bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression induction in vivo by a T helper clone?
Authors: Crise I. Nicholas , Owens Trevor
Published: February 2007

We have previously described a helper T cell clone which augments in vivo cytotoxic T cell responses when injected at 104 cells per mouse, but not at 105 per mouse (Crispe, I. N. et al., Immunology 1984. 52: 55.). To test whether this dose‐response relationship was due to the induction of suppression, naive syngeneic mice were injected with lo5 cloned T helper cells, and their spleen cells were subsequently assayed for suppressive activity in adoptive transfer experiments. Lymphocytes from such mice indeed suppressed an antigen‐specific cytotoxic response, but only in the presence of the same T helper cell clone freshly added at the time of adoptive transfer. On this basis we argue that the distinction between T helper cell activity and T suppressor‐inducer activity corresponds to differences in cell numbers, rather than to two separate cell lineages.
The large sialoglycoprotein of human lymphocytes. I. Distribution on T and B lineage cells as revealed by a monospecific chicken antibody
Authors: Axelsson Bernt , Hammarström Sten , Robertsson Eva‐Stina , Åman Pierre , Perlmann Peter , Mellstedt Hákan
Published: February 2007

Chickens were immunized with highly purified large sialoglycoprotein of human lymphocytes (L‐LSGP; gp 150) which was isolated from neuraminidase‐treated normal peripheral blood lymphocytes by affinity chromatography to HP‐Sepharose and further purified by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Antibodies isolated from plasma and egg yolk were highly specific for desialylated L‐ LSGP (apparent molecular mass ∼ 150 kDa). The antigenic sites recognized by the antibodies are probably located in the peptide moiety of the molecule since antibody binding to lymphocytes was not inhibited by a variety of different sugars or abrogated by absorption on various erythrocytes.

In immunofluorescence experiments, ⩾ 75% of neuraminidase‐treated thymocytes and peripheral blood lymphocytes, virtually all E+ cells and T4+ or T8+ T chronic lymphocytic leukemia (CLL) cells were stained by anti‐gp150. A small fraction (∼ 10%) of thymocytes and a larger fraction (⩾ 30%) of T CLL cells in some patients were stained before neuraminidase treatment. Thymocytes appear to contain considerably lower amounts of a less sialylated form of L‐LSGP than peripheral blood lymphocytes. In contrast to blast cells of 5‐day concanavalin A or leucoagglutinin cultures (⩾ 90% anti‐gpl50+) only about 50% of the blast cells generated in 5‐day mixed leukocyte cultures were anti‐gpl50+. The large majority (⩾ 75%) of both the anti‐gpl50+ and anti‐gpl50− cells were T3+ and T11+.

About 25% of neuraminidase‐treated B cells in normal adult blood and in umbilical cord blood were stained in immunofluorescence using chicken anti‐gpl50. Of the cell lines, 0/2 with progenitor B cell phenotype (Epstein‐Barr virus‐transformed fetal liver cells), 3/5 populations exhibiting a pre‐B cell phenotype, 2/2 of somewhat later maturation and 1/3 myeloma lines were anti‐gpl50+ when stained after neuraminidase treatment. Biopsies from patients with lymphoproliferative disorders similarly showed that 7/7 CLL populations and 2/2 bone marrow biopsies obtained from multiple myeloma patients were anti‐gpl50+, whereas prolymphocytic leukemia cells were anti‐gpl50−. We propose therefore that gp150 may be associated with a separate lineage of B cells rather than expressed during the early stages of maturation.

L‐LSGP was not found on peripheral blood monocytes, granulocytes, platelets or erythrocytes. Rabbit, rat and mouse lymphocytes appear to contain a glycoprotein very similar to human L‐LSGP. It is probably a conservative molecule showing very little species specificity in mammals.

It is suggested that one important role of L‐LSGP may be to maintain cell integrity during the circulatory life of the lymphocyte.
T lymphocyte function during experimental Chagas' disease: production of and response to interleukin 2
Authors: Harel‐Bellan Annick , Joskowicz Mireille , Fradelizi Didier , Eisen Harvey
Published: February 2007

Infection of mice with Trypanosoma cruzi results in a severe immunosuppression, accompanied by the appearance of autoimmune symptoms. We have previously shown that proliferation and interleukin 2 production by concanavalin A‐stimulated T cells from infected mice is severely depressed. In this study we show that at least two phenomena are responsible for this depression. First, mixing experiments showed the existence, in spleens of infected animals, of adherent, Thy‐1‐negative and radioresistant suppressor cells. Second, studies of enriched T cell populations and analysis of precursors by limiting dilution showed that the T cell compartment itself was impaired in infected animals: responses of enriched T cells, even when reconstituted with normal accessory cells, reached only 40% of those obtained with normal uninfected mice.
A clonal analysis of human peripheral blood lymphocytes displaying natural killer‐like activity
Authors: Roberts Kevan , Moore Michael
Published: February 2007

Human Fcγ receptor‐bearing lymphocytes and T cells, prepared by sorting peripheral blood lymphocytes using the B73.1 monoclonal antibody, have been cloned by limiting dilution. Although quiescent lymphocytes of either cell type were unresponsive to interleukin 2 (IL2), following induction with phytohemagglutinin and/or the BSM B lymphoblastoid cell line they could be expanded in IL2 utilizing a mixed irradiated feeder system.

Clones originating from B73.1+ lymphocytes displayed a characteristic large granular lymphocyte (LGL) morphology but were otherwise functionally and phenotypically heterogeneous. Of 36 clones analyzed 19 displayed significant natural killer (NK)‐like activity, each clone having a target cell repertoire identical to uncloned NK effectors. Furthermore, only a minority of clones (i.e. 5) displayed significant antibody‐dependent cellular cytotoxicity, while levels of lectin‐induced cellular cytotoxicity were normally commensurate with a clones level of NK‐like activity. No correlation was evident between the phenotype of a clone and its cytotoxic activity since of 12 cytotoxic clones phenotyped, 8 expressed the OKT3 antigen but lacked the B73.1 antigen; 2 lacked the OKT3 antigen but expressed the B73.1 antigen and one lacked both OKT3 and B73.1 antigens. In addition the expression of OKT8 and OKT4 antigens was not in any way predictive of the cytotoxic capacity of a given clone. Several clones expressing T cell associated antigens bore a phenotype that distinguished them from T cell clones insofar as T cell subset antigens were expressed in the absence of the OKT3 antigen and vice versa.

Although prior to culture NK activity was restricted to B73.1+ lymphocytes, B73.1− lymphocytes propagated in IL2 acquired an NK‐like cytotoxic capacity. Cloned effectors of B73.1− provenance with NK‐like activity had a target cell repertoire indistinguishable from uncloned effectors. All T cell clones appeared agranular and were phenotypically much less diverse than their LGL counterparts, being OKT3+ and either OKT8+ or OKT4+.

These data suggest that cells with NK‐like activity are broadly reactive with a number of NK‐susceptible targets, possibly recognizing a common determinant. However, cloned LGL display phenotypic heterogeneity with preferential expression of early hematopoietic and/or T cell antigens. Consequently, the antigen profile of many clones was uncharacteristic of resting LGL. Such observations support the contention that LGL attributed with NK‐like activity are heterogeneous with a majority acquiring T cell‐like characteristics after appropriate induction.
In vivo self‐reactivity of mononuclear cells to T cells and macrophages exposed to HgCl2
Authors: Pelletier Lucette , Pasquier Régine , Hirsch François , Sapin Catherine , Druet Philippe
Published: February 2007

Mercuric chloride induces in Brown‐Norway rats a polyclonal activation of B cells resulting in a lymphoproliferation and in the production of autoantibodies. Experiments were performed to test the role of cells modified by HgCl2 in the induction of B cell proliferation by using the popliteal lymph node assay. Spleen cells, T cells and peritoneal macrophages exposed in vivo or in vitro to HgCl2 induced a proliferation of T and B cells in the draining popliteal lymph node. Spleen cells from Lewis rats who received HgCl2 were ineffective. These data suggest that modified cells could trigger autologous lymphocyte subsets and be responsible for autoimmunity induced by HgCl2.
Genetic and stimulatory cell type requirements for inducing class I major histocompatibility complex alloantigen‐specific in vivo cytotoxic T cell immunity
Authors: Mizoguchi Kenji , Nakashima Izumi , Isobe Ken‐Ichi , Ando Ko‐Ich , Nagase Fumihiko , Kato Nobuo , Kawashima Kohei , Shimokata Kaoru , Hasegawa Yoshinori
Published: February 2007

Current interpretation based on analytical in vitro works that actions of Ia antigens and accessory cells such as macrophages and dendritic cells are crucial for inducing cytotoxic T cell responses to class I major histocompatibility complex (MHC) alloan‐tigens has been challenged by experiments performed in a newly developed system handling in vivo cytotoxic T cell immunity. We first characterized the transplantation immunity for second‐set rejection of ascitic tumor allografts as principally induced by allogeneic stimulator cells via direct pathway, and as exclusively mediated by class I MHC alloantigen‐specific in vivo cytotoxic T cell activity. By comparison of activities of limiting effective doses (104‐105 cells per mouse) of various stimulator cells in this defined system, we could demonstrate that genetic disparity at the D region of H‐2 to the recipient is just enough for inducing the immunity, and presence of allogeneic or syngeneic Ia antigens in addition to H‐2D alloantigens on stimulator cells does not give any premium effect. Further study revealed that allogeneic peritoneal cells rich in macrophages or glass‐adherent spleen cells enriched for dendritic cells are not stronger stimulators than allogeneic adherent cell‐depleted spleen cells and semiallogeneic thymocytes. These results fit with the alternative concept that the physiological pathway inducing in vivo cytotoxic T cell immunity for graft rejection entirely depends on class I MHC antigens on live lymphocytes as self‐supported stimulators, and does not crucially involve additional stimulator activities of Ia antigens and special accessory cell types, which must be in vivo concerned with induction of other types of transplantation immunity.
Production and characterization of monoclonal anti‐Thy‐1 antibodies that stimulate lymphokine production by cytolytic T cell clones
Authors: MacDonald H. Robson , Bron Claude , Rousseaux Marga , Horvath Clothilde , Cerottini Jean‐Charles
Published: February 2007

In an effort to derive monoclonal antibodies (mAb) which can induce production of macrophage‐activating factor (MAF) by cloned murine cytolytic T lymphocyte (CTL) lines, we have fused spleen cells from a rat immunized with a CTL clone with the nonsecreting mouse myeloma X63‐Ag8.653. Three mAb (designated I‐22, III‐5 and V‐8) were found to stimulate MAF production by the immunizing CTL clone and (with a single exception) two other unrelated CTL clones. However, none of these mAb inhibited the cytolytic activity of the clones. Immunoprecipitation studies indicated that the three mAb reacted primarily with a 25‐30‐kDa protein which could not be distinguished from that precipitated by either a reference anti‐Thy‐1.2 mAb or a polyclonal rabbit anti‐Thy‐1 antiserum. Moreover, competition binding experiments demonstrated that the three mAb competed with each other and with the reference anti‐Thy‐1.2 mAb. Flow cytofluorometric analysis of the strain distribution of the molecules defined by the mAb revealed that two of the antibodies (I‐22 and III‐5) were directed against nonpolymorphic determinants of Thy‐1, whereas V‐8 mAb reacted only with Thy‐1.2+ lymphocytes. One of the mAb (III‐5) was also able to stimulate proliferation and interleukin 2 secretion by normal splenic T cells. Since mAb directed against a number of other surface structures on CTL clones did not stimulate MAF production, it thus appears that Thy‐1 (or molecules associated with Thy‐1) may play a functional role in T lymphocyte triggering.
Association between the human thymic differentiation antigens T6 and TS
Authors: Snow Peter M. , Van de Rijn Matthijs , Terhorst Cox
Published: February 2007

The human T lymphocyte cell surface antigen T8 has been found to be associated on thymocytes with a protein of 46 kDa through disulfide bridges. Analysis by isoelectric focusing, and of peptides obtained by limited proteolysis and chemical cleavage dem‐ onstrated that this 46‐kDa protein was the cell surface antigen T6, which is expressed on cortical thymocytes. The findings are discussed in the context of the importance of the T8 and T6 molecules in thymic differentiation.
Lambda light chain constant and variable gene complements in wild‐derived inbred mouse strains
Authors: Kindt Thomas J. , Gris Carine , Guenet J. Louis , Bonhomme Frangois , Cazenave Pierre‐André
Published: February 2007

Previous investigations of lambda light (L) chains in wild‐derived inbred (WDI) mouse strains revealed large variations in serum levels of this L chain type as well as differences in antibody responses in which λ chains predominate. In the present study a diverse group of WDI strains was analyzed by Southern blot analysis using probes for Vλ, Cλ1 and Cλ2 genes in an attempt to correlate the complement of λ genes present in these strains with their λ expression and with their taxonimic classification. All strains studied had two or three DNA sequences that strongly hybridized with a Vλ probe derived from BALB/c; most strains had Vλ, sequences on restriction fragments similar in size to Vλ1 and Vλ2, sequences from BALB/c. Comparison of Cλl and Cλ2genes in WDI mice to those of BALB/c revealed extensive variation both in number of hybridizing fragments and in their sizes. There were no obvious correlations observed between Cλ and Vλ patterns obtained for mouse strains of any phylogenetic group suggesting that constant and variable regions of lambda have evolved indepen‐ dently. In contrast to variations found for Cλ, a single kappa constant region gene appears to be conserved throughout the various mouse species.
Effect of thymulin on intracellular cyclic nucleotides and prostaglandins E2 in peanut agglutinin‐ fractionated thymocytes
Authors: Rinaldi‐Garaci Cristina , Jezzi Teresa , Baldassarre Anna Maria , Dardenne Mireille , Bach Jean‐Frangois , Garaci Enrico
Published: February 2007

Prostaglandin E2 (PGE2) and other selected agents which elevate intracellular cyclic AMP (CAMP) levels have been demonstrated to induce the appearance of surface markers in immature T lymphocytes. Thymic hormones, which are the natural induc‐ers of these markers, have long been hypothesized to act through the increase of CAMP levels. We have approached this area of investigation by studying the effects of thymulin (a serum thymus‐derived factor, coupled with Zinc) on intracellular cAMP and cyclic GMP (cGMP) levels (expressed as cAMP/cGMP ratio) and on the release of PGEz in different thymocyte subpopulations. Thymocytes were fractionated by the peanut agglutinin (PNA) technique into cortical immature PNA+ and medullary mature PNA− thymocytes. The data presented in this report show that thymulin is able to increase the cAMP/cGMP ratio in PNA+ and in unfractionated thymocytes, depending on its concentration, but not in PNA− thymic cells. Conversely, it is able to increase the release of PGEz by PNA− thymocytes but not by PNA+ and unfractionated thymic lymphocytes. These results are consistent with the hypothesis that thymu‐ lin could act through different mechanisms depending on the differentiation stage of its target cells. In fact, it could be suggested that immature T cells could be activated by thymulin thereby increasing the cAMP/cGMP ratio, whereas more mature T cells would be further differentiated by thymulin through enhanced release of PGE2.
Murine monoclonal antibodies and human alloantisera specific for HLA inhibit monocyte phagocytosis of anti‐D‐sensitized human red blood cells
Authors: Neppert Jürgen , Marquard Felix , Mueller‐Eckhardt Christian
Published: February 2007

Evidence is presented that monoclonal antibodies (mAb) against some human major histocompatibility complex (MHC) gene products and human sera containing HLA antibodies strongly inhibit immune phagocytosis of anti‐D‐sensitized red blood cells by human monocytes. w6.32HL, a mAb against a monomorphic class I antigen of high cell surface density, revealed the strongest inhibition among mAb reactive with MHC class I products. mAb with preferential reactivity for monomorphic and polymorphic DR and DQ epitopes (L203, L227, IIIE3, Tü22, Genox 3.53 and IV12) were noninhibitory. Definite inhibition was also apparent with a mAb against DRw52/MT2 (I‐LR2) and with an antibody to class II antigens of high cell surface density (2MC3). Human sera containing HLA antibodies showed strong inhibition of immune phagocytosis up to a dilution of 1/1000. This inhibition could not be abrogated by platelet absorption.

This indicates that human sera inhibiting immune phagocytosis may comprise at least two types of antibodies: cytotoxic HLA‐specific antibodies which may or may not be inhibitory, and inhibitory antibodies against monocytic antigens not necessarily cytotoxic. These latter antibodies may recognize HLA DR or another as yet unde‐ fined gene product within, or closely associated to, the human MHC.
Immune response against poly(Glu60, Ala30, Tyr10) (GAT): immunization with monoclonal anti‐idiotypic antibodies leads to the predominant stimulation of idiotypically similar immunoglobulins with anti‐GAT activity
Authors: Roth Claude , Sommé Gerard , Schiff Claudine , Thèze Jacques
Published: February 2007

Two monoclonal anti‐idiotypic antibodies (HP‐Id2o and HP‐Id22) recognizing two different public idiotopes expressed in the anti‐poly(Glu60, Ala30, Tyr10) (GAT) response were used to immunize BALB/c and C57BL/6 mice. From these animals hybridomas were isolated. From BALB/c and C57BL/6 mice eight and seven monoclonal antibodies were characterized, respectively. The reagents were classified according to the expression of the public idiotypic specificity p. GAT (recognized by a rabbit antiserum). The anti‐GAT activity and the expression of the various idiotopes characterized on anti‐GAT polyclonal and monoclonal antibodies were also studied. Most of the reagents are Ab1′‐type of antibody resembling anti‐GAT antibodies. One anti‐anti‐idiotypic monoclonal antibody (Ab3) was also isolated from BALB/c mice. This suggests that in this experimental model the repertoire induced after HP‐Id immunization and antigen stimulation is comparable. The idiotypic analysis of a large number of anti‐GAT and of Ab1′ monoclonal antibodies suggests that only two public idiotopes are involved in the anti‐GAT response.
Interleukin 2 induces T cell‐dependent IgM production in human B cells
Authors: Sauerwein Robert W. , van der Meer Walter G. J. , Dräger Angelika , Aarden Lucien A.
Published: February 2007

Conditioned medium, obtained from mononuclear cells after activation with concanavalin A and phorbol myristate acetate, strongly stimulated the in vitro production of IgM by human mononuclear cells. Partial purification by gel filtration showed that this activity co‐eluted with interleukin 2 (IL2). Via removal by adsorption and further purification by chromatofocusing techniques, it was demonstrated that the factor in this conditioned medium, responsible for the IgM production, was in fact IL 2. Experiments with purified IL 2 from the human IL2‐producing Jurkat cell line as well as recombinant IL2 confirmed its capacity to induce IgM production. In the absence of T cells, IL2 could not activate Ig synthesis, suggesting an indirect effect of IL2 in the induction of the helper signals for B cells. Evidence is presented that partially purified conditioned medium contained another factor, distinct from IL2, with the capacity to differentiate human B lymphocytes in the absence of T cells into IgM‐producing cells.
Biochemical characterization and purification of human B cell stimulatory factor (BSF)
Authors: Schwarting Roland , Welte Karl , Chiorazzi Nicholas , Ralph Peter , Lane Caryl L. , Long Cedric , Wang Chang Yi
Published: February 2007

B cell stimulatory factor (BSF)

B cell growth factor (BCGF) was renamed B cell stimulatory factor (BSF) on the proposal of a group of scientists that met on the 5th International Congress of Immunology in Kyoto, Japan 1983.

activity was generated over a period of five days by phytohemagglutinin ‐ stimulated E rosette ‐ positive peripheral blood lymphocytes. This activity was subjected to a multistep purification procedure including ammonium sulfate precipitation, anion‐exchange chromatography, gel filtration, procion redagarose chromatography and reverse phase high performance liquid chromatography (RP‐HPLC). The last purification step dissected BSF activity into two active fractions, one corresponded to the interleukin 2 (IL2) activity whereas the other active fraction was free of IL2 activity. Preparative isoelectric focusing analysis defined isoelectric points of pH 7.2 for both BSF and IL2. Molecular weight analysis of BSF was carried out by preparative sodium dodecyl sulfate ‐ polyacrylamide gel elec‐ trophoresis analysis. BSF activity was eluted from gel strips corresponding to a molecular mass of 16 and 17 kDa. The 16‐kDa fraction was free of IL2 activity wher eas the 17‐kDa fraction overlapped with IL2. Since recombinant IL2 was capable of exhibiting significant BSF activity in anti‐IgM or Staphylococcus aureus Cowan strain I‐dependent assay systems, it cannot be excluded that IL2 itself is a BSF. Nevertheless these studies demonstrate the existence of a BSF free of IL 2 activity.
Anti‐IgM treatment influences immunoglobulin heavy and light chain mRNA levels in mitogen‐stimulated B lymphocytes
Authors: Leanderson Tomas , Hsu Ellen
Published: February 2007

The mechanism by which soluble anti‐IgM inhibits plaque formation by lipopolysac‐charide‐stimulated B cells was investigated. Since lower amounts of immunoprecipitable μ heavy and ϰ light chains were found in cell lysates, this indicated that soluble anti‐IgM was inhibiting not only secretion. Subsequently, Northern blot analysis of poly(A+) RNA showed that the steady state levels of mRNA for immunoglobulin heavy and light chain from B cells stimulated with lipopolysaccharide were reduced if the cultures were treated with soluble anti‐IgM. The steady‐state levels of class I major histocompatibility complex antigen RNA were unaffected by anti‐IgM treatment. Addition of supernatants from mouse spleen cells stimulated with concanavalin A at day 2 of culture partially reversed the effect of soluble anti‐IgM on immunoglobulin expression.
T cell triggering by lectins II. Stimuly for induction of interleukin 2 responsiveness and interleukin 2 production differ only in quantitative aspects
Authors: Roosnek Eddy E. , Brouwer Mieke C. , Aarden Lucien A.
Published: February 2007

We have investigated the requirements for lectin‐induced proliferation of highly purified human T cells. To study activation, independent of growth factor production, we cultured the cells in the presence of an excess of interleukin 2 (IL2), which was a product of cDNA cloned in E. coli. In the presence of IL2, the same cooperative effect of lectin and accessory cells was found that we have previously described for IL2 production. Thus, analogous to induction of IL2 production, the acquisition of responsiveness to IL2 can be completely monocyte dependent, but a 10‐fold increase in lectin concentration completely abolishes the requirement for accessory cells. Furthermore, two stimuli (IL1 and phorbol myristate acetate), which are able to replace monocytes at the level of IL2 production, also induce responsiveness to IL2 under accessory cell‐dependent conditions. Thus, very similar conditions are required for proliferation and for the induction of IL2 production. There is only a quantitative difference: proliferation of cells in the presence of exogenous IL2 occurs already at low lectin concentrations, whereas IL2 production and consequently proliferation in the absence of exogenous IL2 requires higher lectin concentrations.

At high lectin concentrations, when IL2 production has become the only limiting factor, purified T cells cannot be induced to proliferate in the absence of exogenous IL2 because the lectin concentration that induces IL2 production independent of accessory cells inhibits mitogenesis. However, after addition of thiols to the medium, which enhances the IL2 production, a very narrow range of lectin concentration can be found which is just below toxic values and still high enough to induce IL 2 production in the absence of accessory cells. Under these conditions, accessory cells are no longer a prerequisite for lectin‐induced T cell proliferation.
Activation/suppression of the immune response in vitro by antigen and dextran sulfate I. Analysis by limiting dilution methods
Authors: Kettman John R. , Soederberg Anita , Lefkovits Ivan
Published: February 2007

Spleen cells of normal mice which were stimulated with either T‐dependent or T‐ independent antigens and dextran sulfate (DxS) in microcultures at limiting dilution show at low cell densities an increased frequency of responding units (B cells) with both types of antigens. At higher cell densities, DxS induces a suppression of the immune response as assessed by a declining frequency of expressed B cells. When T cells were decreased in number, the stimulating effect of DxS on T‐independent responses remained unaltered while the suppressive effect (dependent on cell density) was eliminated.

It is suggested that DxS lowers the threshold of activation for regulatory T cells, i.e. of cells which under standard in vitro conditions remain unactivated, and which in the presence of DxS become activated. We conclude that the regulatory cells are rare and that they are not present in most low cell density cultures. The net effect is a potent activation in dilute cultures and lack of response in dense cultures.
pl50/95, Third member of the LFA‐1/CR3 polypeptide family identified by anti‐Leu M5 monoclonal antibody
Authors: Lanier Lewis L. , Amin Arnaout M. , Schwarting Roland , Warner Noel L. , Ross Gordon D.
Published: February 2007

Monoclonal antibody (mAb) anti‐Leu M5 reacts with a two‐chain molecule composed of a 150‐kDa α subunit noncovalently associated with a 95‐kDa β subunit and probably is specific for an epitope on the 150‐kDa β chain. This pl50/95 antigen is the third member of a family of polypeptides sharing a common 95‐kDa β chain, which includes the lymphocyte function‐associated antigen LFA‐1 (p177/95) and complement receptor CR3 (Mo1/MAC‐1/OKM1; p165/95) antigens. Sequential immunoprecipitation with anti‐p95 β chain mAb specifically removed the antigens detected by anti‐LFA‐1, anti‐CR3 and anti‐Leu M5 mAb. Certain patients with recurrent bacterial infections are genetically deficient in expression of the LFA‐1 and Mo1 antigens, and have impaired granulocyte function. Granulocytes from a patient with this disease also failed to react with anti‐Leu M5. Stimulation of normal granulocytes with f‐Met‐Leu‐Phe, C5a‐desArg, or calcium ionophore resulted in increased expression of Mo1 and Leu M5 antigens on the cell surface, but did not significantly increase expression of LFA‐1 antigen. In functional assays, anti‐Leu M5 did not inhibit T cell‐mediated or natural killer cell‐mediated cytotoxicity. In addition, anti‐Leu M5 neither inhibited the binding of complement‐coated particles to CR1 or CR3 nor did it affect the binding of EC3dg to neutrophils (CR4). These studies clearly indicate that the p150/95 antigen recognized by the anti‐Leu M5 antibody is a structurally distinct member of the LFA‐ 1/CR3 family.
The lymphoproliferating cells of MRL‐lpr/lpr mice are a polyclonal population that bear the T lymphocyte receptor for antigen
Authors: Nemazee David A. , Studer Suzanne , Steinmetz Michael , Dembić Zlatko , Kiefer Michael
Published: February 2007

Mice bearing the recessive gene Ipr develop an age‐dependent, massive lymphoproliferation, primarily in the lymph nodes (LN), with associated autoimmunity. LN cells from these mice express T cell receptor protein on the cell surface at 50–70% of normal levels. Normal levels of T cell receptor α, β and γ mRNA were found in these cells as compared to normal LN cells. Southern blot analysis of MRL‐lpr/lpr LN DNA showed rearrangements in 80–90% of the chromosomes at the β gene loci. The pattern of rearrangement indicated that a polyclonal rather than monoclonal expansion of T cells occurred. These data support a lymphokine‐induction model of lymphoproliferation in MRL‐lpr mice.
Vλ2 rearranges with all functional Jλ segments in the mouse
Authors: Weiss Siegfried , Meyer Jutta , Wabl Matthias R.
Published: February 2007

We have analyzed 210 λ‐producing hybridomas derived from lipopolysaccharidestimulated spleen cells from a single x‐suppressed mouse. All were classified as λ1, λ2 or λ3 with the exception of four unusual lines. Two of these were due to Vλ2 Jλ1 and the other two to Vλ2 Jλ3 rearrangements. The lines were clonally independent since the point of VJ recombination in each one was different. Southern blot analysis of the Vλ2 Cλ1‐producing lines showed no evidence for an inversion. Under the assumption of a simple deletion model of rearrangement these findings place the Vλ2 cluster upstream of the Vλ1 cluster oriented in the same direction.
Immunoregulation by mouse T cell clones III. Cloned H‐Y‐specific cytotoxic T cells secrete a soluble mediator(s) that inhibits cytotoxic responses by acting on both Lyt‐2− and L3T4− lymphocytes
Authors: Simon Markus M. , Nerz Gaby , Prester Marlot , Moll Heidrun
Published: February 2007

In this study we report that cloned Thy‐1+, L3T4−, Lyt‐1−, Lyt‐2+, H‐Y‐specific and H‐2Db‐restricted cytotoxic T cell lines (CTLL) when induced by lectin or antigen secrete a soluble mediator(s) (SF) that inhibits proliferation and generation of cytotoxic lymphocytes (CTL) in mixed lymphocyte cultures (MLC). The biological activity was separable by gel filtration and appeared as a broad peak in the molecular mass range between 10 000 and 50 000 kDa. It was found that the suppressive activity released by CTLL neither strictly correlates with their cytotoxic potential nor with their ability to produce immune interferon or lymphotoxin. SF was shown to elicit its activity in an antigen‐nonspecific manner in that it suppressed the maturation of T lymphocytes responding to both, the appropriate H‐Y antigen as well as to unrelated H‐2d alloantigens or to the hapten 2,4,6‐trinitrophenyl (TNP). The effect of SF on CTL responses was most pronounced in early phases of primary or secondary MLC. When analyzed for its inhibitory activity on precursor cells in populations selected for either Lyt‐2− or L3T4− lymphocytes, it was found that SF interfered with the maturation of both subsets. The inhibition of CTL responses elicited by SF could not be reversed by the addition of exogenous interleukin 2. The finding that SF also inhibited the proliferation of some but not all antigen‐dependent cloned T cells with helper or cytotoxic potential provides evidence that the factor also may regulate effector lymplrc∼cytes. In addition, the results support the assumption that SF exerts its effect directly on the responder rather than the stimulator population, and demonstrate that the development of CTL from their precursor cells is controlled at least in part by the cytotoxic effector cells themselves via a soluble factor(s) that interferes with distinct stages of T cell maturation. These findings again emphasize the expression of multiple functions by CTL and indicate their possible role during the course of an immune response by their capability to eliminate target cells and to secrete a soluble product(s) that mediates feedback control.
A rapid isolation technique of unmodified human T cells on a polystyrene resin column
Authors: Noma Takeshi , Kawano Yutaka , Yoshimura Naoko , Abe Tsutomu , Inagaki Kenji , Yata Junichi
Published: February 2007

An easy and rapid isolation technique of human T cells on a polystyrene resin particle column has been developed. The cells of the effluent fraction contained more than 90% sheep erythrocyte (SRBC) rosette‐forming cells and less than 1% of cells bearing surface immunoglobulin (Ig) or peroxidase. The T cell (SRBC rosette‐forming cells) recovery rate was 80%. The distribution of OKT antigen T cell subsets was essentially the same as that of T cells separated by rosette sedimentation. Cell functions such as tritiated thymidine uptake by T cells and helper activity in Ig production were also the same as that of T cells separated by SRBC rosette sedimentation. Natural killer‐like activity of the T cells isolated by the present method increased more than that of T cells obtained by the conventional method. Moreover, it was free from functional modification which tends to result from stimulation such as by the SRBC antigen in the SRBC centrifugation method. The combination of a T cell population offered by the present method and B cells depleted of SRBC‐binding B cells minimized background plaque formation and enabled us to quantify the plaque‐forming cell number in an antigen‐specific plaque‐forming assay. Furthermore, these populations produced relatively pure interleukin 2 (IL2) by stimulation of an autologous mixed lymphocyte reaction without any absorption of IL2 produced in the same culture. It seemed to be useful to evaluate the ability of lymphocytes from normal individuals and patients to produce IL2.
Measurement of parasite‐specific immune responses in vitro: evidence for suppression of the antibody response to Trypanosoma cruzi
Authors: Tarleton Rick L. , Kuhn Raymond E.
Published: February 2007

Using the Mishell and Dutton culture system, we have developed an assay for eliciting and quantifying parasite‐specific immune responses in vitro. The ability of spleen cells from noninfected and Trypanosoma cruzi‐infected mice to respond to parasite‐associated antigens was assessed by examining the primary plaque‐forming cell response to trinitrophenylated T. cruzi (TNP‐TC). The response to TNP‐TC of both normal, noninfected, unprimed mice and mice infected with T. cruzi is T cell dependent and appeared to involve recognition of parasite antigens by T. cruzi‐specific T cells. In most experiments, spleen cells from infected mice respond to TNP‐TC at levels equal to, or below, that of spleen cells from normal mice. This near “normal” response is in apparent contrast to the suppressed response of spleen cells from infected mice to another antigen (sheep red blood cells) or TNP on a different carrier (TNP‐chicken erythrocytes). Demonstration that the response of spleen cells from infected mice to TNP‐TC can be potentiated by addition of interleukin 2‐containing supernatants or by depletion of plastic and Sephadex G‐10‐adherent cells suggests that the mechanisms which control the response of infected mice to nonparasite antigens may also limit parasite‐specific immune responses.
Disulfide‐linked surface molecules of monoclonal antigen‐specific suppressor T cells: evidence for T cell receptor structures
Authors: Ballinari Dario , Castelli Chiara , Traversari Catia , Pierotti Marco A. , Parmiani Giorgio , Palmieri Gabriella , Ricciardi‐Castagnoli Paola , Adorini Luciano
Published: February 2007

By two‐dimensional polyacrylamide gel electrophoresis analysis under nonreducing/reducing conditions, five proteins with interchain disulfide bridges are revealed on the surface of the suppressor T cell lymphoma line LH8‐105 obtained by radiation leukemia virus‐induced transformation of hen egg‐white lysozyme‐specific suppressor T lymphocytes. Two disulfide‐linked surface proteins expressed by LH8‐105 cells have been positively identified by immunoprecipitation with specific antisera. The major labeled membrane protein of LH8‐105 cells is the murine leukemia virus env glycoprotein gp70. The second disulfide‐linked molecule identified on LH8‐105 cells has a molecular mass of 84 kDa under nonreducing conditions and 42 kDa after reduction, and is immunoprecipitated by an antiserum which recognizes the T cell receptor for antigen. A disulfide‐linked molecule of a similar molecular mass is also immunoprecipitated from surface‐labeled LH8‐105 cells by a rabbit antiserum directed against a synthetic peptide predicted from the nucleotide sequence of a cDNA clone encoding the β chain constant region of a helper T cell hybridoma. Therefore, a dimeric structure comparable to the T cell receptor expressed by cytotoxic and helper T cells is present on the cell surface of these monoclonal antigenspecific suppressor T cells.
I‐J expression is not associated with murine chromosome 4
Authors: Waltenbaugh Carl , Sun Lizhe , Lei Huan‐Yao
Published: February 2007

I‐J originally mapped within the murine major histocompatibility complex (H‐2) between the EB and Ea, loci using intra‐H‐2 recombinants. Cloning of this segment of H‐2 shows no DNA that can be ascribed to I‐J. Various hypotheses have attempted to explain this dilemma. One hypothesis attributes a chromosome 4 locus with I‐Jk expression. This hypothesis requires the AKR/J and A/WySn mouse strains to be I‐Jk negative. In the present report we show that AKR/J spleen cells express I‐Jk surface molecules and that both the AKR/J and A/WySn mouse strains produce functional I‐Jk‐bearing suppressor factors to poly(Glu50Tyr50). Our data imply that mapping of I‐J‐determining genes to chromosome 4 may be premature.
Cytolytic T cell hybridomas: III. The antigen specificity and the restriction specificity of cytolytic T cells do not phenotypically mix
Authors: Haas Werner , Mathur‐Rochat Jacqueline , Kisielow Pawel , Boehmer Harald Yon
Published: February 2007

We have obtained cytolytic T‐T hybrids by fusing an H‐2Kk restricted clone specific for the hapten 3‐(p‐sulfophenyldiazo)‐4‐hydroxyphenyl acetic acid (SP) with an H‐2Dd‐restricted clone specific for the hapten fluorescein (FL). Several hybrid clones express both parental specificities but fail to lyse SP‐coupled H‐2Dd and FL‐coupled H‐2Kk target cells. We also fused the H‐2Kk‐restricted, SP‐specific clone with a clone which recognizes FL in the context of any class I major histocompatibility complex antigen. Again several hybrids show both parental specificities but fail to recognize SP coupled to target cells which are not recognized by the parental SP‐specific clone. These findings indicate that the observed cytotoxic T lymphocyte specificities for haptens on the one hand and polymorphic as well as nonpolymorphic class I major histocompatibility complex antigenic determinants on the other hand are not carried by independent proteins.
Inhibition of mast cell sensitization in vitro by a human immunoglobulin ϵ‐chain fragment synthesized in Escherichia coli
Authors: Coleman John W. , Helm Birgit A. , Stanworth Denis R. , Gould Hannah J.
Published: February 2007

An immunoglobulin ϵ‐chain fragment was synthesized in E. coli by cloning and expression of the gene coding for the second, third and fourth constant domains of the human IgE heavy chain. The bacterial CH2–4 polypeptide product was assembled by oxidation into a covalently linked dimeric E‐chain molecule presumably analogous to the Fc region of native IgE. This bacterial Fc, preparation, within the concentration range 0.01–10 μglml, inhibited sensitization of human lung mast cells, determined as histamine released upon challenge with specific antigen. Monomer CH2–4 ϵ‐chain polypeptide, prepared by reduction and alkylation of the active bacterial Fcϵ, fragment, was inactive as an inhibitor of sensitization. The molar potency of the active bacterial Fcϵ, product was approximately one fourth of that of native IgE. Since the bacterial Fcϵ, is nonglycosylated, carbohydrate does not make an essential contribution to the Fc receptor binding activity of IgE. These results show that a functionally active immunoglobulin molecule can be synthesized by gene cloning and expression in E. coli.
Activation of Lyt‐2+ T cells by antibodies towards brain‐associated antigens: II. Antibody‐dependent induction of “nonspecific” cell‐mediated cytotoxicity
Authors: Gullberg Martin , Coutinho Antonio
Published: February 2007

Purified IgG from a rabbit anti‐mouse brain antiserum (RaMB), previously shown to activate most Lyt‐2+ T cells, was probed for lectin‐like effects on cell‐mediated cytolysis (CML) and found to induce “nonspecific” killing of syngeneic B cell targets by allospecific cytotoxic T lymphocytes (CTL) as effectively as concanavalin A, and at levels comparable to antigen‐specific cytolysis of target cells. Interestingly, RaMB‐mediated “nonspecific” CML of syngeneic targets, by polyclonally or specifically activated CTL, was restricted to B cell targets and cold target inhibition experiments indicated that syngeneic target cell blasts do not functionally interact with effector CTL in the presence of RaMB. The role of target cell Fc receptors was demonstrated by the competitive inhibition of RaMB‐dependent CML by normal rabbit IgG. We conclude that RaMB both activates and bridges the effector CTL to target cells, RaMB‐mediated “nonspecific” CML being a similar phenomenon to lectin‐facilitated “nonspecific” cytolysis, and the mirror image of classical ADCC.

These observations allowed us to interprete the effects of RaMB on allo‐major histocompatibility complex‐specific CML. Since RaMB stimulates specific CML of B cell targets while selectively blocking that of T cell targets, we conclude that RaMB antibodies interact with structures associated with the CTL antigen receptor, explaining the contradictory effects previously reported with monoclonal antibodies against the CTL receptor complex, which can both stimulate and inhibit T cell functions.
Use of a P815‐derived line with an amplified adenosine deaminase gene: an improved target for cellular cytotoxicity
Authors: Vielh Philippe , Castellazzi Marc
Published: February 2007

We describe a cytotoxic T lymphocyte‐mediated cytotoxicity assay in which the release of a cytoplasmic enzyme, adenosine deaminase (ADA), instead of the widely used radioactive chromium is a measure of target lysis. In this enzyme‐release assay the target is a mastocytoma P815‐derived cell line, noted P815 ADA++, isolated by applying a selection procedure devised to specifically amplify the ADA gene. Gene amplification in P815 ADA++ was indeed demonstrated. Routine measurement of ADA activity from numerous supernatants is performed using a specific and sensitive colorimetric assay. The use of 96‐well microtiter plates as well as of an automatic Multiscan spectrophotometer makes this measurement rapid and convenient.

We show that this ADA‐release assay is significantly more sensitive than the classical chromium‐release test because of its consistently lower (5 to 10‐fold) spontaneous release in 4 h, short‐term cytotoxicity experiments. We also found that it is especially suited for the rapid detection, by visual screening, of rare, active killer clones among large, heterogeneous cytotoxic T lymphocyte populations.

The assay could easily be adapted to other tumor targets (EL4, YAC‐1, K562) of common use in studies involving immune lysis; indeed, the procedure of amplifying the ADA gene used in the isolation of the P815 ADA++ hyperactive line may be generally applied to these targets.
Functional differences between B cell‐depletion techniques in removing memory B cells. Relevance to anti‐erythrocyte autoantibody‐specific suppressor cells
Authors: Watt Graham J. , Elson Christopher J. , Greenwood Mark , Miller Peter
Published: February 2007

The efficiency of a number of B cell‐depletion techniques was examined in a functional assay. CBA (Iga) mice were primed with rat erythrocytes and their spleen cells transferred, before and after B cell depletion, to mice of the allotype‐congenic strain Igb. The recipients were challenged with rat erythrocytes and their anti‐erythrocyte autoantibody response was measured together with the donor (Iga) and host (Igb) anti‐rat erythrocyte antibody levels. Transferred unseparated cells suppressed erythrocyte autoantibodies and produced high levels of anti‐rat erythrocyte antibodies. Transfer of panned, rosetted or nylon wool‐passaged cells neither altered donor anti‐rat erythrocyte antibody levels nor abrogated suppression. By contrast, passage of rat erythrocyte‐primed B cells over Ig‐anti‐Ig‐coated beads resulted in removal of donor rat‐primed B cell activity and loss of suppressor cells. The B cell‐depletion techniques were effective at removing B cells as judged by the reduced number of fluoresceinated anti‐Ig‐labeled cells among unbound cells although analysis on a fluorescein‐activated cell sorter revealed that the most effective method was depletion on Ig‐anti‐Ig‐coated beads.

B cell depletion by panning removed the capacity of virgin but not primed cells to make adoptive antibody responses after transfer suggesting that the primed cells most efficient in adoptive transfer have a lower density of surface Ig than virgin cells. Treatment of donors with drugs which abrogated transferrable suppression of erythrocyte autoantibodies did not alter donor anti‐rat erythrocyte antibody levels in recipients. It is considered that rat primed B cells are involved in the suppression of erythrocyte autoantibodies by acting as selective antigen‐presenting cells for T suppressor inducer cells, rather than through an anti‐rat erythrocyte antibody feedback mechanism.
Role of the Ly 1 antigen in interleukin 1‐induced thymocyte activation
Authors: Lögaberg Lennart , Shevach Ethan M.
Published: February 2007

Interleukin 1 (ILI), but not IL2‐induced thymocyte proliferation was augmented by monoclonal antibodies (mAb) against the Ly 1 antigen. The anti‐Ly 1 mAb could also co‐stimulate thymocytes with phytohemagglutinin (PHA) alone, mimicking the effect of IL1. Moreover, overnight culture with PHA of thymocytes, but not of spleen T lymphocytes led to selectively enhanced expression of the Ly l antigen on the cell surface. Similar data were generated at the clonal level. Thus, a thymocyte hybridoma (22A6) could be stimulated to release IL2 in response to PHA plus IL 1, but also to PHA plus anti‐Ly 1 mAb. In addition, 22A6 exhibited enhanced cell surface expression of the Ly l antigen after overnight culture with PHA. These data suggest a critical role for the Ly1 antigen in thymocyte proliferation, perhaps by serving as an IL 1‐receptor.
Antigen‐specific major histocompatibility complex‐restricted helper T cell clones are sufficient to induce unprimed B cells to switch and to secrete IgG and IgA in a primary in vitro polyclonal response
Authors: Leclercq Lise , Chastagnier Patricia , Mishal Zohair , Bismuth Georges , Thèze Jacques
Published: February 2007

To investigate the role of helper T (Th) cells in the regulation of the production of the various immunoglobulin (Ig) classes and subclasses, we have used poly (Glu60Ala30Tyr10) (GAT)‐specific, major histocompatibility‐complex‐restricted Thcell clones to stimulate unprimed B cells. The T cells used in these studies were Thy‐1+, Lyt‐l+, Lyt‐2− and lacked Fc receptor for IgM, IgG and IgA, and the unprimed splenic B cells were selected by the fluorescence‐activated cell sorter for their lack of expression of surface (s)IgG and by panning for their lack of expression of sIgA. We have taken advantage of the ability of some antigen‐specific major histocompatibility complex (MHC)‐restricted Th cell clones to polyclonally activate unprimed B cells in vitro in the presence of high doses of antigen. We have shown that under these conditions, an antigen‐specific MHC‐restricted Th cell clone is sufficient to induce the switch of sIgG− sIgA− unprimed B cells to IgG and IgA, as well as the expansion of these cells and their differentiation into IgG and IgA‐secreting cells. Isotype‐specific Th cells thus do not seem to be an absolute requirement for the production of the various IgG subclasses and of IgA.