bluuebunny/crossref_metadata_2025 huggingface dataset:
The monoclonal antibody ER‐BMDM1 recognizes a macrophage and dendritic cell differentiation antigen with aminopeptidase activity
Authors: Leenen Pieter J. M. , Melis Marleen , Kraal Georg , Hoogeveen Andre T. , Ewijk Willem Van
Published: March 2007

Here we describe the reactivity of monoclonal antibody (mAb) ER‐BMDM1, directed against a 160‐kDa cell membrane‐associated antigen (Ag) with aminopeptidase activity. The aminopeptidase recognized by ER‐BMDM1 is present on various mouse macrophage (MΦ) and dendritic cell (DC) subpopulations as well as on microvillous epithelia. Analysis of ER‐BMDM1 Ag expression in in vitro models of MΦ maturation revealed that the Ag is expressed at increasing levels upon maturation of MΦ. In vivo, high level expression of the ER‐BMDM1 Ag occurs after thmonocytic stage of maturation, since bone marrow cells and peripheral blood monocytes are essentially ER‐BMDM1 negative. Analysis of isolated‐resident and elicited MΦ populations showed that ER‐BMDM1 recognizes a specific subpopulation of mature MΦ: only some resident peritoneal and alveolar MΦ are ER‐BMDM1 positive, whereas virtually all thioglycollate‐elicited peritoneal exudate MΦ bind the mAb. In lymphoid organs, a subpopulation of MΦ is recognized as well as interdigitating cells (IDC) located in T cell areas. Phenotypic analysis of isolated DC‐ the in vitro equivalents of IDC ‐ from spleen and lymph nodes confirmed that the majority of this important antigen‐presenting cell population expresses the ER‐BMDM1 aminopeptidase. The molecular characteristics of the ER‐BMDM1 Ag suggest that it may represent the mouse homolog of human CD13.
Complement regulatory proteins at the feto‐maternal interface during human placental development: distribution of CD59 by comparison with membrane cofactor protein(CD46) and decay accelerating factor (CD55)
Authors: Holmes Christopher H. , Simpson Karen L. , Okada Hidechika , Okada Noriko , Wainwright Shane D. , Purcell Damian F. J. , Houlihan James M.
Published: March 2007

The complement (C) regulatory proteins decay‐accelerating factor (DAF, CD55)and membrane cofactor protein (MCP, CD46), which control C3 convertases, together with CD59, an inhibitor of the membrane attack complex (MAC), were found to be present in the developing human placenta from at least 6 weeks of gestation until term. Immunostaining revealed differences in the distribution of these proteins on the fetally derived trophoblast epithelium, especially in early placentae which contain trophoblast populations of diverse proliferative potential and differentiation status. Expression of all three proteins occurred on the terminally differentiated syncytiotrophoblast epithelium covering chorionic villi and which is in direct contact with maternal blood. CD59 was also expressed on the underlying villous cytotrophoblast cells and on their extra‐villous derivatives. These two populations showeddifferential expression of the C3 convertase regulators. Villous cytotrophoblast cells expressed MCP but were largely devoid of DAF. Proliferation of this population to generate extra‐villous cytotrophoblast cellcolumns was associated with both an increase in DAF expression and a decrease in MCP expression. Throughout placental development, expression of DAF appeared to be lower than that of MCP and CD59 as assessed by solid‐phase binding assays on isolated trophoblast membranes. Early placentae were also found to contain both DAF+ and DAF− chorionic villi. Conversely, expression of CD59 appeared comparatively high and transcripts for CD59 were found to be much more abundant than those for DAF in purified trophoblast cells. C regulatory proteins appear to play an important role throughout gestation in protectingthe fetally derived human conceptus from maternal C. The differential expression patterns of the proteins on trophoblast may reflect differences in requirement for specific functional activities at different locations within the placenta.
Preferred size of peptides that bind to H‐2 Kb is sequence dependent
Authors: Deres Karl , Schumacher Ton N. M. , Wiesmüller Karl‐Heinz , Stevanovic Stefan , Greiner Georg , Jung Günther , Ploegh Hidde L.
Published: March 2007

The identification of naturally processed viral peptides reveals that major histocompatibility complex (MHC) class I epitopes are composed of nine or eight amino acid residues. Peptides eluted from H‐2 Kb MHC class I molecules have been suggested, as a class, to be eight amino acid residues long. To assay for peptide‐class I interactions, a stabilization assay described for surface labeled “empty” class I molecules was employed, but on biosynthetically labeled class I molecules. The Sendai virus nucleoprotein‐derived octapeptide APGNYPAL does not bind and stabilize Kb molecules, whereas other octameric Kb−restricted peptides and the nonameric peptide FAPGNYPAL interact stably. We attribute the failure of Sendai octamer binding to the presence of proline in position two: replacement of proline renders the resulting octamers as efficient as FAPGNYPAL for binding and stabilization of H‐2 Kb. Substitution of glycine in position three of APGNYPAL slighty improves its Kb stabilizing capacity. Iodination of the tyrosine residue significantly alters the binding properties of the nonamer peptide. We conclude that the length of epitopes as selected by the class I Kb molecule is influenced by their sequence and suggest that proper positioning of the NH2 terminus of peptides is essential for class I stabilizing properties. The ability to stabilize newly synthesized “empty” class I molecules with peptide argues against an involvement of β2 microglobulin exchange in the experiments described here.
The monoclonal antibody MEL‐14 can block lymphocyte migration into a site ofchronic inflammation
Authors: Dawson Janet , Sedgwick Anthony D. , Edwards Jonathan C. W. , Lees Peter
Published: March 2007

The effect of MEL‐14, a monoclonal antibody which binds to the lymphocyte homing receptor (MEL‐14 Ag) on lymphocytes for peripheral lymph node (PLN) high endothelial venules (HEV), was investigated on lymphocyte migration into a delayed‐type hypersensitivity (DTH)‐like lesion produced by sensitization and challenge to Bordetella pertussis vaccine (BPV). Pretreatment of lymphocytes with saturating concentrations of MEL‐14 caused a highly significant inhibition of lymphocyte migration into the chronically inflamed site and PLN. This finding suggests that lymphocyte migration into the BPV‐induced site of chronic inflammation may be regulated by the same mechanism as lymphocyte migration into the PLN. It further indicates that the ligand for the MEL‐14 Ag adhesion molecule, recognized by lymphocyte which home to the PLN, may also be expressed on HEV‐like vessels at sites of BPV‐induced chronic inflammation.
Sensitivity of T cells to anti‐CD3‐stimulated suicide is independent of functional phenotype
Authors: Russell John H. , Rush Brian J. , Abrams Scott I. , Wang Ruduan
Published: March 2007

We have examined mixed populations and cloned murine CD4+ T cell lines for their sensitivity to anti‐CD3‐stimulated suicide. The sensitivity of CD4+ clones to anti‐CD3‐stimulated suicide is independentof their interleukin‐2/interleukin‐4 or interferon‐γ secretion profile or their lytic efficiency in anti‐CD3 redirected lytic assays.
Secretion of granulocyte‐macrophage colony‐stimulating factor by human blood monocytes is stimulated by engagement of Fcγ receptors type I by solid‐phase immunoglobulins requiring high‐affinity Fc‐Fcγ receptor type I interactions
Authors: Herrmann Friedhelm , de Vos Sven , Brach Marion , Riedel Detlef , Lindemann Albrecht , Mertelsmann Roland
Published: March 2007

Despite reports on the secretion of granulocyte — macrophage — colony‐stimulating factor (GM‐CSF) by murine peritoneal macrophages in response to inflammatory stimuli, the ability of human monocytes to generate this growth factor has remained doubtful. Neither endotoxin, phorbol compounds, nor inflammatory cytokines have been shown to elicit GM‐CSF by these cells. Our present studies indicate that exposure of monocytes to solid‐phase murine IgG2a, but not to murine IgG1 and thus cross‐linkage of the 72‐kDa FcγRI results in transcription of the GM‐CSF gene, accumulation of stable GM‐CSF mRNA and finally in release of biologically active GM‐CSF protein. Cross‐linking of FcγRI by a murine anti‐FcγRI monoclonal antibody and goat anti‐mouse antibody failed, however, to stimulate GM‐CSF release. This suggests that high affinity Fc‐FcγRI interactions are required for induction of expression of GM‐CSF by monocytes.
Anergy induced by thymic medullary epithelium
Authors: Schönrich Günther , Momburg Frank , Hämmerling Günter J. , Arnold Bernd
Published: March 2007

Thymocytes can be rendered tolerant by non‐deletional mechanisms upon interaction with major histocompatibility complex (MHC) antigens on thymic epithelium. Whether the epithelial cells in the cortex or medulla could mediate this effect was not clear so far. To address this question, a transgenic mouse was generated in which the bovine keratin IV promoter was used to control expression of the alloantigen Kb. In the periphery the Kb transgene was expressed on a subset of keratinocytes. In the thymus expression was restricted to a subpopulation of medullary epithelial cells. No expression was found in the cortex. Such a tissue distribution has been reported for the keratin IV molecule demonstrating the faithfulness of the promoter used here.

To follow the fate of the Kb‐reactive thymocytes, this mouse was mated with another transgenic mouse expressing an anti‐Kb T cell receptor (TcR). In the double‐transgenic mice the CD8+CD4− thymocytes were not deleted but they were found to be anergic as assayed by their failure to be activated in vitro by either Kb‐positive spleen cells or by cross‐linked anti‐TcR antibodies. These observations establish that expression of an MHC class I antigen in the thymic medullary epithelium is sufficient to induce anergy in the mature CD8+CD4− thymocyte population.
Human monoclonal and polyclonal anti‐human immunodeficiency virus‐1 antibodies share a common clonotypic specificity
Authors: Wang Haitao , Müller Sybille , Köhler Heinz , Zolla‐Pazner Susan
Published: March 2007

Human monoclonal and purified polyclonal anti‐human immunodeficiency virus(HIV)‐1 antibodies were tested for binding to a murine monoclonal anti‐idiotypic antibody (1F7, IgM, χ). Four human monoclonal anti‐p24 and three human monoclonal anti‐gp120 antibodies express the 1F7 clonotype, while one human monoclonal anti‐gp41 antibody does not bind to 1F7. Affinity‐purified anti‐p24 and anti‐gp120 antibodies from HIV‐1‐infected individuals also react with 1F7. Western blot analysis and enzyme‐linked immunosorbent assay confirmed that 1F7 reacts with human antibodies of different HIV‐1 antigen specificities. A survey of sera from 329 HIV‐1‐infected individuals showed binding to 1F7 in 239 sera (72.6%) while 1F7 was not reacting with 109 HIV‐1‐negative sera. These results show that 1F7 idiotype is an HIV‐1 infection‐associated clonotypic marker shared by anti‐HIV‐1 antibodies with different epitope specificites.
CD4+ suppressor cells of autoimmune encephalomyelitis respond to T cell receptor‐associated determinants on effector cells by interleukin‐4 secretion
Authors: Karpus William J. , Gould Karen E. , Swanborg Robert H.
Published: March 2007

We have previously demonstrated that CD4+ suppressor T cells (Ts) inhibit the secretion of interferon (IFN)‐γ, but not interleukin (IL)‐2, by effector cells of experimental autoimmune encephalomyelitis (EAE). Moreover, CD4+ Ts appear to regulate IFN‐γ by secretion of transforming growth factor‐β. We now show that CD4+ Ts produce a lymphokine with IL‐4 activity in response to a determinant associated with EAE effector cells. CD4+ Ts do not proliferate or secrete IFN‐γ, IL‐2, or IL‐4 in response to myelin basic protein, nor do CD4+ Ts proliferate or secrete IL‐2 when co‐cultured with irradiated EAE effector cells. Rather, CD4+ Ts secrete IL‐4 when co‐cultured with either irradiated effector spleen cells or irradiated encephalitogenic line cells. CD4+ Ts do not secrete IL‐4 in response to OVA‐primed spleen cells, suggesting that the suppressor cells recognize a determinant specific to encephalitogenic T cells. Furthermore, CD4+ Ts secrete IL‐4 when cultured with synthetic T cell receptor (TcR) Vβ8, but not TcR Vβ14 peptide, in the presence of antigen‐presenting cells. This response is major histocompatibility complex class II restricted as demonstrated by inhibition of the response with anti‐class II monoclonal antibody. These results suggest that CD4+ Ts recognize a determinant associated with TcR on the surface of EAE effector cells and respond by secreting IL‐4, in a manner analogous to the Th2 lymphocyte subtype.
An anti‐B cell autoantibody from Wiskott‐Aldrich syndrome which recognizes i blood group specificity on normal human B cells
Authors: Grillot‐Courvalin Catherine , Brouet Jean‐Claude , Labaume Sylvaine , Piller Friedrich , Rassenti Laura Z. , Silverman Greg J. , Kipps Thomas J. , Silberstein Leslie
Published: March 2007

We previously identified IgM autoantibodies in the sera of patients with Wiskott‐Aldrich syndrome (WAS) that react with a subset of normal human B lymphocytes and induce B cell differentiation in vitro. From splenocytes of a patient with WAS we generated heterohybridomas (HY18 and HY21) and a lymphoblastoid cell line (LWA10) that produce human IgM λ or IgM χ anti‐B lymphocyte autoantibodies, respectively. Immunohistochemical and multiparameter flow cytometric analyses demonstrate that these autoantibodies are specific for lymphocytes of the B lineage and preferentially stain B cells that reside in the mantle zone of secondary follicles and that constitutively co‐express the CD5 surface antigen and most major autoantibody‐associated cross‐reactive idiotypes; in addition, these antibodies stain most pre‐B cells in adult bone marrow. Molecular studies show that these anti‐B lymphocyte autoantibodies are encoded by a highly conserved VH4 gene, designated VH4.21. The gene encodes a number of autoantibodies, especially anti‐i and anti‐I IgM cold agglutinins. Hemagglutination and surface labeling studies reveal that HY18 and LWA10 recognize the “i” carbohydrate antigenic determinant(s) which is classically found on human cord red blood cells and, as shown now by this study, on a subpopulation of human B cells which expresses it early in B cell development. These studies raise the possibility that the gene product encoded by this highly conserved germ‐line VH4 gene may play a physiological role in B cell development and/or differentiation.
Specificity, T cell receptor diversity and activation requirements of CD4+ and CD8+ clones derived from human melanoma‐infiltrating lymphocytes
Authors: Pandolfino Marie‐Christine , Viret Christophe , Gervois Nadine , Guilloux Yannick , Davodeau François , Diez Elisabeth , Jotereau Francine
Published: March 2007

To try to understand the functional significance of human melanoma‐infiltrating lymphocytes (TIL), a clonal analysis of the specificity, T cell receptor (TcR) diversity and activation requirements of these lymphocytes isolated from four different tumors was carried out. Supporting the presence of in vivo primed tumor‐specific T lymphocytes in these four tumors, a high frequency of the CD8+ and CD4+ clones, obtained from the TIL cultured for a few days with recombinant interleukin (rIL)‐2 and autologous tumor cells, exhibited a restricted lysis or proliferation in response to the autologous tumor cell line. In contrast, no tumor‐specific clone was obtained from freshly extracted TIL, suggesting that the frequency of tumor‐specific effectors remained low in these tumors. Only the CD8+ clones lysed the autologous tumor cells and their activity was major histocompatibility complex MHC class I restricted. Significant expansion of CD4+ and CD8+ tumor‐specific clones required regular restimulation by autologous melanoma cells but also the addition of exogenous IL‐2 and of Epstein‐Barr virus‐transformed B feeder cells. Five different tumor‐specific clones, three CD8+ and two CD4+ clones were identified in a single tumor on the basis of their TcR gene configuration. Together, these data suggest that a spontaneous and diverse immune response, mediated by tumor‐specific CD4+ as well as CD8+ T lymphocytes, arises in most MHC‐bearing human melanomas but that antigen‐MHC complex presentation by tumor cells does not, at least in vitro, allow a significant proliferation of these lymphocytes.
Cell adhesion molecules of the immunoglobulin supergene family as tissue‐specific autoantigens: induction of experimental allergic neuritis (EAN) by PO protein‐specific T cell lines
Authors: Linington Christopher , Kosin Sabine , Mongan Laura , Lassmann Hans , Ozawa Kyoko
Published: March 2007

The PO glycoprotein is a homophilic cell adhesion molecule of the immunoglobulin supergene family which is responsible for maintaining the structure of compact internodal myelin in the peripheral nervous system (PNS). Utilizing a panel of synthetic PO peptides two distinct T cell epitopes have been identified that can induce T cell‐mediated experimental autoimmune neuritis (EAN) in the Lewis rat. One T cell epitope (amino acid residues 56–71), is located within the extracellular, immunoglobulin‐like domain of PO, while the other disease‐inducing T cell epitope (residues 180–199) is located within the proteins cytoplasmic carboxyterminal domain. The adoptive transfer of 106 CD4+ T line cells specific for either of these peptide antigens induced EAN in syngeneic recipients. However, while the pathogenic response induced by both peptide‐specific T cell lines was identical, their epitopes differ markedly in their immunologic properties in vivo. In particular while the response to peptide p180–199 was immunodominant in animals immunized with either purified PO protein or the native membrane‐bound PO protein in autologous rat peripheral nerve myelin, no response to peptide p56–71 was detected, indicating that this epitope is cryptic. This study provides the first experimental evidence that the immunoglobulin‐like domains of members of the immunoglobulin supergene family can function as target autoantigens in T cell‐mediated autoimmune disease.
CD45 isoform expression during T cell development in the thymus
Authors: Fujii Yoshitaka , Okumura Meinoshin , Inada Keiji , Nakahara Kazuya , Matsuda Hikaru
Published: March 2007

Various isoforms of leukocyte common antigen, or CD45, are expressed differentially on T cells at different stages of development and activation. We report studies on CD45 isoform expression on various subsets of human T cells using two‐ and three‐color flow cytometry and cell depletion. Bone marrow cells that were depleted of CD3+ and HLA‐DR+ cells were CD45RA−RO−. The earliest CD3−CD4−CD8−CD19− thymocytes were CD45RO− with 20%–30% CD45RA+ cells. The most prominent population of CD4+CD8+ double‐positive thymocytes were CD45RA−RO+. Even the CD4+CD8+ blasts were >90% CD45RO+. About 80% of single‐positive thymocytes (CD4+CD8− or CD4−CD8+) were also CD45RO+. Only 4.3% of CD4+ and 18% of CD8+ single‐positive thymocytes were CD45RA+. In constrast, cord blood T cells which represent the stage that immediately follows single‐positive thymocytes, contained 90% CD45RA+ cells. Thus, in terms of CD45 isoform expression, single‐positive thymocytes are more like double‐positive cells than cord blood T cells. These results suggest the following sequence of CD45 isoform switching during T cell development: CD45RA−RO− or RA+RO− (double‐negative thymocytes) → RA−RO+ (double‐positive and most single‐positive thymocytes) → RA+RO− (cord blood T cells), the last switch from CD45RO to CD45RA occurring as a final step of maturation in the thymus.
Induction of homotypic T cell adhesion by triggering of leukocyte function‐associated antigen‐1α (CD11a): differential effects on resting and activated T cells
Authors: Koopman Gerrit , Pals Steven T. , de Graaff Michael , Huysmans Anita C. L. M. , Meijer Chris J. L. M.
Published: March 2007

The leukocyte integrin LFA‐1 (CD11a/CD18) plays a key role in many adhesive interactions involving cells of the immune system. Recently, it has been shown that LFA‐1 is not only involved in cell adhesion, but that stimulation of LFA‐1 can also contribute to cell activation. We now demonstrate that triggering of LFA‐1 on T lymphocytes by monoclonal antibodies (mAb) against the LFA‐1α chain, but not against the LFA‐1β chain, promotes cell adhesion. Induction of homotypic adhesion was only observed in T cells that had been pre‐activated with anti‐CD3 and not in resting peripheral blood T lymphocytes. The induced homotypic adhesion is mediated by LFA‐itself, because it was inhibited by anti‐LFA‐1β mAb. This notion is supported by the temperature and divalent cation dependence which is characteristic of LFA‐1‐mediated adhesion. mAb against ICAM‐1 (CD54) did not block LFA‐1α‐induced adhesion. The sensitivity of LFA‐1α‐induced adhesion to H7, which prevents the activation of protein kinase C and protein kinase A, and to cytochalasin B, which inhibits microfilament formation, suggests that the activation of the LFA‐1 pathway through the LFA‐1α chain involves cell activation and requires an intact cytoskeleton.
Eosinophil as antigen‐presenting cell: activation of T cell clones and T cell hybridoma by eosinophils after antigen processing
Authors: Pozo Victoria Del , de Andrés Belen , Martín Elena , Cárdaba Blanca , Fernández Julio Cesar , Gallardo Soledad , Tramón Paloma , Palomino Pilar , Lahoz Carlos , Leyva‐Cobian Francisco
Published: March 2007

We have studied the role of murine eosinophils as antigen‐presenting cells (APC). Eosinophils have several characteristics that support the hypothesis of its function as potential APC: they have phagocytic capacity, express adhesion molecules and major histocompatibility complex (MHC) class II antigens and can produce and release interleukin‐1 (IL‐1).

We have obtained several T cell clones specific for Mesocestoides corti antigens and used T cell hybridoma specific for ovalbumin (OVA) to test this hypothesis. Granulocyte‐macrophage colony‐stimulating factor‐activated pure eosinophils (99.9%), express class II antigens and are able to present M. corti antigens to specific T cell clones or OVA to T cell hybridoma 3DO 11.10, inducing the proliferation of T cell clones and IL‐2 release by the T cell hybridoma. Proliferation of T cells clones is dependent on the number of eosinophils used as APC. We have compared the efficiency of the same number of macrophages and eosinophils as APC, and have found that macrophages are more efficient than eosinophils. Lysosomotropic agents, such as chloroquine and ammonium chloride, that inhibit antigen processing, impaired eosinophil presentation. This presentation is restricted by MHC class II and inhibited by anti‐I‐Ad monoclonal antibody. The present study provides clear evidence of APC function for eosinophils. Our investigation points to a new role for eosinophils in the immune response.
Low‐molecular weight B cell growth factor (BCGF‐12KD) as an autocrine growth factor in B cell chronic lymphocytic leukemia
Authors: Fournier Sylvie , Biron Guy , Rubio Manuel , Delespesse Guy , Sarfati Marika , Jackson James , Kumar Ashok , King Thomas , Sharma Surendra
Published: March 2007

The role of cytokines in the growth and spreading of human hematologic malignancies has been underlined in recent years. Here we report evidence that a human 12‐kDa B cell growth factor (BCGF‐12KD) may function as a growth stimulatory factor in B cell chronic lymphocytic leukemia (B‐CLL). First, recombinant BCGF‐12KD induced dose‐dependent DNA synthesis in neoplastic B cells of four B‐CLL patients tested. Second, seven different B‐CLL clones secreted a BCGF‐12KD‐like product that accounted for their proliferation. A neutralizing monoclonal antibody (mAb; Ac8) directed against a BCGF‐12KD synthetic peptide inhibited the spontaneous growth of the leukemic B cells. The same mAb blocked DNA synthesis in normal tonsillar B lymphocytes induced by the culture supernatant of spontaneously proliferating B‐CLL cells. Finally, BCGF‐12KD mRNA was expressed in freshly isolated (two of three patients) as well as in vitro proliferating B‐CLL cells (three of three patients). These findings strongly suggest that BCGF‐12KD can modulate the growth of B‐CLL cells in vivo as well as in vitro. They may offer significant insights into the biology of this frequent B lymphoproliferative disorder.
Specificity of rat T cell receptor Vβ chain usage in proliferative responses to staphylococcal enterotoxin B
Authors: Sellins Karen S. , Bellgrau Donald , Gold Daniel P.
Published: March 2007

The staphylococcal enterotoxins (SE) are potent stimulators of T cell proliferative responses in humans and in mice. In these systems, the toxins function as superantigens and stimulate T cells bearing particular Vβ. Although homology between the Vβ of mice and humans is limited, related Vβ families may respond to certain SE in a similar fashion. In this report, we have characterized the rat T cell response to staphylococcal enterotoxin B (SEB). Rat T cells from several lymphoid organs proliferated strongly in response to both commercially available and recombinant SEB. Using a polymerase chain reaction assay, we identified the predominant Vβ families stimulated by this enterotoxin. The T cell receptor Vβ elements used by rat T cells were similar to but not completely identical with those used by mice. The Vβ profile stimulated depended on the purity of the SEB preparation used.
TiγA+δTCS1+ T cells in human thymus. Analysis of the T cell receptor
Authors: Bosse Roland , Heiken Hans , Kolanus Waldemar , Delany Patricia , Schmidt Reinhold E. , Triebel Frederic
Published: March 2007

TcR1+ T cells in peripheral blood have been shown to express in an exclusive fashion either the TiγA or the δTCS1 epitope. Here, we characterize a subset of TcR1+ T cells in fresh thymus co‐expressing the TiγA and δTCS1 epitopes. TcR1dim and TcR1bright clones can be distinguished. Biochemical and molecular studies on both types of clones generated from these thymocytes reveal a unique T cell receptor structure characterized by the use of a Vγ9/Cγ2‐encoded 55‐kDa γ chain nondisulfide linked to a Vδ1‐encoded δ chain.
Complexes of IgG molecules and C3a and C4a complement components in human serum
Authors: Nezlin Roald , Freywald Andrew
Published: March 2007

A heterogeneous group of proteins was separated from human serum IgG using 5 M guanidine hydrochloride solution in 0.1 M acetic acid. The protein mixture was fractionated by reverse‐phase high‐performance liquid chromatography and two proteins were isolated and identified as the C3a and C4a complement components (anaphylatoxins) according to their molecular masses and N‐terminal sequences. Using a chemical cross‐linking technique, the capacity of C3a and C4a to reassociate with the heavy and the light chains of IgG was shown. On the basis of the molecular masses of reconstituted complexes one molecule of C3a (or C4a) was bound to one heavy or one light chain of IgG.
Lymphokine profile and activation pattern of two unrelated antigen‐ or idiotype‐specific T suppressor cell clones
Authors: Pauels Hans‐Gerd , Austrup Frank , Becker Christian , Schmitt Edgar , Rüde Erwin , Kölsch Eckehart
Published: March 2007

Two T suppressor (Ts) clones of different specificity have been analyzed for their lymphokine spectrum. BVI/5 is an I‐Ek‐restricted bovine serum albumin (BSA)‐specific Ts cell clone from a CBA/J mouse tolerized by low doses of BSA. It affects directly or indirectly the function of BSA‐specific T helper (Th) cells. The Ts cell clone 178‐4 from a BALB/c mouse is I‐Ed restricted and recognizes the public J558 Id on B cells. It prevents α(1→3)dextran B 1355S (Dex)‐specific IgG antibody production and drives Dex‐specific J558 idiotype‐bearing B cells into an anergic B IgG memory cell state. Both Ts cell clones thus cause specific suppression, yet in different experimental systems using different effector mechanisms. Upon stimulation with concanavalin A or fixed CD3‐specific monoclonal antibody, both clones produce high levels of interferon (IFN)‐γ and tumor necrosis factor (TNF) but in contrast to Th1 cells no interleukin (IL)‐2. Both clones produce low levels of IL‐3 and IL‐6 but no IL‐4, IL‐5 and IL‐9. Furthermore, unlike Th2 cells, both clones do not respond to IL‐1. The mechanism of the idiotype‐specific induction of anergy in Dex‐specific B IgG memory cells by 178‐4 Ts cells is not yet understood. BVI/5 Ts cells suppress in vitro the BSA‐specific proliferation of the BSA‐specific Th cell clone 83/1, as well as the response of BSA‐primed CBA/ LN cells. Whereas the suppressive effect on 83/1 cells is due to IFN‐γ alone the suppression of BSA‐specific lymph node cells can be simulated neither by IFN‐γ nor the combination of IFN‐γ and TNF. Thus these mediators cannot account for the antigen‐specific suppression by BVI/5 Ts cells in polyclonal in vitro responses from lymph node cells and probably not for the induction of in vivo unresponsiveness.
Evidence that mannose recognition by splenic sinusoidal cells plays a role in the splenic entry of lymphocytes
Authors: Weston Susan A. , Parish Christopher R.
Published: March 2007

Previous studies demonstrated that mannan is a potent inhibitor of splenic entry of lymphocytes and mediates its inhibitory effect at an unidentified site in the spleen rather than acting directly on lymphocytes. This report describes the in vivo site of action of mannan. In vivo localization studies with fluoresceinated preparations of mannan (Fl‐mannan) and a mannose‐6‐phosphate‐containing yeast phosphomannan monoester core from P. holstii exopolysaccharide (Fl‐PPME) demonstrated that the polysaccharide specifically localize in the splenic marginal sinuses in cells with a dendritic morphology termed splenic sinusoidal cells (SSC). Uptake of the polysaccharides by SSC was mediated by a mannan‐specific receptor which was saturable and of high avidity. Several lines of evidence suggested that mannan uptake by SSC inhibited splenic entry of lymphocytes. First, the ability of SSC to bind Fl‐mannan and Fl‐PPME closely paralleled the ability of these polysaccharides to inhibit splenic entry of lymphocytes. In fact, doses of mannan and PPME which would saturate SSC mannan receptors completely blocked splenic entry of lymphocytes. Second, SSC are situated at the initial entry point of lymphocytes into spleen and passage of lymphocytes through the SSC region of spleen was profoundly inhibited by mannan. Finally, direct evidence for adhesion between lymphocytes and SSC was obtained with spleen cell suspensions where clustering between Fl‐mannan labeled SSC and lymphocytes was observed. Collectively, these data indicate that mannan (and PPME) inhibit splenic entry of lymphocytes by interacting with SSC, cell which play a critical role in the entry of lymphocytes into the spleen. Whether mannan‐specific receptors on SSC directly mediate lymphocyte‐SSC adhesion or play on indirect role in modifying lymphocyte migration requires further investigation.
A method for rapid screening of recombinant proteins for recognition by T lymphocytes
Authors: Hickling Julian K. , Jones K. Rebecca , Yuan Bin , Rothbard Jonathan B. , Bülow Roland
Published: March 2007

A simple, cost‐effective method is described that allows rapid screening of recombinant protein sequences for their ability to stimulate T cells. Individual microcultures of E. coli each expressing a gene product or peptide sequence fused to protein A are grown in 96‐well plates. Following lysis of the bacteria, the fusion peptide is readily captured with immobilized immunoglobulin in tissue culture wells. No further purification is required. T lymphocytes plus appropriate antigen‐presenting cells are added directly to the wells and assayed for proliferation. The DNA in bacteria from wells stimulating T cell proliferation is then sequenced. The technique allows rapid mapping of T cell epitopes by facilitating screening of truncation mutants without extensive purification. Described here is a further application of the technique to study monosubstituted analogues of a known T cell epitope.
Glycosidase inhibitors (castanospermine and swainsonine) and neuraminidase inhibit pokeweed mitogen‐induced B cell maturation
Authors: Karasuno Takahiro , Kanayama Yoshio , Nishiura Tetsuo , Nakao Hirohisa , Yonezawa Takeshi , Tarui Seiichiro
Published: March 2007

Castanospermine (CSP), an inhibitor of α‐glucosidase, enhanced immunoglobulin (Ig) release in a Staphylococcus aureus Cowan I (SAC)‐induced lymphocyte culture (Scand. J. Immunol. 1990. 32: 529). In a pokeweed mitogen (PWM)‐human lymphocyte culture, unlike the SAC‐stimulated system. CSP strongly decreased the number of IgG‐, IgA‐ and IgM‐secreting cells as well as that of Ig‐bearing cells. Peripheral blood lymphocytes treated with swainsonine, a mannosidase II inhibitor, or with neuraminidase also showed a reduced response to PWM. In cross‐culture experiments, only a mixture of B cells pretreated with either agent and untreated T cells showed such a suppressive effect. Adhesion was decreased between B cells treated with either agent and untreated T cells, but not between treated T cells and untreated B cells. These results demonstrate that a certain alteration in B cell membrane oligosaccharides inhibited the T cell‐B cell adhesion in the PWM culture, leading to an arrest of B cell maturation. Considering that these inhibitors eventually prevent terminal sialic acid addition, the present study provides evidence that sialic acids on B cell surface oligosaccharides play a biological role in the T cell‐B cell interaction.
Subjugation of dominant immunogenic determinants within a chimeric peptide
Authors: Bhardwaj Vatsala , Kumar Vipin , Geysen H. Mario , Sercarz Eli E.
Published: March 2007

The mechanism of immunodominance was investigated using chimeric peptides from mouse myelin basic protein consisting of the immunodominant I‐Au‐restricted Ac1‐11, attached by a peptide bond to I‐Eu‐restricted 35–47. Our results indicate that this chimeric peptide and certain of its derivatives were excellent immunogens both in vitro and in vivo. Notably, on immunization with Acl‐11:35–47 or Ac1‐11 (Ala4):35–47, the proliferative T cell responses to each of its component peptides were almost completely “subjugated” in favor of neo‐determinants that are I‐Eu restricted. Furthermore, each of 11 hybridomas derived after immunization with Ac1‐11:35–47 had specificity for junctional neo‐determinants and none could be stimulated to produce interleukin‐2 from Ac1‐11 or 35–47. Subjugation of the immunogenicity of the original determinants occurred regardless of their dominance when separate. It did not appear to result from non‐availability of the original determinants because the chimeric peptide was able to induce neonatal tolerance to each of its constituents. These results indicate that in an overlapping multideterminant array, the dominant determinant is unpredictable from historical data about any of the components. Determinant choice, at any stage of processing, may be governed by competitive aspects of determinant capture in an environment where all components ‐antigen, major histocompatibility complex and T cell receptor ‐ are available.
A protective NOD islet‐infiltrating CD8+ T cell clone, I.S. 2.15, has in vitro immunosuppressive properties
Authors: Pankewycz Oleh G. , Guan Jing‐Xin , Benedict John F.
Published: March 2007

Type 1, insulin‐dependent diabetes mellitus (IDDM) appears to result from a T cell‐dependent destruction of insulin‐producing pancreatic β cells. In non‐obese diabetic (NOD) mice and in other rodent models of human IDDM, final expression of disease may be controlled by protective, as well as, destructive T cell influences. Previously, a CD8+ T cell clone, I.S. 2.15, was isolated directly from islets of disease‐resistant male NOD mice. Upon transfer to young NOD recipients, the non‐cytolytic I.S. 21.5 T cell clone, confers in vivo protection from two forms of accelerated IDDM. The present study demonstrates that I.S. 2.15 T cells induce in vitro immunosuppression. The suppressive effects of I.S. 2.15 T cells are mediated through soluble factor(s) and are independent of T cell activation, cell contact, antigen specificity or the major histocompatibility complex (MHC). By polymerase chain reaction (PCR), I.S. 2.15 T cells contain mRNA species encoding for the potentially immunosuppressive cytokines, interleukin‐10 (IL‐10) and transforming growth factor‐β (TGF‐β). The T cell suppressive effects engendered by I.S. 2.15 T cells closely mimic those observed with TGF‐β. Moreover, I.S. 2.15‐induced immunosuppression correlates with intracellular levels of TGF‐β mRNA. These results establish that immunoregulatory T cells are present within islets in IDDM‐resistant NOD mice and may impact on final disease expression through the production of soluble mediator(s).
Adhesion molecule‐mediated signals regulate major histocompatibility complex‐unrestricted and CD3/T cell receptor‐triggered cytotoxicity
Authors: Galandrini Ricciarda , Albi Nicola , Zarcone Daniela , Grossi Carlo E. , Velardi Andrea
Published: March 2007

Appropriate experimental conditions were devised to demonstrate that CD58 (LFA‐3), CD54 (ICAM‐1) and CD11a/CD18 (LFA‐1) adhesion molecules are the source of signals that regulate nonspecific major histocompatibility complexunrestricted and CD3/T cell receptor (TcR)‐triggered cytotoxicity. Using anti‐LFA‐3 monoclonal antibody (mAb)‐treated, interleukin‐2 (IL‐2)‐cultured peripheral blood lymphocytes (PBL) or cloned CD3+/CD8+ cells as lymphocyteactivated killer (LAK) effectors, and ligand (CD2)‐negative tumor cell lines as targets, a down‐regulation of CD3− and CD3+ cell‐mediated LAK activity was consistently observed. Anti‐LFA‐3 mAb also down‐regulated tumor cell lysis when T cell clones were triggered to kill P815 cells through stimulation of the CD3/TcR complex by an anti‐CD3 mAb. The inhibitory effect of anti‐LFA‐3 mAb was not prevented by stimulatory anti‐CD2 mAb. Anti‐ICAM‐1 mAb treatment of IL‐2‐cultured PBL consistently up‐regulated LAK cytotoxicity against tumor target cells. However, this effect was only exerted on CD3− LAK effectors. Anti‐LFA‐1 mAb blocked conjugate formation between effector cells and tumor target cells, thus rendering this model unsuitable to evaluate the regulatory role of LFA‐1. Therefore, a cytotoxicity model system was applied in which a hybrid anti‐CD3/anti‐human red blood cell (HuRBC) mAb triggers cytolytic T cells to lyse HuRBC. In these experiments, anti‐LFA‐1 mAb markedly up‐regulated the lytic ability of IL‐2‐cultured PBL.

We conclude that mAb against LFA‐3, ICAM‐1 and LFA‐1 molecules deliver regulatory signals for LAK cells and cytotoxic T lymphocytes. As these stimuli may be delivered by ligands expressed on tumor targets as well as on other immune competent and inflammatory cells, the present observations are relevant in the context of both the host's immune response against tumors and the general functioning of the immune system.
Structural requirements for the peptide‐induced conformational change of free major histocompatibility complex class I heavy chains
Authors: Elliott Tim , Elvin John , Cerundolo Vincenzo , Allen Hamish , Townsend Alain
Published: March 2007

In an attempt to define the structural features of peptides which are important for inducing the folding of free class I heavy chains in the absence of β2‐microglobulin, and to determine whether they are the same as those required to form stable major histocompatibility complex (MHC): peptide adducts, we have used a panel of peptides related to the Db‐binding nonamer ASNENMDAM (influenza nucleoprotein residues 366–374) with altered primary structures, and a number of other peptides which have the Db‐binding “motif”. In this way, we have shown that in addition to the “anchor” residues which define this motif, the α amino and carboxyl groups at the N and C termini also play a major role in both inducing the conformational change in free heavy chain (HC) and formation of a stable Db: peptide complex. We also show that the importance of the key residues is affected by the primary sequence “context” in which they appear. In addition, we have extended our original finding that naturally processed epitopes induce a conformational change in free HC to the H2Kb HC, and show that the effect does not require the presence of the class I α3 domain.
Presence of murine fetal liver cells capable of being induced to differentiate in vitro into T cell receptor‐positive cells
Authors: Shimamura Michio , Oku Manami , Yamagata Tatsuya
Published: March 2007

Mouse fetal liver cells were analyzed for the surface expression of T cell markers. Fetal liver cells prepared from mouse embryos at 14.5 days of gestation contained a small number of CD4+ cells (1.4%), but virtually no cells positive for any other T cell markers such as CD8, CD3 and T cell receptor (TcR). When a fetal liver cell suspension prepared from BALB/c(♂) × AKR(♀) F1 embryos at 14.5 days of gestation was cultured in medium supplemented with culture supernatants of both WEHI−3 and concanavalin A‐stimulated rat spleen cells, TcR αβ+ and CD4+ cells were generated, whereas CD8+ and TcR γδ+ cells were hardly detectable. Most of TcR αβ+ and CD4+ cells were H‐2d+, thus clearly showing their fetal origin. Treatment with anti‐CD4, anti‐CD3 or anti‐TcR αβ antibodies plus complement or electronic sorting to remove cells expressing these markers failed to inhibit the generation of T cell marker‐positive cells following culture in vitro. On the other hand, depletion of Thy‐1.2+ cells reduced their generation. These findings indicate the presence of some progenitor T cells in fetal liver with the Thy‐1+, CD3−, CD4−, CD8−, TcR− phenotype, which can be induced to differentiate into TcR αβ+ cells in the presence of specific humoral supplements without the influence of the thymus.
Processing and presentation of ovalbumin in mice genetically selected for antibody response
Authors: Vidard Laurent , Rock Kenneth L. , Couderc Jacques , Mouton Denise , Benacerraf Baruj
Published: March 2007

Lines of mice selected for high or low antibody production to sheep red blood cells (H‐I and L‐I) were studied for their ability to process and present ovalbumin to a panel of 12 T‐T hybridomas in two different H‐2 haplotypes. When H‐I and L‐I spleen cells were used as antigen‐presenting cells, no difference could be observed in the peptide generation by these mice compared to H‐2‐compatible B.10.Q and B.10.S spleen cells, respectively. Neither normal splenic L‐I B‐cells nor L‐I thioglycolate‐induced peritoneal macrophages were defective at presenting native ovalbumin, to six and eight different I‐As‐restricted T‐T hybrids, respectively. Altogether, these results differ from previous findings which had indicated a deficiency in the processing and presentation of antigen by the low line, L‐I.
Differential effect of transforming growth factor β on the synthesis of Th1‐ and Th2‐like lymphokines by human T lymphocytes
Authors: Fargeas Christine , Wu Chang You , Nakajima Toshiharu , Cox David , Nutman Thomas , Delespesse Guy
Published: March 2007

(TGF)‐β is a pluripotent cytokine exerting differential effects on distinct components of the immune response. The present report, based on lymphokine determination in culture supernatants and Northern blot analysis of lympokine mRNA, demonstrates that TGF‐β2 markedly inhibits interleukin (IL)‐4 and IL‐5 synthesis by polyclonally activatted human T cells in the absence of any significant effect on (IFN)‐γ, lymphotoxin or IL‐2, suggesting a modulatory effect of TGF‐β2 on the ineterferon Th1/Th2) balance of immune respnses. The inhibitory effect of TGF‐β on IFN‐γ production by unfractionated peripheral blood mononuclear cells is likely to reflect the blunting of natural killer cell activation by TGF‐β.
Active lymphocyte traffic induced in the periphery by cytokines and phytohemagglutinin: Three different mechanisms?
Authors: Binns Richard M. , Licence Stephen T. , Wooding F. B. Peter , Duffus W. Philip H.
Published: March 2007

Phytohemagglutinin (PHA) injection induces transient protease‐sensitive traffic of lymphocytes in skin and other tissues in several species. Examination of the possible roles of cytokines in such reactions showed that recombinant bovine and human tumor necrosis factor (TNF)‐α potently induce dose‐dependent lymphocyte traffic in pig skin (and in other tissues including the draining lymph nodes) with early kinetics and a morphology of the inflammatory reaction similar to that of PHA (peaking 9–12 h). Recombinant human interleukin (IL)‐1α also induces dose‐dependent lymphocyte traffic, but it peaks at 4 h. Entry of labeled lymphocytes into inflammatory sites induced by PHA, TNF‐α and IL‐1α, but not into normal skin, is inhibited by approximately 80 % by their pretreatment with trypsin, indicative of the induction of endothelial determinants recognized by protease‐sensitive surface molecules on the lymphocytes. Even the minimal lymphocyte traffic induced by interferon‐γ and lipopolysaccharide was similarly protease sensitive. At the earliest stage (∼2 h) of significant induction of lymphocyte entry by TNF‐α and IL‐1α the inductive signal for each appears easily saturated. Thus lymphocyte entry is little increased by increasing low cytokine doses over 100‐fold: However, these reactions are additive, and this was used to confirm that they are distinct from each other and from PHA. A further distinction was revealed by the homing of lymphocytes pretreated with pertussis toxin: such lymphocytes were >90 % inhibited in their homing to tissues through constitutive high endothelial venules (HEV) and >60 % inhibited in homing to TNF‐α and IL‐1α skin sites, but unaffected in homing to PHA skin sites (like most non‐HEV‐mediated traffic). Moreover, potent chicken anti‐TNF‐α, which prevented TNF‐induced lymphocyte entry, did not affect PHA‐induced traffic. Thus, these three agents which induce peripheral lymphocyte traffic appear to involve different mechanisms as shown by differences in (i) their kinetics; (ii) the effect of anti‐TNF‐α and (iii) the effect of pertussis toxin treatment of the lymphocytes and by the fact that their inductive mechanisms are additive in effect.
Preferential usage of JH2 in D‐J joinings with DQ52 is determined by the primary DNA sequence and is largely dependent on recombination signal sequences
Authors: Suzuki Haruhiko , Shiku Hiroshi
Published: March 2007

Rearrangement of DQ52 with JH in IgH genes takes place in a large part of lymphocytes at a very early stage of differentiation although usage of DQ52 seems to be limited in the functional IgH genes of mature B cells. A possible and likely explanation for this, is secondary D‐JH joinings occurring after the initial DQ52‐JH joinings, which becomes possible only when DQ52 segments join 5′‐located JH segments. Previously we reported the non‐random use of JH in joinings with DQ52, in which DQ52‐JH2 joinings are dominant. We questioned how the preferential usage of JH2 in DQ52‐JH joinings is determined by utilizing extrachromosomal DNA substrates.

Extrachromosomal DNA substrates with a combination of DQ52 and multiple JH segments were prepared. These plasmids with a polyoma‐derived replication system were transfected into pre‐B cell lines and recombination profiles of recovered plasmids were analyzed semi‐quantitatively. Experiments with plasmids containing all four JH segments in normal configuration showed an apparent high frequency of JH2 usage, similar to the rearrangements previously observed in thymocyte genomes. In plasmids containing two JH segments, when one was JH2, it was rearranged more frequently than the other, independent of its proximity to DQ52. The JH3 with recombination signal sequences (RSS) substituted for JH2 was rearranged more frequently than the naive JH2 itself indicating the importance of RSS. A JH3 hybrid with the 200 bp upstream sequence of JH2 but excluding RSS, however, failed to increase JH3 use. The addition of one nucleotide to the 22‐bp spacer of JH1 RSS increased the frequency of JH1 usage. These observations suggest that the preferential usage of JH2 is determined by the primary DNA sequence and is largely dependent on RSS.