bluuebunny/crossref_metadata_2025 huggingface dataset:
Myeloid‐associated antigen 3‐α‐fucosyl‐N‐acetyllactosamine (FAL): location on various granulocyte membrane glycoproteins and masking upon monocytic differentiation
Authors: Tetteroo Pedro A. T. , Mulder Arend , Lansdorp Peter M. , Zola Heddy , Baker Don A. , Visser Frans J. , Kr. von Dem Borne Albert E. G.
Published: February 2007

Seven different granulocyte‐reactive murine monoclonal antibodies (mAb) were studied. The antigens recognized by these mAb were immunoprecipitated from lysates of 125I‐labeled granulocytes of healthy donors. The isolated antigens were analyzed by electrophoresis on sodium dodecyl sulfate‐polyacrylamide gel and autoradiography. All 7 antibodies precipitated the same 6 membrane polypeptides from membrane‐iodinated granulocyte lysates: 105 and 150‐kDa as most pronounced, together with 260‐, 230‐, 67‐ and 52‐kDa polypeptides.

One of the antibodies studied, B4.3, is directed against 3‐α‐fucosyl‐N‐acetyllac‐tosamine as shown by absorption with the synthesized carbohydrate molecule. Competition experiments with 125I‐labeled B4.3 demonstrated complete inhibition of binding by B4.3 and 3 of the other antibodies (VIM D5, UJ308, MI/N1) and partial inhibition by the 3 other antibodies (FMC 10, FMC 12, FMC 13), indicating binding to the same antigenic structure.

None of the 7 mAb reacted with monocytes in the immunofluorescence technique, but after neuraminidase treatment of these cells, positive reactions were obtained with all mAb. Immunoprecipitation with lysates of both native and neuraminidase‐treated monocytes showed no polypeptide bands. Monocytic differentiation of the cell line HL60 by 12‐0‐tetradecanoylphorbol‐13‐acetate (TPA) and of cell line U 937 by dimethylsulfoxide and TPA was accompanied by a decrease in reactivity with these antibodies, which could be recovered by neuraminidase treatment. This indicates that 3‐α‐fucosyl‐N‐acetyllactosamine is masked for the detection of the antibody upon monocytic differentiation by sialylation.
Expression of cell surface determinant(s) on murine myeloma stem cells and hematopoietic stem cells
Authors: Daley Michael J. , Williams Thomas , Warner Noel L.
Published: February 2007

Murine B cell lymphomas and myelomas were examined for the expression of a determinant previously found exclusively on normal pluripotent stem cells colony‐forming unit‐spleen (CFU‐s). This determinant(s), which is defined by a rabbit antimouse brain antiserum (RαMB), is present on the tumor stem cell population of some but not all B cell neoplasms examined. The determinant is not detected on tumor cells of the macrophage or T cell lineage. Absorption of the activity in RαMB with myeloma cells, concomitantly removed reactivity with the normal stem cell, CFU‐s, and the myeloma stem cell, plasmacytoma CFU‐s. Sorting analysis further showed that the antigen was diminished within a positive tumor population as cells acquired the capacity to secrete immunoglobulin. These studies suggest that this normal stem cell‐associated antigen may also be an early differentiation antigen for the B cell lineage, and is expressed on some stem cells of B cell tumors.
Binding and uptake of rabbit IgG complexes by diploid fibroblasts via plasma membrane Fc receptors
Authors: Frey Jürgen , Quentin Hans‐Jürgen , Afting Ernst‐Günter
Published: February 2007

The existence of IgG receptors on the plasma membrane of diploid human fibroblasts is demonstrated. The receptors specifically bind heat‐aggregated rabbit IgG as well as rabbit IgG within antigen‐antibody complexes. Monomeric rabbit IgG were only poor ligands of the receptor. Competition experiments with Fab and Fc fragments of IgG revealed that the receptor specifically recognizes the Fc domain of the IgG molecule. Heat‐aggregated IgG or antigen‐antibody IgG complexes are specifically bound to the receptors, endocytosed and subsequently degraded. The receptors do not seem to be recycled because protein synthesis is a prerequisite for further cycles of endocytosis.
Major histocompatibility complex restriction of tetanus toxoid‐specific human T lymphocyte clones
Authors: Schmitt Christian , Cogné Michel , Agrapart Monique , Ballet Jean‐Jacques
Published: February 2007

Peripheral blood mononuclear cells (PBMC) from an HLA DRw6/7 individual were stimulated with tetanus toxoid (TT). T cell blasts were cloned by the limiting dilution technique in the presence of TT and irradiated autologous PBMC (iPBMC). Twelve were propagated under interleukin 2 and restimulated weekly with TT and iPBMC. All proliferated specifically in response to TT or either the α or β chain of the toxin molecule. HLA restriction of specific proliferative responses was analyzed using a panel of HLA‐typed unrelated donors and selected families, and blocking experiments with anti‐HLA class I and class II monoclonal antibodies (mAb). Three types of restriction were observed: (a) autologous restriction; the inhibition observed using anti‐HLA DR mAb as well as family studies performed previously with a similarly restricted clone obtained from the same donor suggest an HLA DRw6‐linked restriction; (b) an HLA DR7 restriction was found for 2 clones, specific for α or β chain; the identical pattern of inhibition obtained with two different mAb belonging to the same cluster suggests that these clones may be restricted by the same (or a very close) epitope of the HLA DR7 molecule; (c) an unusual restriction pattern was found for one clone; PBMC from more than 80% of donors could present TT whatever their degree of HLA compatibility with the autologous donor. Family studies were unable to disclose any restriction with known class II (or class I) antigens. While no inhibition was observed with anti‐DR or ‐DC reagents, a mAb that recognizes class I antigen when associated with β2‐microglobulin did inhibit the proliferation of this clone.
Studies on antibody repertoire: ontogenic development of mitogen‐reactive B cells producing phosphorylcholine‐specific and/or T15‐associated 10/13 idiotopepositive antibodies
Authors: Lévy Martine
Published: February 2007

Very high frequencies of phosphorylcholine‐specific and 10/13 idiotope‐positive precursor cells were observed in spleen and liver cells polyclonally stimulated by lipopolysaccharide in BALB/c mice. These frequencies do not show any significant difference at birth, in young and adult mice, suggesting that antibody molecules analyzed arose from a single germ line heavy chain variable region gene segment. The order of magnitude of these frequencies was comparable in germ‐free mice and conventionally reared BALB/c mice. Therefore, external antigenic stimulation does not seem to be involved in the establishment of antibody specificity available repertoire.
Inhibition of proliferative and cytotoxic activities of human T lymphocytes with rabbit antibodies directed against leucoagglutinin‐reactive T cell surface components
Authors: Berzins Toini , Axelsson Bernt , Hammarström Marie‐Louise , Hammarström Sten , Perlmann Peter
Published: February 2007

Three rabbit antisera (870, 872 and 873) were raised against leucoagglutinin‐reactive components from the surface of human T cells. The antibodies reacted with two major glycoproteins of 175 kDa and 105 kDa. None of the antibodies triggered peripheral blood lymphocytes or T cells to proliferation when tested under different culture conditions. All antibodies inhibited the proliferative response to concanavalin A or to allogeneic lymphocytes in mixed lymphocyte culture when whole IgG fractions were used. Complete inhibition of cytotoxic activity was obtained in cell‐mediated lympholysis and in natural killer cell cytotoxicity (NK) when fresh peripheral blood lymphocytes were used as effector cells. Weak inhibition was also obtained in NK when mixed lymphocyte culture‐activated effector cells were used. The inhibition was stronger, when NK activity was determined against MOLT4 target cells as compared to K562. Whereas F(ab′)2 fragments of 873 IgG inhibited cytotoxic T lymphocyte activity completely, Fab fragments of 873 IgG neither inhibited proliferation nor cytotoxic T lymphocyte activity, but gave some inhibition of NK against MOLT4 targets. The results indicate that antibodies against these leucoagglutininreactive structures reacted with polypeptides similar to or identical with the human “leukocyte function‐associated antigen‐1” (LFA‐1) considered to be an important mediator of cell‐cell interactions and nonspecific adherence.
Mitogenic capacity of oxidized human B cell lines
Authors: Ren Ee C. , Chan Soh H.
Published: February 2007

A combination of neuraminidase and galactose oxidase alters the membrane glycoproteins to generate highly reactive aldehyde groups on galactose moieties. Human B cell lines oxidized in this way were able to induce strong proliferative responses from normal untreated peripheral blood lymphocytes. Oxidized cell lines that stimulate well were also correlated to some extent with their ability to bind responder lymphocytes. The present investigation demonstrates the usefulness of oxidized B cell lines as a novel mitogen for use in the study of lymphocyte activation.
Evaluation of accessory cell heterogeneity. I. Differential accessory cell requirement for T helper cell activation and for T‐B cooperation
Authors: Ramila Gnanadurai , Studer Susanne , Kennedy Marion , Sklenar Ivo , Erb Peter
Published: February 2007

Several Ia+ tumor cell lines and peritoneal exudate macrophages were tested as accessory cells (AC) for the activation of antigen‐specific T cells and for T‐B cooperation. The macrophages and all the Ia+ tumor lines tested induced the release of lymphokines from T cells in a major histocompatibility complex (MHC)‐restricted fashion and reconstituted the antibody responses of AC‐depleted spleen cells or of purified T and B cells. However, only the normal macrophages but none of the tumor lines induced carrier‐specific T helper (Th) cells which help B cells for specific anti‐hapten antibody responses by linked recognition. For T‐B cooperation accessory cells were also required, but in contrast to Th Cell activation any type of Ia+ AC (e.g. macrophage or tumor line) was effective. Strong MHC‐restriction between the lymphocytes and the AC was seen if antigen‐pulsed AC were added into the AC‐depleted T‐B cooperation cultures. If the AC and antigen were concomitantly added to the AC‐depleted T‐B cultures, MHC‐restriction was less obvious. Concanavalin A supernatant reconstituted the response of AC‐depleted T‐B cultures provided antigen‐specific Th cells and the hapten‐carrier conjugate were present. If, however, tumor line‐activated T cells were added instead of macrophage‐induced Th cells, no cooperation with B cells took place even in the presence of Con A supernatant. The results obtained demonstrate a differential AC requirement for the induction of Th cells depending on the differentiation stage of the Th cells.
Investigation of early T cell activation: Analysis of the effect of specific antigen, interleukin 2 and monoclonal antibodies on intracellular free calcium concentration
Authors: O'Flynn Kieran , Zanders Edward D. , Lamb Jonathan R. , Beverley Peter C. L. , Wallace Diana L. , Tatham Peter E. R. , Tax Wil J. M. , Linch David C.
Published: February 2007

The three mitogenic anti‐T3 antibodies, UCHT1, anti‐Leu‐4 and WT‐32, all produce a rapid increase in T cell intracellular Ca2+ ([Ca2+]j) in all individuals, as measured by quin2 tetra‐acetoxymethyl ester fluorescence. This indicates that the lack of responsiveness of approximately 30% of individuals to UCHT1 in proliferation assays is not due to failure of the antibody to elicit Ca2+ mobilization and that a rise in [Ca2+]j is per se not adequate to induce cell division. Another mitogenic antibody, WT‐31, which is directed against the constant portion of the T cell receptor, did not, however, produce a rapid calcium rise in peripheral blood T cells. The clone HA1.7 gave a similar Ca2+response to UCHT1. WT‐31 did not induce a rise in [Ca2+]j, nor did the specific antigen to which the clone responded. Accessory cells may be required to induce Ca2+mobilization with these ligands. There was no response to IL2, or an antibody (anti‐ Tac) to the IL2 receptor. In contrast to peripheral blood T cells treatment of HA1.7 with WT‐31 led to an enhancement of the calcium response to subsequent UCHT1 addition. Furthermore, cross‐linking of WT‐31 on the surface of HA1.7 cells did produce a small rise in [Ca2+]j. The IL2‐independent malignant T cell line, HUT78, exhibited a calcium response to both UCHT1 and WT‐32. Both of these responses occurred without cross‐linking.

The T cell receptor is closely associated with cell‐surface proteins, including the T3 antigen and these studies confirm the importance of the T3 antigen in T cell activa‐ tion. They also suggest that the relationship between the T cell receptor and the T3 antigen may vary in T cells in different proliferative states.
DNA ligases as markers of lymphoid cell maturation and heterogeneity in the chicken
Authors: David Jean‐Claude , Fedecka‐Bruner Barbara , Vaigot Pierre
Published: February 2007

The activities of 8 S and 6 S DNA ligases have been studied in the chicken lymphoid cells of blood, spleen and bursa of Fabricius at different stages of development, from late embryonic life to about 3 months after hatching. These cells have been sorted with the fluorescence‐activated cell sorter FACS Il on the basis of size and T or B antigenicity (immunofluorescence). The light 6S DNA ligase has been previously demonstrated to be associated to a late stage of differentiation of thymocytes. In the bursa, a unique form of 8 S DNA ligase is found during the whole period of observation. This form of enzyme remains in the B cells of the spleen until 3 weeks after hatching, but is never present in the blood B cells. As far as T cells are concerned, the light DNA ligase is present in the blood from 18‐day embryonic life on. In the spleen T cells, on the contrary, this enzyme appears only 3 weeks after hatching. Before this stage, splenic T cells are devoid of any form of DNA ligase activity. These findings show biochemical differences in T and B lymphocytes colonizing the periphery, blood and spleen, and suggest, at least for the T cells at early stages, a heterogeneity in the degree of differentiation.
Antigen‐specific cytotoxic T cell and antigen‐specific proliferating T cell clones can be induced to cytolytic activity by monoclonal antibodies against T3
Authors: Spits Hergen , Yssel Hans , Leeuwenberg Jet , De Vries Jan E.
Published: February 2007

T3 is a human differentiation antigen expressed exclusively on mature T cells. In this study it is shown that anti‐T3 monoclonal antibodies, in addition to their capacity to induce T cells to proliferate, are able to induce antigen‐specific cytotoxic T lymphocyte clones to mediate antigen nonspecific cytotoxic activity. It is furthermore shown that anti‐T3 reagents are able to trigger lytic activity in T cell clones characterized as noncytotoxic antigen‐specific proliferating T cells. The data presented indicate that perturbation of T3 can trigger the lytic machinery in cytolytic as well as noncytolytic T cell clones.
Chromosome mapping of cell membrane antigens expressed on activated B cells
Authors: Katz Fay E. , Parkar Mohamed , Stanley Karina , Murray Lesley J. , Clark Edward A. , Greaves Melvyn F.
Published: February 2007

Hybrids formed by fusion of either human acute lymphoblastic or chronic lymphocy‐tic leukemia cells and the mouse myeloma P3.X63.Ag81653 have been used to show that the expression of two cell surface antigens, Bp37 and p76, associated with B cell activation and detected by the monoclonal antibodies BB1 and BB2, respectively, segregate with human chromosomes 12 and 19, respectively. Another antigen expressed on activated B cells (p24) also maps to chromosome 12 (Katz et al., Eur. J. Immunol. 1984.13:1008) which is of interest in the light of the frequent involvement of this chromosome in certain B cell leukemias and lymphomas.
Induction of immunoglobulin synthesis by interleukin 2 is T4+/T8− cell dependent. A role for interleukin 2 in the pokeweed mitogen‐driven system
Authors: Miedema Frank , Van Oostveen Johan W. , Sauerwein Robert W. , Terpstra Fokke G. , Aarden Lucien A. , Melief Cornelis J. M.
Published: February 2007

The role of interleukin 2 (IL 2) in the induction of human B cell differentiation in vitro was studied. IL2 was unable to induce immunoglobulin (Ig) production in non‐T cells either in the presence or absence of pokeweed mitogen (PWM). However, IL2 alone could induce Ig production in non‐T cells when irradiated T cells were present. Similar to the PWM‐driven system helper activity was delivered by T4+ but not T8+ cells. Apparently, IL2 acts on T4+ cells and induces these cells to deliver the actual helper signal(s) for Ig production by B cells. Whereas in the PWM‐driven system only T8+ cells suppress Ig synthesis, ILZdriven Ig synthesis was suppressed by both T4+ and T8+ cells added to a mixture of non‐T cells and irradiated T4+ cells. This suppressor activity could be abrogated by irradiation. PWM was shown to induce IL2 production in both T4+ and T8+ cells. Moreover, PWM‐induced Ig synthesis, like IL2‐induced Ig synthesis, could be totally abrogated by a monoclonal antibody against the human IL2 receptor (anti‐Tac). These findings, coupled to the innate Ig‐inducing capacity of IL 2, indicate a role for IL 2 in the PWM‐driven system. The mechanism of suppression in both the PWM‐ and the IL 2‐driven systems was not shortage of IL 2 in the culture due to consumption or inhibition of production of IL 2. Moreover, the T8+ cells produced IL2, despite their failure to help Ig synthesis. Helper T cell activity can thus be divided into two distinct activities: (a) IL2 production and (b) the ability to deliver the actual helper signal such as helper factors for B cell differentiation. This insight allows a better evaluation of the immunoregulatory activities of T cell subsets in Gealth and disease.
Evaluation of accessory cell heterogeneity. II. Failure of dendritic cells to activate antigen‐specific T helper cells to soluble antigens
Authors: Ramila Gnanadurai , Smenar Ivo , Kennedy Marion , Sunshine Geoffrey H. , Erb Peter
Published: February 2007

The activation of antigen‐specific T cells requires Ia+, antigen‐presenting accessory cells (AC). Dendritic cells (DC) and macrophages (Mϕ) isolated from spleen and peritoneal exudate were tested as AC for the activation of T helper cells and the induction of T cell proliferation. The cell separations to obtain DC and splenic Mϕ were performed by discontinuous bovine serum albumin gradients, adherence on petri dishes and rosetting with opsonized sheep erythrocytes. DC as well as the Mϕ were able to induce antigen‐specific T cell proliferation, but only the Mϕ and not the DC activated antigen‐specific T helper cells which help B cells for antibody production to soluble antigens. Keyhole limpet hemocyanin‐specific T cells repeatedly stimulated with DC and antigen also did not express helper activity. The failure of DC to induce T helper cells was not due to the activation of a suppressor pathway. Thus, dendritic cells, although very efficient as AC in the induction of various T cell functions, are not able to activate T helper cells required for carrier‐specific T‐B cooperation and therefore cannot be the sole accessory cells. Based on these results and on previous data using Ia+ tumor cell line as AC, we confirm the existence of functional AC heterogeneity.
Murine intestinal intraepithelial lymphocytes. I. Relationship of a novel Thy‐1−, Lyt‐1−, Lyt‐2+, granulated subpopulation to natural killer cells and mast cells
Authors: Petit Agnes , Erst Peter B. , Befus A. Dean , Clark David A. , Rosenthal Ken L. , Ishizaka Teruko , Bienenstock John
Published: February 2007

Highly purified populations of intraepithelial lymphocytes (IEL) were obtained from the murine small intestine. We found that 84% of IEL expressed Lyt‐2 and that 45‐55% possessed the unique phenotype, Thy‐1−, Lyt‐1‐, Lyt‐2+. Sixty percent of IEL had granules in their cytoplasm and thus resembled the large granulated lymphocytes associated with natural killer (NK) activity. However, less than 15% of IEL had NK activity in a 6‐h assay. This activity resided in a subpopulation of Lyt‐2‐ lymphocytes, leaving a large population of Thy‐1−, Lyt‐1−, Lyt‐2+ granulated cells (45‐55% of IEL) with unknown function. Sensitive radioenzymic assays for histamine showed that IEL from healthy CBA mice do not contain this amine. IgE‐binding assays revealed that IEL, unlike mast cells, do not carry high‐affinity receptors for IgE. Thus, only a small percentage of granulated IEL (< 15%) possess NK activity, whereas 45‐55% of IEL have granules, lack typical characteristics of mast cells, express the unique antigenic phenotype, Thy‐1−, Lyt‐1−, Lyt‐2+ and have unknown function.
Mott cells are plasma cells defective in immunoglobulin secretion
Authors: Alanen Anna , Pira Ulla , Lassila Olli , Roth Jürgen , Franklin Richard M.
Published: February 2007

Plasma cells containing intracellular inclusions of immunoglobulin (Russell bodies) are known as Mott cells, and are found in large numbers in lymphoid organs in autoimmune mice. Hybridoma technique was used to produce cell lines of this phenotype by fusing spleen cells from a NZB mouse with a nonproducing hybridoma cell line (Sp2/0‐Ag14), allowing us to carry out studies of this cell type at the biochemical level. Ultrastructurally the inclusions were distended cisternae of rough endoplasmic reticulum, suggesting a block in the secretory pathway of the cells. Biosynthetic labeling studies confirmed that these cell lines have either a complete or partial block of secretion of immunoglobulin, possibly due to an abnormal light chain.
Accessory function of human leukemic cell lines: properties of B and B‐K562 hybrid cell lines
Authors: Wakasugi Hiro , Dokhelar Marie C. , Garson Dominique , Harel‐Bellan Annick , Fradelizi Didier , Tursz Thomas
Published: February 2007

The accessory function (AF) of various B cell lines has been investigated by studying their ability to replace monocytes inducing the proliferation of highly purified T lymphocytes in the presence of phytohemagglutinin. AF could be exerted by B cells from different origin, including Epstein‐Barr virus (EBV) transformed lymphoblas‐toid cell lines (LCL), Burkitt's lymphoma (BL)‐derived lines, either EBV‐positive or not, pre‐B and B leukemias and lymphomas. The EBV‐converted BJAB‐B95 BL cells could exert an AF as efficient as BJAB cells, their EBV‐negative counterparts, which demonstrates that EBV itself does not play any role in this function. The HLA‐DR antigen‐negative BL‐K562 hybrids PUTKO and DUTKO, T51.4.1.6 cells which derived from an HLA‐DR‐negative variant of the T51 LCL and 721.84.5 cells from a mutagenically dissected HLA‐DR‐negative clone of the 721 LCL, also exerted very efficient AF. 721 LCL, PUTKO and DUTKO hybrids could produce interleukin 1 activity when triggered with 12‐0‐tetradecanoyl‐phorbol 13‐acetate (TPA). Furthermore, addition of anti‐DR monoclonal antibodies which blocked completely the AF of the B cell lines in mixed lymphocyte‐tumor cell reaction did not affect the mitogen‐triggered AF exerted by the same B cell lines. The induction of cellular differentiation with TPA markedly reduced the AF exerted by all B cell lines studied as well as by the hybrid cells DUTKO. By contrast, the PUTKO hybrid was unsensitive to sodium butyrate and TPA treatments, which were unable to abrogate its AF. Taken together, these data indicate that the AF in mitogen‐induced T lymphocyte responses is dependent upon some precise maturational stages of accessory cells and HLA‐DR antigen expression is not required for AF in mitogen‐induced proliferation assays.
Direct demonstration that the monoclonal antibody AMT‐13 and interleukin 2 bind to the same molecule
Authors: Osawa Hisao , Diamantstein Tibor
Published: February 2007

125I‐labeled surface molecules from mouse T lymphoblasts were fractionated by affinity supports coupled with recombinant interleukin 2 (IL2) and the monoclonal anti‐ body (mAb) AMT‐13. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) analysis demonstrated that two molecules of ∼ 55 kDa and of ∼ 180 kDa were bound in both cases. Sequential precipitation and SDS‐PAGE analysis of the precipitated molecules revealed that only the ∼ 55‐kDa molecule eluted from AMT‐13 mAb support was rebound to IL2 affinity support. In addition, IL2 inhibited specifically the binding of 125I‐labeled AMT‐13 mAb to T lymphoblasts. Thus the results directly demonstrate that the a ∼ 55‐kDa cell surface molecule repre‐ sents the IL2binding protein and that the mAb AMT‐13 reacts with this molecule.
Biochemical events initiated by exposure of human T lymphocyte clones to immunogenic and tolerogenic concentrations of antigen
Authors: Zanders Edward D. , Feldmann Marc , Lamb Jonathan R.
Published: February 2007

Interleukin 2‐dependent helper T cells, cloned from human peripheral blood lymphocytes activated with strain A influenza virus hemagglutinin, proliferate in response to a 24‐residue synthetic peptide (p20) of hemagglutinin, but become unresponsive to a subsequent immunogenic challenge when pretreated with a high concentration of p20. This phenomenon is associated with a loss of the T3 antigen complex, presumably in association with the T cell receptor. We have examined this phenomenon in more detail and show that in addition to changes in the expression of T3 molecules on the cell surface, high doses of p20 cause changes in the expression of certain biosyntheti‐ cally and surface‐labeled proteins, although total DNA and protein synthesis was unaltered. Thus, by examining these biochemical phenomena we can begin to define some of the processes which occur during antigen activation of human T lymphocytes at the clonal level.
Analysis of human T lymphocyte activation in a T cell tumor model system
Authors: Landegren Ulf , Andersson Jan , Wigzell Hans
Published: February 2007

The human T leukemia line Jurkat maintains functional characteristics of normal T cells in responding to inducing stimuli by the release of interleukin 2 (IL2). Presence of a phorbol ester during stimulation eliminated the requirement for specialized accessory cells in the response to cell mitogenic agents such as the lectin con‐canavalin A or treatment with neuraminidase and galactose oxidase. Antibodies directed against the T cell receptor‐associated antigen T3 served as efficient stimuli, especially if aided by agents that cross‐link immunoglobulin, indicating that a triggering signal is received by a T cell via aggregation of its antigen receptor complex. A Burkitt lymphoma cell line, Raji, was found to selectively trigger Jurkat cells, suggesting the ability of those cells to respond to certain foreign stimuli. The Jurkat cell line has been instrumental in the purification of IL2 and cloning of the corresponding gene. Our data suggest it can also serve as a useful model for induction of T cell responses.
Induction of proliferative and cytotoxic responses in resting Lyt‐2+ T cells with lectin and recombinant interleukin 2
Authors: Vohr Hans‐W. , Hünig Thomas
Published: February 2007

The lectin leucoagglutinin has been used to induce reactivity to interleukin 2 (IL2) in unseparated spleen cells and in highly purified Lyt‐2+ lymph node T cells. Recombinant human IL2 and various other IL2‐containing preparations, including con‐canavalin A‐induced spleen cell supernatant, were compared for their capacity to support DNA synthesis and cytotoxic activity. In contrast to published reports, we found that the capacity of all preparations tested was identical in both functional assays, if they were adjusted to the same IL2 titer. Our inability to detect a requirement for an externally added cytotoxic T cell differentiation factor could either mean that IL2 is sufficient for the promotion of both proliferation and differentiation in leucoagglutinin‐activated resting cytotoxic T cell precursors, or that under our experimental conditions, T cell differentiation factor is endogenously produced by Lyt‐2+ T cells.
Mycoplasma infection of cell lines can simulate the expression of Fc receptors by binding of the carbohydrate moiety of antibodies
Authors: Lemke Hilmar , Krausse Rea , Lorenzen Johann , Havsteen Bent
Published: February 2007

During the production of Fc receptor (FcR)‐bearing hybridomas it was observed with a particular monoclonal anti‐sheep red blood cell antibody (anti‐SRBC 1/5, IgG1) that the contamination with Mycoplasma arginini of in vitro cultured cell lines leads to an apparent FcR activity. This property did not correspond with the serological typing since other antibodies of the same isotype could not support FcR rosette formation. Another mycoplasma strain M. orale lacked this property. Analysis of the binding reaction revealed that M. arginini contains a lectin which binds the carbohydrate moiety of the anti‐SRBC 1/5 antibody, i.e. anti‐SRBC 1/5 synthesized under the influence of tunicamycin or deglycosylated by NaIO4 oxidation did not support rosette formation. These data suggest that binding of antibodies to certain mycoplasma strains may be a pathogenic factor during mycoplasma infections by masking the microorganisms with the host's own defense molecules.

The experiments with M. arginini‐infected cell lines gain immunological importance since we obtained identical results with staphylococcal protein A, as another bacteriological FcR, and cell lines expressing intrinsic membrane FcR. Although it is an open question whether the glycoconjugates are directly bound by the FcR or else by influencing the three‐dimensional structure of the antibodies, it seems possible that FcR in general may be lectins.
Analysis of autoreactive I region‐restricted T cell colonies isolated from the guinea pig syngeneic mixed leukocyte reaction and from immune responses to conventional foreign antigens
Authors: Dosreis George A. , Shevach Ethan M.
Published: February 2007

Guinea pig proliferating T cell colonies were isolated from T cell populations stimulated during the syngeneic mixed leukocyte reaction (SMLR) or following positive selection of immune T lymphocytes specific for pork insulin (PI) or the copolymer of L‐glutamic acid, L‐lysine (GL). SMLR‐responding T cell colonies could be isolated in the absence of any extrinsic antigen and were strictly restricted to the recognition of Ia molecules on stimulator peritoneal exudate cells (PEC) and required both stimulator cells and interleukin 2‐enriched fluids for optimal proliferative responses. Blocking of T cell colony proliferation with a panel of monoclonal anti‐la antibodies showed that SMLR T cell colonies were restricted by discrete and distinct self‐la epitopes. Analysis of individual T cell colonies generated against PI and GL revealed three types of colonies: (a) antigen specific, I region‐restricted; (b) autoreactive, I region‐restricted; and (c) antigen specific, but also autoreactive. These doubly reactive colonies were restricted to the same Ia epitope when stimulated with self‐PEC alone or when stimulated with self‐PEC in the presence of the relevant exogenous antigen. These results substantiate the hypothesis that both the SMLR and antigen‐specific responses are mediated by a common set of precursor T lymphocytes and that the guinea pig SMLR is at least in part the result of the polyclonal proliferative responses of several distinct antigen‐reactive T cell clones in the absence of exogenous antigen.
Regulation of Epstein‐Barr virus infection by recombinant interferons. Selected sensitivity to interferon‐γ
Authors: Lotz Martin , Tsoukas Constantine D. , Fong Sherman , Carson Dennis A. , Vaughan John H.
Published: February 2007

Interferons (IFN) are antiviral proteins that may be important in mediating cellular defenses against Epstein‐Barr virus (EBV) infection. However, the means by which IFN‐α, ‐β and ‐γ modify EBV infectivity are not clear. We have evaluated the effects of purified recombinant preparations of all three classes of IFN on EBV‐induced B lymphocyte proliferation and Ig secretion. When added early after EBV infection, all three recombinant IFN reduced B cell outgrowth and Ig secretion. IFN‐γ exerted a 7‐10‐fold more potent antiviral effect than IFN‐α or ‐β. All three types of IFN act directly on B cells. Monocytes and natural killer cells are not necessary for the anti‐EBV activity. Of the three recombinant IFN, only IFN‐γ reduced EBV‐induced proliferation and Ig secretion when added 3–4 days after virus infection; IFN‐α/β were only effective up to 24 h. B lymphoblastoid lines already transformed by EBV are insensitive to the anti‐proliferative actions of all three types of IFN.

On the basis of these findings, we propose three phases of regulation during EBV infection. In the early phase, EBV‐infected cells can be regulated by all IFN. Subsequently, there is an intermediate period where only IFN‐γ is capable of directly affecting EBV‐induced B cell responses. In the third phase, B lymphocytes become insensitive to direct actions of all IFN and are now subject to regulation only by cytotoxic cells.
Differentiation in the murine B cell lymphoma 1.29: inductive capacities of lipopolysaccharide and Mycoplasma fermentans products
Authors: Sitia Roberto , Rubartelli Anna , Deambrosis Sandro , Pozzi Donata , Hammerling Ulrich
Published: February 2007

Cells from the murine B lymphoma 1.29, expressing IgM or IgA of identical idiotype, were found inducible by lipopolysaccharide to differentiate into plasma cells. Within 3 days, differentiating cells lost membrane‐bound immunoglobulin (Ig) and accumu‐ lated large quantities of intracytoplasmic Ig. At day 6 of culture, IgA secretion increased 50‐100‐fold, as determined by enzyme‐linked immunoassay. Proliferation increased for the first days of culture but decreased thereafter; by day 10 very few viable cells were present in lipopolysaccharide‐stimulated cultures. Similar results were obtained by culturing 1.29 cells in the presence of supernatants of certain B cell lines (e.g. BF0.3). The finding of a strict correlation between the inductive activity and presence of contaminating Mycoplasma fermentans suggested that factor(s) released by mycoplasma were responsible for the mitogenic activities. This was further indicated by the findings that: (a) the supernatants of BF0.3 that were rendered free of mycoplasma were not inductive, and (b) a nonactive cell line could be made active by infection with supernatants of BF0.3 cells containing viable micro‐ organisms. Thus, supernatants of mycoplasma‐infected cell lines may act as potent polyclonal activators on both normal and malignant B lymphocytes. The ability to induce membrane Ig on 70Z/3 cells indicates that mycoplasma‐related mitogens are also active on pre‐B cells. The possibility of mycoplasma contamination should thus be carefully excluded when presumptive factors of cloned cell lines are being evalu‐ ated.
Human clones with natural killer function can activate B cells and secrete B cell differentiation factors
Authors: Vyakarnam Anna , Brenner Malcolm K. , Reittie Joyce E. , Houker Clare H. , Lachmann Peter J.
Published: February 2007

Large granular lymphocyte clones were prepared from normal human mononuclear cells. Seven clones were studied in detail. All had high cytotoxic activity against the natural killer (NK) cell target K562 and all were T11‐ and DR‐positive but T4‐ and T8‐negative: none released migration inhibitory factor, a characteristic of helper T cell clones. When these NK cell clones were co‐cultured with autologous B cells in a 1:1 ratio, 4 of the 7 induced both IgM and IgG synthesis. Ig production could not be further enhanced by the addition of B cell differentiation factors. The cells stimulated included antigen‐specific memory B cells, as the Ig induced contained specific antibody to an antigen, tetanus toxoid, to which the B cell donors had recently been immunized. Supernatants from the helper/NK clones contained B cell differentiation factors, and were able to induce IgG synthesis from the lymphoblastoid cell line CESS and from co‐cultured T and B cells. However, NK clone supernatants, unlike the clones themselves, were not effective at inducing Ig synthesis from purified B cells. Instead it appears that NK clones first activate B cells and thus render them responsive to the factors that the clones secrete.
Immunoglobulin‐bearing stem cells for clones of B (bursa‐derived) lymphocytes
Authors: Pink J. Richard L. , Ratcliffe Michael J. H. , Vainio Olli
Published: February 2007

Treatment of neonatal chickens with cyclophosphamide depletes bursal lymphocytes while maintaining the bursal epithelium intact. The bursae of normal young chickens contain “bursal stem cells” which can reconstitute the lymphoid compartment in the bursa of the cyclophosphamide‐treated recipient. Using bursal stem cells from IgM allotype‐heterozygous donors we show that most bursal follicles in the reconstituted host are colonized by single stem cells which are committed to the expression of one or other IgM allotype. In addition we show that the reconstituting bursal stem cells express allelically excluded surface IgM at the time of transfer. Our results suggest that B lymphocyte numbers in hatched chickens are maintained by self‐renewal of committed precursors rather than by de novo production from multipotential stem cells.
Early B cell precursors in long‐term bone marrow culture: selective development in the bone marrow of irradiated recipients
Authors: Nishikawa Shin‐Ichi , Kina Tatsuo , Amagai Takashi , Katsura Yoshimoto
Published: February 2007

The primary site for the growth and differentiation of B cell precursors in irradiated recipient mice was investigated. Bone marrow (BM) cells from lipopolysaccharide (LPS)‐responder C57BL/6 mice were transferred into irradiated LPS‐nonresponder C57BL/10ScCr mice, and the generation of donor‐derived B cells in the recipient was monitored by determinating the immunoglobulin‐producing cells developed in the LPS‐stimulated cultures of recipient's spleen cells as well as BM cells. As previously stated, the transfer of fresh BM cells resulted in the development of LPS‐reactive cells both in spleen and BM simultaneously. On the other hand, when long‐term cultured BM cells which were shown to be devoid of B cells and pre‐B cells were used as the donor cells, the development of LPS‐reactive cells was first observed only in BM, and subsequently in both BM and spleen. The failure to detect LPS‐reactive cells in the spleen in the early phase, or day 11 after irradiation and reconstitution, was not attributed to the culture condition or the existence of suppressive activity in day 11 spleen cells. These results indicate that B cell precursors lodge only in the BM of irradiated recipients, grow and differentiate in the same place, and then the differentiated progeny migrate to peripheral lymphoid organs.
Regulation of interleukin 2 (IL2) receptor expression: IL 2 as an inducing signal for the expression of its own receptor on a murine T helper cell line
Authors: Bismuth Georges , Moreau Jean‐Louis , Sommé Gérard , Duphot Maryse , Dautry‐Varsat Alice , Robb Richard J. , Thezè Jacques
Published: February 2007

The interleukin 2 receptor (IL2R) expression of a terpolymer of L‐Glu60, L‐Ala30, L‐ Tyr10 (GAT)‐specific T helper (Th) cell line, L14, was studied using two different rat monoclonal antibodies specific for the murine IL2R, 7D4 and 5A2‐2. L14 T cells expressed IL2R transiently, but contrary to the general assumption that IL2R expression is maintained only by periodic antigen stimulation, we observed that IL2 itself was able to regulate the level of IL2R on L14 Th lymphocytes. In particular, it was found that L14 T cells, which had not been recently stimulated and which expressed a very low level of high affinity IL2R, could be induced to exhibit a high level of this receptor after exposure to recombinant IL2, in the absence of any specific signal. In contrast, the Th cell line 52.3 used as control could be induced to express high levels of IL2R only after exposure to GAT; nevertheless, IL2 seems to play a critical role in the in vitro survival of the resting state of 52.3 T cells.
T15‐specific helper T cells: analysis of idiotype specificity by competitive inhibition analysis
Authors: Dunn Eileen Becker , Bottomly Kim
Published: February 2007

Optimal activation of T15 idiotype‐bearing B cells has been shown previously to be influenced by two subsets of Thy‐1+, Ly‐1+,2−sIg− helper T cells. One of the helper T cell sets appears to be T15 specific in that its presence results in a selective augmentation of T15‐bearing anti‐phosphorylcholine (PC) plaque‐forming cell responses. To determine the precise specificity of the idiotype‐specific helper T cell (ThId), Ly‐1 T cells were tested in an in vitro anti‐PC response for their ability to bind directly to T15 myeloma protein‐coated plastic plates. Specificity of this binding was ascertained by competitive inhibition of plate binding using idiotypically related myeloma or hybridoma proteins. These data suggest that the Ly‐1 T cells which augment T15‐bearing plaque‐forming cell responses can bind to T15‐coated plates and are T15 idiotype specific. This approach is being used currently to attempt to clone ThId cells to further analyze their activation requirements and specificities.
Rapid activation of ornithine decarboxylase by mitogenic (but not by nonmitogenic) ligands in human T lymphocytes
Authors: Scott Ian G. , Poso Hannu , Akerman Karl E. O. , Andersson Leif C.
Published: February 2007

The T cell mitogens, concanavalin A and the monoclonal antibody OKT3, cause a rapid activation of ornithine decarboxylase (ODC) activity in human T lymphocytes, maximal within 10 min of mitogen addition. Nonmitogenic ligands to T cell surface structures do not induce ODC. The enzyme induction is dependent upon an intact mobility of ligand‐receptor complex, requires a functioning energy metabolism, but is independent of de nuvo protein synthesis. The early induction of pre‐existing ODC molecules appears to be specifically linked to the initiation of T lymphocyte proliferation.
Enhancement of IgG anti‐carrier responses by IgG2 anti‐hapten antibodies in mice
Authors: Coulie Pierre G. , van Snick Jacques
Published: February 2007

Isologous IgG2a, and IgG2b anti‐hapten antibodies injected along with trinitrophenylated or fluoresceinated keyhole limpet hemocyanin (KLH) were found to considerably stimulate primary IgG responses to the carrier protein in mice. No such stimulation was observed with IgG1, IgM and IgA anti‐hapten antibodies. Depending on the antigen antibody combination, the amplification obtained after a single injection of IgG2‐complexed haptenated KLH ranged from 20‐ to 1000‐fold. By comparison, secondary responses were only marginally enhanced (≈ 3‐fold) when IgG2‐complexed rather than free antigen was used to boost irradiated recipients previously reconstituted with primed spleen cells. The IgG2‐mediated enhancement was effective over a wide range of antigen/antibody ratios, did not require the use of high affinity antibodies and occurred whatever the route of injection. The stimulation was specific for the complexed antigen and developed to the same extent whether complexes were formed in vitro or in vivo. A comparable stimulation of the anti‐carrier response was obtained with several other haptenated proteins but with formaldehyde‐treated diphtheria and tetanus toxoids inhibition rather than stimulation was observed.
Interactions of small B lymphocytes with unprimed noncytolytic T cells: dissociation between “presentation” and growth induction
Authors: Bandeira Antonio , Pereira Pablo , Martinez‐A Carlos , Coutinho Antonio
Published: February 2007

The accessory cell requirements in lectin‐dependent triggering and growth of unprimed Lyt‐2− T lymphocytes were analyzed by quantitatively comparing the ability of small B cells and peritoneal macrophages to either induce reactivity to growth factors or support growth.

Lightly or nonirradiated small B cells were 15 to 30‐fold less efficient as compared to T cell‐depleted peritoneal cell populations, in the support of lectin‐stimulated Lyt‐2− T cell proliferation. In contrast, lightly irradiated small B lymphocytes were quantitatively as efficient as macrophages in mediating lectin‐driven Lyt‐2− T cell proliferation, if relevant supernatants were added into culture. Finally, supernatants derived from cultures where T‐small B cell ratios were optimal for growth of responder Lyt‐2− lymphocytes were two orders of magnitude less efficient than conditioned medium obtained from cultures containing optimal T‐macrophage ratios, in their ability to support growth of activated T cells.

We conclude from these experiments that: (a) in contrast to cytolytic T cell precursors, lectin‐dependent induction of unprimed Lyt‐2− T lymphocytes requires accessory cells; (b) small B cells and macrophages are equally competent in this respect; and (c) growth support by small B cell populations is due to contamination by macrophages which are the only cell type performing this function. We therefore interprete reports on Lyt‐2− T cell proliferation upon stimulation with high numbers of small B cells as a two‐step process: “presentation” and induction of T cells which is essentially B cell dependent, and factor production ensured by contaminating macrophages.
Effects of monoclonal antibodies to the a and β chains of the human lymphocyte function‐associated (H‐LFA‐1) antigen on T lymphocyte functions
Authors: Dongworth David W. , Gotch Frances M. , Hildreth James E. K. , Morris Alan , McMichael Andrew J.
Published: February 2007

The ability of two antibodies, one specific for the a chain, p180, and the other for the β chain, p95, of the human lymphocyte function‐associated (LFA‐1) antigens, to inhibit T cell function was measured. Both antibodies inhibited T cell‐mediated lysis of virus‐infected target cells and of K562 cells. Only the anti‐β chain antibody inhibited natural killer cell lysis of K562. The antibodies inhibited cytotoxic T lymphocyte cell (CTL) lysis of HLA‐mismatched target cells in the presence of concanavalin A at 6.25–12.5 μg/ml, but at higher doses of Con A no inhibition was seen. When the lytic process was divided into calcium‐independent (adherence) and ‐dependent (lysis) steps the antibodies were found to block at the initial step of conjugate formation. The effects of these antibodies on T cell proliferative responses showed that responses to antigens, alloantigens, mitogens and anti‐CD3 (UCHT1) antibody were greatly inhibited. All of these responses are adherent cell dependent and proliferation of adherent cell‐depleted mononuclear cells to Sepharose‐coupled UCHT1 was not inhibited by anti‐LFA‐1 antibodies. Proliferation to paired anti‐CD2 (T11) antibodies was also only weakly inhibited. Release of interferon‐γ by CTL on contact with target cells was also inhibited by anti‐LFA antibody. These results are evidence that the LFA antigen is necessary for a nonspecific interaction with antigen ‐presenting cells that is essential for activation of T cells through the CD3‐T cell receptor complex.