bluuebunny/crossref_metadata_2025 huggingface dataset:
Defined antigens secreted by the larvae of schistosomes protect against schistosomiasis: induction of cytotoxic antibodies in the rat and the monkey
Authors: Auriault Claude , Damonneville Marline , Joseph Michel , Capron Monique , Verwaerde Claudie , Billaut P. , Capron Andrè
Published: February 2007

The study of the immunology of schistosomiasis has allowed a clear understanding of the basic mechanisms of resistance, emphasizing the important role played by cellular and humoral factors. Whereas the production of polyclonal or monoclonal antibodies and the precise inventory of immune effector mechanisms in the rat and in man have led to the identification of potentially protective antigens, immunization with soluble schistosome components has not allowed a successful control of the destruction of schistosomula after infection. The experiments reported here show that schistosomulum‐released products (SRP) were able to induce the production of antibodies, in the rat and the monkey, highly cytotoxic in antibody‐dependent cellular cytotoxicity, using monocyte monolayers, platelets or eosinophils as effector cells. The immunization of rats with either total SRP or 25‐30‐kDa molecules purified from schistosomula conferred a significant protection towards a challenge infection by the parasite. IgE and to a lesser extent IgG antibodies represented the major humoral factors of cell activation leading to the schistosomulum killing when anti‐SRP antisera, obtained after immunization of the monkey, were incubated with human effector cells.
Cytotoxic T lymphocyte‐mediated lysis via the Fc receptor of target cells
Authors: Staerz Uwe D. , Bevan Michael J.
Published: February 2007

The murine monoclonal antibody F23.1 reacts with an allotypic determinant on the T cell receptors of about 25% of peripheral T lymphocytes in most common mouse strains. In this report we demonstrate that this IgG2, antibody bound to the receptor of a cytotoxic effector T cell can direct that cell to lyse any target cell which expresses receptors for IgG2,. Thus, allotype‐positive, Lyt‐2′ T lymphocytes from either concanavalin A‐ or F23.1‐activated cell cultures are recruited as cytotoxic effector cells which lyse targets via the Fc receptor. Concanavalin A‐induced T cell blasts depleted of Lyt‐2′ cells do not mediate cytotoxic effects in this system. The data presented here confirm earlier observations that monoclonal anti‐T cell receptor antibodies attached to the surface of a cell can act as target structures for T cell‐mediated lysis.
Inhibition of helper function with anti‐Lyt‐2 or anti‐L3T4 monoclonal antibodies depending on stimulating antigens
Authors: Guimezanes Annick , Schmitt‐Verhulst Anne‐Marie
Published: February 2007

The role of L3T4+ and Lyt‐2+ cells in the induction of cytotoxic T cells (CTL) after stimulation with trinitrobenzene sulfonate (TNBS)‐treated syngeneic cells, or with cells differing for the entire major histocompatibility complex or for class I molecules alone was investigated using anti‐L3T4 and anti‐Lyt‐2 monoclonal antibodies (mAb). Anti‐L3T4 mAb inhibited both induction of CTL and interleukin 2 (IL2) production by T cells stimulated with allogeneic (class I + class II differences) or by TNBS‐treated syngeneic cells. In the same culture conditions, anti‐Lyt‐2 mAb inhibited CTL induction but had no effect on IL2 production. By contrast, only anti‐Lyt‐2 mAb inhibited both CTL induction and IL2 production when T cells were stimulated by allogeneic cells differing only for class I antigens. Anti‐L3T4 mAb had no inhibitory effect in this situation.

These results indicate that two helper pathways can be activated, depending on the type of T cell stimulation: one, implicating L3T4+ cells, is used when stimulation involves class I and class II alloantigens or hapten on syngeneic cells; the other, involving Lyt‐2+ T cells, is preferentially stimulated when responding and stimulating cells differ only for class I major histocompatibility complex antigen.
2,4‐Dinitrophenyl (DNP)‐specific continuous B cell lines as a model system for studying B cell activation and tolerance
Authors: Aldo‐Benson Marlene , Scheiderer Linda , Dwulet Francis E.
Published: February 2007

Various model systems have been used to study isolated B cell response to receptor cross‐linking and to lymphokines. Although each model is useful it is advantageous to have continuous cell lines of nonmalignant antigen‐specific B lymphocytes to study antigen‐induced B cell function. We further studied the characteristics of the 2,4‐dinitrophenyl (DNP)‐specific continuous B lymphocyte lines which we previously described (J. Exp. Med. 1983. 157: 342). If the cell line lymphocytes are cultured with the antigen DNP‐Ficoll without the presence of T cell factors or filler cells they do not produce an immune response above background, but the addition of supernatant from EL4 lymphoma and irradiated normal spleen filler cells results in a 7‐ to 10‐fold increase in plaque‐forming cells. The kinetics of the immune response is the same as that seen with normal B cells. Each cell line has a majority of cells which are small surface (s)IgM− lymphocytes which have cytoplasmic IgM and react with 14.8 antibody. There are also large sIgM+‐bearing cells, which may be either in the resting or activated state. Some of the sIgM+ cells also bear IgD and Ia antigens but they do not bear IgG. From these studies we conclude that the continuously growing antigen‐specific B cell lines can be a useful model to study B cell function.
The high idiotypic connectivity of “natural” newborn antibodies is not found in adult mitogen‐reactive B cell repertoires
Authors: Holmberg Dan , Wennerström Gunilla , Andrade Luis , Coutinho António
Published: February 2007

Unselected IgM‐secreting hybridoma collections were established either from unprimed naturally activated newborn spleen cells or from mitogen‐stimulated adult B cells. These were then screened for reactivity with a panel of monoclonal anti‐idiotypic antibodies and haptens. While the finding of hapten‐specific antibodies was equally frequent in either collection, newborn antibodies reacted at least 10 times more frequently with the anti‐idiotypic reagents. The reactivity patterns of individual antibodies readily demonstrated the overall specificity of these V‐region interactions. Since some of the idiotopes screened are characteristically not expressed in immune responses by the strains analyzed, and are in fact not expressed in the adult induced hybridoma collection, we explain these findings by a unique property of the set of natural (newborn) antibodies i.e. the high levels of idiotypic connectivity previously described within this repertoire.
Molecular requirement for interleukin 1 induction by lipopolysaccharide‐stimulated human monocytes: Involvement of the heptosyl‐2‐keto 3‐deoxyoctulosonate region
Authors: Lebbar Souad , Cavaillon Jean‐Marc , Caroff Martine , Ledur Annick , Brade Helmut , Sarfati Robert , Haeffner‐Cavaillon Nicole
Published: February 2007

Experiments were undertaken to localize in the lipopolysaccharide (LPS) the minimal structural determinants sufficient to initiate the signal leading to interleukin 1 (IL 1) secretion by human monocytes. Our results clearly demonstrated that this signal is triggered by structures present in the so‐called inner‐core region which chemically consists of 2‐keto‐3‐deoxy‐wD‐manno‐octulosonic acid (KDo) and heptose in many LPS of gram‐negative bacteria. Thus, the isolated polysaccharide region of Bordetella pertussis endotoxin as well as fragments derived therefrom containing the reducing KDO unit were able to induce similar levels of IL1 induction as the native LPS. Similarly, the trisaccharide α‐D‐manno‐heptopyranosyl‐(1–3)‐α‐D‐manno‐heptopyranosyl‐(1–5)‐3‐deoxy‐D‐manno‐octulosonic acid (hep‐hep‐KDO), representative for the inner‐core region of a large number of enterobacterial LPS, was a very potent IL 1 inducer. Neither KDO monosaccharide, nor the α‐(2–4)‐linked 3‐deoxy‐D‐manno‐octulosonic acid disaccharide isolated from Salmonella rough‐form LPS promoted the signal indicating that the minimal structure of endotoxin able to induce IL 1 secretion resides in the hep (1–5)‐KDO disaccharide.
A 30‐kDa protein is disulfide linked to IgM on normal and neoplastic murine B lymphocytes
Authors: Haustein Dieter , Ahe Dietmar Von Der
Published: February 2007

Four cloned continuously cultured mouse B lymphoma cells of the lines WEHI‐279, BCL1 and 38C‐13 were used to study the surface presentation of IgM. Cells of all lines expose, in addition to μ2L2, various disulfide‐linked subunits as already shown for normal B lymphocytes (Koch, N. and Haustein, D., Mol. Immunol. 1982. 19: 477). In contrast to normal B cells, B lymphoma cells also carry IgM structures of higher molecular weight than μ2L2 on their surface. Furthermore, B lymphoma cells of all investigated lines expose a μ2L2 structure to which a 30‐kDa protein is disulfidelinked. This 30‐kDa protein could also be identified on normal mouse B lymphocytes when more drastic conditions were employed. μ2L2 disulfide linked to this 30‐kDa protein is the main IgM structure on normal and neoplastic B cells whereas only small amounts of μ2L2 (unlinked to this protein) can be detected.
Avian B cell precursors: Surface immunoglobulin expression is an early, possibly bursa‐independent event
Authors: Ratcliffe Michael J. H. , Lassila Olli , Pink J. Richard L. , Vainio Olli
Published: February 2007

The avian bursa of Fabricius contains about 1 × 104 discrete follicles, each of which is colonized by a small number of lymphoid progenitor cells during embryonic life. We have previously shown (J. R. L. Pink et al., Eur. J. Immunol. 1985. 15: 617) that all, or almost all B cell progenitors in the bursae of 4‐day‐old chicks express cell surface IgM. In this report, we have analyzed the distribution of cell surface (s)IgM‐1 allotypes within individual follicles of (M‐1a/M‐1b) allotype heterozygous birds. Although the majority of follicles contained a mixture of sIgM‐1a+ and sIgM‐1b+ cells, a significant proportion of isolated follicles contained exclusively sIgM‐1a+ or sIgM‐1b+ cells. Statistical analysis of the frequency of such “M‐1a” and “M‐1b” follicles demonstrated that the sIg+ B cells in the bursae of 4–8‐week‐old birds are derived from 2–4 allotypically committed precursor cells per follicle. Since we have previously shown that each bursal follicle is colonized by 2–5 pre‐bursal stem cells, these cells must be committed to the eventual expression of one or other allotypic haplotype before they have undergone extensive proliferation within the bursa.

In addition, we show that almost all B progenitor cells from the bursae of chicks which had been allotype suppressed as embryos were committed to synthesis of the nonsuppressed allotype, showing that this commitment was essentially complete at the time of suppression (i.e. before 19 days of incubation). Finally the bone marrow of 16‐day embryos was used to reconstitute the bursal lymphocytes of cyclophosphamide‐treated host embryos. Reconstitution was inhibited by anti‐Ig antiserum indicating that most 16‐day embryonic BM‐derived bursal cell precursors also express sIgM. These results raise the possibility that expression of sIgM may be controlled by a “biological clock” rather than by any inductive capacity of the bursal microenvironment. Furthermore, these results provide further evidence that in normal birds a self‐renewing sIg+ B cell population in the hatched chicken is the sole source of B cells in the adult.
Quantitative and qualitative differences in HLA‐DR molecules correlated with antigen‐presentation capacity
Authors: Bontrop Ronald , Ottenhoff Tom , Miltenburg Rob Van , Elferink Diënne , De Vries René , Giphart Marius
Published: February 2007

The monoclonal antibodies 7.3.19.1 (anti‐DRw52‐like) and B8.11.2 (anti‐DR framework) were used for the isolation and characterization of HLA class II molecules expressed by HLA‐DR3 and DR5 homozygous B cell lines. Sequential immunoprecipitation studies demonstrated that from these cells class II molecules can be isolated which are characterized by the presence or absence of DR framework (DR) and DRw52‐like (DRw62) determinants: (DR+, DRw52+), (DR+, DRw52−) and (DR−, DRw52+). The DR3 donor cells appeared to express only the (DR+, DRw52+) and (DR−, DRw52+) class II molecules whereas DR5‐positive cells express only the (DR+, DRw52+) and (DR+, DRw52−) class II molecules.

Besides qualitative differences some of the above‐mentioned molecules appeared to differ in their levels of expression. To investigate whether this might have functional implications, cells with the HLA‐DR3 and −5 haplotypes were used to present antigen purified protein derivative of tuberculin (PPD) to PPD‐specific T cell lines and the blocking capacity of the two monoclonal antibodies 7.3.19.1 and B8.11.2 was determined. A remarkable correlation was observed between the type of class II molecule blocked by these monoclonal antibodies and its quantitative expression. However, (DR−, DRw52+) molecules, clearly expressed by DR3 cells, were not involved in the presentation of PPD. This indicates that not only quantitative but also qualitative aspects may play a role in the selection of the type of class II molecule that will be involved in antigen presentation.
Transfer of immune complexes from lymphocytes to follicular dendritic cells
Authors: Heinen Ernst , Braun Michel , Coulie Pierre G. , Van Snick Jacques , Moeremans Marc , Cormann Nadine , Kinet‐Denoël Cécile , Simar Léon J.
Published: February 2007

Antigens in the form of immune complexes are retained on the membranes of follicular dendritic cells (FDC) for long periods of time. To examine how immune complexes reach germinal centers, where FDC are located, we injected mice with anti‐2,4‐dinitrophenyl (DNP) antibodies complexed to DNP‐myoglobin‐coated gold particles. The distribution of the particles in spleens or draining lymph nodes was then determined with the electron microscope. The vast majority of the particles were cell bound. Shortly after injection they were phagocytized by macrophages or fixed on lymphocytes. The latter were found even in the corona of lymph follicles but not in germinal centers. Already 30 min after injection, FDC in contact with the corona were faintly positive but were negative in the center. FDC precursor cells were occasionally observed but in too small a number to account for the transport of immune complexes to the germinal centers. Twenty‐four hours after injection colloidal gold particles were found in phagolysosomes of macrophages or on cytoplasmic extensions of FDC in all parts of the germinal centers.

Experiments performed on isolated FDC showed that they are not only able to take up free immune complexes but are also able to adsorb immune complexes from pulsed lymphocytes. These results strengthen the idea that lymphoid cells binding immune complexes by their Fc receptors may transport these complexes inside germinal centers.
A monoclonal antibody against altered LFA‐1 induces proliferation and lymphokine release of cloned T cells
Authors: Pircher Hanspeter , Groscurth Peter , Baumhütter Susanne , Aguet Michel , Zinkernagel Rolf M. , Hengartner Hans
Published: February 2007

A murine monoclonal antibody (I‐17, IgM) has the following functional effects on murine long‐term T cell clones: inhibition of cell‐mediated lysis, induction of proliferation, release of lymphokines and change of the cell morphology. The determinant detected by I‐17 is expressed on long‐term T lines but not on thymocytes, lymph node cells and spleen cells. I‐17 precipitated proteins with apparent molecular mass of 220 kDa, 170 kDa, 150 kDa and 100 kDa. Biochemical studies indicate that the determinant recognized by I‐17 is tunicamycin sensitive and that I‐17 binds to the a chain of the lymphocyte function‐associated antigen (LFA‐1).
The influence of phagocytic stimuli on the expression of HLA‐DR antigens; role of reactive oxygen intermediates
Authors: Gruner Stefan , Volk Hans‐Dieter , And Peter Falck , Baehr Rudiger Von
Published: February 2007

Human peripheral blood mononuclear cells show after one day of culture with opsonized zymosan a decreased expression of HLA‐DR (but not HLA‐A, B, C) antigens, which can be prevented by the scavenger of reactive oxygen intermediates β‐carotene, or superoxide dismutase or indomethacin. Mononuclear cells of a patient with a heterozygous form of chronic granulomatous disease show no alterations in HLA‐DR antigen expression after culture with opsonized zymosan. Possible roles of reactive oxygen intermediates or prostaglandins in the modulation of HLA‐DR antigens are discussed.
Antibody recognition of ragweed allergen Ra3: Localization of the full profile of the continuous antigenic sites by synthetic overlapping peptides representing the entire protein chain
Authors: Atassi Hammad , Atassi M. Zouhair
Published: February 2007

A comprehensive synthetic approach, for the localization of the full profile of the continuous antigenic sites on proteins, previously introduced by this laboratory, was applied here to localize the continuous antigenic sites of ragweed allergen, Ra3. The following 10 consecutive peptides, each comprising 15 residues (except for peptide 91–101) and overlapping each of its neighbors by 5 residues, were synthesized and purified: 1–15, 11–25, 21–35, 31–45, 41–55, 51–65, 61–75, 71–85, 81–95 and 91–101. Quantitative radiometric titrations of protein and peptide adsorbents were performed with 125I‐labeled anti‐Ra3 IgG antibodies from rabbit, outbred mouse and human antisera. The specificity of antibody binding to peptide adsorbents was confirmed by inhibition experiments. These studies established the full profile of antigenic (IgG‐binding) sites of Ra3 and permitted comparison with the allergenic (IgE‐binding) sites recently localized. It was found that the recognition by IgG antibodies was independent of the host species in which the antibodies were raised. Furthermore, the regions recognized by human IgE antibodies coincided with those recognized by IgG antibodies in three different species. Thus, Ra3 was found to have 4 continuous antigenic sites which occupy the same locations as the allergenic sites.
The p150,95 molecule is a marker of human mononuclear phagocytes: Comparison with expression of class II molecules
Authors: Hogg Nancy , Takacs Laszlo , Palmer David G. , Selvendran Yogi , Allen Catherine
Published: February 2007

A new monoclonal antibody (mAb), named 3.9, is described that is specific for the p150,95 molecule, a member of the LFA‐1, CR3, p150,95 family of human leukocyte differentiation antigens. The LFA‐1 molecule participates in a variety of T cell interactions and the CR3 molecule is the receptor for the complement component iC3b, but little is known about the p150,95 molecule. Here we show that the expression of p150,95 is confined to myeloid cells. mAb 3.9 reacts variably with neutrophils, more strongly with monocytes and is most strongly expressed on tissue macrophages. Using this mAb and others, we have examined the heterogeneity of tissue macrophages. Cells such as Langerhans' cells, dendritic reticulum cells and osteoclasts failed to react with these mAb and thus, probably do not belong to the mononuclear phagocyte lineage. Using a new double‐labeling technique, we investigated lymphoid tissue for dendritic cells bearing class II molecules which might function in interactions with T cells. In T cell areas macrophages expressing class II markers were seen but there was no evidence for other types of dendritic or interdigitating cells which expressed class II molecules but not macrophage epitopes. The conclusion from this survey was that the most prominent cell with dendritic morphology found in the T cell areas of lymphoid tissue was a macrophage.
Regulation of thymocyte proliferation and survival by deoxynucleosides. Deoxycytidine produced by thymic accessory cells protects thymocytes from deoxyguanosine toxicity and stimulates their spontaneous proliferation
Authors: Penit Claude , Papiernik Martine
Published: February 2007

Deoxyguanosine (dGuo) inhibits thymic blast DNA synthesis and then induces thymocyte cell death. The dGuo inhibitory action, measured with four different assays (spontaneous thymidine incorporation, immunofluorescent detection of 5‐bromodeoxyuridine incorporation, dye exclusion, tetrazolium salt cleavage), was suppressed in the presence of supernatants from cultures containing phagocytic cells. In particular, we studied the anti‐dGuo activity in supernatants from thymic reticulum cultures (TRS) and in those from phagocytic cells isolated from TR cultures (P‐TR). The anti‐dGuo substance was identified as deoxycytidine (dCyd) by high performance liquid chromatography and other physicochemical studies. Secretion of dCyd by P‐TR is accompanied by thymidine but not by purine nucleoside secretion. A dual mechanism of thymocyte rescue by dCyd was demonstrated by a study of the dose‐dependencies of dCyd‐mediated prevention and reversal, respectively, of the dGuo inhibition. In addition to this exogenously added anti‐dGuo action, dCyd and dCyd‐containing TRS induced significant stimulation of spontaneous thymic blast proliferation, and the kinetics of both effects were identical.

These findings might suggest that a major role of thymic phagocytic cells is the supply of pyrimidine nucleosides to thymocytes resulting in the maintenance of proliferation and protection of at least some thymic blasts from the toxic effects of dGTP accumulation. The role of this system in the intrathymic selection process is discussed.
The receptor for IgE on blood platelets
Authors: Joseph Michel , Capron André , Ameisen Jean‐Claude , Capron Monique , Vorng Han , Pancré Véronique , Kusnierz Jean‐Pierre , Auriault Claude
Published: February 2007

Highly purified blood platelets from man and rat could be induced into cytotoxic effectors against schistosome larvae by an IgE‐dependent mechanism. Such a process implied the existence of a receptor for the Fc part of IgE on the surface of these blood elements. Normal platelets, incubated in the serum of infected individuals as well as in the IgE‐rich serum from asthmatic patients, showed similar capabilities. Flow cytofluorometric analysis evidenced that the platelets bearing IgE receptors represented a subpopulation (20%), the percentage of which was significantly increased (up to 50%) in rats or patients with high levels of circulating IgE. Radiolabeled IgE, whose binding was specifically inhibited by an excess of unlabeled IgE or by anti‐Fcϵ receptor antibody, allowed the demonstration that the receptor for this isotype on the platelet surface was saturable. The binding of increasing amounts of IgE followed a bimodal curve, with less than 1000 sites per platelet showing an affinity coefficient of 3.3 × 107 M−1 at low concentrations, and a Ka of 7.8 × 105 M−1 for higher concentrations. Beyond their interest in the demonstration of cytotoxic properties of thrombocytes, these observations place emphasis on the potential role of the platelets in immediate‐type allergic reactions by their direct interaction with IgE antibody molecules, through a specific receptor.
The role of immunoglobulin receptors in “cognate” T‐B cell collaboration
Authors: Pereira Pablo , Forsgren Stina , Portnoi Denis , Bandeira António , Martinez‐A. Carlos , Coutinho António
Published: February 2007

The functional effects of anti‐Ig antibodies have been investigated, using an experimental system where B cell activation is brought about by direct and specific interactions with T helper (Th) cells without participation of surface Ig releptors on the responding B cell. We have used Th cell lines and clones directed to class II major histocompatibility complex antigens of the responding B cells, and titrated into cooperative cultures either purified rabbit anti‐mouse μ, or monoclonal mouse anti‐δ antibodies. Both types of antibodies greatly enhanced B lymphocyte responses to suboptimal concentrations of functionally efficient Th cells, while they had no effect in cultures containing optimal Th: B cell ratios. In contrast, helper activity by low efficiency Th was, at all Th: B cell ratios, enhanced by appropriate concentrations of anti‐Ig antibodies. Anti‐Ig effects were exclusively observed when B cells were the targets for “cognate” recognition by Th cells. We conclude that ligand binding to surface Ig receptors on resting B cells fails, in our experimental conditions, to overcome “linked” collaboration, but it greatly facilitates productive Th−B cell interactions. Whatever the mechanisms underlying this facilitation, the observations imply roles of surface Ig in Th−dependent B lymphocyte activation other than either passive “focusing” of antigen or activation into reactivity to soluble, unspecific factors.
In situ identification of idiotype‐positive cells participating in the immune response to phosphorylcholine
Authors: Razzeca Kristin J. , Pillemer Eric , Weissman Irving L. , Rouse Robert V.
Published: February 2007

The phosphorylcholine idiotype (Id)/anti‐Id system has been used to study the role of antigen‐specific cells in antigen‐induced microenvironmental changes. Anti‐Id staining of lymph nodes following PC immunization shows the presence of Id on follicular dendritic cells at 12 h and in plasma cells beginning at day 3. Germinal centers began to form at day 3, peaking in size and number at days 8‐10. Scattered Id‐positive small lymphocytes are present in germinal centers but with rare exceptions over 98% of germinal center cells are Id‐negative. Idiotype‐positive small lymphocytes are depleted from primary follicles adjacent to germinal centers but not from distant, unstimulated nodes.

These results extend previous studies showing architectural alterations in lymph nodes following antigenic stimulation and demonstrate antigen‐specific cells are a prominent component of these antigen‐induced microenvironmental changes.
Effector functions and specificities of normal murine T cells stimulated by syngeneic blasts
Authors: Björklund Mariana , Beretta Alberto , Coutinho Antonio , Gullberg Martin
Published: February 2007

Large numbers of syngeneically stimulated T cells are easily obtained by stimulation of splenic T cell populations with irradiated lipopolysaccharide (LPS) blasts. Thus, proliferative T cell responses were obtained after stimulation with allogeneic LPS blasts, concanavalin A (Con A) blasts, normal spleen cells or peritoneal macrophages while only LPS and Con A blasts were competent syngeneic stimulators. The cytolytic activity of T cells stimulated with allogeneic LPS blasts was H‐2 specific, while that of T cells stimulated with syngeneic LPS blasts was often completely nonspecific, and higher for LPS than for Con A blast target cells. In other experiments, “self” H‐2K‐and I‐A‐specific cytotoxic T cells were obtained, without apparent reasons for the development of either type of cytolytic cells. Stimulation of Lyt‐2− T cells with syngeneic LPS blasts led to the generation of T helper effector cells which induced normal B cell proliferation in an H‐2 restricted manner. This restriction was overcome, the proliferative responses were augmented and plaque‐forming cell responses generated, through addition of Con A to the cultures. The results imply the ability of B blasts to induce stimulation of syngeneic T cells, and generation of effector cells displaying cytolytic and helper activity. This phenomenon might play a role in the regulation of the immune system.
NK‐9, a distinct sialylated antigen of the T200 family
Authors: Nieminen Pekka , Saksela Eero
Published: February 2007

The nature and properties of antigens detected by a novel monoclonal antibody, NK‐9, were studied. The NK‐9 antigens had apparent molecular masses of 190, 200 and 220 kDa and were sensitive to neuraminidase and sodium metaperiodate treatments, which destroy the sialic acid residues of the cell surface glycoproteins. Trypsin treatment also removed the NK‐9 reactivity, but the antigens were restored within a few hours thereafter. Tunicamycin, which inhibits the N‐linked glycosylation after neuraminidase treatment, had no effect on the reappearance of the NK‐9 positivity. Neither did endoglycosidase F, which removes the N‐linked sugars, abolish the NK‐9 antigenity. Monensin, which blocks the cellular secretion, inhibited the restoration of the antigens, and monensin block also without preceding treatment with neuraminidase led to the disapperance of NK‐9 reactivity, suggesting possible recycling molecules as carriers of the NK‐9 detected epitopes. The NK‐9 antigens appear to belong to the T200 antigen family, but are distinct from the antigens reactive with the available anti‐T200 antibodies anti‐LC, T29/33 and HLe‐1, based on their different cell type distribution and absence of cross‐reactivity in sequential immunoprecipitations.
Construction of chimeric thymuses in the mouse fetus by in utero surgery
Authors: Salaün Josselyne , Calman Françoise , Coltey Monique , Le Douarin Nicole M.
Published: February 2007

Normal thymuses develop in the coelomic cavity of mice following grafts carried out in utero into embryonic day 16 to 17 fetuses of the third branchial arch region removed from 10‐day embryos. The recipients were killed at various times (up to 29 days after birth) and the thymic lobes which developed from the graft were recovered. Microscopical examination and immunocytochemistry revealed that these thymuses developed normally whether the grafts involved syngeneic or allogeneic (between BALB/c and C3H) strain combinations. Two major populations of class II‐expressing cells could be recognized by the Ia allotype they expressed: epithelial cells of donor type anti accessory cells of host origin.
Characteristics and functional aspects of nonlymphoid cells in rat germinal centers, recognized by two monoclonal antibodies ED5 and ED6
Authors: Jeurissen Suzanne H. M. , Dijkstra Christine D.
Published: February 2007

In this study two newly developed monoclonal antibodies, ED5 and ED6, are described, which specifically recognize nonlymphoid cells in B cell follicles of spleen and lymph nodes. Enzyme and immunocytochemical techniques demonstrated that ED5 and ED6 stain two different types of reticulum cells. The staining patterns were compared with those of the monoclonal antibody Ox2.

ED5+ cells are able to retain immune complexes and are considered to be the follicular dendritic cell; in contrast ED6+ lack this capacity. Peyer's patches contain many ED6+ and Ox2+ cells but are completely devoid of ED5+ cells. After the application of immunomodulatory agents, like X‐irradiation, cyclophosphamide and lipopolysaccharide, ED5+ and ED6+ cells remain detectable. The nature of the new type of dendritic reticulum cell in lymphoid follicles, recognized by ED6, is discussed.
Human monoclonal antibody to purified protein derivative of tuberculin produced by hybrids constructed with Epstein‐Barr virus‐transformed B lymphocytes and mouse myeloma cells
Authors: Garzelli Carlo , Puglisi Carla , Falcone Giuseppe
Published: February 2007

A method of producing human monoclonal antibody by combining somatic cell hybridization technology with the capability of Epstein‐Barr virus (EBV) to transform human B lymphocytes is described.

Peripheral blood lymphocytes from a donor with positive tuberculin skin test reaction were transformed by EBV and then tested for antibody production to mycobacterial purified protein derivative (PPD) by an enzyme‐linked immunosorbent assay. Two EBV‐transformed lymphoblastoid cell lines making IgM antibodies to PPD were obtained. One of these cell lines was fused by polyethylene glycol with a murine hypoxanthine‐guanine phosphoribosyl transferase‐deficient myeloma cell line that had been selected for resistance to ouabain. The human‐mouse hybrids were selected in ouabain‐containing HAT medium and 11 heterohybridomas producing IgM antibody to PPD were obtained. one of these was cloned by limiting dilution with efficiency at least 20‐fold higher than parent EBV‐transformed cell line. Heterohybridoma subclones reached levels of IgM antibody as high as 75.0 μg/ml of culture medium, whereas IgM production of EBV‐transformed B cell clones ranged between 3.0 and 4.0 μg/ml.
Expression on human thymocytes of the idiotypic structures (Ti) from two leukemia T cell lines Jurkat and HPB‐ALL
Authors: Carrel Stefan , Isler Patrick , Schreyer Magali , Vacca Angelo , Salvi Susanne , Giuffre Laura , Mach Jean‐Pierre
Published: February 2007

The expression on a significant number of thymocytes of idiotypic structures (Ti) restricted to HPB‐ALL or Jurkat cells is demonstrated. As many as 2‐4% of thymocytes were stained with anti‐Ti HPB‐ALL or anti‐Ti Jurkat monoclonal antibodies, when analyzed by flow microfluorometry. Immunohistochemical localization studies performed on frozen thymus specimens of either fetal or pediatric origin indicated a scattered distribution of Ti‐positive cells in both the cortex and the medulla. From lysates of 125I‐labeled pediatric thymocytes, anti‐Ti HPB‐ALL and anti‐Ti Jurkat monoclonal antibodies precipitated disulfide‐linked heterodimers comparable to those precipitated from 125I‐labeled HPB‐ALL or Jurkat cells as shown by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis analysis.
Differentiation of human mature thymocytes: Existence of a T3+4−8− intermediate stage
Authors: De La Hera Antonio , Toribio Maria Luisa , Marquez Carlos , Marcos Miguel Angel R. , Cabrero Esther , Martinez‐A. Carlos
Published: February 2007

A T3 complex‐bearing subpopulation was characterized within an in vivo cycling T4−8− early thymocyte compartment which contains cells constitutively expressing interleukin 2 and transferrin receptors. We show differentiation in vitro of both mature subsets of thymocytes (T3+4+8− and T3+4−8+) from the above T4−8− compartment, their appearance being preceded by cells in a T3+4−8− intermediate stage. Furthermore, those mature thymocytes generated in vitro contain functionally competent cells which use T3, T4 and T8 structures for their cytolytic activity. The finding of T3+4−8− thymocytes in vivo, together with the observation that T3 antigen expression precedes that of T4 or T8 molecules in vitro, shows that T3 (and presumably Ti) is present early in ontogeny, and suggests that T3+4−8− cells constitute an “intermediate” stage relevant to the connection between early precursors and mature thymocytes during T lymphocyte ontogeny.
Liver‐associated macrophage precursors as natural cytotoxic effectors against Candida albicans and Yac‐1 cells
Authors: Decker Thomas , Baccarini Manuela , Lohmann‐Matthes Marie‐Luise
Published: February 2007

Liver nonparenchymal cells of maleic anhydride divinyl ether or cyclophosphamide‐treated mice were assayed for cytotoxic activity against the yeast form of Candida albicans. A strong increase in this activity was observed after both in vivo treatments, as compared to untreated control mice. The effector cell was enriched by nylon wool passage and separation of nonadherent liver nonparenchymal cells on a discontinuous Percoll gradient. By means of direct and indirect rosetting techniques, based on the presence of Fc receptors and the F4/80 and M143 macrophage surface markers, we could separate a nearly homogeneous effector cell population. It displayed, besides the candidacidal activity, Fc receptors and the M143 and F4/80 antigens, also strong natural cytotoxicity against Yac‐1 lymphoma cells. When cultured in medium containing colony‐stimulating factor‐1, this effector population reacted with a strong proliferative response as measured through incorporation of tritiated thymidine. The data presented show that nonadherent, nonphagocytic macrophage precursors, which we characterized previously from in vitro bone marrow cultures, occur in vivo as organ‐associated effector cells in the liver after elicitation with maleic anhydride divinyl ether or cyclophosphamide. These macrophage precursors have prior to their maturation the ability to serve as a microbicidal and tumoricidal natural killer cell.
Cross‐reactive recognition by antigen‐specific, major histocompatibility complex‐restricted T cells of a mitogen derived from Mycoplasma arthritidis is clonally expressed and I‐E restricted
Authors: Lynch David H. , Cole Barry C. , Bluestone Jeffrey A. , Hodes Richard J.
Published: February 2007

In order to determine whether or not the major histocompatibility complex (MHC)‐ encoded restriction element used by a T cell in the recognition of its primary antigen affected its ability to be cross‐reactively stimulated by MAS (a soluble product of Mycoplasma arthritidis), a panel of cloned, soluble antigen‐specific I‐A‐ and I‐E‐ restricted T cells were tested for their ability to cross‐reactively recognize and respond to MAS. Initial studies indicated that all of the cloned T cells tested were capable of responding to MAS in the presence of genetically EαEβ‐expressing (I‐E+), but not EαEβ‐non‐expressing (I‐E‐) accessory cells (AC). However, subsequent studies demonstrated that the ability of most of these T cell clones to mount proliferative responses to MAS in the presence of I‐E+ AC was dependent upon the presence of Lyt‐1+2− T cells in the irradiated spleen cells which were used as AC sources. When T cell‐depleted, I‐E+ populations of spleen cells or an I‐E+ antigen‐presenting line (WEHI‐5) were used as AC sources, only 6 of the 34 clones tested were found to be directly responsive to MAS. Subsequent to stimulation by MAS plus I‐E product, these MAS‐reactive T cell clones were capable of “recruiting” bystander T cells to proliferate. Finally, the ability of a given T cell clone to respond to MAS plus I‐E product did not appear to be influenced by the restriction element used by that clone in its response to other antigens since both I‐A‐restricted and I‐E‐restricted T cell clones were responsive to MAS plus I‐E in equivalent proportions. Thus, the data presented indicate that I‐E‐restricted T cell reactivity to MAS is a clonally expressed property of T cells that is independent of their conventional antigen specificities and MHC restriction patterns.
Discrete stages of human thymocyte activation and maturation in vitro: correlation between phenotype and function
Authors: Blue Marie‐Luise , Daley John F. , Levine Herbert , Schlossman Stuart F.
Published: February 2007

Using light scatter, flow cytometric and functional analyses, three major stages in the in vitro activation of human thymocytes were defined. The earliest stage (day 0–2) was characterized by the induction of the interleukin 2 (IL2) and transferrin receptors, the T cell lineage specific Tal antigen, and increased reactivity with anti‐T8 antibody. At this time, major changes in nuclear morphology but not cell size were observed. Early‐stage thymocytes were immature with regard to T3 and cytotoxic capacities. The second stage (day 3–4) of in vitro culture was distinguished by loss of T6, maximal activation (both in cell size and nuclear morphology) and maximal expression of both transferrin and IL2 receptors. At this stage, nearly all thymocytes expressed T3, 30–70% of thymocytes were T4+T8+, and functionally, only small increases in cytotoxic capacities were observed. The third stage of maturation (day 5–7) represented thymocytes with reduced levels of activation as measured by forward and right angle light scatter analysis and declining IL 2 and transferrin receptor expression. However, these thymocytes exhibited high levels of T3 antigen density, loss of T4, T8 coexpression and pronounced cytotoxic and detectable inducer function capabilities.
Interculture variation and evolution of B lineage lymphocytes in long‐term bone marrow culture
Authors: Witte Pamela L. , Kincade Paul W. , Větvička Václav
Published: February 2007

A recently described long‐term culture system offers a unique experimental approach for dissecting regulatory mechanisms that control the developmental progression of B‐lineage lymphocytes. Lymphoid cells, including B cells and their precursors, can be maintained for prolonged periods in strict dependence on a layer of adherent cells. However, before this system can yield to interpretable manipulation, much information is needed as to the identity and temporal phenotypic stability of both lymphoid and nonlymphoid cells. The findings reported here provide answers to some of those important questions. Successful establishment of lymphoid cells in culture was extraordinarily dependent on the batch of fetal calf serum used in the medium, and some undesirable serum lots supported cultures that were virtually all myeloid. With standardized culture conditions, various populations of lymphoid cells were identified on the basis of B‐lineage differentiation markers and culture to culture variation was assessed. Lymphocytes that were firmly attached to the adherent cells were carefully compared to nonadherent lymphocytes in terms of cycle status, phenotype, size, and transferrin receptor expression. They were essentially identical in all of these respects and a partitioning of proliferating cells and their progeny in the cultures was therefore not apparent. It is also noteworthy that although a high mitotic rate was maintained, a majority of the cells were small lymphocytes. The outgrowth of identifiable B‐lineage cells (detected with monoclonal 14.8 antibodies) in replicate cultures was initially similar, but the extent of interculture variation increased dramatically during the period 4–6 weeks after initiation of culture. Replicate cultures established from the same marrow cell pool often differed as much as 20‐fold in numbers of 14.8‐positive cells. After this time, the composition of individual cultures evolved much more gradually, and numbers of B cells and pre‐B cells remained relatively constant. This indicates that subsets of lymphocytes become established in each culture dish during a discrete phase.

At least two types of supporting adherent cells predominated in these cultures: typical macrophages and very large, nonphagocytic cells resembling adventitial reticular cells. The latter included subpopulations resolved on the basis of alkaline phosphatase content. In contrast to the lymphoid populations, proportions of these adherent cell types were relatively invariant among replicate cultures. The dramatic expansion or contraction of particular B‐lineage populations which occurred prior to 6 weeks of culture did not appear to be reflected in the composition of the adherent layers on which they depended.
Contact interaction between lymphocytes is a general event following activation and is mediated by LFA‐1
Authors: Hamann Alf , Jablonski‐Westrich Dorothee , Thiele Heinz‐Günther
Published: February 2007

When lymphocytes are activated in vitro, discrete cell‐cell contacts are initiated which result in cluster formation. This contact interaction is found in syngeneic or allogeneic mixed leukocyte reactions as well as in mitogen‐stimulated cultures (concanavalin A, periodate, lipopolysaccharide). T cells as well as B cells display the binding phenomenon. This activation‐dependent lymphocyte‐lymphocyte adhesion involves LFA‐1, since monoclonal antibodies (including Fab fragments) against this molecule inhibit adhesion between clustering lymphocytes in a dose‐dependent manner, whereas antibodies directed to several other cell surface antigens are inactive. Since a wide variety of functional interactions are inhibited by antibodies to LFA‐1, it may be concluded that LFA‐1‐mediated cell contact is a discrete and essential step between a recognition event and the generation of functional activities by lymphocytes in general.
Production of oligosaccharide‐binding monoclonal antibodies of diverse specificities by immunization with purified tumor‐associated glycolipids inserted into liposomes with lipid A
Authors: Brodin Thomas , Thurin Jan , Strömberg Niklas , Karlsson Karl‐Anders , Sjögren Hans Olov
Published: February 2007

Two species of neutral glycosphingolipids purified from rat colon carcinoma tissue, isoglobotetraosylceramide [GalNAc(β1→3)Gal(α1→3)Gal(β1→3)Glc(β1→1)Cer] and a related 6‐sugar “analogue” were inserted into liposomes together with lipid A (from bacterial lipopolysaccharide) and used for immunization of mice and monoclonal antibody production. The yield of hybridomas producing glycolipid‐specific antibody was 5–10% using a high‐dose booster schedule with liposome‐inserted glycolipid. In contrast the frequency was below 0.1% (no glycolipid‐binding antibodies were found) when using the previously described method of immunizing with glycolipid coated on the surface of acid‐treated S. minnesota. Monoclonal antibodies were screened on the purified glycolipids used for immunization and selected for differential reactivity to the two glycolipids. A diversity of specificities was demonstrated by binding to the purified antigens, in a thin‐layer chromatogram binding assay and in binding tests to tumor and normal target cells.
Immunoglobulin heavy chain gene rearrangements in X‐linked agammaglobulinemia
Authors: Mensink Ewald J. B. M. , Schuurman Ruud K. B. , Schot Johannes D. L. , Thompson Allan , Alt Fred W.
Published: February 2007

X‐linked agammaglobulinemia (XLA) appears to involve a defect in human B lymphocyte differentiation which is manifested at the pre‐B cell stage. The defect segregates as an X‐linked recessive trait but is not a single genetic entity. IgM‐producing B cell clones were established by Epstein‐Barr virus transformation of peripheral blood mononuclear cells of patients with the XLA defect linked to the DXS3 and DXS17 chromosomal loci. Individual XLA B cell clones were demonstrated to have rearrangements of the JH regions of both immunoglobulin VH region loci. The rearranged JH regions of the B cell clone ALA 19 were molecularly cloned and their nucleotide sequence was determined. Both JH‐associated rearrangements (designated 191 and 192) resulted from the juxtaposition of variable (VH), diversity (D) and joining (JH) segments (VHDJH rearrangements). The 191 rearrangement employed a VH segment belonging to VH subgroup III and a JH4 segment. The 192 rearrangement employed a VHII and a JH6 segment. The D191 and D192 segments encompassed 21 and 28 nucleotides, respectively, and showed little homology to each other or to previously reported human D sequences. Surprisingly, both VHDJH complexes had open reading frames. However, in accord with principles of allelic exclusion, only the 191 allele was detectably expressed in the total RNA of the cell. A possible mechanism for the lack of expression of the 192 allele is discussed. We conclude that the DXS3‐DXS17‐linked XLA defect does not preclude VH to DJH rearrangements or the expression of VHcontaining heavy chain molecules.
B cell growth and differentiation induced by supernatants of transformed epithelial cell lines
Authors: Rawle Frances C. , Shields John , Smith Susan H. , Iliescu Virginia , Merkenschlager Matthias , Beverley Peter C. L. , Caliard Robin E.
Published: February 2007

Growth and differentiation of B cells is thought to be regulated by soluble factors derived from T cells. However, human T cell lines and hybridomas have proved to be notoriously unreliable and unstable sources of such factors. We report here that three stable human bladder carcinoma cell lines T24, RT4 and 5637 produce, in a constitutive fashion, factors which promote growth and differentiation of human B cells.
Ligation of the CD23, p45 (BLAST‐2, EBVCS) antigen triggers the cell‐cycle progression of activated B lymphocytes
Authors: Gordon John , Rowe Martin , Walker Leonie , Guy Graeme
Published: February 2007

CD23, p45 (BLAST‐2, EBVCS) is a 45‐kDa lineage‐restricted antigen which appears on the surface of human B cells shortly after activation. A monoclonal antibody (MHM6) to CD23, p45, as well as a polyclonal rabbit antibody raised against the purified antigen were found to promote DNA synthesis in purified tonsillar B cells which had been activated with phorbol ester. Interleukin 1, which was not, by itself, stimulatory for either resting or activated B cells, significantly augmented the growth‐promoting properties of MHM6. Kinetic studies indicated that while MHM6 exerted its influence in early G1, interleukin 1 acted later in the cycle just prior to the entry of cells into S phase. The findings demonstrate a role for CD23, p45 in triggering the progression of activated B lymphocytes through the G1 phase of the cell cycle. The possibility that this antigen serves as a receptor for a B cell stimulatory factor is discussed.