bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of the immune complex‐complement interaction by protein H of the alternative complement pathway and the natural inhibitor heparin
Authors: Spycher Martin O. , Nydegger Urs E.
Published: February 2007

The potential of the negative regulatory protein H of the alternative complement pathway convertase and of heparin in modulating the complement‐dependent capacity of fresh serum to inhibit immune complex precipitation (CIICP) between bovine serum albumin (BSA) and rabbit anti‐BSA as well as tetanus toxoid (TT) and human anti‐TT was assessed. Additions of purified H to serum to increase the intrinsic concentration of this protein by 80% (BSA‐anti‐BSA system) and 190% (TT‐anti‐TT system) resulted in an inhibition of CIICP by 50% and 60%, respectively, whereas further increase of the amount of H lead to a decrease of its inhibitory activity. A similar effect was observed with heparin: at a concentration of 400 U/ml a 90% inhibition of CIICP in the TT‐anti‐TT system was obtained which diminished at higher heparin concentrations. The effect of H on C3 deposition to immune aggregates was assessed through its influence on C3b‐mediated immune adherence hemag‐glutination; factor H dose‐dependently suppressed such hemagglutination induced by aggregated human IgG or preformed TT‐anti‐TT complexes when added to the immune complex‐fresh serum mixture at the outset but not after 45 min of the 37 °C incubation period which means that H inhibited more likely decoration of immune complexes with C3b than it did inhibit the interaction of C3b‐coated immune complexes with erythrocytes. This suppressive effect of H was reversed by the simultaneous addition of the activating protein B. Complement‐mediated binding of tritiated C3 to latex‐bound human IgG was assessed and H was found to dose‐dependently inhibit such binding with a maximal inhibition of 37% at a H concentration of 7 μg/ml.
Binding of a murine monoclonal anti‐DNA antibody to Raji cells. Implications for the interpretation of the Raji cell assay for immune complexes
Authors: Tron François , Jacob Laurent , Bach Jean‐François
Published: February 2007

A murine monoclonal anti‐DNA antibody binds to the plasma membrane of Raji cells at its antigen‐combining site. This result urges caution in the interpretation of a Raji positivity in human sera containing anti‐DNA antibodies.
The effect of T lymphocyte depletion on neonatal tolerance induction, graft‐vs.‐host disease and cellular chimerism
Authors: Rayfield Lee S. , Brent Leslie
Published: February 2007

Treatment with a monoclonal anti‐Thy‐1 antibody and complement completely prevented C57BL spleen cells from causing graft‐vs.‐host disease following their inoculation into newborn CBA mice. The proportion of mice that became tolerant to C57BL antigens, as measured by skin grafting, was significantly less compared with mice given (CBA × C57BL)F1 hybrid cells. This was not due to the elimination of T cells, for antibody‐treated F1 cells induced tolerance as readily as complement‐treated control F1 cells.

To investigate whether the apparent superiority of F1 cells over C57BL cells is attributable to differences in the mechanism inducing and maintaining unresponsiveness, two approaches were followed. First, the level of donor cell chimerism in the spleens of tolerant animals was studied. Though no difference between F1 and C57BL cells was uncovered, the presence of T cells in the donor inocula favored the establishment of chimerism. Second, the involvement of suppressor T cells was examined in adoptive transfer experiments. Splenic suppressor T cells were associated with tolerance regardless of how it was elicited. Preliminary results with F1 cells show that the tolerogenic property is not confined to any one cell type. It is proposed that the greater tolerogenicity of F1 cells is brought about by the presence of host‐type (self) antigens, which enable the tolerogenic signals to operate without recourse to antigen processing by host cells.
Mechanism of T lymphocyte activation by OKT3 antibodies. A general model for T cell induction
Authors: Landegren Ulf , Andersson Jan , Wigzell Hans
Published: February 2007

The OKT3 monoclonal antibody has unique reactivity for human T cells and induces a mitogenic response equal to that of concanavalin A (Con A). However, significant differences were found in activation requirements for the two T cell mitogens. Although both OKT3 and Con A required living accessory cells for stimulation of T cells, the OKT3 antibody was optimally mitogenic at a molar concentration 103 times less than Con A. Under such conditions, the two mitogens showed similar kinetics as well as magnitude or responses. Furthermore normal IgG blocked the OKT3‐induced proliferation selectively. The inhibition is most likely caused by the Fc portion of IgG competing for Fc receptors on accessory cells. The different requirements for activation are discussed in relation to the T cell receptor and its role in T cell activation.
Nucleotide sequence of a cDNA encoding the constant region of a rabbit immunoglobulin light chain of the λ type
Authors: Duvoisin Robert M. , Kocher Hans P. , Garcia Irène , Rougeon François , Jaton Jean‐Claude
Published: February 2007

A cDNA library has been constructed in the plasmid pBR322 using as template 12 S poly(A)‐RNA isolated from spleen cells of a hyperimmunized Basilea rabbit. One of these cDNA‐containing clones was used to determine the nucleotide sequence coding for the λ light chain constant (C) region. The deduced amino acid sequence of this cDNA was found in good agreement with a Basilea rabbit Cλ region amino acid sequence previously determined. The nucleotide sequence of the rabbit Cλ‐coding region was compared with man, mouse and chicken Cλ sequences and showed 78%, 72% and 66% homology, respectively. Southern blot hybridization analyses of liver DNA from various rabbits were carried out. The comparison of the restriction patterns suggests that a few Cλ‐related genes occur in the rabbit genome. In addition, discrete differences in the restriction patterns may exist between rabbits of different genetic backgrounds.
Surface markers of cytotoxic T lymphocyte clones
Authors: Haas Werner , von Boehmer Harald
Published: February 2007

Several class II major histocompatibility complex antigen‐specific murine cytolytic T cell clones express Lyt‐2 but not MT4 surface antigens.
Reactions among IgM antibodies derived from normal, neonatal mice
Authors: Holmberg Dan , Forsgren Stina , Ivars Fredrik , Coutinho Antonio
Published: February 2007

Attempting to obtain a representative sample of the “natural antibody” repertoire in the developing immune system, we have derived IgM‐secreting hybridomas from 4 normal untreated BALB/c mice of the same litter on day 6 after birth. Partially purified IgM preparations obtained in the supernatants of 70 such clones were each screened in binding assays for reactivity with a panel of 9 IgM antibodies, randomly selected from the same collection. Five of these 9 IgM antibodies were found to react with a considerable number of other IgM in the collection, while the other 4 showed only sporadic reactivity. On the other hand, more than half of the 70 antibodies were found to bind specifically to at least one of these five. With a few exceptions, these reactions showed quantitative levels ranging from 5 to 20% of those observed between either of the two interacting IgM and monoclonal rat anti‐μ antibodies. The selectivity of these reactions indicated V‐region specificity, which was confirmed by analyzing in some detail the reaction between 2 IgM antibodies isolated from the same mouse.
Direct demonstration of multiple VH allotopes on rabbit Ig molecules: allotope characteristics and Fab arm rotational flexibility revealed by immunoelectron microscopy
Authors: Roux Kenneth H.
Published: February 2007

Immune complexes composed of rabbit IgG and Fab fragments of antibody specific for the VH framework allotypes were analyzed by molecular immunoelectron microscopy. In this manner, the number of allotypic epitopes (allotopes) and their approximate topological location could be determined. A monoclonal anti‐allotype Fab was used to show that relatively fine details of allotope location and orientation are demonstrable with this technique. Each of the three VH allotypes (a1, a2 and a3) was found to express at least two spacially separated allotopes. The locations of the allotopes varied for each of the three allotypes. Some allotopes were observed near the VH‐CH1 switch region while others were in close proximity to the complementarity‐determining region or were at intermediate positions. In addition to the information concerning allotope topology, the variety of configurations resulting from the interaction of monoclonal antibody Fab with IgG suggest considerable rotational flexibility (twisting) of the Fab arm of IgG about its long axis.
Autoregulation of autoantibody synthesis in mercuric chloride nephritis in the Brown Norway rat II. Presence of antigen‐augmentable plaque‐forming cells in the spleen is associated with humoral factors behaving as auto‐anti‐idiotypic antibodies
Authors: Chalopin Jean Mark , Lockwood Christopher M.
Published: February 2007

Plaque‐forming cell (PFC) assays were used to investigate in vitro the immunoregulatory mechanism operating in the self‐limiting anti‐glomerular basement membrane (GBM) autoantibody response of Brown Norway (BN) rats given HgCl2. The peak splenic PFC response occurred at day 9; thereafter the response fell sharply and was rarely detected after day 12. In specificity studies, incorporation of soluble GBM in the PFC assays of animals at day 9 had two distinct effects. In some animals the PFC response was inhibited in a dose‐dependent fashion; however, in others an augmented number of PFC was observed. Furthermore, addition of GBM to the PFC mixture from certain animals studied at day 12 (or after) revealed large numbers of GBM‐specific PFC when originally no GBM‐specific PFC had been observed in the standard PFC assay. Sera from such animals, with and without antigen‐augmentable PFC, were incorporated in the PFC mixture containing cells taken from day 9 animals. Sera from animals with revealed plaques could inhibit the GBM‐specific PFC response of day 9 animals, whereas sera from animals without revealed plaques could not. Thus sera, from BN rats whose own antibody levels were falling, could inhibit the GBM‐specific plaque‐forming capability of cells from animals at an earlier stage of the autoimmune response and showed the potential importance of humoral factors, putatively anti‐idiotypic antibodies, in effecting autoregulation of autoantibody formation in this model.
Monoclonal antibodies to stromal cell types of the mouse thymus
Authors: van Vliet Els , Melis Marleen , Van Ewijk Willem
Published: February 2007

Seven hybridoma cell lines secreting monoclonal antibodies (mAb) to nonlymphoid cells of the mouse thymus have been prepared. These mAb clearly demonstrate the heterogeneity of the thymic stroma. Based on their anatomical distribution patterns observed with the immunoperoxidase technique on frozen tissue sections, they were subdivided into four groups. The first group of mAb, ER‐TR1, 2 and 3, detects antigens encoded for by the I region of the major histocompatibility complex. These antigens are expressed on both stromal and lymphoid cells in lymphoid organs. mAb of the second category, ER‐TR4, react with epithelial cells in the thymic cortex. mAb of the third group detect stromal cells of the thymic medulla. One antibody of this group, ER‐TR5, exclusively reacts with medullary epithelial cells. ER‐TR6, the other antibody of this group, reacts with medullary interdigitating cells and macrophages. The fourth type of antibodies, ER‐TR7, detects the reticular fibroblasts of the thymus. The possible role of the thymic cell types detected by the present antibodies in T cell differentiation is discussed.
The role of B cell surface Ia antigen recognition by T cells in B cell triggering. Analysis of the interaction of cloned helper T cells with normal B cells in differing states of activation and with B cells expressing the xid defect
Authors: Tite John P. , Kaye Jonathan , Jones Barry
Published: February 2007

Two discrete mechanisms of T‐B cell collaboration appear to exist. In cognate recognition, B cell triggering results from a direct recognition of antigen and MHC determinants at the B cell surface. Alternatively, B cells can be triggered by transstimulation, in which the Th cell is activated by an antigen‐presenting cell to produce soluble factors which in turn trigger the B cell. This report addresses the question of whether antigen recognition at the B cell surface in association with Ia determinants delivers a signal to the B cell, which is qualitatively different from the signals delivered by the soluble mediators released by the activated Th cell. Previous reports from a number of laboratories suggest that cognate recognition is obligatory for the triggering of small resting B cells and B cells of the Lyb‐5− phenotype, whereas enlarged B cell blasts and the Lyb‐5+ subset can be triggered solely by soluble mediators. Contrary to these findings, the experiments described here indicate that B cells isolated in different states of activation from normal spleens on the basis of their bouyant density in Percoll density gradients, or unfractionated B cells from mice differing genetically due to the xid defect [Lyb‐5− B cells from (CBA/N × BALB/c)F1 male mice], do not discriminate between the two modes of Th cell function. In both stimulation modes, the high density B cells, and the B cells from xid mice made very poor immunoglobulin secretory responses measured in terms of reverse plaque formation on protein A‐coupled erythrocytes. When the responses of different density fractions of B cells were compared under conditions where stimulation occurred either directly or indirectly via transstimulation, the following hierarchy of responsiveness in both the proliferative and plaque‐forming cell (PFC) responses was observed in the density fractions 60% > 65% > 70% > 75%. The hierarchy was the same in both modes of interaction and the deficiency of the high density, small B cells was far more marked in the PFC assay than in the proliferative assay. We conclude that the initial proliferative response of the resting B cell can be triggered comparably in vitro under conditions of direct or transstimulation. Thus, recognition of B cell surface Ia by Th cells is not obligatory for B cell activation and does not transfer an essential transmembrane signal to the B cell.
Human T cell antigens involved in cytotoxicity against allogeneic or autologous chemically modified targets. Association of the Leu 2a/T8 antigen with effector‐target cell binding and of the T3/Leu 4 antigen with triggering
Authors: Platsoucas Chris D.
Published: February 2007

Monoclonal antibodies (mAb) recognizing human T cell differentiation antigens were employed to analyze the role of these antigens on T cell‐mediated cytotoxicity against autologous 2,4,6‐trinitrophenyl (TNP)‐modified targets. The OKT3/anti‐Leu 4 and anti‐Leu 2a/OKT8* mAb inhibited T cell‐mediated cytotoxicity against autologous or unrelated TNP‐modified targets, in the absence of complement and at the effector cell level. These cytotoxic effector cells were T3+, T8+, T11+, T4−. To analyze the role of the T3/Leu 4 and Leu 2a/T8 T cell differentiation antigens in the cytolytic process, we investigated the stages of this process that were inhibited by the OKT3/anti‐Leu 4 and anti‐Leu 2a/OKT8* mAb. Using: (a) visual adhesions, and (b) a single cell cytotoxicity assay in agarose, we observed that the OKT3 and anti‐Leu 4 mAb did not inhibit binding of effector cells to allogeneic targets or to autologous E rosette‐negative TNP‐modified targets, although they significantly inhibited both the proportions of target cells in conjugates that were lysed, and the 51Cr release. In contrast, the anti‐Leu 2a and OKT8* mAb blocked cytotoxicity by inhibiting binding of effector cells to the allogeneic or to autologous chemically modified targets. To further analyze the stages of the cytolytic process (adhesion; programming for lysis or lethal hit; and cytotoxic cell‐independent lysis) that were inhibited by these mAb, we employed the detachment and dispersion method. This method is based on the differential temperature requirements of adhesion (which occurred both at 37 °C or 20 °C) and of programming for lysis (which occurred at 37 °C but not at 20 °C). Operational adhesions were determined by the 51Cr‐release assay after dispersion of effector and target cells in a 10% solution of dextran (mol. wt. 500000). Programming for lysis was determined by the 51Cr‐release assay after detachment of effector‐target cell conjugates with 10 mM EDTA and dispersion in 10% dextran solution. Using this method we determined that mAb recognizing the Leu 2a/T8 antigen blocked cytotoxicity by inhibiting adhesion and binding of effector cells to target cells. These antibodies do not affect post‐adhesion stages of the cytolytic process. In contrast, the OKT3 and anti‐Leu 4 mAb inhibit a post‐adhesion step of the cytolytic process, that occurs before irreversible events of the programming for lysis stage have taken place.

These results and other properties (lymphokine production, mitogenic properties) of the OKT3/anti‐Leu 4 mAb suggest that the T3/Leu 4 antigen may be associated with triggering of lethal hit (and triggering of T cell functions in general) and signal transfer or transduction. In contrast, the Leu 2a/T8 antigen appears to be involved in binding of effector to target cells and may contribute to the affinity of the effector cells for the target.
Purification and characterization of an antigen involved in neutrophil chemotaxis and degranulation using a monoclonal antibody
Authors: Cotter Thomas G. , Henson Peter M.
Published: February 2007

In a previous study we described an anti‐neutrophil monoclonal antibody, which inhibited human neutrophil chemotaxis and degranulation without any detectable effect on phagocytosis or oxidative metabolism (Cotter, T. G., Spears, P. and Henson, P. M., J. Immunol. 1981. 127: 1355). This antibody was termed NCD 1. In this study we determined the number of NCD 1‐binding sites per neutrophil. Approximately 25000 NCD 1 IgG‐binding sites per cell were found with an equilibrium dissociation constant (Kd) of 6.5 μM for antibody binding. NCD 1 Fab bound to approximately 39000 sites per cell with a Kd of 16.5 μM. Affinity chromatography columns prepared by coupling NCD 1 to Sepharose 4B beads were used to purify the antigen which bound this antibody. The antigen was a 110‐kDa glycoprotein which was not susceptible to reduction by 2‐mercaptoethanol. The antigen was not internalized following phagocytosis of opsonized sheep erythrocytes by neutrophils.
Schistosoma mansoni: escape from complement‐mediated parasiticidal mechanisms following percutaneous primary infection
Authors: Ruppel Andreas , McLaren Diane J. , Diesfeld Hans Jochen , Rother Ursula
Published: February 2007

Schistosomula were recovered from the skin of mice following primary infections. On the surface of such “infecting schistosomula”, mouse C3 could not be detected by immunofluorescence. Subsequent incubation in vitro with fresh mouse serum led to the effective deposition of mouse C3 on schistosomula only when they were recovered within a few hours but not after one or two days following infection. In vitro deposited murine C3c was lost from i.v. injected schistosomula in the mouse circulation within one day as was human C3c. Infecting schistosomula exhibited a close to complete resistance to the lytic in vitro activity of human complement. This resistance was complete in older parasites. It existed in spite of the presence of parasite‐bound human C9, which was detectable on all developmental stages of schistosomes following incubation in fresh, but not inactivated human serum. Lung schistosomula, 3‐week and 6‐week‐old schistosomes were resistant to cellular cytotoxicity upon incubation with fresh human serum and rat peritoneal exudate cells although cell adherence mediated by human C3b was demonstrated with lung worms. The data suggest that schistosomula may evade in vivo the lytic activity of complement and also complement‐mediated cellular cytotoxicity. Depending on the species of serum, this can be demonstrated in vitro by lack of opsonization or by resistance to lytic and cellular attack mechanisms.
Preservation of the helper and suppressor/cytotoxic T‐lymphocyte phenotype in continuous culture
Authors: Gramatzki Martin , Baum Wolfgang , Burmester Gerd R. , Kalden Joachim R.
Published: February 2007

The objective of the present investigation was to culture helper or suppressor/cytotoxic T cell subsets after extensive purification in interleukin 2‐containing medium to determine whether phenotype changes for OKT4/91d6‐ or OKT8/Leu‐2a‐defined antigens do occur with prolonged culture. Repeated and sequential analysis of such polyclonally activated cultured T cells documented stability of the OKT4/91d6+ and OKT8/Leu‐2a+ phenotype. Both populations could be considerably expanded in culture. However, mixing experiments revealed a growth advantage of the OKT8/Leu‐2a+ subset. A significant number of cells expressing both phenotypic markers was not detectable. While cultured T cells promoted on interleukin 2 were stable for expression of these functionally important differentiation markers, additional studies on activation antigens revealed high numbers of Tac+ cells at an early time of culture and decreasing numbers during further incubation. The expression of Tac antigen preceded the exponential expansion of the culture. In contrast, the number of cells bearing Ia determinants steadily increased with prolonged culture.
Self‐ and allo‐specific suppressor T cells evoked by intravenous injection of F protein
Authors: Lukic Miodrag L. , Avrion Mitchison N.
Published: February 2007

The liver/serum protein F appears to inactivate clones reactive towards itself in the T helper cell but not the B cell compartment. To examine the extent of self‐reactivity in the T suppressor cell compartment, the well‐established procedure of i.v. injecting milligram doses of the protein was used. To detect suppression, an entirely in vitro proliferation assay was devised, based on use of immunopurified F antigen. In this way T suppressor cells could be detected after activation either by allogeneic F, or (though to a lesser extent) by self‐F protein. Thus the T suppressor cell compartment contains potentially self‐reactive clones, and to that extent the receptor repertoire of T suppressor cells overlaps with B rather than T helper cells.
Production of IgE‐potentiating factor in man by T cell lines bearing Fc receptors for IgE
Authors: Young Michael C. , Leung Donald Y. M. , Geha Raif S.
Published: February 2007

The regulation of human IgE production in vitro by soluble T cell factors was examined. T cells were isolated from the peripheral blood of 2 patients with the hyper‐IgE syndrome on the basis of their expression of Fc receptors for human IgE (FcϵR). The T cells were incubated with human myeloma IgE (10 μg/ml), washed, reacted with immunosorbent‐purified goat anti‐human IgE conjugated with fluorescein isothiocyanate, and then separated into FcϵR and FcϵR− T cells on the fluorescence‐activated cell sorter. FcϵR T cells and FcϵR− T cells were propagated in culture using supernatants of phytohemagglutinin‐stimulated peripheral blood mononuclear cells (PBMC) and irradiated autologous PBMC. Supernatants of FcϵR T cell lines but not of FcϵR− T cell lines selectively enhanced IgE synthesis in cultures of B cells obtained from patients with allergic rhinitis but not from normal nonallergic subjects. The surface phenotype of the FcϵR T cell line was predominantly T3−, T4, Ia with few (15%) T8 cells. Two T cell clones were grown from the FcϵR− T cell line by limiting dilution (0.3 cells/well). These clones possessed the T4− helper/inducer phenotype and secreted IgE‐enhancing factor(s). The IgE‐enhancing factor(s) which had affinity for insolubilized human IgE was sensitive to treatment with trypsin and neuraminidase, and had as its target an IgE‐bearing B cell. These results suggest that a subset of human T cells bearing an FcϵR secretes an IgE‐binding glycoprotein which selectively enhances IgE synthesis by IgE‐bearing B cells.
T cell clones interacting with accessory and T helper cells for a proliferative response
Authors: di Pauli Raimund , Brückner Thomas
Published: February 2007

The requirement for cell interactions in T cell activation has been studied with two continuously in vitro growing T cell clones. These clones are specific for minor histocompatibility antigens, are H‐2K restricted, and one clone is functionally a cytolytic T lymphocyte. Both can proliferate when interleukin 2 is added to the cultures, but for continuous growth they require irradiated spleen cells carrying the specific minor histocompatibility antigen and the restricting H‐2.

In this study we show that for proliferation the clones require at least two cell populations in the stimulator spleen, one is a splenic‐adherent cell (SAC), the other a T cell. The SAC are plastic adherent, Thy‐1−, Ia. The T cells are nylon wool nonadherent, Thy‐1, Lyt‐12− and Ia−. Cell mixing experiments of stimulator cells (all were done with H‐2‐syngeneic cells), depleted of either SAC or T cells confirm the requirement for a specific interaction between these two cell types and the T clone. Neither SAC, syngeneic with the T clone when mixed with T cells of the stimulator type, nor T cells syngeneic with the clone added to stimulator SAC, can induce an optimal proliferative response. Such a response is obtained only if both cell types, SAC and T cells, are of the stimulating genotype. This suggests that, in addition to an interaction of clonal T cells with SAC, a specific recognition at the T cell level between T stimulator and T clone is necessary.

The interaction of the T clones with stimulator SAC and T cells leads to an activation, mediated by antigen recognition, of all three cell populations. Since we also show that each of the stimulator cell types are impaired by ultraviolet light irradiation, we conclude that factor production by SAC and T helpers is the final prerequisite for clonal expansion.
The immunoglobulin heavy chain variable region (Igh‐V) locus in the mouse. I. One hundred Igh‐V genes comprise seven families of homologous genes
Authors: Brodeur Peter H. , Riblet Roy
Published: February 2007

Seven families of Igh‐V genes have been defined by Southern blot analysis of genomic DNA from eighteen inbred strains of mice. Each of twenty‐four cloned Vh genes hybridized to one of seven nonoverlapping sets of Eco RI restriction fragments. These families contain from 2 to ∼40 hybridizing fragments. From these data we estimate that the mouse Igh‐V locus consists of one hundred Vh genes. Genes within a Vh family share >80% sequence homology while the sequence homology between families is generally <70%. There is extensive restriction fragment length polymorphism among the strains analyzed allowing the assignment of complete (Igh‐V + Igh‐C) Igh haplotypes for eighteen inbred mouse strains.
Protection of mice against the intracellular bacterium Listeria monocytogenes by recombinant immune interferon
Authors: Kiderlen Albrecht F. , Kaufmann Stefan H. E. , Lohmann‐Matthes Marie‐Luise
Published: February 2007

Immune interferon, available at high specific activity through recombinant DNA technology, is known to activate macrophages to intra‐ and extracellular cytotoxicity. We now report that murine recombinant IFN‐γ activates macrophages to cytotoxicity also when applied in vivo. Furthermore, recombinant IFN‐γ can protect mice in vivo against the intracellular bacterial pathogen Listeria monocytogenes in a local as well as in a systemic infection model. The role of T lymphocyte‐produced lymphokines in acquired resistance to facultative intracellular pathogens and their possible involvement in novel immunotherapy are discussed.
Thymocytes appear to ignore class I major histocompatibility complex antigens expressed on thymus epithelial cells
Authors: von Boehmer Harald , Schubiger Katrin
Published: February 2007

BALB/c nu/nu mice were grafted with embryonic 14‐day‐old C57BL/6 thymi which were transplanted either nontreated or after elimination of hemopoietic cells with 2‐deoxyguanosine. In both types of grafts host cells developed normally into functional thymocytes. Thymocytes from 2‐deoxyguanosine‐treated but not from untreated grafts contained as many cytolytic T lymphocyte precursors specific for class I MHC antigens on thymus epithelium as normal BALB/c thymocytes. As cytolytic T lymphocyte precursors were neither suppressed nor activated in these grafts it is concluded that thymocytes ignore class I MHC antigens expressed on thymus epithelium.
Frequent coexpression of cytolytic activity and lymphokine production among human T lymphocytes. Production of B cell growth factor and interleukin 2 by T8+ and T4+ cytolytic clones
Authors: Mingari Maria Cristina , Moretta Alessandro , Maggi Enrico , Pantaleo Giuseppe , Gerosa Franca , Romagnani Sergio , Moretta Lorenzo
Published: February 2007

These studies were designed to determine the degree of overlapping between cytolytic function and lymphokine production among peripheral blood human T lymphocytes. T8+ and T4+ cells were obtained by sorting purified T cells using the fluorescence‐activated cell sorter (FACS) and cloned at 0.25 cells/well in a microculture system that allows clonal growth of every T cell. 49/49 T8+ clones but only 5/102 T4+ clones displayed cytolytic activity, as assessed by a lectin‐dependent assay. Cytolytic clones were further analyzed for their ability to release interleukin 2 (IL 2) and B cell growth factor(s) (BCGF) upon 24 h stimulation with phytohemagglutinin. Fifteen percent and 18% of T8+ cytolytic clones were producing IL2 and BCGF, respectively; in addition 3 out of 5 T4+ cytolytic clones released both lymphokines. Although the majority of cytolytic clones producing IL2 were also producing BCGF, 5 clones released either BCGF or IL2. The present studies indicate that the coexpression of cytolytic and helper/inducer functions is relatively common among peripheral blood T lymphocytes, irrespective of their T8+ or T4+ phenotype.
B cell activation potential of insulin‐reactive T cells in H‐2b mice
Authors: Huber Brigitte T. , Hochman Paula S.
Published: February 2007

The murine T cell response to heterologous insulins provides a good model system for studying the mechanism of immune response (Ir)‐gene function, since insulin is a small, chemically well‐defined molecule. H‐2b mice respond predominantly to A chain loop determinants of beef insulin, presented by the I‐A epitope Ia.W39. However, using a library of insulin‐specific T cell hybridomas (THy), we previously found that immunization of H‐2b mice with beef insulin activates a much wider population of T cells than are detected in T cell proliferation assays. Using such cloned THy we were able to study Ir‐gene control at the level of antigen presentation. We compared the ability of the various THy to induce differentiation in I‐A‐matched B cells in response to antigen. Although both A and B chain‐reactive clones respond with interleukin 2 production, they differ markedly in their potential to activate B cells in that only the former are able to induce B cell differentiation in the presence of the intact beef insulin molecule. The latter, however, can serve as helper cells in the presence of isolated B chain, and can synergize with a suboptimal concentration of A chain‐reactive THy to induce an optimal B cell response. These results suggest that the insulin molecule is presented by I‐Ab antigen‐presenting cells in a very specific configuration that allows more effective T cell recognition of the A chain loop than the B chain determinants.

To explain the discrepancy between the interleukin 2 assay and the induction of polyclonal activation, it can be assumed that in the former assay antigen is presented by macrophages, while presentation by B cells is necessary for induction of polyclonal activation. Macrophages are able to process the intact beef insulin molecule and, therefore, present B chain determinants, while nonimmune B cells may be unable to process antigen and could present B chain determinants only when the isolated B chain is given as antigen.
Mouse monoclonal antibodies against the idiotype of human B cell non‐Hodgkin lymphomas: production, characterization and use to monitor the progress of disease
Authors: Rankin Elaine M. , Hekman Annemarie
Published: February 2007

Four monoclonal anti‐idiotype (Id) antibodies against B cell non‐Hodgkin lymphomas have been made by a simple and rapid procedure for hybridoma production that does not use isolated Id‐carrying immunoglobulin. Mice were immunized with plasma membranes from the tumor cells. Screening of hybridoma colonies using an autologous T cell line and a cell line bearing the same immunoglobulins as the malignant lymphocytes as well as the capping phenomenon on the patient's own tumor cells, allowed selection of hybridomas producing anti‐Id antibodies. These anti‐Id antibodies were used to demonstrate variations in the circulating malignant cell population and fluctuations in the level of circulating free Id.
Detection and localization by the monoclonal antiinterleukin 2 receptor antibody AMT‐13 of IL 2 receptor‐bearing cells in the developing thymus of the mouse embryo and in the thymus of cortisone‐treated mice
Authors: Takacs Laszlo , Osawa Hisao , Diamantstein Tibor
Published: February 2007

During embryonic development of the mouse, before expressing classical T cell markers, the blast cells colonizing the thymus react with the monoclonal antibody AMT‐13 shown previously to detect interleukin 2 receptors. The proportion of AMT‐13+ cells decreases as gestation time increases. On the other hand, the proportion of Thy‐1+, Lyt‐1+ and Lyt‐2+ cells increases during ontogenesis. On the 19th day of gestation when the thymus architecture is comparable to the adult thymus, the AMT‐13+ cells become localized in the subcapsular area of the cortex. In the adult thymus after cortison treatment the regenerating cells express the AMT‐13 antigen. The AMT‐13 antigen presumably the interleukin 2 receptor is the first marker of the early embryonic thymocytes reported until now that may be related to cellular function.
Human monocyte heterogeneity: Interleukin 1 and prostaglandin E2 production by separate subsets
Authors: Khansari Nemat , Chou Yvan K. , Fudenberg H. Hugh
Published: February 2007

Human peripheral blood monocytes were separated into four different subpopula‐tions by means of a discontinuous bovine serum albumin gradient. Of the least dense population, 7% were present in fraction A, 11% in fraction B, 28% in fraction C and of the most dense, 34% were in fraction D. The rest (17%) of the recovered cells sedimented as a pellet, of which 95% were dead. The monocytes of fraction D (ϱ = ⩾ 1.075 kg/l) were major interleukin 1 (IL1) producers and their presence enhanced immunoglobulin synthesis in vitro. Fraction C (ϱ = ⩾ 1.070 kg/l) were the major prostaglandin E2 (PGE2) producers and demonstrated suppressor activity on in vitro IgG and IgM synthesis. Fractions A and B had minimal production of either IL1 or PGE2 and lesser effects on the IgG and IgM synthesis. These data demonstrate functional heterogeneity of peripheral blood monocytes with respect to production of both IL1 and PGE2 as well as accessory cells for immunoglobulin synthesis.
The regulatory locus rλ1 affects the level of λl light chain synthesis in lipopolysaccharide‐activated lymphocytes but not the frequency of λl ‐positive B cell precursors
Authors: Sanchez Pierre , Primi Daniele , Levi‐Strauss Mathieu , Cazenave Pierre‐Andrë
Published: February 2007

Several strains of mice, most notably the SJL strain, have a greatly reduced level of circulating λl immunoglobulins (rλ110 phenotype) compared with other mice. The locus responsible for this phenotype has been shown to be closely linked to the structural Cλl gene. Functionally this locus has been said to reduce the number of lymphocytes expressing surface λl molecules. In order to gain a better understanding of this phenomenon we compared the functional properties of activated B cells secreting λl immunoglobulins in the splenocytes of both BALB/c and SJL mice.

Our results indicate that regulatory T cells, as well as regulatory ontogenetic processes, are not responsible for the rλ1lo phenotype. In addition, limiting dilution analyses revealed that the number of lipopolysaccharide‐sensitive precursors of λl‐secreting B cells was similar in the splenocytes of the two strains of mice tested. The quantity of λl molecules produced by a B cell clone, however, was found to be lower in SJL than in BALB/c mice. As the level of λl mRNA is greatly reduced in lipopoly‐saccharide blasts of SJL mice, as compared to the mRNA detected in BALB/c blasts, we conclude that the impairment responsible for the rλ110 phenotype is probably transcriptional. We tentatively propose that sequences 5′ to the Cλl region are defective in their capacity to enhance the λl transcripts in SJL mice.
Recombinant interferon‐γ can induce the expression of HLA‐DR and ‐DC on DR‐negative melanoma cells and enhance the expression of HLA‐ABC and tumor‐associated antigens
Authors: Carrel Stefan , Schmidt‐Kessen Andreas , Giuffrè Laura
Published: February 2007

Recombinant interferon‐γ (IFN‐γ) induced the expression of HLA‐DR when added to the culture medium of HLA‐DR− melanoma cell lines. In addition, IFN‐γ induced the expression of another class II antigen, HLA‐DC, on a HLA‐DR+ and ‐DC− melanoma cell line and to a lower level on a ‐DR and ‐DC− melanoma line. IFN‐γ also enhanced the expression of HLA‐ABC and β2‐microglobulin, as well as HLA‐DR on DR+ melanoma cells. In contrast, IFN‐α gave no induction of expression of HLA‐DR and DC on two DR− melanoma lines, while it did enhance the expression of HLA‐ABC and of β2‐microglobulin. The expression of 3 out of 6 melanoma‐associated differentiation antigens was enhanced by IFN‐γ treatment. The modulation of antigens by IFN‐γ was both dose and time dependent. A minimum incubation time of 48 h was necessary for the appearance of HLA‐DR on the two HLA‐DR− melanoma lines, whereas HLA‐ABC and β2‐microglobulin were already increased after 24 h. A dose of 20 U/ml IFN‐γ started to induce the expression of HLA‐DR and DC on melanoma cells GLL‐19 and Me‐43 and a plateau of maximum antigen expression was reached with 100 U/ml. Analyses of IFN‐γ‐treated cells by flow micro‐fluorometry showed a homogeneous distribution of increased staining intensity rather than the appearance of two cell populations. Immunoprecipitation experiments using detergent‐solubilized 125I‐labeled membrane proteins of IFN‐γ‐treated melanoma cells and a monoclonal anti‐HLA‐DR antibody confirmed the presence of HLA‐DR antigens. When IFN‐γ‐treated cells were cultured without IFN the induced or enhanced expression of HLA antigens was reversible. Eight days after removal of IFN, the HLA‐DR level was reduced by more than 90% and the level of HLA‐ABC and β2‐microglobulin by more than 50%. The demonstration of the ability of HLA‐DR− melanoma cells to express HLA‐DR after IFN‐γ treatment was extended to cells from other types of tumor such as gliomas, colon carcinomas and one cervical carcinoma cell line.
Immediate hypersensitivity to drugs and simple chemicals: the efficacy of monovalent elicitors
Authors: Schneider Conrad H. , Guenin Raymond , Toffler Olga
Published: February 2007

Introduction of a reactive monohaptenic chemical into the sensitized organism will not normally result in elicitation of immediate reactions. Rather, the first products of chemical conjugation to suitable carriers in vivo are monohaptenic conjugates which are inhibitory according to the bridging concept, stating that the initiating event for mast cell and basophil activation is a cross‐linking of membrane‐bound antibody by dihaptenic or oligohaptenic antigen. Simple calculations and quantitative data are presented to show that built‐in inhibition is indeed a powerful barrier to any rapidly occurring allergenic manifestation which depends on the formation of divalent conjugates. If and when such a reaction does nevertheless occur, special requirements have to be invoked. One possibility is that the chemical or drug as such, i.e. without conjugation to a carrier, is an elicitor of anaphylaxis. Such compounds are known in a guinea pig passive cutaneous anaphylaxis model system, but there is evidence that they may also play a role in clinical situations. These monovalent elicitors possess in addition to the haptenic moiety an auxiliary group. The auxiliary group requirements were studied in the guinea pig passive cutaneous anaphylaxis system by using synthetic peptides with an N‐terminal 2‐carboxy‐4,6‐dinitrophenyl group as the hapten and phenylalanine and modified phenylalanine at the C‐terminus as auxiliary group. The conclusions are that effective auxiliary function depends on the benzene ring and neighboring carboxyl groups in selected positions. Anaphylactogenicity is high when the haptenic and auxiliary groups can act independently, i.e. when separated by a peptide chain of considerable length. Potent anaphylactogens with close linkage of the two groups have, however, also been found. It is unlikely that the passive cutaneous anaphylaxis elicitations observed here are mediated by some form of indirect bridging of membrane‐bound antibody.
Molecular and antigenic heterogeneity of the rat leukocyte‐common antigen from thymocytes and T and B lymphocytes
Authors: Woollett Gillian R. , Barclay A. Neil , Puklavec Michael , Williams Alan F.
Published: February 2007

The molecular forms and antigenic heterogeneity of the leukocyte‐common antigen (L‐CA) of rat lymphocytes have been analyzed. Thymocytes show one main band at 180 kDa, T cells four bands at 180,190, 200 and 220 kDa and B cells one broadband at about 240 kDa. T helper and T cytotoxic cell subsets show the same four bands with some differences in the proportion of each.

Four mouse monoclonal antibodies (MRC OX‐1, 28, 29 and 30) reacted with all molecular forms of L‐CA and fell into two sets that were noncompetitive in binding to L‐CA (MRC OX‐1, 28, 29 vs. OX‐30). The antigenic determinants seen by all these antibodies were lost when L‐CA was reduced and alkylated. Three antibodies (MRC OX‐22, 31 and 32) reacted selectively with B cells, T cytotoxic cells and about 2/3 of T helper cells. OX‐22 and OX‐31 competed for binding but were noncompetitive with OX‐32. All these antibodies bound to a subfraction of the 190, 200 and 220‐kDa forms of T cell L‐CA but not at all to the 180‐kDa form of T cells or thymocytes. One antibody bound to B cells only (MRC OX‐33) and precipitated a subfraction of B cell L‐CA. With all the antibodies that did not label thymocytes the antigenic determinants survived reduction and alkylation. Subsequent proteolysis with trypsin then destroyed all determinants except the one reacting with MRC OX‐22 antibody, In this case tryptic peptides retained full antigenic activity which was, however, destroyed by further proteolysis with pronase.
Very large and isotypically atypical polyclonal plaque‐forming cell responses in mice infected with Trypanosoma cruzi
Authors: Lima Maria Regina D'Imperio , Joskowicz Mireille , Coutinho Antonio , Kip Tereza , Eisen Harvey
Published: February 2007

Normal C3HIHeJ mice, acutely infected with T. cruzi, develop large numbers of splenic Ig‐secreting plaque‐forming cells (PFC). IgG2a, IgG2b and IgGl PFC account for over 90% of all PFC, while the numbers of IgG3‐ and IgA‐secreting PFC are lower than in normal animals. These effects appear to be due to both T helper‐dependent regulation and to a mitogenic activity associated with the parasites themselves.
A 3β‐cholestanyl‐containing mono‐benzylpenicilloyl oligoamide and peptide suppress anti‐benzylpenicilloyl antibody formation in mice
Authors: Lüscher Immanuel F. , De Weck Alain , Gitler Carlos
Published: February 2007

A long‐chain linear mono‐benzylpenicilloyl (BPO) oligoamide and a succinoylated mono‐BPO decalysine were tested in BALB/c mice for suppression of IgE and IgG1 antibody formation. Both compounds were available with either a free C‐terminal end or were C‐terminally linked to a hydrophobic 3β‐cholestanyl residue. Only the sterol‐containing derivatives suppressed hapten‐specific IgE and IgG1 responses. Substantial suppression was obtained when the compountds were administered before primary or secondary, but not later immunizations.

In an adoptive cell transfer experiment, spleen cells from tolerized animals actively suppressed anti‐BPO IgE antibody formation of immune spleen cells. This effect was reversed by pretreatment of the tolerized spleen cells with anti‐Lyt‐2.2 antibody plus complement.

The requirement for macrophages in the induction of T suppressor cells was demonstrated by injecting antigen‐pulsed macrophages into naive recipients; upon immunization, only mice treated with tolerogen‐pulsed macrophages showed suppressed anti‐BPO IgE responses. It is suggested that lipid modification of antigens alters their processing and presentation by macrophages in a manner that leads to the induction of T suppressor cells.

Injection of the cholestanyl derivatives into passively sensitized guinea pigs elicited anaphylactic reactions. By immune precipitation analysis and molecular weight estimation, these derivatives were shown to form micelles in aqueous solution. Therefore, the anaphylactic response appeared to be due to their behavior as multivalent antigens.
Abnormalities in autologous mixed lymphocyte reaction‐activated immunologic processes in systemic lupus erythematosus and their possible correction by interleukin 2
Authors: Takada Shinsuke , Ueda Yuji , Suzuki Noboru , Murakawa Yohko , Hoshino Takashi , Green Ira , Steinberg Alfred D. , Horwitz David A. , Sakane Tsuyoshi
Published: February 2007

The autologous mixed lymphocyte reaction (AMLR) represents the activation, proliferation and differentiation of T cells in response to signals from autologous non‐T cells. Upon stimulation by autologous non‐T cells, OKT4+ cells produce interleukin 2 (IL2); cells contained within both OKT4+ and OKT8+ cell populations can also be activated by autologous non‐T cells to become sensitive to IL2. Once these activated OKT4+ and OKT8+ cells are exposed to IL2 produced by OKT4+ cells, they will proliferate and go on to differentiate into effector cells.

Patients with systemic lupus erythematosus (SLE) have a defect in the AMLR. The ability of OKT4+ cells to produce IL 2 in the AMLR is impaired. Upon triggering with autologous non‐T cells, their OKT8+ cells become sensitive to proliferative signals of IL2; however, their OKT4+ cells fail to express IL2 receptors. These defects are a consistent feature in patients with SLE. AMLR‐induced immunologic processes which require cell interactions between OKT4+ cell subpopulations are not correct‐ able even by the addition of normal IL2. However, the immunologic processes medi ated through OKT4+‐OKT8+ cell interactions can be corrected with normal 1L2. The latter finding suggests that the partial correction of the AMLR‐induced immunologic processes with IL 2 might lead to suppressed B cell hyperactivity of patients with SLE.