bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of gp140, a C3b‐binding membrane component present on Raji cells: a comparison with factor H
Authors: Frade Raymond , Barel Monique , Krikorian Laure , Charriaut Christiane
Published: February 2007

In a previous report (M. Barel et al. FEBS Lett., 1981. 136: 111) using radiolabeling methods, we characterized from the membrane of the human B lymphoblastoid cell line Raji, a 140000‐Mr glycoprotein (gp140) carrying a C3b‐binding activity with 125I‐labeled C3b or Sepharose‐bound C3b. The facts of absence on Raji cells of CR1, the C3b receptor purified from human erythrocytes, the observations made by others that H‐like activity (the 150000 Mr C3b binding serum protein) was present in Raji cells and the same molecular weight range of H and gp140, led us to investigate the relationship between both antigens.

A rabbit antibody anti‐5.4 was prepared against gp140, highly purified from Raji cells. However, anti‐H specificities were detected in crude anti‐5.4 IgG, while anti‐serum H IgG did not react with gp140 antigen. The crude anti‐5.4 IgG fraction, anti‐gp140 IgG or F(ab′)2 and anti‐H specificities present in anti‐5.4 IgG, separated by absorption on Sepharose‐bound H, and anti‐serum H IgG were tested on Raji cells by immunofluorescence techniques, by measuring the inhibition of specific cytotoxic assays and the inhibition of specific binding of soluble or particle‐bound C3b to the cell surface and on solubilized antigens by immunoblotting techniques. All the data obtained support that: (a) anti‐H specificities are not shared by antibodies bearing anti‐gp140 specificities and their presence in crude anti‐5.4 IgG is more likely due to a contamination by H antigen of gp140 antigen used in the immunization process, and (b) gp140 antigen is highly expressed on Raji cell surface, whereas H antigen can not be detected under the same conditions. Molecular analysis of gp140 and H antigens confirmed differences between both antigens in molecular weight, trypsin sensitivity and charge properties.

All the results presented herein support the notion that gp140 is not identical with the H molecule and that C3b binding to gp140 is not mediated by H. The relationship between gp140 and C3 receptors described by others is discussed.
The interaction of high endothelial venules with T and B cells in peripheral lymph nodes after antigenic stimulation
Authors: Kraal Georg , Twisk Agaath
Published: February 2007

The influence of an ongoing immune response on the specific interaction of high endothelial venules (HEV) in peripheral lymph nodes with T and B cells was determined using short‐term homing experiments and an in vitro HEV adherence assay. It was demonstrated that stimulation with various antigens did not change the receptor specificity of the HEV. However, the retention and/or the efflux of immigrant cells in the stimulated lymph nodes had changed.
Allosuppression: evidence for the involvement of both “noncytotoxic” and cytotoxic T cells
Authors: Zamoyska Rose , Waldmann Herman
Published: February 2007

Allogeneic suppressor cells were generated by priming to a minor histocompatibility antigen. C57BL/10 female mice were primed to the male‐specific minor transplantation antigen, H‐Y. After boosting, anti‐male‐primed cells could potently suppress the secondary antibody response of male spleen cells in vitro. Anti‐male suppressor cells were H‐2‐restricted, radiation‐resistant T cells which could act on either T or B cells in the responding population. Mapping the restriction elements for anti‐male suppressor cells revealed two distinct subpopulations of effector cells. The majority subpopulation was restricted to H‐Y in the context of the H‐2Db molecule. These cells were probably cytotoxic T cells as they were inhibited by culture of the suppressor cells in pyrilamide (a histamine1 receptor antagonist, which prevents the maturation of cytotoxic T cells from their precursors). The second subpopulation of suppressor cells was restricted to H‐Y in the context of H‐2K or I region‐coded molecules. As neither H‐2Kb nor H‐2Ib molecules can act as restriction elements for anti‐male‐specific cytotoxic T cells, this subpopulation was almost certainly not composed of conventional cytotoxic cells. Furthermore, these cells were not affected by culture in pyrilamide. Together these two populations act to completely inhibit the anti‐trinitrophenyl (TNP) plaque‐forming cell response of male spleen cells in vitro.
Specificity, duration and mechanism of idiotype suppression induced by neonatal injection of monoclonal anti‐idiotope antibodies into mice
Authors: Takemori Toshitada , Rajewsky Klaus
Published: February 2007

Monoclonal antibodies detecting idiotopes on the germ line‐encoded anti‐(4‐hydroxy‐3‐nitrophenyl)acetyl (NP) antibody B1‐8 were injected at various doses into newborn mice and the expression of B1‐8 idiotopes was measured in anti‐NP responses in later life. Suppression was long lasting, and a 100‐fold increase in the dose of anti‐idiotope delayed recovery from suppression by 5‐6 weeks. Upon injection of a single anti‐idiotope, suppression was observed for all B1‐8 idiotopes to various degrees. Certain idiotopically defined antibody phenotypes were much more efficiently suppressed, and later recovered from suppression, than others. This specificity pattern was observed at the level of both B and T cells from the manipulated animals, as demonstrated in cell transfer experiments in which such cells were mixed with normal T and B cells. In these experiments, there was evidence for suppression mediated by regulatory T (and possibly also B) cells. Whereas the B cells from the manipulated animals were idiotypically unresponsive in a T cell‐dependent adoptive primary response, the frequency of lipopolysaccharide‐reactive B cells expressing the target idiotype was only slightly reduced in these animals as compared to control mice.

Together with data on the elimination of anti‐idiotope antibody from the neonatally injected animals these results are interpreted in the following way: idiotype suppression is induced through the reaction of anti‐idiotope with idiotopes expressed on the surface of newly generated B cells, at microgram concentrations of anti‐idiotope. When the concentration of anti‐idiotope falls below that level, recovery from suppression sets in. Two types of suppression are induced. The first, namely, direct blockade of B cell maturation, is short‐lived. The second involves the induction of regulatory cells, perhaps through idiotope‐bearing antibody V regions complexed by anti‐idiotope. This type of suppression is long‐lived and its specificity depends upon the distribution of the target idiotope in the antibody repertoire and/or peculiarities of the T cell receptor repertoire. It impinges on the selection of the B cell repertoire in the animal as expressed in T cell‐dependent (and possibly other) responses and is thus hardly seen at the level of lipopolysaccharide‐reactive (immature) cells. Idiotype suppression by regulatory cells may be perpetuated by antigen interacting with idiotypic antibodies on the B cell surface and may therefore play a role in establishing tolerance not only for the expressed antibody repertoire, but for self antigens in general.
Low sialic acid‐bearing mouse thymocytes do not express helper T cell properties in vitro
Authors: Herron Lynne R. , Collins Janet M. , Abel Carlos A. , Campbell Priscilla A.
Published: February 2007

Immature, presumably cortical, mouse thymocytes were isolated by removing mature thymocytes by agglutination with the sialic acid‐specific lectin, lobster agglutinin 1 (LAg1). These immature cells do not respond to the mitogenic effects of concanavalin A (Con A), even in the presence of interleukin 2. Moreover, they do not exhibit two properties of helper T cells; they do not secrete interleukin 2 when stimulated with Con A, nor do they provide T help for an in vitro immune response by spleen B cells to the T‐dependent antigen, sheep erythrocytes. LAg1‐negative thymocytes fail to provide T help even though Con A is added to the cultures, regardless of the number of LAg1‐negative thymocytes added per culture, and even in the presence of exogenous macrophages. Unseparated thymocytes, LAg1‐positive thymocytes and cortisone‐resistant thymocytes all provide T cell help under these conditions. These experiments indicate that immature, presumably cortical mouse thymocytes, isolated by virtue of their low levels of surface sialic acid, are inherently unable to provide T cell help in vitro.
Feedback regulation of immune suppression by a suppressor factor
Authors: Ikezawa Zenro , Nagy Zoltan A. , Klein Jan , Arden Bernard
Published: February 2007

Mouse hybridomas generated by fusion between a lactate dehydrogenase‐B (LDH‐B)‐specific B10.A(2R) T suppressor (Ts) cell line and the BW5147 thymoma secrete two suppressor factors, TsF‐A and TsF‐E. The factors carry the same antigen‐binding chains but different major histocompatibility complex (MHC) chains (Aβ‐like and Eβ‐like, respectively). The TsF‐A suppresses the proliferation of A‐restricted, LDH‐B‐specific T helper (Th) cells. In this report we demonstrate that the addition of the TsF‐E (isolated on immunosorbent columns with Ek‐ or Jk‐specific antibodies) to the culture of LDH‐B‐primed B10.A(2R) lymph node cells turns the nonrespnder (suppressed) cultures into proliferating ones, and that this change is antigen specific. This enhancing effect occurs in the early phase of the cell culture; the factor has no effect when added 2 days after the initiation of the culture. Because pretreatment of the Ly‐2+ but not of the Ly‐1+2− cells with TsF‐E induces responsiveness, it is very likely that the targets of the factor are the Ts cells or their precursors that belong to the Ly‐2+ subset. An incubation period of about 4 h is necessary for the TsF‐E to expert its action. The enhancing effect of the TsF‐E is abrogated by monoclonal antibodies specific for Ek and Jk antigenic determinants. However, only some of the antibodies that retain the TsF‐E on the immunosorbent column neutralize the factor in a functional test. Antibody blocking studies also indicate that the MHC determinants involved in the interaction between the antigen‐presenting and the Ts cell during Ts cell activaton, and in the TsF‐E Ts cell interaction are either very similar or identical. We interpret the data as indicating that the Ts cells or their precursors recognize the TsF‐E with the same receptors as they use for the recognition of LDH‐B together with the Ek on the antigen‐presentign cells. The recognition of the TsF‐E inactivates the Ts cell so that proliferation of Th cells then occurs unhindered. Thus, the production of the TsF‐E may provide a feedback mechanism that regulates the activation of the Ts cells and, consequently, the degree of suppression in the response to LDH‐B.
Macrophage‐chemotactic factor‐producing T cell hybridomas reactive to phosphorylcholine in I‐E‐restricted manner
Authors: Sugimura Shingo Harita, Kazuhisa , Watanabe Takeshi
Published: February 2007

Macrophage‐chemotactic factor (MChF)‐producing T cell hybridomas were established. These hybridomas produced MChF upon the specific antigenic stimulation with phosphorylcholine (PC)‐conjugated protein in the presence of I‐Ed‐positive antigen‐presenting cells. The hybridomas also secreted MChF after co‐culture with concanavalin A in the absence of antigen‐presenting cells. The MChF‐secreting hybridomas were positive for Kd, Dd, Lyt‐1.2 but negative for I‐Ad, Lyt‐2.2. The molecular weight of MChF produced by the hybridomas was 43000 and the factor was focused at pH 6.6‐6.8 in the chromatofocusing procedure. The MChF was protease sensitive but resistant to neuraminidase treatment, and it was stable by heating at 80°C for 15 min. The MChF‐producing hybridomas established in this study did not produce macrophage migration inhibitory factor (MIF), macrophage‐activating factor (MAF) or interleukin 2, suggesting molecular nonidentity between MChF and these lymphokines. The MChF‐producing T cell hybridomas reactive to specific antigens (PC) will be promising tools for analysis of molecular nature of MChF as well as molecular aspects of antigen recognition mechanism of T cells.
Interactions between immunoglobulins and I region antigens on the B lymphocyte membrane
Authors: Forni Luciana
Published: February 2007

Modulation and co‐modulation of membrane‐bound IgM and IgD and of I region‐encoded antigens (I‐A and I‐E) were studied by immunofluorescence with the use of monoclonal antibodies. The two sets of molecules displayed different ability to be redistributed, by divalent ligands: immunoglobulins could be easily redistributed, while this was not the case for I‐A and I‐E molecules. After short periods of activation, however, this property was found to change drastically: I‐region antigens were redistributed into polar caps, and immunoglobulins were modulated without clear polar redistribution.

Cross‐linking and removal of one of the molecules always resulted in the modulation of at least one other, often two membrane molecules. Concomitantly, an additional molecule was expressed in higher amount. The results are compatible with the existence of specific interactions at the level of the B cell membrane, involving the four molecules in the order I‐A → IgM → I‐E → IgD. Such interactions, probably reversible in the unperturbed state, are likely to change in affinity when one molecule interacts with a ligand. The possible relevance of membrane interactions between immunoglobulin and class II antigens in the regulation of the B cell is discussed.
Surface carbohydrate epitopes of Thy‐1.1 and Thy‐1.2 thymocytes are distinguished by a monoclonal antibody with a specificity common to peanut agglutinin
Authors: Graham Christine M. , Thomas D. Brian
Published: February 2007

NIMF4‐31.7 is a monoclonal IgM antibody with affinity for terminal galactose residues of membrane glycoproteins, Sepharose and agarose. It is cytotoxic for a subpopulation of murine thymocytes and peripheral lymphocytes, corresponding to the peanut agglutinin‐positive population, but reacts with a majority of cells after neuraminidase treatment. It has revealed a genetic linkage between the Thy‐1 locus and quantitative expression of carbohydrate determinants on the thymocyte membrane.
Immunoregulation of lysozyme‐specific suppression. II. Hen egg‐white lysozyme‐specific monoclonal suppressor T cell factor suppresses the afferent phase of delayed‐type hypersensitivity and induces second‐order suppressor T cells
Authors: Adorini Luciano , Colizzi Vittorio , Doria Gino , Ricciardi‐Castagnoli Paola
Published: February 2007

Culture supernatant from a monoclonal T cell lymphoma line (LH8‐105) obtained by radiation leukemia virus‐induced transformation of hen egg‐white lysozyme (HEL)‐specific suppressor T lymphocytes is able, when injected into mice, to specifically suppress the delayed‐type hypersensitivity (DTH) reaction induced by HEL. The suppressor T cell factor (TsF) exhibits fine antigenic specificity since it suppresses the DTH response induced by HEL without affecting the DTH response induced by ring‐necked pheasant egg‐white lysozyme (REL), a lysozyme closely related to HEL. Conversely, LH8‐105 TsF is able to suppress the DTH response induced by human lysozyme, distantly related to HEL but sharing a common epitope critical for induction of suppressive activity. The fine antigenic specificity of LH8‐105 TsF for a restricted epitope on the HEL molecule is confirmed by binding to HEL but not to REL immunosorbents. This TsF also bears I‐J determinants, as demonstrated by binding to monoclonal anti‐I‐J immunosorbents, and it suppresses the afferent but not the efferent phase of the DTH response to HEL. The afferent suppression is controlled by genes apparently mapping in the I‐J subregion of the H‐2 complex since I‐J‐incompatible mice are not suppressed by LH8‐105 TsF injection. This inducer‐type TsF induces second‐order effector suppressor T cells only in HEL‐primed mice indicating the primary role of antigen, in association with H‐2 (I‐J) products, in the afferent portion of this suppressive circuit.
The augmentation of tumor‐specific immunity by virus help. II. Enhanced induction of cytotoxic T lymphocyte and antibody responses to tumor antigens by vaccinia virus‐reactive helper T cells
Authors: Shimizu Yoshio , Fujiwara Hiromi , Ueda Shigeharu , Wakamiya Nobutaka , Kato Shiro , Hamaoka Toshiyuki
Published: February 2007

The present study investigates the role of vaccinia virus‐reactive helper T cells in causing enhanced induction of syngeneic tumor immunity. Vaccinia virus‐reactive helper T cell activity capable of inducing the augmented generation of cytotoxic T lymphocyte (CTL) or antibody responses was generated in C3H/HeN mice by inoculating i.p. live virus. Immunization of these mice with vaccinia virus‐infected syngeneic X5563 plasmacytoma or MH134 hapatoma cells led to augmented induction of immune resistance against the challenge with corresponding viable tumor cells when compared with the incidence of resistance observed in control mice not primed to vaccinia virus. In vitro cytotoxicity tests utilizing spleen cells and serum from mice which resulted in the augmented tumor resistance by virus help have revealed that spleen cells from C3H/HeN mice immune to the X5563 plasmacytoma exhibited appreciable anti‐X5563 CTL activity, whereas serum from these mice failed to display any antibody response. In contrast, MH134‐immune mice exhibited potent anti‐MH134 antibody, but not CTL responses. Such an anti‐tumor CTL or antibody response augmented by vaccinia virus‐reactive helper T cells was found to be tumor specific. These results are discussed in the context of (a) the functional diversity of tumor antigens, and (b) mechanisms of virus help that are involved in various forms of augmented induction of syngeneic tumor immunity.
Antibody‐mediated allotype suppression in adult mice: The role of antigen, effector isotype and regulatory T cells
Authors: Curling Elisabeth M. A. , Dresser David W.
Published: February 2007

It has been reported (Contemp. Top. Immunobiol. 1974. 3: 41) that allotype‐specific T suppressor cells can be induced after monoclonal anti‐allotype treatment of neonatal (BALB/c × SJL) F1 (Igha/b) mice. Here we show that (BALB/c × CB20)F1 adult‐derived spleen cells (SC) are, by contrast, potently suppressed by monoclonal allotype‐specific reagents, (when transferred into irradiated BALB/c recipients) in the absence of primary T suppressor cell induction. Such suppression is only induced in activated B cells [exposed to lipopolysaccharide or sheep red blood cells (SRBC)], and is probably dependent on the isotype of the anti‐allotype sera administered. For example, two independently produced IgG1 monoclonal reagents raised against the Igh‐1b allotype were poorly suppressive or nonsuppressive, whereas an IgG3 and an IgG2a monoclonal antibody induced a 90% suppression of the target allotype in transferred adult SC. It was found that suppression was not due to a depletion of antigen‐specific T cell help since: (a) the addition of SRBC‐educated T cells did not break suppression and (b) suppressed SC were as good a source of T cell help as normal SC, in the response of virgin or memory B cell (Thy‐1‐depleted) responses to SRBC in vivo.

Suppression was maintained in suppressed cells which had been rechallenged with SRBC after transfer into a second irradiated recipient, but was not induced in normal SC when these were admixed with an equal number from this suppressed SC population.

These findings point to a possible mechanism for the regulation of B cell expression, through the formation of an antibody‐Ig receptor complex at the surface of the B lymphocyte. After complexing the target cell is either deleted or inactivated. The response to SRBC was reduced or ablated for at least 70 days after treatment with a single dose of anti‐allotype serum.
Culture of thymic epithelial cells from mice and agerelated studies on the growing cells
Authors: Small Myra , Barr‐Nea Liliane , Aronson Moshe
Published: February 2007

Culture of epithelial cells from the thymus of mice was achieved in a medium modified to favor epithelial growth while inhibiting proliferation of fibroblasts. Epithelial cells were identified by the presence of desmosomes in electron microscopic preparations and by antibody to intermediate filaments containing keratin. Morphologically, the cells thus positively identified displayed two main patterns: carpets of large flat cells resembling paving stones which are confluent along the length of their membranes, and networks of cells interconnected by long cytoplasmic processes. These two types of cells were dominant in cultures derived from mice of all ages tested (newborn to nine months) but the relative proportion of each type appeared to change with the age of the donor mice and also with the concentrations of cortisone in the culture medium. Autoradiography revealed that the cultured cells were dividing, and that (in the presence of cortisone) the rate of DNA synthesis was decreased in a portion of the epithelial cells derived from mice in which thymic involution was already underway.
Inulin‐induced activation of factor B in whole serum: Description of structural modifications in the Ba fragment
Authors: Davrinche Christian , Charlionet Roland , Rivat Claude , Helal Ahmed Nourredhine , Lefranc Gérard
Published: February 2007

The investigation of inulin‐induced conversion of human factor B in serum by isoelectrofocusing revealed physiological modifications in the primary structure of the Ba fragment. Evidence has been obtained that a nascent Ba, generated by the hydrolytic action of the D component on B in serum, was a short‐lived product and that a fast release of carboxy‐terminal arginine and lysine residues occurred involving a serum carboxypeptidase B enzyme.
Irreversible inactivation of activated cytotoxic T lymphocyte precursor cells by “anti‐self” suppressor cells present in murine bone marrow T cell colonies
Authors: Muraoka Shizuko , Ehman David L. , Miller Richard G.
Published: February 2007

When added to a mixed lymphocyte culture, cells in T cell colonies grown from bone marrow (BM) suppressed the development of cytotoxic activity against H‐2 antigens shared by the colony cells and the stimulator cells, apparently by inactivating cytotoxic T lymphocyte precursor cells (CTLP). From the point of view of the added suppressor cells, the suppression was against self‐reactive cells. The suppressor cells were resistant to γ irradiation (1500 rds) but sensitive to UV irradiation. Inactivated CTLP separated from the suppressor cells by cell sorting could not be reactivated on being recultured with fresh stimulator cells, suggesting the suppression is irreversible. There was a critical time window, extending roughly from 20 to 40 h after culture initiation, during which the suppressor cell had to be present if CTLP were to be inactivated. During the first 20 h and after 40 h of exposure to stimulator cells, CTLP were resistant to the suppressor cell. Direct experimental evidence is presented against the possibility that the suppressor cells derived from BM colonies act by augmenting the production of Lyt‐2+ suppressor cells from the responder population which then produce the suppression, or that the suppressor cells interfere with an early interaction between CTLP and stimulator cells. We conclude that the suppressor cells in T cell colonies grown from BM act directly on activated CTLP and permanently inactivate them.
The role of B cell differentiation factors and specific T cell help in the pathogenesis of primary hypogammaglobulinemia
Authors: Brenner Malcolm K. , North Margaret E. , Chadda Hakikat R. , Newton Christine A. , Malkovsky Mirek , Webster A. David B. , Farrant John
Published: February 2007

We have examined the function of T and B cells from patients with late onset primary acquired hypogammaglobulinemia (PHG). T cells from these patients give effective help to normal B cells for antigen‐dependent antibody synthesis. PHG mononuclear cells also synthesize normal quantities of B cell differentiation factors, which enhance IgG, IgM and antigen‐dependent antibody synthesis by normal lymphocytes. While patient T cells appear to behave appropriately, the responsiveness of patient B cells is abnormal. Although they respond to differentiation factors with increased synthesis of IgM, overall levels are 10–50‐fold lower than normal B cells, and they produce little or no IgG. This pattern of response is not altered if normal T cells are the source of help. The poor response of the B cell appears to represent immaturity rather than an inherent defect, as IgG‐secreting clones can be obtained after Epstein‐Barr virus transformation of lymphocytes from certain patients, and some of these clones respond to differentiation factors with increased IgG production. The lack of any functional defect in the T population, and the apparent immaturity rather than abnormality of the B cells, may implicate accessory cells in the pathogenesis of the disease.
The effects of idiotype on the ability of IgG1 antiphosphorylcholine antibodies to protect mice from fatal infection with Streptococcus pneumoniae
Authors: Briles David E. , Forman Colynn , Hudak Susan , Claflin J. Latham
Published: February 2007

Anti‐phosphorylcholine (PC) antibodies of the mouse are found in three different idiotype families: T15, M603 and M511. These subgroups exhibit different specificities for PC analogs and utilize light chains of different VL subgroups. In this study we have found that IgG1 antibodies of the T15 idiotype are much more protective against pneumococcal infection than IgG1 antibodies of the M511 or M603 idiotypes. This finding provides additional evidence that the T15 VH and VL genes may have evolved to protect mice from infection with PC‐bearing pathogens.
The D segment defines the T15 idiotype: the immunoresponse of A/J mice to Pneumococcus pneumoniae
Authors: Berek Claudia
Published: February 2007

In the immune response of BALB/c mice (Igha) to Pneumococcus the majority of antibodies express the idiotype of the myeloma protein TEPC15 (T15). In contrast mice of the A/J strain (Ighe) do not express this idiotype. Using (BALB/c × A/J)F1, F2 or backcross mice it could be shown that in allotype heterozygous animals (Igha/e) Pneumococcus pneumoniae preferentially stimulates B cells expressing a heavy chain (H) encoded by genes in the BALB/c H chain gene complex. Phosphorylcholine (PC)‐specific hybridoma lines were established from BALB/c and A/J spleen cells and idiotypically analyzed using monoclonal antibodies (mAb) specific for the T15 idiotopes 32/65, 10/13, 16/13 or 21A5. Whereas the majority of the BALB/c PC‐binding mAb express these idiotopes, only some of the A/J mAb are positive for one or the other of the idiotopes formed by the variable (V) regions of the H and the light chain of the myeloma protein T15. However, 80% of the A/J PC‐binding hybridoma proteins were bound by the anti‐idiotopic mAb 21A5. This mAb is specific for a determinant partially formed by the Cα and partially by the V regions of the myeloma protein T15. The mRNA of one of these T15− A/J PC‐binding hybridoma lines was sequenced. VH and Vx were identical with sequences found for BALB/c T15‐like antibodies. The sequence of the D segment was structurally very different. The importance of the D segment in the dominant expression of the T15 idiotype is discussed.
Direct evaluation of antigen binding to human T lymphocyte clones: involvement of major histocompatibility complex products in antigen binding
Authors: Zanders Edward D. , Feldmann Marc , Green Nicola , Lamb Jonathan R.
Published: February 2007

Cloned human helper T lymphocytes reactive with a defined peptide (p20; residues 306‐329) of the HA‐1 molecule of influenza virus hemagglutinin were analyzed for their capacity to specifically bind peptide antigen. Three different methods of analyzing antigen binding to T cell receptors were compared. One method involved the binding of radiolabeled T cells to antigen‐pulsed populations of sheep erythrocyte rosette‐negative (E−) cells (B cells and monocytes). The binding was antigen specific, in that only E− cells pulsed with the appropriate antigen bound the treated T cells, and was inhibitable by free peptide. Furthermore, antigen binding was major histocompatibility complex‐restricted in that only E− cells histocompatible at the HLA‐D region locus bound the T cells, and monoclonal antibody of the relevant specificity was able to inhibit the binding. Secondly, it was demonstrated that tritiated T cells could bind to insolubilized antigen (p20) in the absence of E− cells. The binding was inhibited by anti‐class II antibody suggesting that the interaction of antigen with the T cells involves recognition of T cell major histocompatibility complex class II determinants. Finally, radiolabeled peptides were also used to detect binding to the appropriate clones in the absence of presenting cells. This binding was specific, inhibitable by the appropriate unlabeled peptide and temperature dependent. These studies demonstrate that the process of antigen binding to receptors is analyzable and should in turn facilitate the analysis of the mechanism of T cell activation.
Analysis of immunological tolerance to major histocompatibility complex antigens. I. High frequencies of tolerogen‐specific cytotoxic T lymphocyte precursors in mice neonatally tolerized to class I major histocompatibility complex antigens
Authors: Heeg Klaus , Wagner Hermann
Published: February 2007

Injection of (CBA × A)F1 cells into neonatal CBA mice rendered them tolerant to skin grafts of (CBA × A)Fi origin. Limiting dilution analysis revealed a very low frequency of tolerogen‐inducible cytotoxic T lymphocyte precursors (CTL‐P) in spleens of tolerant mice. Two in vitro procedures allowed, however, the induction of tolerogen‐specific CTL‐P of high frequencies in tolerant mice: (a) the “by‐pass” activation of spleen cells from tolerant mice by concanavalin A under short‐term bulk culture conditions followed by culture of limiting numbers of activated responder cells, and (b) absorption of spleen cells from tolerant mice on monolayers of tolero‐gen‐activated T cells from normal syngeneic mice. Furthermore, spleen ceils from tolerant mice, recently challenged with a tolerogen ‐ bearing skin graft, specifically suppressed the activation of tolerogen ‐ reactive splenic CTL‐P from normal CBA mice under limiting dilution conditions. These data confirm the presence of tolerogen‐specific CTL‐P of high frequency in tolerant mice and suggest their functional inactivation through a suppressive mechanism.
The murine thymic nurse cell: An isolated thymic microenvironment
Authors: Andrews Paul , Boyd Richard L.
Published: February 2007

The thymic nurse cell (TNC) consists of an epithelial cell enclosing lymphoid elements and is found in enzymic digests of the thymus. Although these structures have been implicated in the normal intrathymic development of T lymphocytes, little is known about the in situstructure of this unusual cell complex. In this study, various dyes were introduced into the intact thymus and their differential permeability was used to demonstrate that the TNC exists as a sealed structure in situ.The lymphocytes within the TNC were shown to be isolated from the general thymic environment. Prelimi‐ nary studies on these lymphocytes and the physiology of their active release from individual, micromanipulated TNC in microcultures are reported.
Suppression of polyclonal B cell activation by IgG‐binding factors. Requirement for T cells
Authors: Bich‐Thuy Lě Thi , Revillard Jean‐Pierre
Published: February 2007

IgG‐binding factors (IgG‐BF) prepared from cell‐free supernatant of human peripheral blood mononuclear cells interfere with the polyclonal activation of peripheral B cells by decreasing the numbers of IgG‐containing cells and Ig plaque‐ forming cells. Using Nocardia opaca delipidated cell mitogen (NDCM), a T helper cell‐independent polyclonal B cell activator, it was found that the suppressive effect of IgG‐BF was no longer demonstrable after removal of T cells. In pokeweed mitogen‐stimulated cultures, the suppression by IgG‐BF required the presence of radiosensitive T cells. Selective depletion of OKT4+ or OKT8+ subsets in NDCM‐stimulated cultures showed that IgG‐BF required the presence of OKT4+ lymphocytes to induce suppression. It is concluded that the effect of human IgG‐BF was mediated by one or several subsets of T cells.
Early expression in (NZB × DBA/2)F1 hybrids of thymus dysfunction and abnormal antibody production inherited from the NZB parent
Authors: Quere Pascale , Savino Wilson , Dardenne Mireille , Bach Marie‐Anne
Published: February 2007

NZB mice, DBA/2 mice and reciprocal F1 hybrids between both strains were studied from birth to two months of age for the secretion of a serum thymic factor, thymulin (formerly named Facteur Thymique Sérique) and for spontaneous and antigen‐induced immune responses: spontaneous splenic anti‐2,4,6‐trinitrophenyl (TNP) plaque‐forming cells (PFC), spontaneous IgM serum levels, immune direct anti‐sheep red blood cells (SRBC) PFC and immune serum antibody production to human gamma globulin (HGG) as well as susceptibility to tolerance induction by deaggregated HGG. An early decline of thymulin serum level was detected from two weeks of age both in NZB mice and F1 hybrids, the latter maintaining a level intermediate between that of both parental strains. Such a fall of circulating thymulin was associated to a decreased number of thymulin‐secreting cells.

F1 hybrids and NZB mice exhibited at two and three weeks of age spontaneous anti‐TNP PFC in the spleen, and increased IgM serum levels as compared to DBA/2 mice. When immunized at birth with SRBC or at two weeks of age with HGG, NZB mice and F1 mice similarly exhibited a higher anti‐SRBC antibody response, as measured 5 days later by PFC numbers, and a higher anti‐HGG serum antibody production 2 weeks post‐immunization, than age‐matched DBA/2 mice. F1 hybrids tended to develop with age spontaneous and immune antibody responses lower than NZB mice but still much higher than DBA/2 mice. Conversely, after tolerization at birth with deaggregated HGG NZB mice but not the F1 hybrids produced higher titers of anti‐HGG antibodies upon challenge than similarly tolerized DBA/2 mice. DBA/2 mothered and NZB mothered Fl hybrids did not differ for any parameter tested and no influence of the sex could be detected.
Genetic control of B cell function. III. IgVH‐controlled polymorphism in the frequencies of B cells that recognize xenogeneic red blood cells
Authors: Saizawa Kay M. , Melchers Inga , Eichrnann Klaus
Published: February 2007

Previous work has shown that the primary IgM plaque‐forming cell response of inbred mice to xenogeneic red blood cells (RBC) including sheep, horse and chicken RBC is under the control of two polymorphic genes or sets of genes, one linked to the Igh linkage group and the other of unknown linkage but unlinked to H‐2 and a variety of other known genetic markers. Both genes together control B cell function but do not influence the function of T cells and macrophages. Thus, this system permits the study of two polymorphic loci that control B cell responsiveness. In this study we analyze the role of the Igh region in further detail. In bulk cultures and limiting dilution experiments, we confirm its exclusive influence on B cells also when analyzed separately from the background gene, i.e. in Igh‐congenic strains. Moreover, we find in the majority of experiments 4‐5‐fold differences in sheep RBC‐specific B cell precursor frequencies among lipopolysaccharide‐reactive cells from 3 pairs of Igh‐congenic high and low‐responder strains. Similar frequency differences exist for horse RBC and chicken RBC‐specific B cells but not for B cells with specificity for (4‐hydroxy‐5‐iodo‐3‐nitrophenyl)acetyl (NIP)‐gelatine. These differences are independent of the frequencies of B cells responding to lipopolysaccharide which are shown to be equal between Igh‐congenic pairs of strains. Since the differences in RBC‐specific B cell frequencies closely resemble the differences in bulk culture responses to the corresponding RBC, we conclude that the role of the Igh linkage group in controlling responsiveness to RBC lies in a selective influence on the B cell repertoire concerning precursor cells for RBC specificity. In addition, we find that the VH part of Igh is responsible for the observed frequency differences, suggesting that VH germ‐line genes directly influence the composition of the mature B cell repertoire.
Monoclonal antibodies specific for murine IgM. II. Activation of B lymphocytes by monoclonal antibodies specific for the four constant domains of IgM
Authors: Leptin Maria
Published: February 2007

Seventeen monoclonal antibodies specific for IgM and one ϰ light chain‐specific antibody were used to test the effect of immunoglobulin (1g)‐specific antibodies on B cell activation. In soluble form, either alone or together with T cell‐derived growth and maturation factors, none of the antibodies stimulated resting B cells to divide or secrete Ig. The soluble antibodies inhibited lipopolysaccharide‐induced B cell activation. The inhibitory effect of the antibodies was independent of their Fc part. When immobilized, the same antibodies could activate B cells to proliferate and together with T cell‐derived maturation factors to mature to plasma cells. Occupation by immobilized antibody of determinants on any of the four constant region domains and on the light chain of surface Ig can lead to the stimulation of B cells.
Frequency and surface phenotype of human T lymphocytes producing interleukin 2. Analysis by limiting dilution and cell cloning
Authors: Moretta Alessandro
Published: February 2007

In this study we have determined the frequency and distribution of interleukin 2 (IL2)‐producing cells and their precursors (IL2‐P) in the two major subsets of human T cells. The two subsets were identified on the basis of their reactivity (or lack thereof) with anti‐T4 or anti‐T8 monoclonal antibodies. T4+T8− and T4−T8+ cells were first isolated from peripheral blood T cell populations by positive or negative selection using the fluorescence‐activated cell sorter, and then analyzed for total IL2‐P and cytolytic T lymphocyte precursor (CTL‐P) frequencies using a limiting dilution microculture system which allows clonal growth of every T cell. The results indicated that 50‐60% of peripheral blood T cells consisted of IL2‐P. In the T4+T8−subset (which represents 60‐65% of all T cells) about 75% of the cells were IL2‐P, whereas about 15% of T4−T8+ cells exhibited this functional potential. In contrast, about 3% and > 95% of T4+T8− and T4‐T8+ cells, respectively, were CTL‐P. Thus, these data provide direct evidence that there is no absolute correlation between the surface phenotype and the functional potential of human peripheral blood T cells. Moreover, it is evident from this frequency analysis that a significant proportion of T4−T8+ cells have a dual functional potential. IL2‐P and CTL‐P frequencies were also determined in T cell populations which had been activated in allogeneic mixed lymphocyte culture. The IL2‐P frequencies in total T, T4+T8− and T4−T8+ MLC populations were 30, 45 and lo%, respectively. Comparative analysis of IL 2 production and CTL activity at the clonal level confirmed that up to 20% of alloreactive CTL with the T4−T8+ surface phenotype were able to produce IL2 upon specific stimulation. This dual functional capacity was also observed among T4+TS− CTL.
Antibodies to surface IgM and IgD increase the expression of various class II antigens on human B cells
Authors: Godal Tore , Davies Catharina , Smeland Erlend B. , Heikkilä Reino , Funderud Steinar , Steen Harald B. , Hildrum Kari
Published: February 2007

Antibodies to surface IgM and IgD were found to induce increased expression of class I1 antigens on normal and neoplastic human B cells within 24 h of stimulation. Antigens associated with different class II sub‐locus genes (DC, DR and SB) were all found to be increased as determined by monoclonal antibodies (Leu‐10 and B 3/4 for DC, D1/12 for DR and MHM4 for SB‐associated antigens). The increased expression of class 11 antigens was selective as anti‐immunoglobulins failed to increase expression of other surface antigens such as B1 and β2‐microglobulin. The effect of anti‐μ and anti‐μ could be blocked specifically by corresponding myeloma proteins suggesting that antibodies to surface IgM and IgD, respectively, were responsible for the effect observed. Moreover, antibodies to another surface antigen (B1) failed to induce such changes. Increased class II antigen expression appeared to be dependent on protein synthesis, and early changes in ion fluxes, but could not be elicited by membrane depolarization as reported in murine systems.
The action of human C3 in soluble or cross‐linked form with resting and activated murine B lymphocytes
Authors: Erdei Anna , Melchers Fritz , Schulz Thomas , Dierich Manfred
Published: February 2007

The third component of complement C3 has been implied in the stimulation of B lymphocytes to proliferation and maturation for Ig secretion. We have reinvestigated the extent of this activation with either activated or resting murine splenic lymphocytes in serum‐substituted cultures. Human C3 was used in either soluble or cross‐linked form. Soluble as well as Sepharose‐bound or glutaraldehyde‐cross‐linked C3, over a range of concentrations, was inactive with resting splenic lymphocytes of (C57BLW/6J × DBA/2)F1 C3H/HeJ and C57BL/6J nu/nu mice. However, lipopolysac‐charide‐activated spleen cells, enriched for B cell blasts, were stimulated by immobilized and cross‐linked C3, while they did not respond to soluble C3. The extent of restimulation was comparable to that indiced by lipopolysaccharide and resulted in both increased proliferation and maturation to Ig‐secreting cells. The stimulation of the blast cells appears to be C3 specific, since it can be inhibited by free c3.
B cell growth factor activity of immunoaffinity‐purified and recombinant human interleukin 2
Authors: Mingari Maria Cristina , Gerosa Franca , Moretta Alessandro , Zubler Rudolf H. , Moretta Lorenzo
Published: February 2007

We investigated the effect of recombinant and affinity‐purified human interleukin 2 (IL2) on human B cell proliferation. Five × lo4 nonadherent spleen cells that had been depleted twice of T cells were activated by 3‐day culture with formaldehyde‐killed Staphylococcus aureus Cowan strain I (SAC) prior to addition of tested growth factors. Cultures were harvested 72 h later. It was found that both IL 2 preparations led to optimal cell proliferation compared with a control supernatant obtained by 36 h phytohemagglutinin stimulation of spleen mononuclear cells. Moreover, the effect of such spleen supernatant on B cell proliferation correlated with the IL2 activity since its B cell growth factor activity (BCGF) was not greater than that of purified IL2 and no residual BCGF activity could be detected after absorption of all IL 2 activity by the IL2‐dependent cytotoxic T lymphocyte line cells. T cells, enumerated as E‐rosetting cells as well as T3+ cells, represented 0.2 to 2% of the cells recovered at termination of the cultures (day 6) and there were < 1% E‐rosetting cells in freshly purified or SAC‐activated (day 3) B cell populations. Therefore, we conclude that IL2 is a growth factor not only for activated T cells but also for activated human B cells.
B cell activation and adjuvant activities of chemically synthesized analogues of the nonreducing sugar moiety of lipid A
Authors: Kumazawa Yoshio , Matsuura Motohiro , Homma J. Yuzuru , Nakatsuru Yoko , Kiso Makoto , Hasegawa Akira
Published: February 2007

Immunological activities of synthetic lipid A analogues (derivatives of 3‐O‐tet‐ radecanoyl D‐glucosamine) were investigated. Compounds possessing a N‐tet‐ radecanoyloxytetradecanoyl group with or without a 4‐O‐phosphoryl group exhibited both mitogenic and polyclonal B cell activating activities. Among these, the phos‐phorylated compound exhibited strong activity. 4‐O‐phosphorylated analogues with a N‐tetradecanoyl group or 6‐O‐tetradecanoyl group in addition to N‐3‐hydroxyacyl groups showed no activity. All the analogues tested showed adjuvant activity, which was determined by augmentation of IgM antibody response against sheep erythrocytes. Relationship between chemical structure and biological activities is also discussed.
Segregation of reactivity to the mitogens lipopolysaccharide, lipoprotein and dextran sulfate in clones of the B cell lymphoma line WEHI 279.1
Authors: Kleine Bernhard , Bessler Wolfgang , Coutinho António
Published: February 2007

The B cell lymphoma line WEH1279.1 (surface IgM+, I‐A+ and I‐E+) was used as a model system to analyze functional reactivity of B lymphocytes to mitogens. Among the mitogens tested, lipopolysaccharide (LPS), lipoprotein (LP), and dextran sulfate (DxS) all induced a strong, dose‐dependent growth inhibition of tumor cells. The analysis of independently derived clones, however, revealed that mitogen sensitivity could be lost in the absence of detectable alterations in the expression of those surface markers. Moreover, reactivity to LPS, LP and DxS segregated independently in these clones, suggesting distinct triggering mechanisms and functional receptors for these mitogens on the B cell membrane.
Murine intestinal intraepithelial lymphocytes. II. Comparison of freshly isolated and cultured intraepithelial lymphocytes
Authors: Ernst Peter B. , Petit Agnes , Befus A. Dean , Clark David A. , Rosenthal Ken L. , Ishizaka Teruko , Bienenstock John
Published: February 2007

Highly enriched preparations of intraepithelial lymphocytes (IEL) containing a large subpopulation of granulated cells were isolated from the murine small intestinal mucosa. We cultured IEL in media containing interleukin 2 (growth media conditioned with 20% concanavalin A supernatant; Con ACM) or mast cell growth factor(s) (growth media conditioned with 40% WEHI‐3 supernatant; WEHI CM) and compared the physical and functional properties of the cultured cells to freshly isolated IEL. IEL cultured in Con A CM developed enhanced cytotoxicity against YAC‐1, compared to freshly isolated IEL, and spontaneous cytotoxicity for P815 targets. Most of these cultured cells were Thy‐1+ Lyt‐1− Lyt‐2+, and contained cyto‐ plasmic granules similar to those seen in electron photomicrographs of other cytotoxic cell populations.

IEL cultured in WEHI CM gave rise to cells that morphologically resembled mast cells. Unlike freshly isolated IEL, the cells stained metachromatically, contained 20C‐450 ng of histamine/106 cells and expressed high‐affinity receptors for IgE. Our data clearly show that, although IEL do not themselves have physical characteristics of mast cells, they do contain mast cell precursors. In addition, IEL grown in the presence of T cell growth factors give rise to an activated cytotoxic cell population which is mostly granulated and Thy‐1+ Lyt‐1− Lyt‐2+.