bluuebunny/crossref_metadata_2025 huggingface dataset:
Alteration of the humoral immune response against muscle acetylcholine receptor by timed administration of α(1 → 3)dextran
Authors: Tong Zhou , Dwyer Donard S.
Published: March 2007

Previously, we discovered a profound idiotypic connectivity among antibodies involved in the immune responses to α(1 → 3)dextran (Dex) and the acetylcholine receptor (AChR). The present studies were undertaken to assess whether these connections represent functional pathways for regulation. It was found that immunization of mice with Dex prior to challenge with AChR reduced the subsequent response to receptor. The timing of the Dex administration was crucial for this effect with a 6‐day delay between Dex and AChR being optimal whereas 0‐or 12‐day delays proved ineffective. The suppressive effect was specific for Dex, as treatment with the closely related, but idiotypically distinct, α(1 → 6)dextran did not diminish the anti‐AChR response. Consistent with functional connections in the AChR‐Dex network, an inverse relationship between anti‐AChR and anti‐Dex antibodies was observed in these studies. Thus, high levels of anti‐AChR antibodies were associated with low levels of anti‐Dex antibodies and vice versa. A similar relationship was observed for serum antibodies from patients with myasthenia gravis. To investigate the mechanism for the antigen‐induced cross‐regulation, hybridomas were constructed from spleen cells of mice treated 6 days earlier with Dex. A variety of idiotypes (Id), anti‐Id and anti‐anti‐Id were obtained from this fusion. In addition, sera from day‐6 mice were examined for the expression of key anti‐Id which might provide regulation in the anti‐AChR response. The main feature of these sera was the presence of EB3‐7‐reactive antibodies which did not bind Dex, and hence were not identical to J558. A monoclonal antibody with similar properties was obtained from the day‐6 fusion (DX6) which had additional binding specificity for anti‐AChR antibodies. Antibodies induced by Dex immunization appear to participate in the crossregulation observed here. Understanding the mechanisms involved in this phenomenon will have important implications for network theory and for prediction of immune responsiveness.
Induction of B cell activities by interleukin 4 is inhibited by a receptor‐specific monoclonal antibody in vitro
Authors: Maliszewski Charles R. , Sato Timothy A. , Bos Tim Vanden , Beckmann M. Patricia , Grabstein Kenneth H.
Published: March 2007

The effects of interleukin (IL) 4 on B cell growth and differentiation are mediated through binding of IL 4 to a specific cell surface receptor. The murine T cell IL 4 receptor (IL 4R) has recently been cloned and monoclonal antibodies (mAb) which bind specifically to the IL 4R have been developed. The ability of two of these anti‐IL 4R mAb (M1 and M2) to inhibit IL 4‐induced B cell functions in vitro was examined. The M1 mAb inhibited the ability of IL 4 to induce B cell proliferation in a dose‐related fashion. The inhibition was specific for proliferation induced by IL 4 in that the antibody did not affect induction of proliferation by IL 1. Similarly, M1 inhibited IL 4‐dependent B cell differentiation as measured by induction of IgG1 and IgE secretion, decreased IgG3 secretion, increased Ia expression, and increased FcϵR (CD23) expression. In contrast, the anti‐IL 4R‐specific mAb M2 had no effect upon any of these activities. The ability of M1 but not M2 to inhibit IL 4‐induced B cell growth and differentiation correlated with the inhibition of binding of radiolabeled IL 4 by M1. These reagents should be valuable tools with which to analyze the involvement of IL 4 in immune responses.
Identification of the intracytoplasmic region essential for signal transduction through a B cell activation molecule, CD40
Authors: Inui Seiji , Kaisho Tsuneyasu , Kikutani Hitoshi , Stamenkovic Ivan , Seed Brian , Clark Edward A. , Kishimoto Tadamitsu
Published: March 2007

CD40 is a 45‐kDa glycoprotein expressed on human B lineage cells. Anti‐CD40 induces the proliferation of B cells and the extracellular region of CD40 is related to those of a certain kind of growth factor receptors. Therefore, it has been proposed that CD40 might be a receptor for a molecule involved in the growth regulation of B cells. The cDNA coding for CD40 was transfected into the murine B lymphoma cell line M12 and the murine thymoma cell line EL4. The growth of both M12 and EL4 transfectants expressing human CD40 was inhibited by anti‐CD40. Phorbol 12‐myristate 13‐acetate (PMA) augmented the growth inhibitory effects of anti‐CD40 on transfectants. The CD40 molecule was constitutively phosphorylated not only in human tonsil B cells but also in transfectants expressing CD40. PMA augmented the phosphorylation of CD40 in these cells. These results indicate that in spite of the growth inhibitory effect of anti‐CD40, the augmentative effect of PMA is conserved in CD40+ transfectants and suggest that the transfectant might be useful for the study of signal transduction mechanism through CD40. To investigate which part of the CD40 molecule is important for signal transduction, transfectants expressing mutant CD40 cDNA were established and their growth response to anti‐CD40 was evaluated. The mutant molecule, which had an Ala for Thr substitution at position 234, and the deletion mutants lacking Thr234 were inactive in growth signal transduction, indicating that Thr234 itself or the region around Thr234 is essential for signal transduction through CD40.
Recombinant interleukin 2‐activated natural killer cells regulate IgG2a production
Authors: Amigorena Sebastián , Bonnerot Christian , Fridman Wolf Herman , Teillaud Jean‐Luc
Published: March 2007

In this report we have analyzed the effect of recombinant interleukin 2 (rIL 2) and rIL 2‐activated natural killer (NK) cells on the production of immunoglobulin isotypes by lipopolysaccharide (LPS)‐stimulated spleen cells from nude mice. We found that rIL 2 induced a dose‐dependent increase of IgG2a secretion and a concomitant inhibition of the secretion of other Ig isotypes. The analysis of the phenotype of LPS‐ and LPS+rIL 2‐stimulated nude spleen cells showed the appearance of a Thy‐1+asialo GM‐1+slgM−CD3−CD4−CD8− cell population in the presence of rIL 2. A population with a similar phenotype was generated upon stimulation of spleen cells from nude mice with rIL 2 alone. These cells lysed YAC‐1 cells, did not contain the α or γ transcripts encoding the corresponding T cell receptor chains and are therefore NK cells activated by rIL 2. In co‐culture experiments, these cells selectively increased the secretion of IgG2a by LPS‐stimulated splenocytes from nude mice. The IgG2a induction triggered by rIL 2‐activated NK cells, as well as that triggered by rIL 2, were blocked by an anti‐interferon γ monoclonal antibody. Thus, rIL 2 activated‐NK cells enhance the production of IgG2a by secreting interferon‐γ.
Resistance to lymphoid engraftment in lpr recipients of normal bone marrow: characterization of chimeric stem cell, monocyte and peripheral lymphoid lineages
Authors: Glaser Roseann M. , Marshak‐Rothstein Ann
Published: March 2007

Lethally irradiated MRL/lpr mice reconstituted with T cell‐depleted bone marrow stem cells from the non‐autoimmune strain A. Thy had been shown to develop a state of long‐term split chimerism; erythrocytes were derived from the A. Thy donor, while peripheral lymphocytes were derived from the lpr recipient. In contrast, recipients of the non‐lpr‐congenic strain, MRL/+, were fully repopulated in both lineages by donor‐derived hematopoietic cells. In order to more fully understand the mechanisms responsible for this type of split chimerism, we have investigated additional genetic and developmental parameters. We found that histocompatible normal B cell precursors engrafted C3H/HeJ and C57BL/6/+ mice much better than they engrafted the corresponding lpr congenic strains, indicating that resistance to lymphoid engraftment was not unique to the MRL background. Bone marrow cells and peritoneal macrophages were found to express the donor H‐2 phenotype in both non‐lpr and lpr recipients, limiting resistance to the lymphoid lineage. Moreover, we showed that normal bone marrow stem cells passaged in an lpr host environment were subsequently able to repopulate the B cell lineage of non‐lpr secondary recipients, proving that prelymphoid stem cells were intact. Although lymph node cells from A. Thy → MRL/lpr chimeras were lpr‐derived, they did not show the abnormal surface marker expression associated with the lpr phenotype, nor did they develop lymphoid hyperplasia or elevated autoantibody levels. However, A. Thy → MRL/lpr chimeras differed from normal mice in that their spleens were markedly deficient in IgM+ B cells.
Interleukin 6 is a differentiation factor for human megakaryocytes in vitro
Authors: Kimura Hideo , Ishibashi Toshiyuki , Uchida Tatsumi , Maruyama Yukio , Friese Paul , Burstein Samuel A.
Published: March 2007

The response of cells of the megakaryocytic lineage to interleukin 6 (IL 6), a cytokine with multiple biological activities, was studied by adding the factor to human bone marrow (BM) cultures. IL 6 alone had no effect on megakaryocytic colony formation in methylcellulose; however, in the presence of maximally stimulating concentrations of IL 3, almost a twofold increment in colony formation was observed. Tritiated thymidine suicide studies of BM incubated for 2 h with growth factors showed that almost one‐half of megakaryocytic progenitors (CFU‐Mk) preincubated with IL3 or IL3 plus IL6 were in S phase, whereas BM incubated with IL 6 alone was similar to control (∽ 24% of CFU‐Mk in S phase). When ≧ 1 ng/ml of IL6 was added to liquid suspension cultures of BM, the size of individual megakaryocytes was significantly augmented compared with that seen in control cultures. Moreover, the DNA content of megakaryocytes grown in the presence of IL6 was increased (modal ploidy 16N) compared with cultures grown with IL3 (modal ploidy 8N). To determine if the effect of IL6 could be direct rather than mediated via accessory BM cells, the factor was added to cultures of isolated single megakaryocytes. Seventy‐one percent of cells increased in diameter in the presence of IL6, while only 27% increased in size in the absence of the factor. The data show that IL6 is a direct maturation factor for human megakaryocytes, promoting increments in size and ploidy of these cells.
The human intracellular Mx‐homologous protein is specifically induced by type I interferons
Authors: Von Wussow Peter , Jakschies Detlef , Hochkeppel Heinz‐Kurt , Fibich Christian , Penner Lothar , Deicher Helmuth
Published: March 2007

The murine Mx‐1 protein is one of the best biochemically and functionally characterized interferon (IFN)‐induced proteins that is necessary, and sufficient, for providing resistance to murine cells against viral influenza infection. Recently an intracellular human protein homologous to the murine Mx‐1 protein has been identified by means of a specific monoclonal antibody. The restricted induction of this intracellular protein in human mononuclear cells (MNC) by various cytokines was investigated. MNC from 26 of 28 healthy people and 35 of 36 cancer patients before IFN‐α therapy had no detectable Mx‐homologous protein. Incubation of human MNC with IFN‐α and IFN‐β for 24 h at different concentrations led to a dose‐dependent induction of the Mx‐homologous protein. All IFN‐α or IFN‐β preparations tested were equally effective in eliciting this intracellular protein. IFN‐γ induced only 1% of the Mx amount elicited by type‐1 IFN compared on a weight basis. Neither interleukin (IL) 1 nor IL 3, IL 4, IL 5, IL 6, tumor necrosis factor‐α/β, granulocyte colony‐stimulating factor (CSF) or granulocyte macrophage‐CSF at any of the concentrations tested were capable of eliciting any detectable amount of the Mx homolog, while IL 2 was a poor Mx‐homologous protein inducer. In the presence of high‐titered IFN‐α antisera both IL 2 and IFN‐γ were unable to stimulate this protein, proving that IFN‐γ and IL 2 indirectly induce the Mx homolog via IFN‐α. Therefore, the human Mx‐homologous protein is a strictly by type I IFN‐regulated protein in human peripheral blood lymphocytes.
Severe combined immunodeficiency in man with an absence of immunoglobulin gene rearrangements but normal T cell receptor assembly
Authors: Thompson Allan , Hendriks Rudolf W. , Kraakman Margriet E. M. , Koning Frits , Bergh Renée Langlois‐Van Den , Vossen Jaak M. , Weemaes Corry M. R. , Schuurman Ruud K. B.
Published: March 2007

An autosomal recessive type of severe combined immunodeficiency disease (SCID) was characterized by an absence of immunoglobulins (Ig) in the serum and of Ig+ lymphocytes in bone barrow (BM) and peripheral blood. In the BM CD10+/terminal deoxynucleotidyl transferase‐positive lymphocytes were identified. Epstein‐Barr virus‐transformed B lymphoblastoid cell lines (BLCL) obtained from BM and peripheral blood did not synthesize Ig. The Ig heavy and light chain gene complexes in the BLCL had retained the germ‐line configuration. Mature T cells were present but their numbers in peripheral blood were decreased. T lymphoblastoid cells derived from peripheral blood expressed normal T cell receptor (TcR) CD3 complexes and manifested various genomic TcR rearrangements. It was concluded that this type of SCID entailed a complete arrest of B lymphocyte differentiation in an early stage prior to Ig rearrangements and a quantitative defect of T lymphocytes which nevertheless allowed development of mature T cells. Repeated failures of BM transplantation and the striking absence of Ig assembly suggested that this SCID defect resides in the BM microenvironment.
Idiotypic interactions between normal human polyspecific IgG and natural IgM antibodies
Authors: Rossi Françoise , Guilbert Brigitte , Tonnelle Cécile , Ternynck Thérèse , Fumoux François , Avrameas Stratis , Kazatchkine Michael D.
Published: March 2007

Pooled normal human polyspecific IgG (IVIg) contain anti‐idiotypes against a variety of autoantibodies from patients with autoimmune diseases and IgG autoantibodies present in IVIg. The present study indicates that IVIg may also react through idiotypic/anti‐idiotypic interactions with human natural IgM antibodies. Sixty‐four percent of IgM secreted by B lymphoid cell lines derived from B cells of healthy elderly donors and 18% of IgM secreted by cloned EBV‐transformed cord B cells that were tested, bound through their variable region to F(ab')2 fragments of IVIg. The binding to 2,4,6‐trinitrophenyl (TNP) of a polyreactive IgM with anti‐TNP specificity, was inhibited by F(ab')2 fragments from IVIg, indicating the presence in IVIg of anti‐idiotypes that may interfere with the antibody‐combining site of polyreactive IgM antibodies. The ability of IgM antibodies to interact with idiotypes on IVIg was not related to the degree of polyreactivity of natural antibodies. Our observations further document that IVIg contain antibody specificities against Ig from normal individuals and suggest that IgG originating from the physiologically expressed repertoire may modulate the expression of the potential B cell repertoire. The results may be relevant to the suppressive effect of IVIg in autoimmune diseases.
Structural comparison of α/β and γ/δ T cell receptor‐CD3 complexes reveals identical subunit interactions but distinct cross‐linking patterns of T cell receptor chains
Authors: van Neerven Joost , Coligan John E. , Koning Frits
Published: March 2007

Here we compare the subunit interactions within the α/β and γ/δ T cell receptor‐CD3 (TcR‐CD3) complexes. By using different detergent solubilization protocols, subunit interactions can be defined within such cell surface receptor complexes. It was found that in both TcR‐CD3 complexes analogous subunit interactions can be defined: CD3γ and CD3δ each form a stable complex with separate CD3ε chains. Both the TcRγ/δ and TcR α/β form stable receptor complexes with these CD3 γ/ε and CD3 δ/ε subunits. A ζ homodimer is present in these TcR‐CD3 complexes. However, biochemical cross‐linking results in a covalent bond between the CD3γ chain and the TcRβ chain in α/β TcR‐CD3 complexes and between the CD3γ chain and the TcRδ in γ/δ TcR‐CD3 complexes. This latter observation was independent of the type of TcR γ/δ studied (e.g. disulfide or non‐disulfide linked). These cross‐linking results either indicate that the TcR β and δ chains are each others structural homolog or that in TcR‐CD3 complexes both TcR chains (α and β, γ and δ) are spatially closely associated with the CD3γ chain. The identical subunit interactions in the α/β and γ/δ TcR‐CD3 complexes indicate no large structural differences between these receptor complexes but rather suggest a striking conservation of crucial interaction between subunits in the TcR‐CD3 complexes.
In vitro human cytotoxic T cell responses against influenza A virus can be induced and selected by synthetic peptides
Authors: Martinon Frédéric , Gomard Elisabeth , Hannoun Claude , Lévy Jean‐Paul
Published: March 2007

Studies on human anti‐influenza cytolytic activities have demonstrated that cytotoxic T lymphocytes (CTL) from HLA‐B37 individuals react preferentially with the peptide corresponding to residues 335–349 of the nucleoprotein, whereas CTL from HLA‐A2 donors recognize peptide 57–68 from the viral matrix as a dominant epitope. We studied the secondary CTL response, obtained from peripheral blood mononuclear cells, of an HLA‐A2+, B37+ individual stimulated either by infectious virus or by synthetic peptides. Only an HLA‐B37‐restricted response was detected after stimulation by the whole virus, showing an immunodominance of this activity over that restricted by HLA‐A2. Moreover, human cytotoxic cell lines were successfully obtained after stimulation of peripheral blood mononuclear cells with synthetic peptides. Under these conditions, it was possible to selectively reveal the existence of an HLA‐A2‐restricted activity directed against the matrix peptide. These results demonstrate that, at least in vitro, it is possible to stimulate a latent repertoire by using synthetic peptides. Nevertheless, we could not induce a response against the matrix or the nucleoprotein peptides in HLA‐A2− or B37− individuals, suggesting that a finer selection of synthetic peptides would be necessary for their possible utilization to induce CTL during vaccination.
Immunoglobulin heavy chain variable region family usage is independent of tumor cell phenotype in human B lineage leukemias
Authors: Deane Miriam , Norton John D.
Published: March 2007

During B cell development, immunoglobulin heavy chain (IgH) variable region (VH) genes are rearranged and expressed in a programed manner and accumulating evidence suggests recurrent utilization of developmentally restricted VH genes in malignant B lymphoid populations. We have used polymerase chain reaction gene amplification in conjunction with a panel of VH family‐specific amplimers to directly compare the repertoire of VH region rearrangement in mature, CD5+ B cell chronic lymphocytic leukemia with that in immature, CD5 B lineage acute lymphoblastic leukemia. The results revealed a diverse pattern of VH family utilization common to both disease groups in which VH regions most proximal to the IgH joining locus were preferentially rearranged relative to their family sizes with recurrent utilization of several known developmentally restricted VH genes in close to germ‐line configuration. These results indicate that biased VH family usage is independent of tumor cell phenotype in B lineage leukemias. This bias may reflect similar stages or compartments in normal B lymphopoiesis from which diverse types of B cell malignancy may arise. Moreover, since blast cells in acute lymphoblastic leukaemia do not express functional immunoglobulin, we infer that the tumor cell‐associated VH family repertoire is determined through antigen‐independent mechanisms.
Glycosylation of IgG, immune complexes and IgG subclasses in the MRL‐lpr/lpr mouse model of rheumatoid arthritis
Authors: Bond Angela , Cooke Anne , Hay Frank C.
Published: March 2007

The MRL‐lpr/lpr (MRL/lpr) mouse spontaneously develops a disease syndrome which, in many respects, is similar to human rheumatoid arthritis. These mice develop joint inflammation, circulating rheumatoid factors and immune complexes. We now show that the parallel with human disease extends to a glycosylation defect which is observed on IgG from rheumatoid arthritis patients. Using the lectins ricin and Bandeiraea simplicifolia II we have found that terminal N‐acetylglucosamine is clearly raised in MRL/lpr IgG. Increased exposure of galactose was also detected, indicating that a second glycosylation site must be present on these molecules. Polyethylene glycol‐precipitated IgG complexes bound significiantly more of each lectin than did free IgG, indicating that the changes in glycosylation were associated with complex formation. The sugar abnormality was most marked in the IgG2a/IgG3 fraction from protein A IgG subclass chromatography. Our results suggest that the IgG glycosylation defect seen in rheumatoid arthritis is apparent in the MRL/lpr mouse and may contribute, through complex formation, to the pathological processes in the rheumatoid syndrome.
Ca2+ influx in human T lymphocytes is induced independently of inositol phosphate production by mobilization of intracellular Ca2+ stores. A study with the Ca2+ endoplasmic reticulum‐ATPase inhibitor thapsigargin
Authors: Gouy Hélène , Cefai Daniel , Christensen Soren Brogger , Debré Patrice , Bismuth Georges
Published: March 2007

Thapsigargin (TG), a sesquiterpene lactone and non‐phorbol 12‐myristate 13‐acetate tumor promoter, stimulates a rapid increase in intracellular free Ca2+ ([Ca2+]i) in human T lymphocytes clone P28. The [Ca2+]i response to TG is sustained in the presence of 1 mM extracellular Ca2+, while it becomes transient in Ca2+‐free medium suggesting that TG activates both the release of Ca2+ from intracellular stores and the entry of Ca2+ from extracellular spaces. TG‐induced Ca2+ influx is completely abolished after cell depolarization caused by increased extracellular concentrations of K+. The rise in [Ca2+]i stimulated by TG occurs in the absence of detectable production of inositol phosphates. Moreover, TG does not alter the early biochemical events of T cell activation triggered through the CD2 or the CD3 T cell antigens. Indeed, both inositol phosphate production and intracellular pH increase induced by specific monoclonal antibodies (mAb) remain unchanged after TG treatment. These data suggest that in human T lymphocytes TG releases Ca2+ from an intracellular pool by a mechanism which is independent of the phospholipase C metabolic pathway. Preincubation with TG of T cell clone P28 empties both the CD2 and the CD3‐sensitive intracellular Ca2+ pool(s). Conversely, prestimulation of T cell clone P28 by CD3 or CD2‐specific mAb inhibits the Ca2+‐mobilizing effect of TG. Thus it appears that TG and CD2‐or CD3‐specific mAb mobilize Ca2+ from common Ca2+ pool(s). Taken together, these results demonstrate that Ca2+ influx in human T cells may be linked to mobilization of intracellular Ca2+ pools and by a mechanism independent of phosphoinositide hydrolysis. They further indicate that the release of intracellular Ca2+ pool(s) may play a major role in the opening of cell membrane Ca2+ channels observed during the CD2‐ or CD3‐induced stimulation of human T lymphocytes.
Age‐related decrement in cytotoxic T lymphocyte (CTL) activity is associated with decreased levels of mRNA encoded by two CTL‐associated serine esterase genes and the perforin gene in mice
Authors: Bloom Eda T. , Umehara Hisanori , Bleackley R. Chris , Okumura Ko , Mostowski Howard , Babbitt Jane T.
Published: March 2007

The age‐related decline in cytotoxic T lymphocyte (CTL) activity has been recognized for many years. Age‐related alterations in several immunologic events have been suggested to be partly or completely responsible for this decline. We had previously demonstrated (Bloom et al., Cell. Immunol. 1988. 144: 440) in mice that a deterioration in the lytic mechanism may be at least in part responsible for the decline in CTL activity. We now report that this decline correlates with an age‐related decrease in serine esterase activity released into the supernatant medium in the process of generating CTL. Northern analyses were then used to examine the effect of age on expression of genes encoding for perforin and two CTL‐associated serine esterases. The products of all three of these genes have all been postulated to play roles in CTL‐mediated lysis. We show that the expression of all three of these genes appears to decline with age in the process of generating allogeneic CTL. These alterations in gene expression correlated both with diminished cytolytic and released esterase activities generated by mixed leukocyte culture in spleen cells of old mice compared to young. The age‐related decline in gene expression could not be attributed to shifts in T cell subsets, but CD8+ cells generated by allogeneic stimulation of nylon wool‐passed spleen cells from old mice expressed significantly less cytolytic activity than those from young. This report is the first demonstration of an age‐related decrease in expression of a functionally related group of genes. In addition, these findings are compatible with the suggested roles for perforin and serine esterase release in CTL‐mediated target cell lysis.
Porcine γ/δ T lymphocyte subsets differing in their propensity to home to lymphoid tissue
Authors: Saalmüller Armin , Hirt Werner , Reddehase Matthias J.
Published: March 2007

Three types of Tcell receptors (TcR) γ/δ were identified in swine, all of which are disulfide‐bonded cell surface heterodimers. The first, a 38/40‐kDa molecule, is related to the TcR γ/δ of sheep and cattle, and defines in swine a subset of CD4−CD8− T lymphocytes that is enriched in the circulatingT lymphocyte pool. The other two receptors are private to swine. The second, a 37/40‐kDa molecule, is expressed by the major subset of CD2−CD4−CD8− T lymphocytes that is neither enriched in nor excluded from lymphoid tissue. By contrast, the third type of TcR γ/δ, a 40/46‐kDa molecule, is found on CD2+CD4−CD8− T lymphocytes accumulating in lymphoid tissue. Thus, TcR γ/δ T lymphocyte subsets differing in homing propensity are typified by the expression of distinct molecular forms of the TcR γ/δ.
HLA‐DQ molecules and the control of Mycobacterium leprae‐specific T cell nonresponsiveness in lepromatous leprosy patients
Authors: Ottenhoff Tom H. M. , Walford Charlotte , Nishimura Yasuharu , Reddy N. B. B. , Sasazuki Takehiko
Published: March 2007

The major histocompatibility complex (MHC) controls of the outcome of the immune response to T cell‐dependent antigens by dictating whether T cell responsiveness will result (MHC‐immune response [Ir] genes) or alternatively T cell nonresponsiveness will occur, possibly through the activation of suppressor cells (MHC‐immune suppression [Is] genes).

In mice, I‐A molecules typically restrict antigen‐specific helper T cells. In contrast, H‐2 I‐E molecules have been reported to control nonresponsiveness to a variety of antigens through antigen‐specific suppressor cells. In analogy, HLA‐DR molecules are the dominant restriction elements for helper Tcells in man. This forces the question whether DQ molecules may be involved in controlling nonresponsiveness in man, e.g. through suppression. In one system, T cell nonresponsiveness to Schistosoma japonicum, evidence has been presented supporting this notion. We have now used a second system, Mycobacterium leprae‐specific T cell nonresponsiveness, that is typically found in lepromatous leprosy patients.

We find positive but limited evidence for a role for HLA‐DQ molecules in controlling Tcell nonresponsiveness to M. leprae of the 22 nonresponder patients tested, 4 showed a proliferative T cell response to M. leprae after the addition of DQ‐ but not DR‐specific mAb to the cell cultures. In one of the four BCG nonresponders, anti‐DQ mAb had a similar effect.
Uptake of antigen by afferent lymph dendritic cells mediated by antibody
Authors: Harkiss Gordon D. , Hopkins John , McConnell Ian
Published: March 2007

Dendritic cells isolated from sheep afferent lymph were examined for their ability to bind soluble protein and peptide antigens labeled with fluorescein both in in vitro assays and following intradermal injection of antigen in vivo. Analysis of dendritic cells by flow cytometry revealed weak direct binding of proteins and peptide antigens. However, the degree of uptake was greatly enhanced in the presence of specific antibody in vitro or if antigen was injected intradermally into antigen‐primed sheep. About 60% of dendritic cells possessed the ability to take up antigen in both the in vitro and in vivo experiments. The uptake of antigen occurred very rapidly, reaching maximum values in terms of cell numbers and fluorescence intensity in less than 5 min in vitro and 20–40 min following in vivo challenge. Both sheep IgG subclasses could mediate this effect, but F(ab')2 fragments were ineffective. Procedures adopted to remove complement components from the in vitro test mixtures did not result in any reduction in the binding of antigen by dendritic cells. Two‐color flow cytometry analysis of the dendritic cell population further showed that 43% of cells taking up the antigen/antibody complexes were CD1+, suggesting a relationship between these cells and Langerhans' cells or other dendritic cells in skin. The results, thus, indicate that approximately two thirds of sheep afferent lymph dendritic cells bind antigen/antibody complexes via an Fc receptor, a mechanism which could be important in the accentuated accessory function of these cells known to occur following secondary antigen challenge.
Parasite‐accessory cell interactions in Theileriosis. Antigen presentation by Theileria annulata‐infected macrophages and production of continuously growing antigen‐presenting cell lines
Authors: Glass Elizabeth J. , Spooner Roger L.
Published: March 2007

Theileria annulata, a protozoan parasite of cattle, infects major histocompatibility complex (MHC) class II+ cells, particularly macrophages, and transforms them into continuously growing cell lines. We examined the effects of parasitism by T. annulata on antigen‐presenting cell function. T. annulata‐infected cells (TaH) presented ovalbumin (as measured by [3H]thymidine incorporation) to both resting autologous bovine T cells and ovalbumin‐specific bovine CD4+ T cell lines. However, the former cells were also stimulated by TaH without exogenous antigen although to a lesser degree than in the presence of antigen. This “nonspecific” proliferation was not seen with the ovalbumin‐specific T cell lines. The magnitude of response by resting T cells in the presence of antigen, to TaH or purified peripheral blood monocytes, was essentially similar. However, on a per cell basis fewer TaH were required. Considerably greater proliferation to antigen was seen with the ovalbumin‐specific T cell lines in the presence of TaH compared to monocytes and again fewer TaH were required to elicit a response. The kinetics of processing did not appear to be substantially altered in TaH and the increased proliferation may be due to the elevated MHC class II expression of these cells. Genetic restriction studies with the T cell lines indicated that the restricting elements used to present ovalbumin by TaH were the same as those used by monocytes, as identified by an isoelectric focusing technique. The continuously growing cell lines provide us with a unique model for investigating parasite‐accessory cell interactions in theileriosis. The augmented antigen presenting cell activity of TaH may play an important role in the pathogenesis of the disease. TaH will also provide us with a valuable resource for our antigen presentation studies. In particular, the enhanced antigen presentation by TaH enabled us to detect responses to lower levels of antigen, often an important consideration for experiments where the quantity of antigen available is the major limiting factor.
Inhibition of the mixed lymphocyte reaction by T cell vaccination
Authors: Lohse Ansgar W. , Mor Eitan , Reshef Tamara , Meyer Zum Karl‐Hermann , Büschenfelde  , Cohen Irun R.
Published: March 2007

Immunization with attenuated activated autoreactive T cell lines and clones induces a response in syngeneic animals which can induce protection or recovery from autoimmune disease. This process has been termed T cell vaccination. The aim of the present study was to investigate the effect of immunization with MHC‐reactive T cells on the mixed lymphocyte reaction (MLR). By injecting attenuated activated T cells primed for an alloantigen, we markedly reduced the MLR in both rats and mice. This depression appeared to be mediated by active suppression; lymphoid cells from T cell‐vaccinated animals suppressed the MLR responsiveness of T cells from naive animals. Suppression of the MLR was not restricted to the major histocompatibility complex (MHC) alleles used to prime the animals from which the T cell vaccines were prepared; the MLR to other MHC allelic stimulator cells was also suppressed. This MHC‐unrestricted suppression could not be attributed to an anti‐ergotypic response to non‐MHC‐linked activation markers on T cells; an anti‐ergotypic response augmented rather than suppressed the MLR. We herein propose that T cell vaccination might influence the MLR by suppressing the responses of diverse T cells which bear shared T cell receptor idiotypes.
Immunization of susceptible hosts with a soluble antigen fraction from Leishmania major leads to aggravation of murine leishmaniasis mediated by CD4+ T cells
Authors: Bogdan Christian , Schröppel Klaus , Lohoff Michael , Röllinghoff Martin , Solbach Werner
Published: March 2007

This study was performed in order to define Leishmania major antigens that function as disease‐modulating immunogens in susceptible BALB/c mice. A soluble leishmanial antigen preparation (S‐SLA) derived from highly infective stationary‐phase L. major parasites was fractionated by preparative gel electrophoresis. In vitro, the low molecular mass fraction (<31 kDa) of S‐SLA fraction D (FR D) was found to be a potent stimulator of L. major‐specific Th1 and Th2 helper cell clones. In vivo, immunization with FR D induced a Th2‐biased immune response in BALB/c mice as determined by the numbers of splenic CD4+ cells secreting interleukin 4 and interferon‐γ according to limiting dilution analyses. In addition, FR D caused significant disease exacerbation in parasiteinfected susceptible mice as assessed by the local lesion development and the numbers of parasites in lymph nodes and spleen. This effect was observed after local subcutaneous application of FR D as well as after systemic immunization (intrasplenic or intraperitoneal). Transfer experiments revealed, that the disease‐aggravating effect of FR D was mediated by CD4+ T cells.

From these results it is concluded that leishmanial protein preparations exist that not only fail to induce protective antiparasitic immunity, but can mediate disease exacerbation, independently of the primary application site of the immunogen. The existence of such structures may serve the parasite as a means to evade the host's immune attack and may also have implications for the development of vaccines.
Effects of prolonged incubation of rat peritoneal mast cells with compound 48/80
Authors: Levi‐Schaffer Francesca , Riesel‐Yaron Naomi
Published: March 2007

Rat peritoneal mast cells (MC) co‐cultured on a monolayer of 3T3 fibroblasts (MC/3T3) were continuously exposed to compound 48/80 for 14 days. As early as 2 days following continuous exposure to compound 48/80, the MC/3T3 appeared as a heterogeneous population, with various MC appearing partially or fully degranulated or intact; this morphological pattern continued throughout the duration of the experiment. MC/3T3 remained functionally active as demonstrated by their ability to secrete histamine 15 min after each replacement with fresh medium containing compound 48/80, although this capacity diminished towards the end of the 14‐day experiment. Concomitant with the histamine release, a significant increase in cellular histamine pools was observed. When MC/3T3 continuously exposed to compound 48/80 for 7 or 14 days were acutely challenged with anti‐IgE antibodies, they were able to secrete histamine and prostaglandin D2 in amounts similar to those produced by control MC. In contrast, when these cells were challenged on day 7 or 14 with a higher dose of compound 48/80 or with substance P, the release of histamine was partially inhibited. Our results indicate that continuous in vitro exposure to compound 48/80, and the resulting MC degranulation product histamine, does not adversely affect the ability of MC/3T3 to synthesize histamine and to respond to activation stimuli of a related secretagogue for 7 days and a non‐related one for at least 14 days.
The neonatally T cell receptor 2‐suppressed rat : lymphocyte subset composition and immune reactivity
Authors: Schlipköter Eva , Hünig Thomas
Published: March 2007

Rats were injected intraperitoneally from birth on with a mouse monoclonal antibody (R73) to a constant determinant of the rat T cell receptor (TcR)2. Throughout the observation period (6 months), TcR2+ cells in peripheral lymphoid organs and blood were absent in treated animals with the exception of few (< 10%) cells with a tenfold reduced TcR2 density; peripheral TcR2−CD3+ cells, i.e. most likely TcR1+ T cells, were increased in frequency. Among thymocyte subpopulations, only those expressing the TcR2 at a high level were reduced in number. The lack of a visible effect on immature thymocytes may, however, be due to the fact that despite high serum levels, thymic R73 determinants were incompletely saturated.

Spleen and lymph node cells from TcR2‐suppressed rats were completely unresponsive in mixed lymphocyte reaction (two fully allogeneic haplotypes tested) even in the presence of interleukin 2. Reactivity to the T cell mitogen concanavalin A was, in contrast, only partially reduced. Since rat TcR1 cells are activated by concanavalin A, these results suggest that the TcR1 cells present in TcR2‐suppressed rats are functional, but do not respond to foreign major histocompatibility complex antigens at a high frequency, a finding of possible importance for immunosuppression with anti‐TcR2 monoclonal antibody in human allografting. Neonatally TcR2‐suppressed rats were unable to respond to the strong T‐dependent antigen keyhole limpet hemocyanin administered intraperitoneally in alum with B. pertussis. Thus, in the absence of peripheral TcR2 cells, the numerically expanded TcR1 T cells are not capable of providing help for B lymphocytes.
Heavy and light chain sequences of four monoclonal antibodies that bind galactosylgloboside (GalGb4)
Authors: Snyder James G. , Weng Nanping , Yu‐Lee Li‐Yuan , Marcus Donald M.
Published: March 2007

We recently described IgM monoclonal antibodies directed against the glyco‐spingolipid galactosylgloboside (GalGb4; Marcus, M. D. et al., Arch. Biochem. Biophys. 1988. 262: 620). We now present the nucleotide and deduced amino acid sequences of the heavy and light chains of these antibodies. The antibodies were generated in a single fusion, their heavy as well as their light chains are almost identical, and they appear to be clonally related. The light chains were encoded by Jx5 and a Vx gene belonging to the Oxl family, but they are only 93% homologous to the most closely related germ‐line gene, and they are probably encoded by a germ‐line gene that has not yet been identified. The heavy chains were all encoded by VH441 and JH2, and have identical N segments. The VH441 germ‐line gene encodes a potential glycosylation site at Asn58 in the complementarity‐determining region 2. This site, which has been retained in all VH441‐encoded monoclonal antibodies sequenced previously, was mutated out by a single base change in all four anti‐GalGb4 antibodies.
Chemical and immunochemical identification of the second major rabbit immunoglobulin λ chain polypeptide bearing c7 epitopes
Authors: Jaton Jean‐Claude , Hayzer David J. , Frutiger SéVerine , Hughes Graham J. , Young‐Cooper Glendowlyn O. , Mage Rose G.
Published: March 2007

The purification of λ chain‐containing IgG fraction from pooled sera of Basilea rabbits, which were bred and selected for the expression of a high level of λ chains positive for c7 but negative for c21, was carried out. On the basis of specific binding to anti‐c7 antiserum, the c7 λ chain fraction in serum IgG was shown to account for up to 70% of the total immunoglobulin light chains, the remaining 30%, bearing the expected κ2 bas isotype. Peptide mapping of the mixed light chains (λ + κ2 bas) followed by microsequencing of the constant region fragments indicated that the Cλ region originated from the cDNA sequence derived from a c7+,c21− Basilea rabbit (i.e. identical to gene Cλ6), as described in the preceding report (Hayzer, D. J. et al., Eur. J. Immunol. 1990. 20: 2707). In addition, a synthetic peptide encompassing residues 139–159 of the constant region derived from the predicted sequence of gene Cλ6 was shown to partially inhibit the c7‐anti‐c7 binding reaction in a sensitive enzyme‐linked immunosorbent assay. Taken together, the chemical and immunochemical data clearly demonstrate that gene Cλ6 indeed encodes c7 epitopes.
Induction of tolerance in peripheral T cells with monoclonal antibodies
Authors: Qin Shixin , Wise Matt , Cobbold Stephen P. , Leong Louise , M. Kong Yi‐Chi , Parnes Jane R. , Waldmann Herman
Published: March 2007

Our goal has been to develop ways to tolerize the mature immune system to any defined antigen. In this report we show that peripheral (post‐thymic) T cells of mice can become tolerant to a range of antigens (human and rat immunoglobulins, and bone marrow and skin grafts that differ at multiple minor transplantation antigens). In the case of human gamma globulin (HGG), this required that the antigen be given under the cover of a short course of non‐depleting anti‐CD4 antibody, while for tolerance to skin and marrow grafts anti‐CD8 antibody was also required. Tolerance to HGG could be reinforced by repeated injections of HGG, but was lost in the absence of any further exposure to antigen. This reversal of tolerance with time was due to new Tcells being exported from the thymus, as it was not observed in tolerized, adult thymectomized mice. In contrast, tolerance to marrow and skin grafts was permanent, presumably because the established grafts acted as a continuous source of antigen to reinforce the tolerant state. Tolerance could not be broken by the infusion of unprimed spleen cells and in one example (tolerance to Mls‐1a) there was clear evidence that specific peripheral T cells were anergic. We propose that anergic cells may themselves participate in reinforcing the tolerant state by competing at sites of antigen presentation.
Differential effects of anti‐CD45 monoclonal antibody on human B cell proliferation: a monoclonal antibody recognizing a neuraminidase‐sensitive epitope of the T200 molecule enhances anti‐immunoglobulin‐induced proliferation
Authors: Alsinet Emili , Inglés‐Esteve Julia , Vilella Ramón , Lozano Francisco , Milá Jordi , Rojo Isabel , Martorell Jaume , Vives Jordi , Gayá Antoni
Published: March 2007

We have generated seven monoclonal antibodies (mAb) that recognize the T200 molecule. These mAb have been classified by competitive binding assay in flow cytometry into three groups each reacting with a different epitope of the T200 molecule: (a) 136‐4B5, that shows a sialic acid nature, (b) 135‐4H9, 135‐4C5, 144‐2, 155‐2 and (c) 72‐5D3, 124‐2H12b. A heterogeneous effect was observed when they were tested on an anti‐immunogiobulin‐induced B cell proliferation. Whereas 72‐5D3 and 135‐4H9 mAb inhibited the proliferative response of B cells, 136‐4B5 mAb greatly enhanced it, both effects being dose dependent. We can conclude that anti‐CD45 mAb have a different and contrary functional behavior on anti‐Ig‐induced B cell proliferation, depending on the epitope recognized. The basis for such a difference could reside in the glucidic nature of the epitope recognized by the 136‐4B5 mAb.
Expression of the human Vβ8 gene product preferentially correlates with class II major histocompatibility complex restriction specificity
Authors: Imberti Luisa , Sottini Alessandra , Spagnoli Giulio , Primi Daniele
Published: March 2007

We report that, in peripheral blood T cells, the Vβ8 gene product is much more represented on CD4+CD8− than on CD4−CD8+ lymphocytes. This skewing was observed in all individuals tested and with two independent strategies, one of which allows the selection of Vβ8+ T cells independently from their major histocompatibility complex‐antigen specificity. Our data imply that the human Vβ8 gene product confers class II restriction specificity and that both the T cell receptor chains and CD4 molecule are involved in the selection of the T cell repertoire.
Human IgG subclass pattern of inducing complement‐mediated cytolysis depends on antigen concentration and to a lesser extent on epitope patchiness, antibody affinity and complement concentration
Authors: Michaelsen Terje E. , Garred Peter , Aase Audun
Published: March 2007

The relative complement‐mediated lytic capability of the IgG subclass isotypes was studied using a matched set of mouse‐human chimeric anti‐(4‐hydroxy‐3‐nitrophenyl)acetyl (NP) antibodies. The subclass pattern was shown to be highly dependent on variations in antigen concentration and to lesser extent on variation in epitope patchiness, antibody binding affinity and complement concentration. In general, the IgG3 subclass was most effective in inducing cytolysis at the different conditions used and only at high antigen concentration did the IgG1 subclass mediated more efficient cytolysis than IgG3. The IgG2 isotype required a relative high antigen concentration to be cytolytic while the IgG4 isotype was not cytolytic at any of the conditions tested. These individual characters of each of the IgG subclasses makes it conceivable that a subtle system of immunoregulation exists among the subclasses.
Thymus colonization in the developing mouse embryo
Authors: Palacios Ronald , Samaridis Jacqueline
Published: March 2007

We have directly followed the formation of and the thymus colonization by pro‐T lymphocytes in the developing C57BL/6 mouse embryo by using the monoclonal antibody JORO 37‐5 specific for pro‐T lymphocytes, immunofluorescence staining and flow fluorocytometry or microscopy analysis. The results show that JORO 37‐5+ cells begin to appear in the liver at day 9 of gestation. These JORO 37‐5+ cells migrate to and colonize the thymus 1 day later, where they expand vigorously during the next 4–5 days and, subsequently, switch off expression of JORO 37‐5 as they further differentiate into mature thymocytes.
Nerve growth factor specifically induces human IgG4 production
Authors: Kimata Hajime , Yoshida Akira , Ishioka Chihiro , Kusunoki Takashi , Hosoi Susumu , Mikawa Haruki
Published: March 2007

The effect of nerve growth factor (NGF) on human IgG4 production was studied. NGF specifically enhanced IgG4 production in cultures of human tonsillar mononuclear cells without affecting production of other isotypes or other IgG subclasses. Optimal enhancement of IgG4 production by NGF required the presence of T cells. However, NGF induced significant IgG4 production by small resting B cells in the absence of T cells, and this production was enhanced by stimulation with Staphylococcus aureus Cowan strain I (SAC). In contrast to small B cells, large activated B cells produced IgG4 spontaneously; this production was enhanced by NGF. NGF also enhanced IgM and IgA production by large B cells, while production of IgG1, IgG2, IgG3 and IgE was not affected. The enhancement of IgG4 production was blocked by anti‐NGF serum but not by control serum. NGF, T cells and SAC, separately or together, failed to induce IgG4 production by surface (sIgG4+)‐depleted B cells. In contrast to NGF, other recombinant human cytokines including interleukin (IL) 1β, IL 2, IL 4, IL 5, IL 6, granulocyte‐macrophage colony‐stimulating factor, interferon α and γ failed to induce IgG4 production. These results suggest that NGF directly and preferentially stimulates activated sIgG4+ B cells to produce IgG4.