers G. L. , Pressman D.
Published: February 2007

We have previously reported that the immune response of BALB/c mice to α(1→3) linkage groups of dextran B1355 and the in vivo growth of MOPC 104E tumor cells were specifically suppressed by the administration of oxidized dextran B1355. In the present study, we report on membrane events that occur after 104E cells are incubated with either the native dextran B1355 or the oxidized dextran B1355. The 104E cells, which possess membrane‐associated receptors that are specific for the α(1→3) linkage groups of dextran, were monitored for the clearance of receptor‐antigen complexes, and the subsequent re‐expression of receptors that follow the interaction of cells with either the native ligand, dextran, or the suppressor ligand, oxidized dextran. Following incubation of 104E cells with the native ligand, complexes of dextran plus receptors aggregate and are gradually cleared (2–4 h) from the membrane. Subsequent to the receptor‐antigen clearance induced by the native ligand, a second set of dextran‐binding receptors is observed. The second set of receptors appears to be derived from a presynthesized precursor pool of receptors within the cell and not from the synthesis of new receptors. These receptors appear diffusely over the entire surface of the cell membrane as opposed to a single discrete area within the membrane. The receptors remain within the membrane for at least 48 h unless perturbed again by antigen. Re‐expression of receptors is not observed following a second perturbation with the native ligand.

The membrane events which succeed the incubation of the 104E cells with the suppressor ligand differ significantly from those which are observed following incubation with the native ligand. Exposure to the suppressor ligand results in a rapid (10–30 min) and complete clearance of the complexes of oxidized dextran plus receptor from the membrane of the 104E cell, and the clearance of these complexes occurs without any detectable receptor aggregation. The most significant difference observed following the pulse with the suppressor ligand is the complete absence of a receptor re‐expression. Thus, 104E cells, following a brief pulse with oxidized dextran, fail to incorporate the presynthesized second set of receptors into the plasma membrane. This apparent suppressive signal occurs without any detectable change in cell viability.

The inability of the 104E cell to express a second set of antigen‐binding receptors following a suppressor antigen‐induced clearance of the first set is presented as a possible link of a membrane event with an alteration in cell function (i.e. suppression of proliferation of the 104E cell in vivo by this antigen). The possible relationship of the 104E cell membrane events to normal B cell membrane events associated with immunity or tolerance is discussed.
Influenza virus‐specific cytotoxic T cells in man; induction and properties of the cytotoxic cell
Authors: McMichael A. J. , Askonas Brigitte A.
Published: February 2007

Human peripheral blood lymphocytes have been sensitized in vitro to influenza virus antigen. After an induction period of 4–14 days, cytotoxic cells which lyse autologous influenza virus‐infected lymphoid cells could be demonstrated. The cytotoxic cell is a T lymphocyte which shows specificity for sensitizing influenza virus type A or B. It cannot distinguish between major subtypes of influenza A virus. The use of virus‐infected normal lymphoid cells as target cells overcame the difficulties of nonspecific killing encountered with some transformed cells.
Immune depression in trypanosome‐infected mice I. Depressed T lymphocyte responses
Authors: Pearson T. W. , Roelants G. E. , Lundin Lena B. , Mayor‐Withey Kathleen S.
Published: February 2007

Using a wide range of experimental conditions, several kinds of T lymphocyte responses in spleen cell populations from trypanosome‐infected mice were studied. Lymphocyte stimulation after culture with the mitogen concanavalin A or with histoincompatible cells differing at H‐2 or minor lymphocyte‐stimulating loci was reduced or abolished in spleen cells from infected mice when compared with responses of spleen cells from uninfected controls. In addition, cytotoxic lymphocytes were not generated in mixed lymphocyte cultures which contained spleen cells from infected animals. Allogeneic skin grafting experiments performed with normal and infected mice showed that a decreased T lymphocyte response also occurs in vivo. The depressed immune responses were not simply due to low numbers of T lymphocytes in spleens of infected animals, but reflected a generalized immune depression which was not antigen‐specific.
Chemiluminescence and immune cell activation I. Early activation of rat thymocytes can be monitored by chemiluminescence measurements
Authors: Wrogemann K. , Weidemann M. J. , Peskar B. A. , Staudinger H. , Rietschel E. T. , Fischer H.
Published: February 2007

Immediately after the addition of concanavalin A, rat thymocytes respond, in the presence of luminol, with a burst of chemiluminescence (CL) that can be conveniently monitored in an ordinary liquid scintillation spectrometer. Peak CL is reached after 50 sec. Addition of catalase suppresses 65% of the CL, suggesting that H2O2 generation may be its major source. CL with different kinetic characteristics can also be generated by the calcium ionophore A23187.

Our rat thymocytes contain approximately 0.1% endogenous macrophages. Bone marrow‐derived rat macrophages also respond to concanavalin A or A23187 stimulation with a burst of CL. However, the kinetic properties of CL as well as the inhibition of CL by catalase in these cells differ markedly from those of thymocyte preparations, suggesting that the major portion of the CL in rat thymocytes actually originates in T lymphocytes.

Because CL measurements allow the monitoring of very early events in cell activation and because of the simplicity of the technique, CL measurements may become a useful method for the study of lymphocyte activation, of macrophage‐lymphocyte interactions, as well as for the rapid screening for specificity and reactivity of T lymphocyte populations.
Helix pomatia A hemagglutinin: selectivity of binding to lymphocyte surface glycoproteins on T cells and certain B cells
Authors: Axelsson B. , Kimura A. , Hammarström S. , Wigzell H. , Nilsson K. , Mellstedt H.
Published: February 2007

Human and mouse lymphocytes were surface‐labeled by lactoperoxidasecatalyzed iodination, or by galactose oxidase oxidation followed by reduction with tritiated sodium borohydride. The labeled cells were lysed with Nonidet P‐40. Proteins binding to Helix pomatia A hemagglutinin (HP) were isolated by affinity chromatography on HP‐Sepharose and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography.

A major cell surface glycoprotein (apparent mol. wt. 150000, using reducing conditions) on human lymphocytes was responsible for almost all binding of HP. This protein was present on normal and malignant thymus‐derived lymphocytes, e.g. thymocytes, blood T cells and T leukemia cell lines. It was also found on chronic lymphocytic leukemia cells, one null cell leukemia line, one unidentified leukemia line, one lymphoblastoid cell line of B origin and on one stem cell lymphoma line. In contrast, this protein was not found on various B cells at different steps of differentiation, e.g. four B lymphoma lines or one myeloma line. It was also absent from a histiocytic leukemia line. However, two of the four B lymphoma lines and the myeloma line had another HP‐binding surface glycoprotein (mol. wt. 200000) instead of the 150000 protein.

Studies of mouse lymphocytes similarly showed that thymus‐derived lymphocytes (normal and malignant) but not normal adult B cells expressed a major HP‐binding surface glycoprotein of apparent mol. wt. 130000 (reducing conditions).
Nature of T cell‐macrophage interaction in helper cell induction in vitro I. Evidence for genetic restriction of T cell‐macrophage interactions prior to T cell priming
Authors: Erb P. , Meier Barbara , Kraus Daniele , Von Boehmer H. , Feldmann M.
Published: February 2007

The nature of the genetic restriction of T cell‐macrophage interaction in helper cell induction has been investigated. By incubating F1 hybrid T cells with keyhole limpet hemocyanin and macrophages of one parental haplotype, helper cells were generated that cooperated with B cells of either parental haplotype, provided macrophages of the haplotype used for the initial priming were present in the cooperative culture. The experiment is in line with the view that F1 T cells reactive to a given antigen contain at least two independent clones, each responsive to antigen recognized in conjunction with macrophages of one parental strain, and moreover, indicates that genetic restriction of T cell‐macrophage interaction may be induced by priming. However, by using F1 T cells it is not possible to exclude that restriction is already manifest prior to priming. Thus, experiments were performed using T cells from chimeric mice instead of F1 mice. Chimeric mice, prepared by injecting lethally irradiated F1 mice with anti‐θ‐treated bone marrow cells of both parental types, have two histoincompatible lymphoid pools which are mutually tolerant. T cells of one type, prepared by treatment with anti H‐2 serum and complement, were not able to interact with macrophages of the other histoincompatible parental type indicating that genetic restrictions in interaction may be expressed prior to antigenic stimulation.

The possibility that suppression is the mechanism of the restriction of T cell‐macrophage interaction in helper cell induction has been investigated and excluded, based on several lines of evidence. First, genetic restriction is not broken by treatment of helper cells induced by allogeneic genetically related macrophage factors (GRF) (or mixtures of syngeneic and allogeneic GRF) with antisera which kill suppressor cells, which may have masked the help induced with allogeneic GRF. Second, chimeric mice, which have not been shown to have suppressor cells, still show the same genetic restriction. The implication of these findings for patterns of T cell recognition is discussed.
Preparation and characterization of anti‐framework antibodies to the heavy chain variable region (VH) of mouse immunoglobulins
Authors: Ben‐Neriah Y. , Wuilmart C. , Lonai P. , Givol D.
Published: February 2007

The heavy chain variable portion of mouse myeloma protein MOPC‐315 (α, λ2) was obtained from its Fv fragment (J. Hochman, D. Inbar and D. Givol, Biochemistry 1973. 12: 1130.) and was used to immunize rabbits. Rabbit anti‐VH antibodies precipitated VH, Fv and the intact protein 315. The VH region specificity of these antibodies was evident from the line of identity in agar gel diffusion between Fv and M315, and from the lack of precipitation with another a chain of XRPC‐25 or with light (L) chains. Radioimmunoassay binding and inhibition studies demonstrated that anti‐VH 315 antibodies cross‐react with heavy (H) chains derived from various mouse myeloma proteins (MOPC‐460, XRPC‐25, MOPC‐104E, UPC‐10, TEPC‐15, HOPC‐8, MOPC‐167) as well as with H chains derived from mouse IgG. These H chains can inhibit 90–100% of the binding of VH 315 by anti‐VH indicating extensive sharing of antigenic determinants by various VH regions. The relative affinity of anti‐VH for various H chains was 20–1000‐fold weaker than its affinity for the MOPC‐315 H chain. The cross‐reaction of the various H chains was independent of antibody specificity, subclass, subgroup or CH allotype. This suggests that anti‐VH may be considered as anti‐V framework antibody.

Anti‐VH 315 cross‐reacts with isolated H chains but not with intact molecules and can therefore be used to detect VH determinants only in the absence of chains.
Idiotype suppression. III. Induction of unresponsiveness to sensitization with anti‐idiotypic antibody: identification of the cell types tolerized in high zone and in low zone, suppressor cellmediated, idiotype suppression
Authors: Hetzelberger Doris , Eichmann K.
Published: February 2007

Unresponsiveness of strain A/J mice to sensitization with guinea pig IgG anti‐A5A idiotypic antibody is induced by prior injection of guinea pig IgG2 anti‐A5A idiotypic antibody or unfractionated anti‐A5A antiserum. Two different forms of unresponsiveness could be induced depending on the dose of IgG2 anti‐A5A: high‐zone suppression was maximal one week after injection, could not be transferred by lymphocytes and disappeared within 3 to 4 weeks. Low‐zone suppression took 7 weeks to fully develop and could be transferred by splenic and lymph node T cells.

High‐zone suppression is expressed as transient unresponsiveness in both the A5A‐idiotype‐positive T helper as well as B precursor cell compartments. Low‐zone, suppressor cell‐mediated suppression is expressed as chronic unresponsiveness in the A5A‐idiotype‐positive T helper cell compartment only, whereas the A5A‐idiotype‐positive B precursor cells remain fully responsive as revealed by addition of nonsuppressed T helper cells. These data satisfactorily explain that suppression of T helper cell‐independent idiotypes does not involve T suppressor cells. However, since the presence of suppressor T cells is accompanied by selective unresponsiveness of A5A‐positive B cells, the data imply that idiotypic restrictions exist for T‐B cooperation.
Recognition of idiotypes in lymphocyte interactions II. Antigen‐independent cooperation between T and B lymphocytes that possess similar and complementary idiotypes
Authors: Eichmann K. , Falk I. , Rajewsky K.
Published: February 2007

Antigen‐independent cooperation between T and B lymphocytes is demonstrated in vitro in two different experimental protocols: (a) B cells from A/J mice immunized in vivo either with Group A streptococcal vaccine (Strep.A) or with the IgG1 fraction of guinea pig anti‐idiotypic antibody to the A5A idiotype, mature into plaque‐forming cells (PFC) with specificity for Group A streptococcal carbohydrate (A‐CHO) during a 4‐day culture together with T cells from A/J mice immunized in vivo with A5A idiotypic antibody. (b) B cells from A/J mice immunized in vivo with Strep.A generate PFC specific for A‐CHO when cultured in the presence of small concentrations of anti‐A5A idiotypic antibody and of T cells primed with Strep.A. In both cases, antigenindependent cooperation is idiotypically selective, such that only those B cells respond that secrete antibody with the A5A idiotype.

The data are interpreted to suggest that, in addition to antigen‐specific helper cells, idiotype‐specific may participate in antibody responses, and that the latter type of help may be responsible for the idiotypic selectivity in T‐B cooperation observed previously. Furthermore, idiotype‐specific cooperation may be a means to generate and maintain B cell diversity during the evolution and ontogeny of the immune system.
Cytological and functional analysis of inflammatory infiltrates in human malignant tumors II. Functional investigations of the infiltrating inflammatory cells
Authors: Tötterman T. H. , Häyry P. , Saksela E. , Timonen T. , Eklund B.
Published: February 2007

Six individual human carcinomas displaying an unusually strong inflammatory reaction were dispersed by a mixture of collagenase and deoxyribonuclease and fractionated in 1 × g velocity sedimentation. This method gave an excellent separation of cancer cells from infiltrating inflammatory cells. The viability in both cell populations exceeded 95%. Blood mononuclear leukocytes and tumor‐infiltrating inflammatory cells from the cancer‐bearing patients were then tested in the short‐term 51Cr release test for in vitro cytotoxicity to their autochtonous tumor cells and to target cells known to be sensitive to the socalled “natural killer” (NK) lytic effects. In two patients with testicular seminoma, the blood leukocytes were strongly cytotoxic to the patients' own tumor cells; in one case of thyroid carcinoma, the patient's blood leukocytes also exhibited a distinct albeit slight cytotoxic activity towards his autochtonous tumor. Blood mononuclear leukocytes of all these cancer patients were strongly cytotoxic to the NK targets MOLT‐4, K‐562, chicken red cells and human embryonic fibroblasts (Ef). In striking contrast, the tumor‐infiltrating inflammatory cells were entirely unable to lyse the autologous tumor cells. Neither, with the exception of the Ef targets, did the tumor‐infiltrating cells display any cytotoxic activity towards the NK targets. The findings demonstrate a widespread functional paralysis (or absence) of effector cells directed to the patients' own autologous tumor cells and to NK target cells in the tumor‐infiltrating inflammatory cell population.
Induction in vitro of reversible immunosuppression and inhibition of B cell receptor regeneration by defined metabolites of cyclophosphamide
Authors: Shand F. L. , Howard J. G.
Published: February 2007

A number of defined metabolites and derivatives of cyclophosphamide (CY) were compared with the parent compound for their capacity to induce suppression of humoral antibody responses in vivo and in vitro and to inhibit the regeneration of surface immunoglobulin (sIg) receptors on B cells subsequent to capping with anti‐Ig serum. Both functions were inhibited by exposing spleen cells in vitro to the most active compounds (4‐hydroperoxycyclophosphamide and phosphoramide mustard) in concentrations of 10 μg/ml or less. Although these inhibitory activities were found to be restricted to those molecules with demonstrable alkylating activity, they are nevertheless reversible and not dependent on events leading to cell death.

Inhibition with microsomally activated CY in vitro rendered splenic B cells hyper‐susceptible to tolerance induction by levan, although in the absence of this antigen they recovered full responsiveness to it within 7–10 days. Since lethally irradiated mice repopulated with adult bone marrow cells do not regenerate normal responsiveness to polysaccharide antigens in less than 50–100 days (Howard, Moreno, Hale and Vicari, Eur. J. Immunol. 1977. 7: 431.), it is considered that the rapid recovery by CY‐treated spleen cells involves reversal of suppression in B cells and not renewal from stem cells. Our previous proposal (Shand and Howard, Nature 1978. 271: 255.) that impairment of B cell receptor regeneration by CY is causally related to its capacity to promote B cell tolerance induction by thymus‐independent antigens is supported by the present data.
Detection and partial characterization of a new murine T‐lineage antigen: evidence for its enzymatic modulation
Authors: Thiele Heinz‐Günter , Arndt Rüdiger , Hamann Alf , Stark Rosemarie
Published: February 2007

A molecule with an apparent molecular weight of 21000 daltons was found to be a predominating differentiation antigen of peripheral rat T lymphocytes. This antigen is also expressed on the cell surface of thymus lymphocytes though partially in masked form. The observation that these determinants could be unmasked by neuraminidase treatmentin vitrosuggests that enzymatic processes may play an important role in antigenic transformation along the differentiation pathway of T axis lymphocytes. Since this structure was found to be displayed also by peritoneal exudate macro‐ phages, it is referred to as T lymphocyte‐macrophage antigen. The finding that an identical antigen could be identified in the mouse suggests its more common biological significance.
Immune depression in trypanosome‐infected mice. III. Suppressor cells
Authors: Pearson Terry W. , Roelants Georges E. , Pinder Margaret , Lundin Lena B. , Mayor‐Withey Kathleen S.
Published: February 2007

Spleen cells from trypanosome‐infected mice strongly suppressed lymphocyte stimulation induced in normal spleen cell populations by lipopolysaccharide, concanavalin A or allogeneic (H‐2‐different) stimulator cells. This suppression was not H‐2‐restricted, as responses of spleen lymphocytes both allogeneic and syngeneic to the suppressors were inhibited. Irradiation or mitomycin C treatment of suppressor populations markedly reduced but did not eliminate suppressor activity. Suppressor populations were effective when present in very low numbers. Addition of suppressor cells to mixed lymphocyte cultures at various intervals after initiation of the cultures showed that the suppressors require 48 h to manifest their activity. Cell depletion or enrichment experiments indicate that the mechanism of suppression is complex and involves more than one cell type.
T cell‐produced immunoglobulin binding factor (IBF) bears determinants coded for by the I region of the major histocompatibility complex and lacks allogeneic restriction
Authors: Rabourdin‐Combe Chantal , Fridman Wolf H. , Dorf Martin E. , Guimezanes Annick
Published: February 2007

An immunoglobulin binding factor (IBF) produced by in vivo alloantigen‐activated T cells suppresses in vitro antibody production to sheep red blood cells (SRBC) and probably represents the soluble form of the T cell Fc receptor. To study the relationship between IBF and the major histocompatibility complex (MHC), two types of experiments were undertaken. First, different IBF were prepared by injecting thymocytes from mice of H‐2k, H‐2b and H‐2d haplotypes into irradiated, allogeneic recipient mice. Cells recovered in the spleens five days later were incubated for 2 h at 37 °C, and IBF was purified by affinity chromatography on insolubilized IgG. Purified IBF was then applied to immunosorbents prepared with anti‐H‐2 and anti‐Ia anti sera. Acid eluates were then tested for their suppressive activity on in vitro antibody production to SRBC. Under these conditions, IBF was found to react with anti‐sera raised against products of the whole MHC and of the I region of the MHC, but not with anti‐H‐2 D antisera. These data indicate that IBF bears, or is associated with Ia determinants. Second, IBF preparations from mice of H‐2k, H‐2b, H‐2d haplotypes were tested for their capacity to suppress the in vitro antibody production to SRBC by spleen cells of a series of mouse strains. The data indicate that IBF is not genetically restricted in its function.
The migration of lymphocytes in the fetal lamb
Authors: Paper Short , Cahill Ross N. P. , Poskitt David C. , Hay John B. , Heron Iver , Trnka Zdenek
Published: February 2007

The migration of 51Cr‐labeled autologous lymphocytes from intestinal or prescapular lymph was compared in fetal lambs and adult sheep. A subpopulation of lymphocytes present in intestinal lymph of adults which migrated to the small intestine was not found in fetal intestinal lymph. There were marked differences in the migration of fetal and adult lymphocytes to the lungs and liver. In spite of the absence of circulating antibodies or immunoglobulins and of extrinsic antigen in the immunologically virgin sheep fetus, the circulation of lymphocytes through the spleen and lymph nodes of fetal lambs was more intense than in the adult.
Expression of Ly‐6 alloantigen during differentiation of cytotoxic T cells
Authors: Horton Michael A. , Beverley Peter C. L. , Simpson Elizabeth
Published: February 2007

We have prepared anti‐Ly‐6.2 by immunization of (CBA/Ca × A‐Thy‐la)F1 with AKR/Crc lymphocytes and used the antiserum to study heterogeneity of peripheral T lymphocytes. The Ly‐6 alloantigen is found on all activated cytotoxic T cells studied, directed to a variety of different target antigens. The antiserum reveals heterogeneity among the precursors of T killer cells, i.e. allogeneic precursors are Ly‐6−, whereas the generation of cytotoxic cells to hapten‐modified syngeneic cells and xenogeneic cells is partially abrogated by serum pretreatment. Precursors of some in vivo primed responses are also Ly‐6+. These findings indicate that the expression of Ly‐6 antigen is, at least, partially related to the stage of T cell activation. The in vitro proliferative response of T cells to allogeneic Ia antigens is substantially reduced by pretreatment with anti‐Ly‐6.2 serum suggesting that this antiserum may be a useful tool for the study of heterogeneity in the Ly‐l+ pool of T cells.
Identification of Ia glycoproteins in rat thymus and purification from rat spleen
Authors: McMaster W. Robert , Williams Alan F.
Published: February 2007

A fraction of la‐like glycoproteins was prepared from rat thymocytes by lentil lectin affinity chromatography and gel filtration in deoxycholate. Spleen cells from mice immunized with this preparation were fused with myeloma cells to produce antibody‐secreting hybrid cell lines. Antibody from four lines called MRC OX, 3, 4, 5, 6 reacted with the la‐like glycoproteins, and MRC OX 3 antibody recognized an antigenie determinant polymorphic in the rat. All four antibodies also bound to mouse spleen cells and all detected polymorphisms. Studies on recombinant mouse strains suggest that the determinants are coded by the I‐A subregion of the H‐2 complex. MRC OX 3 correlates with Ia specificity 9, while MRC OX 4, 5, 6 correlate with specificity 17 or 18. MRC OX 4 monoclonal antibody was used for affinity chromatography to purify Ia glycoproteins from rat spleen. The rat Ia glycoprotein complex was composed of two noncovalently linked polypeptide chains of apparent mol. wt. (unreduced) 30 000 and 24 000 as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The purified Ia glycoprotein partially inhibited the binding to thoracic duct lymphocytes of an alloantiserum which detects Ia antigens linked to the major histocompatibility complex. The monoclonal anti‐la antibodies bound to the majority of peripheral B lymphocytes and 18% of thymocytes, but did not significantly bind to peripheral T lymphocytes. There were on average 150000 molecules of Ia glycoprotein per la‐positive B lymphocyte, and 45 000 molecules per la‐positive thymocyte.

From the same fusion, another cell line was prepared called MRC OX 2 which secretes monoclonal antibody to a previously undefined thymus glycoprotein of apparent mol. wt. 60000. Preliminary studies showed that the antigen was expressed on all thymocytes and on peripheral B lymphocytes in smaller amounts. It was also present in brain, but not liver or kidney homogenate.
Lysis of enucleated tumor cells with allogeneic and syngeneic cytotoxic thymus‐derived lymphocytes
Authors: Hale Arthur H. , Paulus Leslie K.
Published: February 2007

These studies were initiated to understand the minimal requirements for lysis of target cells by cytotoxic thymus‐derived lymphocytes (CTL). In particular, the significance of the nucleus to the susceptibility of the target cell to be lysed by CTL have been studied. P815 mastocytoma cells and EL4 lymphoma cells were enucleated by cen‐ trifugation through a discontinuous Ficoll gradient containing 10 μg/ml of cytochalasin B. The resultant vesicles were then analyzed for susceptibility to lysis by different CTL specific for the H‐2K and H‐2D gene products, minor histocompatibility antigens, trinitrophenyl groups, and Sendai virus‐specific antigens. The results indicate that enucleated vesicles obtained from both EL 4 and P 815 cells are susceptible to lysis by these CTL. The lysis of EL 4‐enucleated vesicles (unlike P 815‐enucleated vesicles), however, required 2–4 times more effector cells than were required for equivalent lysis of intact EL 4 cells. This reduced susceptibility to lysis of enucleated EL 4 vesicles was not the result of an inability of the CTL to recognize and bind the vesicles. This conclusion was suggested by the fact that both enucleated EL 4 vesicles and intact cells inhibited equally well the lysis of 51Cr‐labeled concanavalin A‐stimulated BALB. B spleen cells by anti‐H‐2b CTL. Although enucleated vesicles obtained from both P 815 and EL 4 cells were susceptible to lysis by CTL, they exhibited a reduced capacity to “cap” their serologically defined H‐2 antigens.

Lysis of these enucleated vesicles by CTL has the same requirements as lysis of intact cells. This conclusion was based upon the requirement for Ca++ and Mg++ and also because lysis of the modified vesicles (trinitrophenyl or viral antigens) occurred in an H‐2‐restricted fashion. Moreover, the enucleated vesicles were susceptible to antibody and complement‐mediated lysis and also lectin‐dependent cell‐mediated cytotoxicity.
Specific binding of radiolabeled membrane vesicles by T cells activated in the mixed lymphocyte reaction
Authors: Elliott Bruce E. , Takács Béla , Nagy Zoltan
Published: February 2007

An assay was developed to quantitate binding of radiolabeled membrane vesicles by T cells activated in the primary mixed lymphocyte reaction (MLR). T blasts generated in unidirectional, reciprocal MLR combinations were found to bind much more effectively membrane vesicles prepared by nitrogen cavitation from allogeneic stimulator cells than from syngeneic spleen and lymph node cells which had been previously labeled biosynthetically with [3H]leucine. Specific inhibition of binding with cold vesicles prepared from stimulator cells but not from responder cells was observed. The number of specific antigen‐binding cells is proportional to the concentration of membrane vesicles used. The proportion of labeled cells increases between 15 and 60 min of incubation with membrane vesicles, but thereafter remains constant. The binding of stimulator material is H‐2‐specific: cells bind membrane vesicles from congeneic mouse strains only if they share the H‐2 antigens of the original stimulator strain. Responder blasts bind labeled stimulator membrane fragments after as early as 2 days of primary MLR culture; no binding of membrane vesicles by small lymphocytes was detected between 2 and 5 days of culture. However, between 8 and 12 days of culture, a significant proportion of small lymphocytes bind specifically stimulator membrane vesicles. The recognition function is sensitive to trypsin treatment but is regenerated within 5 to 6 h.
Wheat germ agglutinin activates macrophages for collaboration with B cells
Authors: Bernabe Rosa R. , Martinez‐Alonso Carlos , Larsson Eva‐Lotta , Coutinho Antonio
Published: February 2007

Wheat germ agglutinin (WGA), added to Mishell‐Dutton‐type cultures of nude spleen cells challenged with erythrocyte antigens, allows a primary specific plaque‐ forming cell (PFC) response. WGA, however, does not display direct mitogenicity to either T or B lymphocytes. The activity of WGA in the specific PFC response is macrophage‐dependent and parallels a nonspecific PFC response in the same cultures.
Cytotoxic T cell responses to haptenated cells I. Primary, secondary and long‐term cultures
Authors: Pohlit Helmut , Haas Werner , von Boehmer Harald
Published: February 2007

Cytotoxic T lymphocyte (CTL) responses were obtained in vitro to cells coupled with several different haptens. The degree of lysis of target cells was dependent on the amount of hapten coupled to stimulator and target cells. Spleen cells from normal mice responded to high‐hapten density cells but not to low‐hapten density cells. However, spleen cells from immunized CBA mice could be stimulated in vitro by low‐ hapten density cells to generate effector cells able to lyse low‐hapten density cells. In vitro primed responder cells could be restimulated in the presence of the original hapten‐coupled stimulator cells or in the presence of supernatant from concanavalin A‐stimulated mouse or rat spleen cells. Large numbers of hapten‐specific and H‐2‐ restricted CTL could be generated by repeated exposure to fresh supernatant.
The in vitro cellular response of human lymphocytes totrinitrophenylated autologous cells: HLA‐D restrictionof proliferation but apparent absence of HLArestriction of cytolysis
Authors: Charmot Dominique , Mawas Claude
Published: February 2007

Primary as well as secondary proliferative and cytotoxic responses to 2,4,6‐trinitrophenyl (TNP)‐modified autologous human cells have been studied. Proliferativeresponses have been obtained both by primary (peak on day 6) and secondary (peakon day 2–3) stimulation. Both responders and nonresponders were found among thepanel of unrelated individuals tested. All responders in a secondary reaction also gavesignificant primary responses. Intrafamilial studies showed that the ability to restimulate a proliferative response followed the major histocompatibility complex haplotypeof the responder; in some cases, the two haplotypes differed in their ability to restimulate.

Using unrelated individuals typed for HLA‐A, B and C, as well as HLA‐D and DR, proliferation was shown to occur only when the unrelated stimulator shared HLA‐Dregion products with the responder.

In contrast, no HLA restriction was found in cell‐mediated lympholysis (CML)(neither in primary nor in secondary responses) in most cases. The data suggest thatthe observed killing is independent of sensitization. Both responders and nonresponders in proliferation yielded high levels of lysis; no increase of lysis was found in kineticstudies; most allogeneic CML combinations were highly lytic for the TNP‐modifiedresponder cells at a time when the lysis of the specific allogeneic target is negligible. These preliminary data suggest that the killing observed might be different fromclassical T cell‐mediated lympholysis.
Education of mouse lymphocytes against human lymphoblastoid cell lines: Specific recognition of determinants independent of serologically defined HLA allotypes and Epstein‐Barr virus‐coded antigens
Authors: Carnaud Claude , Errasti Pedro , van der Gaag Ruth
Published: February 2007

In this report, a model of xenogeneic education is described, whereby cytotoxic mouse spleen cells are generated against human target cell antigens. To generate a significant response, a primary in vivo immunization followed by an in vitro boosting 4 to 8 weeks later is required.

Lysis is totally abrogated after treatment of the effector cells by anti‐Thy‐1.2 antiserum plus complement confirming the T origin of these effectors. Such cytotoxic T lymphocytes (CTL) do not discriminate between two lymphoblastoid cell lines carrying different HLA‐A and HLA‐B specificities, either by direct assay or by competition assay with unlabeled target cells. Moreover, Daudi cells which lack the serologically defined (SD) HLA antigens, are susceptible to CTL specifically raised against Daudi. However, CTL raised against another B line do not lyse Daudi, and, reciprocally, anti‐Daudi CTL do not lyse other B lines thus suggesting a polymorphic distribution of xenogeneic determinants on human lymphoid lines. A third specificity is revealed when mouse spleen cells are educated against human T lines. The CTL generated under these conditions lyse not only the line used for sensitization but the three other human T lines of the panel. On the other hand, they affect none of the B cell lines (including Daudi) nor phytohemagglutinin or concanavalin A‐induced T blasts. In conclusion, the mouse T cell repertoire is capable of recognizing a polymorphic system of antigens expressed on human lymphoblastoid cell lines that is not related to the expression of HLA‐SD antigens nor to that of the Epstein‐Barr virus genome.
IgG‐binding sites on macrophage cell membrane. I. Identification of two distinct Fc receptors on mouse peritoneal macrophages
Authors: Sulica Andrei , Gherman Maria , Medesan Cornel , Sjöquist John , Gheţie Victor
Published: February 2007

Evidence is presented concerning the existence on mouse peritoneal macrophages of two separate and distinct Fc receptors, one for cytophilic monomeric IgG (mIgG) and the other for polymeric IgG. The latter Fc receptor recognizes both heat‐aggregated IgG and antigen‐complexed IgG. The major findings of our studies are: (a) the different susceptibility of the two Fc receptor types by pronase, trypsin or phospholi‐ pase C; (b) the independent modulation of these two binding sites on the cell membrane; (c) the inability of mIgG to inhibit the binding of particulate antigen‐complexed IgG ligand; (d) the ability of mIgG molecules which are devoid of the cytophilic property to attach to the macrophage surface upon their polymerization induced by heating or antigen.

The results are discussed in terms of “cytophilic” and “opsonic” Fc receptor types which may provide different functional abilities for normal macrophages.
Generation of effector cells from T cell subsets. II. Lyt 123 T cells contain the precursors for all primary cytotoxic effector cells and for cells involved in the regulation of cytotoxic responses
Authors: Simon Markus M. , Abenhardt Birgit
Published: February 2007

Mixed responder populations, consisting of selected Lyt‐2,3+ cells and unselected T cells from two congenic mouse strains differing in their Lyt‐2,3 alleles, were used to study the role of Lyt‐1,2,3+ cells in the generation of cytotoxic effector cells in vitro. The fact that, under these conditions, all primary alloreactive and H‐2‐restricted killer cells are generated from the unselected T cell population and not from the selected Lyt‐2,3+ subset is demonstrated. Isolated, unsensitized Lyt‐2,3+ cells are able to produce primary alloreactive cytotoxic T lymphocytes (CTL) when incubated with alloantigen alone, but appear to be suppressed in the presence of Lyt‐1,2,3+ cells. In contrast, mixtures of Lyt‐2,3+ cells selected from C 57 BLI6 T cells previously primed to alloantigen in vitro, and unselected T cells from the Lyt‐2,3‐congenic partner after exposure to the same antigen give rise to cytotoxic effector cells which derive mainly from the primed Lyt‐2,3+ cell pool and not from the unselected T cell population. Both populations were able to generate CTL when sensitized separately with the alloantigen. The data suggest that Lyt‐1,2,3+ cells contain all primary precursors for both H‐2‐restricted and alloreactive killer cells, as well as lymphocytes suppressing the formation of cytotoxic effector cells from unsensitized Lyt‐2,3+ cells. The Lyt‐ 2,3+ cell pool most likely contains the secondary CTL precursors. In addition, the same antigen‐primed Lyt‐2,3+ pool contains suppressor cells which inhibit the formation of primary CTL from Lyt‐1,2,3+ cells. The data are discussed with respect to the regulation of cytotoxic responses.
Expression of blood group I and i active carbohydrate sequences on cultured human and animal cell lines assessed by radioimmunoassays with monoclonal cold agglutinins
Authors: Childs Robert A. , Kapadia Anupsheela , Feizi Ten
Published: February 2007

Human monoclonal anti‐I and anti‐i antibodies, reactive with known carbohydrate sequences, have been used as reagents to quantitate (by radioimmunoassay) and visualize (by immunofluorescence) the expression of the various blood group I and i antigenic determinants in a variety of cultured cell lines commonly used in laboratory investigations. It has been shown that the antigens they recognize are widely distributed on the surface of human and animal cell lines, expressed in varying amounts in different cell lines and on individual cells within a given cell line. In two cell lines, a transformation‐associated increase in the expression of I antigen was observed. Because of their precise specificity for defined carbohydrate chain domains, these autoantibodies have become valuable reagents in biological chemistry.
Epitope specificity of the T cell proliferative response to lysozyme: proliferative T cells react predominantly to different determinants from those recognized by B cells
Authors: Maizels Richard M. , Clarke Jessica A. , Harvey Michael A. , Miller Alexander , Sercarz Eli E.
Published: February 2007

The fine specificity of murine B 10.A/SgSn (B 10.A) T cells reactive with hen egg‐white lysozyme (HEL) has been studied through the use of reduced, carboxymethylated HEL, a set of peptides encompassing the entire molecule, and a set of variant lysozymes from other species. Cells were taken from the lymph nodes draining the site of immunization at the base of the tail, and were restimulated in vitro with immunogen or analogue to measure T cell reactivity.

Unlike B cell reactivity, which we have shown to be mainly associated with an epitope preserved in the N‐C peptide (residues 1–17, Cys 6‐Cys 127, 120–129) most T cell reactivity appears to be directed towards a limited number of determinants on cyanogen bromide cleavage fragment II of HEL (LII) (13–105). This was confirmed by a cell‐dilution assay in which antigen‐reactive units are measured; reactivity was highest to LII, intermediate to N‐C, and low but significant to cyanogen bromide cleavage fragment III (LIII) (106–129). Furthermore, priming with LII is as effective as immunization with HEL and results in the same extensive cross‐reactivities to variant lysozymes.

Although LII reactivity predominates in the response to HEL, injection of LIII and N‐C reveals sizeable reactivity to the homologous peptides and to HEL. By crossstimulation studies, specific epitopes could be defined in certain regions of HEL. B 10. A is clearly responsive to the overlap between N‐C and LII (residues 13–17), and to an epitope in the region 106–121, but is poorly responsive to the C‐terminal portion (120–129). The response to 106–121 is characterized by an exquisite specificity in which as little as a single amino acid substitution (Asn for Gln) is recognized.
Antigen‐independent binding of IgG dimers to C1 q as studied by sedimentation equilibrium, complement fixation and electron microscopy
Authors: Tschopp Jürg , Villiger Werner , Lustig Ariel , Jaton Jean‐Claude , Engel Jürgen
Published: February 2007

Rabbit anti‐SII pneumococcal polysaccharide IgG antibody was cross‐linked by dithiobis (succinimidyl propionate). The IgG dimers were visualized by electronmicroscopy and resembled two Y‐shaped structures connected in random orientations. The three arms of the Y's were of equal length. The six globular domains of the IgG protomers could be seen, but the Fab arms and Fc stems could not be distinguished from each other. Electron microscopy revealed that the dimers were bound to the globular heads of C1 q. From the dependence of the weight average molecular weight on dimer concentration, an equilibrium constant of about 106 M−1 was derived for the binding of dimers to C1 q. The number of IgG dimers which could be accommodated at a single C1q molecule was derived to be three. The data do not allow a clear distinction between noncooperative and cooperative binding.

The binding equilibrium was independent of whether the IgG dimers were liganded with an SII nonasaccharide hapten or not. The results are at variance with an allosteric mechanism of the action of antigen in C1 activation. They lend support to the association hypothesis of complement activation. The data suggest that clusters of about six IgG molecules, connected by a multivalent antigen or arranged at the cell surface, are recognized by C1 q with a binding constant of about 1010 M−1.
Major histocompatibility complex‐restricted and unrestricted T helper cells recognizing minor histocompatibility antigens of B cell surfaces
Authors: Coutinho António , Augustin Andrei A.
Published: February 2007

The present experiments analyze the functional properties of helper T cells specific for “minor” histocompatibility antigens. T cells from C3H/HeJ mice, primed in vivo and highly enriched in vitro for reactivity to membrane antigens of C3 H/Tif B cells, specifically proliferate, and provide polyclonal help to splenic B cells from strains carrying a variety of different H‐2 haplotypes on C3H or BALE backgrounds, while failing to respond to cells carrying the same H‐2 haplotypes on C 57 BL or A backgrounds. Since it has been previously demonstrated (A. A. Augustin and A. Coutinho, J. Exp. Med. 1980. 151: 587) that B cell activation in this system strictly requires direct, specific recognition of B cell surface antigens by helper cells and does not result from the production of soluble “mitogenic” or “nonspecific helper factors”, it is concluded that this phenomenon represents specific, major histocompatibility complex (MHC)‐unrestricted T cell help. In addition, it has now been found that expression of helper activity requires viability of the helper cells and is partially radiation‐sensitive. Lack of MHC restriction is not a general property of specific helper cells which directly recognize B cell “minor” antigens, since BALB.C3 H anti‐C3 H/Tif T cells appear to be restricted by H‐2 in their polyclonal helper activity. The helper activity mediated by specific anti‐“minor”, H‐2‐restricted helper cells could not be inhibited by anti‐VH antibodies, and the inhibition obtained with anti‐Ia antibodies appeared to operate at the level of B cell induction, rather than at the level of helper cell activation.