bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous production of interleukin 6, interferon‐β and colony‐stimulating activity by fibroblasts after viral and bacterial infection
Authors: Damme Jo Van , Ronald Schaafsma M. , Fibbe Willem E. , Frederik Falkenburg J. H. , Opdenakker Ghislain , Billiau Alfons
Published: March 2007

Different viruses were compared with the double‐stranded RNA poly(rl)· poly(rC) and interleukin (IL) 1 for their IL 6‐inducing potential in several human and animal cell types. The laboratory viruses Sendai, Mengo and Newcastle disease virus were found to dose dependently stimulate IL 6 production in diploid fibroblasts. A similar effect was obtained with the human pathogens, measles and rubella virus. Concomitantly with IL 6, two other cytokine activities, i.e., interferon‐β and colony‐stimulating activity for granulocytes and monocytes, were induced. In addition, these three activities were also produced by fibroblasts in response to Escherichia coli, whereas lipopolysaccharide was only marginally active. The specificity of the induction phenomenon was confirmed by the lack of IL 6 induction with inactivated infectious agents and by the complete neutralization of produced IL 6 by specific antibodies. This study indicates that the coordinate production of hemopoietic growth factors and interferon, originating from cells that do not classically belong to the immune system, can influence the local and systemic reactions observed during host defence against various infectious agents.
Schwann cells co‐cultured with stimulated T cells and antigen express major histocompatibility complex (MHC) class II determinants without interferon‐γ pretreatment: synergistic effects of interferon‐γ and tumor necrosis factor on MHC class II induction
Authors: Kingston Ann E. , Bergsteinsdottir Kristin , Jessen Kristjan R. , Van Meide Pieter H. Der , Joseph Colston M. , Mirsky Rhona
Published: March 2007

Schwann cells (SC) do not express major histocompatibility complex (MHC) class II antigens under normal culture conditions. SC can, however, be induced in vitro to express MHC class II molecules by exposure to high concentrations of interferon‐gamma (IFN‐γ) and can present antigens to antigen‐specific T cell lines. In the present study immunohistochemical labeling showed that most SC (>90%) prepared from rat neonatal sciatic nerves expressed MHC class II molecules when cultured together with mycobacterial antigen and T cells, and as a consequence were able to function as antigen‐presenting cells in lymphoproliferation assays, without requiring pretreatment with IFN‐γ. Antigen or T cells alone were ineffective in stimulating MHC class II expression and induction of class II molecules was MHC restricted, requiring the presence of syngeneic T cells. Addition of monoclonal antibody DB1, directed against IFN‐γ to co‐cultures of SC and T lymphocytes stimulated with antigen, prevented the induction of MHC class II antigen on SC. When SC were incubated with recombinant (r)IFN‐γ alone, up to 50% of SC showed positive labeling for MHC class II antigen. This level of expression was enhanced to > 80% when recombinant tumor necrosis factor (rTNF) was also added. rTNF alone had no effect, and addition of DB1 antibody inhibited the synergistic effects of rTNF on MHC class II expression. The effects of rIL4 were also investigated but neither rIL4 alone nor rIL4 in combination with rIFN‐γ induced MHC class II expression by SC. These results show that in the presence of sensitized T lymphocytes and antigen, SC do not require pretreatment with exogenous rIFN‐γ to express MHC class II antigens and function as antigen‐presenting cells. T cell‐derived TNF and IFN‐γ appear to act as mediators of the T cell‐induced expression of MHC class II by SC.
Functional expression of CD28 on T cell antigen receptor γ/δ‐bearing T lymphocytes
Authors: Testi Roberto , Lanier Lewis L.
Published: March 2007

T lymphocytes express a T cell antigen receptor (TcR) complex composed of either an TcR α/β or TcR γ/δ heterodimer in noncovalent association with the CD3 glycoproteins. CD28, a 44‐kDa disulfide‐linked homodimer, is present on the surface of the majority of TcR α/β‐bearing T lymphocytes. Monoclonal antibodies (mAb) directed against CD28 potentiate activation signals delivered through the CD3/TcR α/β complex. Herein, we demonstrate that CD28 is expressed on ∼40%–60% of TcR γ/δ‐bearing T lymphocytes in most donors. Anti‐CD28 mAb substantially augmented proliferative signals delivered through the TcR γ/δ, demonstrating the presence of functional CD28 molecules on TcR γ/δ‐bearing T lymphocytes. The majority of TcR γ/δ thymocytes also expressed CD28.
Mouse strain variation in Ly‐24 (Pgp‐1) expression by peripheral T cells and thymocytes: implications for T cell differentiation
Authors: Lynch Felicity , Ceredig Rhodri
Published: March 2007

The cell surface glycoprotein Ly‐24 has been proposed as a useful marker for the identification of in vivo‐primed T cells. Analysis of Ly‐24 surface expression by T cells from different mouse strains has shown variation in Ly‐24 expression that is not H‐2 linked; however, mice of the Ly‐24.1 allele (e.g. BALB/c) express relatively high amounts, whereas Ly‐24.2 strains (e.g. C57BL/6) are low expressors. In BALB/c (Ly‐24 high) and C57BL/6 (Ly‐24 low) mice, Ly‐24 was expressed by both CD4‐CD8+ and CD4+CD8‐ subpopulations of single‐positive T cells and thymocytes. Among CD4‐CD8‐ thymocytes, the overall expression of Ly‐24 was similar in both mouse strains. Analysis of CD4+ and CD8+ single‐positive thymocytes from newborn and adult BALB/c mice showed that the neonatal population contained fewer Ly‐24+ cells. However, using the cell surface markers J11d and CD3, neonatal single‐positive thymocytes were found to contain larger numbers of cells with the Ly‐24‐J11d+CD3 low to negative phenotype. Taken together, these results show that in BALB/c (Ly‐24 high) mice, as soon as functional mature phenotype (CD3+) CD4+ and CD8+ single‐positive thymocytes are generated, they already express Ly‐24. These data cast doubt on the usefulness of Ly‐24 expression as a universal marker of in vivo‐primed T cells and suggest that in BALB/c mice thymus migrants may well be Ly‐24+. Expression of Ly‐24 by thymocytes is discussed in the context of current models of intrathymic T cell differentiation.
T helper cells grown with hapten‐modified cultured Langerhans' cells produce interleukin 4 and stimulate IgE production by B cells
Authors: Hauser Conrad , Snapper Clifford M. , Ohara Junichi , Paul William E. , Katz Stephen I.
Published: March 2007

Hapten‐specific CD4 T helper (Th) lines generated by repeated stimulation with hapten‐modified, cultured Langerhans' cells (cLC) release interleukin (IL 4) (B cell stimulatory factor 1) but not detectable IL 2 into the culture media. The growth of Th cells in response to hapten‐modified cLC was inhibited by an anti‐IL 4 monoclonal antibody (mAb) but not by mAb to either IL 2 or the p55 chain of the IL 2 receptor. Furthermore, these cells could be stimulated to proliferate by concanavalin A and IL 1. These results indicate that IL 4 is the autocrine growth factor for these Th lines and that IL 1 plays a critical role in their growth. The Th cells exhibited 1500–10000 high‐affinity IL 4 receptors cell. When cultured with syngeneic, hapten‐modified, small resting B cells, Th cells caused specific IgE production of up to 20 ng/104 B cells. Thus, IL 4 producing Th lines appear to result from their selective stimulation by cLC, suggesting that T cell responses elicited in this way profoundly influence the B cell isotype pattern.
Autoregulation of interleukin 1 production
Authors: Manson Jean C. , Symons Julian A. , Di Glovine Francesco S. , Poole Stephen , Duff Gordon W.
Published: March 2007

Interleukin 1 (IL 1) α and β are distinct cytokines with a common receptor on target cells. Both have been implicated in immunity, inflammation and connective tissue metabolism. Their production is stimulated by microbial products and also by other cytokines derived from accessory cells and lymphocytes. Following reports that IL 1 can stimulate its own production, we have tested the effects of recombinant IL 1 on the synthesis and release of IL 1 α and β by human blood mononuclear cells (MNC). We confirmed that autoinduction occurs but report also the novel finding that this effect is very concentration dependent. At some concentrations within the range found in vivo, recombinant IL 1 not only failed to stimulate further IL 1 production but also inhibited the background level of synthesis in 20‐h MNC cultures. The negative feedback appears unrelated to prostaglandin E2 and interferon‐γ levels and could not be reproduced by adding transforming growth factor β. This previously unrecognized autoregulation may be relevant to clinical diseases associated with pathogenic over‐production of IL 1.
Inhibition of cryoprecipitation of murine IgG3 anti‐dinitrophenyl (DNP) monoclonal antibodies by anionic DNP‐amino acid conjugates
Authors: Spertini François , Coulie Pierre G. , Snick Jacques Van , Davidson Eugene , Lambert Paul‐Henri , Izui Shozo
Published: March 2007

Previously we have demonstrated that eight out of nine IgG3 monoclonal antibodies (mAb) obtained from autoimmune MRL‐lpr/lpr mice were able to self‐associate and to precipitate in the cold (Gyotoku et al., J. Immunol. 1987. 138: 3785). To determine whether the cryoprecipitation of IgG3 mAb is enhanced or inhibited in the presence of specific ligand, we have established eight IgG3 mAb reactive with 2,4‐dinitrophenol (DNP) hapten: four mAb were obtained from fusion of spleen cells of C57BL/6 mice immunized with 2,4, 6‐trinitrophenylated keyhole limpet hemocyanin, three from 129/Sv and one from BALB/c immunized with DNP‐lipopolysaccharide. Five of them induced cryoglobulins composed exclusively of the IgG3 mAb. The binding of negatively charged monomeric DNP‐amino acid conjugates completely inhibited the cryoprecipitation of all the five cryoprecipitating anti‐DNP IgG3 mAb, while the incubation with positively charged or neutral DNP‐amino acid conjugates had variable effects: increase, inhibition or no change of the cryoprecipitation. In addition, positively charged DNP‐amino acid conjugates were able to induce the cryoprecipitation of one of the non‐cryoprecipitating anti‐DNP IgG3 mAb. Our data showed that (a) IgG3 mAb derived from non‐autoimmune strains of mice, similar to IgG3 mAb derived from an autoimmune MRL‐lpr/lpr strain, possessed the unique property to self‐associate and were able to form cryoglobulins in most cases; (b) although the Fc‐Fc interactions of IgG3 mAb play a decisive role in IgG3 cold solubility, IgG3 cryoprecipitation was markedly influenced after interacting with their specific ligand, depending on the charge of the hapten‐amino acid conjugate. This suggested that even minor interferences with the electrostatic equilibrium of the IgG3 by the binding of charged hapten molecules induced dramatic changes in the solubility of the IgG3 mAb at low temperature.
Human interleukin 4 down‐regulates the surface expression of CD5 on normal and leukemic B cells
Authors: Defrance Thierry , Vanbervliet BÉAtrice , Durand Isabelle , Banchereau Jacques
Published: March 2007

CD5 is a pan‐T cell antigen which is expressed on a minor subset of normal B lymphocytes and on most chronic lymphocytic leukemia B cells (B‐CLL). In this study, it is demonstrated that interleukin (IL) 4 down‐regulates the surface expression of CD5 on tonsil B cells and B‐CLL cells, but not on T cells. IL 4 inhibits both the spontaneous and the phorbol myristate acetate (PMA)‐induced hyperexpression of CD5 on tonsil B cells. In contrast, IL 4 only suppresses the PMA‐induced hyperexpression of CD5 on B‐CLL, whereas the spontaneous CD5 expression is essentially unaffected. The IL 4 concentrations required to down‐regulate CD5 are the same as those required to up‐regulate CD23. The IL 4‐mediated down‐regulation of CD5 is an intrinsic property of this IL, since an anti‐IL 4‐neutralizing antiserum blocks this effect. Interferon (IFN)‐γ, which inhibits the IL 4 induced CD23 expression, does not block the IL 4‐induced down‐regulation of CD5. Recombinant IL lα, IL 2, IL 3, IL 5, IL 6, tumor necrosis factor (TNF)‐α, IFN‐γ and granulocyte macrophage colony‐stimulating factor neither inhibit nor stimulate CD5 expression on B cells, there fore suggesting that the capacity to down‐regulate CD5 expression on B cells is specific to IL 4.
Internalization of interleukin 1 (IL 1) correlates with IL 1‐induced IL 2 receptor expression and IL 2 secretion of EL4 thymoma cells
Authors: Hoegen Ilka Von , Falk Werner , Kojouharoff Georgi , Krammer Peter H.
Published: March 2007

The cytokine interleukin 1 (IL 1) plays an important role in the induction of IL 2 secretion and high‐affinity IL 2 receptor (IL 2R) expression by T cells. The events that follow binding of IL 1 to IL 1R, however, are still unknown. In this study we describe two variants of the murine thymoma EL4 (5D3 and D6/76) that express comparable numbers of cell surface IL 1 receptors and bind IL 1 with the same affinity, but show distinct IL 1‐dependent IL 2 secretion and IL 2R expression. In the presence of the tumor promoter phorbol 12‐myristate 13‐acetate IL 1 augments IL 2 secretion and IL 2R expression of EL4 5D3 but not of EL4 D6/76 cells. Comparison of the internalization of IL 1 by both clones revealed that EL4 D6/76 was unable to transport cell surface‐bound IL 1 to the cytoplasm. These findings suggest that internalization of receptor‐bound IL 1 is required for the action of this cytokine.
Antibody 12‐15 cross‐reacts with mouse Feγ receptors and CD2: study of thymus expression, genetic polymorphism and biosynthesis of the CD2 protein
Authors: Altevogt Peter , Kohl Ulrike , Hoegen Paul Von , Lang Elke , Schirrmacher Volker
Published: March 2007

Previously we described a monoclonal antibody (mAb 12–15) that reacted with murine Fc receptor proteins (betal, beta2 and alpha) and an undefined molecule of 37 kDa (beta3) on certain types of cells. Here we present serological and biochemical evidence that the beta3 chain is expressed on mouse thymocytes and that it is identical to the CD2 antigen. By immunofluorescence staining and cytofluorographic analysis >95% of thymocytes were positive. Brightly staining cells coincided with cortison‐resistant thymocytes suggesting that mature thymocytes expressed higher levels of the antigen. Biosynthetic labeling of DBA/2 thymocytes with [35S]methionine showed that the size of the CD2 precursor molecule was 43 kDa which was processed to approximately 55–65 kDa in the mature molecule. mAb 12–15 was also reactive with the tunicamycin‐treated form of the CD2 antigen suggesting that the cross‐reactive epitope was of protein nature. Comparison of different mouse strains indicated that two molecular forms of CD2 exist. On BALB/c thymocytes, the relative mass of the native molecule was approximately 60–70 kDa (CD2.1) and slightly larger than in DBA/2 (CD2.2). Following endoglycosidase F treatment both proteins still showed a slight difference in electrophoretic mobility. Several inbred mouse strains were analyzed for expression of CD2 forms. When mAb 12–15 was used in cyotoxic T lymphocyte inhibition experiments using specific CTL and tumor target cells it was found that the antibody could specifically inhibit CTL‐mediated lysis presumably by interfering with CD2 function.
The epigenetic influences of bone marrow and fetal liver stroma cells on the developmental potential of Ly‐1pro‐B lymphocyte clones
Authors: Palacios Ronald , Stuber Susanne , Rolink Anthonius
Published: March 2007

The Ly‐1 Mac‐1 B‐220 CC11 progenitor clones LyD9 and LyB9 were previously shown to give rise to Ly‐1IgM B lymphocytes either in vivo or in vitro by coculture with nonlymphoid accessory cells from spleen and lipopolysaccharide. The clones did not generate T lymphocytes either in vivo or in vitro. We now find that both LyD9 and LyB9 progenitors are induced to differentiate in vitro by co‐culture with the RP.0.10 bone marrow stroma clone or with heterogeneous marrow‐adherent stroma cell populations obtained from adult mice into Ly‐1‐IgM B lymphocytes as well as myeloid GM1.2 Mac‐1 cells. We could obtain evidence that a high proportion of LyD9 and LyB9 cells already switched off expression of Ly‐1 and CC11 (interleukin 3 receptor) surface molecules 2 days after initiation of the cultures, and by days 8–10 of culture no detectable Ly‐1 cells and only about 20% CC11 cells were observed. Ly‐1 surface expression could not be re‐induced on the progeny of LyD9 and LyB9 progenitors generated under the influence of marrow stroma cells. Remarkably, the LyD9 and LyB9 progenitors gave rise to both Ly‐1IgM and Ly‐1‐IgM B cells upon culture with heterogeneous stroma monolayers obtained from 18‐day fetal liver. Finally, the differentiating property of the stroma cells for the LyD9 and LyB9 progenitors could not be replaced with soluble factors produced either spontaneously or after stimulation by the marrow stroma cells. Our results show the importance of epigenetic influences provided by a given microenvironment on the developmental potential of B cell progenitors. They provide direct evidence that the same pro‐B lymphocyte can give rise to both Ly‐1 and Ly‐1‐IgM B cells depending on both the time of development and the tissue of origin of stroma cells with which the B cell progenitor interacts. Also, the results strongly suggest that cell contact between the stroma cell and the B cell progenitor is essential to induce rearrangement and expression of the Ig genes in pro‐B lymphocytes.
Characterization and growth factor requirements of SJL lymphomas. II. Interleukin 5 dependence of the in vitro cell line, cRCS‐X, and influence of other cytokines
Authors: Lasky Jennifer L. , Jeanette Thorbecke G.
Published: March 2007

Follicular B cell lymphomas of SJL mice [reticulum cell sarcoma (RCS)] are dependent on syngeneic Ly‐1,2‐ T cells for their growth. These T cells produce a number of lymphokines in response to stimulation with γ‐irradiated RCS cells including interleukin (IL) 2, interferon‐γ (IFN‐γ), IL 4 and IL 5, some of which may be required for growth of the tumor. Previous studies have shown that an RCS cell line, cRCS‐X, can be maintained in vitro indefinitely, if the cultures are supplemented with Y‐irradiated lymph node (LN) cells or with a preparation of human B cell growth factor (BCGF). In the present studies, the growth requirements of this cell line were analyzed in more detail in short‐term assays of both [3H]thymidine incorporation and colony formation in agarose. Recombinant murine IL 5 caused dose‐dependent proliferation of cRCS‐X cells similar to that induced with BCGF. The level of colony formation by cRCS‐X cells induced by optimal concentrations of BCGF was not increased further by the addition of IL 5, suggesting that the two factors act via a common mechanism. IL 1 and IFN‐y each enhanced cRCS‐X proliferation induced by BCGF or IL 5 in both assays. The effects of IL 1 plus BCGF, IFN‐γ plus BCGF, and IL 1 plus IL 5 were clearly synergistic. Preincubation of cRCS‐X cells with IL 1 enhanced their ability to proliferate in response to BCGF or IL 5 in [3H]thymidine incorporation assays, but the reverse sequence of cytokine addition showed no effect of IL 1. No such effect was seen with IFN‐gM. Indeed, IL 1 and IFN‐gM appeared to affect BCGF‐induced cRCS‐X growth by different mechanisms and their combined effects were greater than that of IL 1 or IFN‐gM added separately. None of the other cytokines studied, including IL 2, IL 3, IL 4, IL 6, tumor necrosis factor‐γ, granulocyte monocyte‐colony‐stimulating factor or transforming growth factor‐β, had any detectable effect on cRCS‐X cells, either alone or in combination with BCGF or IL 5.

Like IL 5, SJL γ‐irradiated LN cells induced cRCS‐X colony‐forming units (CPU) in a dose‐dependent manner. IL 1, or the combination of IL 1 plus IFN‐γ, clearly synergized with LN cells in the induction of cRCS‐X CFU, suggesting that LN cells contribute IL 5. The level of CFU induced by an optimal dose of BCGF was enhanced further in the presence of LN cells and IL 1. However, this was not observed when both IL 1 and IFN‐γ were added to the medium, in which case the level of CFU induced by an optimal dose of BCGF was not further enhanced by the addition of an optimal dose of γ‐irradiated LN cells. In combination with previous observations, these data support the hypothesis that RCS growth in vivo and in vitro is dependent on and promoted by IL 5 and IFN‐γ produced by syngeneic RCS‐specific helper T cells, and IL 1 produced by macrophages.
Resistance to experimental autoimmune encephalomyelitis induced by neonatal tolerization to myelin basic protein: clonal elimination vs. regulation of autoaggressive lymphocytes
Authors: Qin Yufen , Sun Deming , Goto Masamichi , Meyermann Richard , Wekerle Hartmut
Published: March 2007

The target autoantigen of experimental autoimmune encephalomyelitis (EAE), myelin basic protein (MBP), appears late in ontogeny. In the rat MBP is expressed first on days 2–3 post partum, at a development stage, when self tolerance to most other autoantigens has already developed.

To shed light on the cellular mechanisms that lead to immunological self tolerance to MBP, we treated neonatal rats with high doses of MBP before ontogenetic appearance of this autoantigen. We found that high doses are required to confer MBP‐specific tolerance lasting until the adult life. Neonatally tolerized, adult rats are completely resistant to induction of EAE by injection of MBP in complete Freund's adjuvant (CFA). Upon MBP CFA challenge, these animals develop a limited humoral response to MBP, but are completely unreactive to MBP on the T cell level. The function of antigen‐presenting cells is unchanged by neonatal tolerization, and there is no evidence for the induction of suppressive mechanisms. Transfers of large numbers of tolerized lymphocytes to normal hosts fails to interfere with EAE inducibility. Moreover, neonatally tolerized lymphocytes do not reduce MBP reactivity of primed lymph node cells or T line cells in vitro. Finally, neonatally tolerized rats are susceptible to EAE transferred by activated primed lymphocytes or by in vitro‐activated MBP‐specific T line cells.

The apparent deletion of MBP‐specific T lymphocytes in neonatally tolerized rats is in striking contrast to the physiological self tolerance to MBP, which is characterized by the presence of MBP‐specific clones in the normal immune repertoire.
Tolerance to class I major histocompatibility complex antigens in chicken B cell chimeras. Effect of B cell depletion on transferability of tolerance
Authors: Lehtonen Lasse , Vainio Olli , Veromaa Time , Toivanen Paavo
Published: March 2007

B cells from bursa of Fabricius of newly hatched chickens are able to reconstitute the B cell compartment of chemically bursectomized chickens. The resulting B cell chimerism can be detected with monoclonal antibodies against donor B cell alloantigen. Chimeric chickens accept donor‐type skin grafts and are unresponsive to donor major histocompatibility complex (MHC) antigens in graft‐vs.‐host splenomegaly assay and mixed lymphocyte reaction. To study the capability of B cells to induce tolerance to selected MHC antigens, we transplanted class I or total MHC‐incompatible bursa cells into cyclophosphamide‐treated recipients. The recipients of class I or total MHC‐incompatible bursa cells were equally tolerant of donor‐MHC antigens. To further analyze the mechanisms of tolerance to class I antigens vs. total MHC, spleen cells from tolerant chickens were transferred to irradiated, histocompatible secondary hosts. The secondary recipients were also unresponsive to bursa cell donor‐strain MHC antigens. However, if the chimeric B cells were depleted before the spleen cell transfer, the transfer of tolerance to total MHC was severely inhibited. Instead, most recipients of B cell‐depleted spleen cells tolerant of class I antigens were still tolerant of bursa cell donor MHC. Our results indicate differences in the transferability of tolerance to class I antigens vs. entire MHC, although in primary recipients of bursa cells the tolerance is similar. These data suggest that a mechanism that is not dependent on the presence of donor cell chimerism contributes to the maintenance of tolerance to donor class I antigens. The transfer of tolerance to total MHC disparity requires the presence of chimeric cells indicating that donor alloantigen expression is needed for induction of tolerance in the secondary hosts.
Molecular characterization of the VH region of murine autoantibodies from neonatal and adult BALB/c mice
Authors: Sollazzo Maurizio , Hasemann Charles A. , Meek Kateryn D. , Glotz Denis , Donald Capra J. , Zanetti Maurizio
Published: March 2007

We report on the molecular characterization of the heavy (H) chain variable (V) region of two murine autoantibodies reacting with a conventional self antigen, thyro‐globulin (Tg), originated from unimmunized/unstimulated neonatal mice (clone B10H2) and from an adult hyperimmunized mouse (clone 62), respectively. Serologically, both hybridoma antibodies express the same idiotype (Id). By cloning and sequencing we demonstrated that their VH regions are encoded by identical VDJ gene elements including the VD and DJ joints. This VH belongs to the VH 7183 gene family, the most 3′‐end proximal family in the murine genome. The D segment is unique and only 50% similar to any murine D segment. The J segment utilized is germ‐line JH4. The cloned DNA rearrangement was transfected into the J558L myeloma cells and the secreted antibody was found to express the reference Id on the H chain, hence proving that the productive VDJ rearrangement had been identified. These results show that a spontaneously arising and an antigen‐induced autoantibody use an identical VDJ gene rearrangement and that after hyperimmunization somatic mutation did not occur. The significance of this finding with respect to ontogeny of the B cell repertoire is discussed.
The mucosa of the male genital tract; part of the common mucosal secretory immune system?
Authors: Fritz Franz Joachim , Westermann JÜRgen , Pabst Reinhard
Published: March 2007

The selective migration of mucosal‐derived lymphoid blasts to other mucosal organs is taken to be an essential part of the common secretory immune system. In rats, proliferating lymphoid cells from mesenteric lymph nodes (mLN) and peripheral lymph nodes (pLN) were labeled in vitro using two different techniques, in order to test the hypothesis that the mucosa of the male genital tract is a preferential site for mLN lymphoid blasts to home to. A low but significant migration to male genital organs was found, but with no difference between blasts from pLN and mLN. Thus there is no evidence to include the male genital tract in the common mucosal secretory immune system.

Recirculating lymphocytes from the thoracic duct entered the male genital organs with a similar distribution to the pattern of lymphoid blasts. There is probably an exchange between these immigrating lymphocytes and the different subsets, which are localized in the epithelium (T suppressor) and interstitial tissue (T helper) in male genital organs. The lymphoid cells in the male genital tract might play an important role in the immune function of seminal fluid and in sexually transmissible diseases.
Co‐cross‐linking of surface immunoglobulin Fcγ receptors on B lymphocytes uncouples the antigen receptors from their associated G protein
Authors: Rigley Kevin P. , Harnett Margaret M. , Klaus G. B.
Published: March 2007

Cross‐linking of surface Ig receptors (sIg) by mitogenic forms of anti‐Ig antibodies (e.g. F(ab′)2 fragments of rabbit anti‐Ig) causes the rapid, and prolonged breakdown of phosphatidylinositol 4,5‐bisphosphate. This response involves an unidentified guanine nucleotide regulatory protein (termed Gp), which couples sIg to the polyphosphoinositide‐specific phosphodiesterase. Intact (IgG) rabbit anti‐Ig antibodies, which co‐cross‐link sIg and Fcγ receptors on B cells, only induce short‐lived inositol phospholipid breakdown and abortive B cell activation. We show here that in permeabilized B cells intact anti‐Ig inhibits the reconstituted breakdown of inositol phospholipids given by a combination of F(ab′)2 anti‐Ig and the non‐hydrolyzable GTP analogue guanosine‐5′‐O‐(3‐thiotriphosphate) (GTPγS), but not the basal stimulation of Gp induced by GTPγS alone. These results therefore indicate that cocross‐linkage of sIg and Fcγ receptors on B cells uncouples the antigen receptors from the associated G protein, but does not affect coupling between Gp and the phosphodiesterase. These observations therefore provide further insight into the mechanisms whereby engaging Fc receptors on B cells, by antigen‐antibody complexes for example, could modulate antigen‐induced B cell activation.
Permanent alteration of the murine Ly‐1 B repertoire due to selective depletion of Ly‐1 B cells in neonatal animals
Authors: Lalor Paul A. , Stall Alan M. , Adams Sharon , Herzenberg Leonore A.
Published: March 2007

Studies presented here demonstrate that paternal allotype Ly‐1 B cells are permanently depleted following neonatal treatment with antibodies to the paternal IgM allotype. Paternal allotype conventional B cells, in contrast, are temporarily depleted by treatment with either anti‐IgM or anti‐IgD allotype antibodies and return rapidly to normal frequencies once the antibody treatment disappears. These differences are explained by basic developmental differences between Ly‐1 B and conventional lineage B cells. That is, the conventional B cell population is replenished from Ig‐ precursors throughout life and, therefore, is only temporarily affected when depleted in neonates. The Ly‐1 B cell population, in contrast, develops from Ig‐ progenitors during the prenatal and neonatal life but survives because it is exclusively self‐replenishing in adults. Therefore, elimination of a population of Ly‐1 B cells from neonates is tantamount to removing it forever.

These findings suggest that while conventional B cells turn over rapidly and have an effectively unlimited repertoire, Ly‐1 B cells express a repertoire whose composition is strongly influenced by neonatal conditions that favor or select against the retention of cells producing certain antibody molecules. Thus, Ly‐1 B cells play a unique role in the immune system in that they retain indefinitely the history of the neonatal animal's immunological experience.
The immune response of BALB/c mice to influenza hemagglutinin: commonality of the B cell and T cell repertoires and their relevance to antigenic drift
Authors: Barnett Barbara C. , Graham Christine M. , Burt David S. , Skehel John J. , Brian Thomas D.
Published: March 2007

An extensive analysis of the class II (I‐Ad)‐restricted T cell repertoire for influenza hemagglutinin (HA) of the H3 subtype, elicited by natural infection, has shown that a majority of CD4 memory T cell clones focus on antibody‐binding regions of HA, sites B and E, and are sensitive to the residue substitutions that have occurred in these regions during antigenic drift. The proliferative responses of CD4 clones to synthetic peptides have identified T cell epitopes within site B, HA1 177–199 and HA1 182–199, and site E, HA1 56–76. The recognition specificity of T cell clones for antibody‐selected mutant viruses, with single amino acid substitutions within these recognition sites identified residues 63, 189, 193 and 198 as being important for T cell recognition and thus established that BALB/c, CD4 T cell clones were sensitive to the same substitutions known to abrogate BALB/c antibody recognition of the native HA. Our findings indicate extensive commonality of the B cell and T cell repertoires for HA, which may be relevant to an understanding of the immune pressures for antigenic drift, and, moreover, suggest that the antigen‐specific B memory cell may be instrumental in selection of the peripheral T cell repertoire.
The structural requirements for class II (I‐Ad)‐restricted T cell recognition of influenza hemagglutinin: B cell epitopes define T cell epitopes
Authors: Graham Christine M. , Barnett Barbara C. , Hartlmayr Irene , Burt David S. , Faulkes Ralph , Skehel John J. , Brian Thomas D.
Published: March 2007

A majority of I‐Ad‐restricted CD4 clones elicited by influenza X31 (H3N2) virus infection, recognize a synthetic peptide of hemagglutinin (HA) corresponding to an antibody binding region of the HA1 subunit (site B: HA1 177–199). The structural requirements for class II‐restricted T cell recognition were investigated by determining the proliferative responses of representative CD4 clones to truncated HA1 peptides and synthetic peptide analogues. Two distinct T cell epitopes were identified and CD4 clones, specific for either determinant, were sensitive to the same single amino acid substitutions in synthetic peptides at HA1 193 S→N or HA1 198→E, that had featured in antigenic drift and abrogated antibody binding to native HA. Competitive inhibition studies, between stimulatory HA1 peptides and non‐stimulatory analogue peptides, for antigen presentation to CD4 clones established that the 193 S → N and 198 A → E substitutions could affect either interaction with the T cell receptor or class II molecule, according to the specificity of the CD4 clone examined. The structural requirements for class II‐restricted T cell recognition of the linear sequence determinants of HA are, therefore, integrally linked to conformationdependent antibody recognition of the native molecule.
Regulation of human B cell activation and antibody production by non‐major histocompatibility complex‐restricted cytotoxic T lymphocytes
Authors: Boué François , Goujard Cécile , Delfraissy Jean‐françois , Galanaud Pierre , Hercend Thierry
Published: March 2007

To determine whether non‐major histocompatibility complex‐restricted cytotoxic human T lymphocytes (NrCTL) are involved in the regulation of antibody response, we studied the effect of a CD3, T cell receptor (TcR)‐α/β, NKH1 clone named JT9 on B cell proliferation and differentiation. It was found that low amounts of JT9 clone (5%) profoundly inhibited (> 80%) in vitro specific anti‐trinitrophenyl primary antibody response. This inhibition did not need the presence of autologous T cells and took place at the induction phase of the antibody response. JT9 clone had no effect on resting B cells but enhanced proliferation of anti‐μ‐stimulated B cells. Respective involvements of cell to cell interaction, cytotoxicity and lymphokines were investigated. (a) The effect of monoclonal antibodies (mAb) inhibiting cytotoxic properties of JT9 clone, i.e. an anti‐clonotypic structure mAb and a mAb directed against a target cell antigen similar to 4F2, were studied. These mAb did not reverse the effects of JT9 on B cell activation and differentiation. Thus, these contrasting effects of JT9 clone on B cell response did not seem to involve an interaction of JT9 clone TcR with its target or, further, cytotoxic properties for which this clone had been characterized. (b) Supernatant of JT9 clone stimulated by cross‐linking of TcR complex, in the absence of interleukin 2, exerted a proliferative effect on anti‐μ‐stimulated B cells but not on resting B cells. These findings suggest that JT9 clone could secrete a B cell growth factor – like activity and that NrCTL cells may play an important role in the regulation of antibody response.
Production of macrophage‐, granulocyte‐, granulocyte‐macrophage‐ and multi‐colony‐stimulating factor by peripheral blood cells
Authors: Oster Wolfgang , Lindemann Albrecht , Mertelsmann Roland , Herrmann Friedhelm
Published: March 2007

The specific cell sources and signals for induction of various colony‐stimulating factors (CSF) in peripheral blood mononuclear cells (PBMC), purified T lymphocyte and monocyte (Mo) populations have been investigated. In the absence of exogenous activating stimuli, human PBMC, T cells and Mo failed to produce stable cytoplasmic mRNA for CSF for macrophages (M‐CSF or CSF‐1), for granulocytes (G‐CSF), for granulocytes and macrophages (GM‐CSF) and for multilineage CSF [multi‐CSF, interleukin (IL) 3] and thus failed to release CSF proteins. However, after stimulation with phorbol myristate acetate and phytohemagglutinin, M‐, G‐, GM‐ and multi‐CSF mRNA became detectable in PBMC, resulting in the secretion of the respective proteins. Identical culture conditions resulted in synthesis of only G‐ and M‐CSF by purified Mo, whereas purified T lymphocytes produced GM‐CSF and multi‐CSF only. When Mo or T lymphocytes were exposed to recombinant human interferon‐γ or were stimulated by triggering the epitopes recognized by the monoclonal antibodies anti‐T112 and T113, respectively, again disparate CSF expression patterns were found to be associated with both cell species. Moreover, IL2‐receptive T lymphocytes showed the same distinct pattern of CSF secretion when activated by recombinant human IL2.
Alternative T cell receptor gene usage induced by self tolerance
Authors: Frangoulis Bernard , Pla Marika , Rammensee Hans‐Georg
Published: March 2007

Ab‐restricted, H‐Y‐specific T cell clones from C57BL/6 mice were found to use predominantly Vβ6 T cell receptor genes, conferring Mls‐1a reactivity. However, the expression of Mls‐1a as a self antigen in (DBA/2 × C57BL/6)F1 mice did not turn these mice into nonresponders to H‐Y. Instead of Vβ6, they used other T cell receptor genes in this response. Thus, self tolerance appears to bias the repertoire of T cell receptor genes used in response to foreign antigens, without necessarily impairing the immune responsiveness to these antigens.
Cloned T cells provide help for malaria‐specific polyclonal antibody responses
Authors: Dean Goldring J. P. , Brake David A. , Cavacini Lisa A. , Long Carole A. , Weidanz William P.
Published: March 2007

Athymic mice grafted with antigen‐reactive cloned T cells and challenged with Plasmodium chabaudi adami produced antibodies against multiple parasite antigens. Antibody reactivities were similar to those seen in infected euthymic mice and contrasted with their absence in infected athymic mice. These results suggest that it will not be possible to determine the antigenic specificity of clonal T cell populations in malarial infections by their capacity to provide help to restricted populations of B lymphocytes.
The abnormal T lymphocytes in lpr mice transcribe interferon‐γ and tumor necrosis factor‐α genes spontaneously in vivo
Authors: Murray Lesley , Martens Christine
Published: March 2007

The autoimmune mouse strain MRL/MPJ/lpr/lpr is characterized by accumulation of an abnormal T cell population which does not express CD4 or CD8 surface antigens. These cells were thought to be immunologically inert based on their inability to proliferate in response to a variety of T cell mitogens. We investigated the capacity of these cells to express lymphokine genes using a sensitive RNase protection assay. RNA was isolated from abnormal T cells which were purified directly from diseased animals, either as CD4−/CD8− or as fluorescence‐activated cell sorter‐isolated B220/Thy‐1 cells. These RNA preparations contained no detectable interleukin (IL)2, IL4, IL5 or IL6 transcripts, but did contain transcripts of genes for interferon‐γ and tumor necrosis factor‐α. Thus, this expanded population of abnormal cells spontaneously expresses these two lymphokines which have many interacting effects on the immune system, and may have important roles in the pathogenesis of autoimmune disease in lpr mice.
Isoelectric focusing of bovine major histocompatibility complex class II molecules
Authors: Watkins David I. , Shadduck John A. , Rudd Christopher E. , Stone Marc E. , Lewin Harris A. , Letvin Norman L.
Published: March 2007

Serological approaches have been relatively unsuccessful in defining the allelic products of the bovine major histocompatibility (MHC) class II loci. We demonstrate that bovine class II allelic products can be characterized by precipitation with a polyclonal antiserum and separation using one‐dimensional isoelectric focusing. Polymorphic β chains were present in immunoprecipitates from both biosynthetically and surface‐labeled lectin‐stimulated bovine T cells. Precipitates from biosynthetically labeled but not surface‐labeled T cells contained a basic invariant chain and a non‐polymorphic structure. The non‐polymorphic structure appears to be a β chain. The polymorphic class II β chain co‐segregated with bovine MHC class I allelic products in a half‐sibling family, providing evidence for linkage between bovine class I and class II loci. This approach to the biochemical analysis of the bovine class II structures should facilitate the investigation of the association between the bovine products and disease susceptibility.
Organization and orientation of a human T cell receptor δ chain V gene segment that suggests an inversion mechanism is utilized in its rearrangement
Authors: Takihara Yoshihiro , Champagne Eric , Ciccone Ermanno , Moretta Lorenzo , Minden Mark , Mak Tak W.
Published: March 2007

A human T cell receptor (TcR) δ chain variable region segment, Vδ3, has been mapped 2 kilobases 3′ to the constant (Cδ) gene. The Vδ3 gene segment is in an inverted transcriptional orientation to the diversity regions (Dδ), joining regions (Jδ) and Cδ gene segments. Analyses of TcR δ cDNA clone, KT041, showed that Vδ3 is linked to Dδ1, Dδ2, Jδ3 and Cδ and that this message encodes a potentially functional TcR δ chain. These findings indicate that a functional TcR δ gene can be constructed through a chromosomal inversion, suggesting that in human, chromosomal inversion is one of the important rearrangement mechanisms.
Human tonsillar dendritic cell‐induced T cell responses: analysis of molecular mechanisms using monoclonal antibodies
Authors: King Philip D. , Katz David R.
Published: March 2007

Dendritic cells, isolated from human tonsillar tissue, were found to be potent stimulators of the sodium periodate T cell oxidative mitogenesis reaction. Monoclonal antibodies against CD2, CD4, CD11a, CD18, LFA‐3, ICAM‐1, class I and class II major histocompatibility complex (MHC) inhibited T cell proliferation in this response, whereas antibodies against CD8, CD11b, CD11c and CD16 had no effect. Further, antibodies against CD2, CD11a, CD18, LFA‐3 and ICAM‐1 inhibited the early dendritic cell‐T cell clustering event which occurs in this cell interaction. In contrast, antibodies against CD4, class I and class II MHC did not inhibit clustering. Studies examining the expression of the respective molecules upon isolated dendritic cells and T cells suggest that anti‐LFA‐3 and anti‐class II MHC antibodies inhibit at the level of the dendritic cell, whereas anti‐CD2 and anti‐CD4 antibodies inhibit at the level of the T cell. However, antibodies against CD11a, CD18, ICAM‐1 and class I MHC may inhibit at either or both cell levels.

These findings have enabled us to propose a molecular mechanism for dendritic cell‐T cell interaction in oxidative mitogenesis. Dendritic cell‐T cell clustering is mediated by bidirectional binding of LFA‐1 (CD11a and CD18) and ICAM‐1 (involving both molecules on both cell types) and unidirectional binding of CD2 and LFA‐3 (involving T cell CD2 and dendritic cell LFA‐3). This initial event permits a second interaction of dendritic cell and T cell molecules, involving T cell CD4, class I MHC (possibly at both cellular levels) and dendritic cell class II MHC, which deliver the signal for proliferation.
Definition of the thymic generative lineage by selective expression of high molecular weight isoforms of CD45 (T200)
Authors: Pilarski Linda M. , Gillitzer Reinhard , Zola Heddy , Shortman Ken , Scollay Roland
Published: March 2007

Selective expression of CD45 isoforms distinguishes naive and memory T cells in peripheral blood. Paradoxically, although the most recent thymic emigrants are CD45R+ CD45 p180−, the majority of thymocytes are CD45 p180+. Speculating that the small subset of thymocytes selectively expressing only the high molecular weight isoforms of CD45 constitute the thymic generative lineage giving rise to peripheral T cells, we characterized the phenotypic and functional properties of CD45 p180− thymocytes. All cells bearing CD45 p180 were removed by rigorous depletion or all CD45R+ thymocytes were removed in a parallel depletion. CD45R− thymocytes were essentially the same in phenotype and CD4/CD8 subset distribution as unfractionated thymus, and dissimilar to naive peripheral blood lymphocyte (PBL) T cells. In contrast, CD45 p180− thymocytes, mainly CD45R+, were CD1− CD38− pgp 1+, corresponding closely to the phenotype of naive CD45R+ PBL T cells. This subset is enriched in CD4+ or CD8+ single positives, includes a high proportion of CD4−8− thymocytes which are predominantly CD3−, and appears to have a medullary location. Approximately 40%–50% of CD45 p180− thymocytes expressed a high density of CDw29 (4B4), which in the periphery is expressed at high density only on CD45 p180+ memory T cells and at low density on CD45R+ naive T cells. However, the expression of high density CDw29 in the absence of CD45 p180 indicates a close resemblance to fetal lymphocytes and suggests an essential role for CDw29 in both the least and the most mature of T cells. If CD45 p180− thymocytes constitute the generative lineage and CD45 p180+ cells are commited to intrathymic death, then the CD45 p180− subset should have enhanced proliferative potential. By combining depletion methods with a limiting dilution assay for clonogenic potential, we found that 100% of the clonogenic precursors present in unfractionated thymus were CD45R+ CD45 p180− cells. This indicates that the CD45 p180+ majority of thymocytes has a very limited capability for proliferation consistent with a commitment to intrathymic death. The clonogenic potential of CD45 p180− thymocytes indicates a greater functional resemblance to PBL T cells than to CD45 p180+ thymocytes. In so far as clonogenic potential in vitro reflects generative potential in vivo, expression of high molecular weight CD45 isoforms appears to define the generative thymic lineage. Our working hypothesis proposes that expression of CD45 p180 implements the mechanism for eliminating thymocytes with self‐reactive receptor specificities.
Cytotoxic T lymphocyte recognition of HLA‐A2 antigens in normal and HLA‐Cw3‐transgenic mice
Authors: Hämmerling Günter J. , Hunt Thurman , Dill Othmar , Moreno José
Published: March 2007

It is well established that a large fraction of murine cytotoxic T cells can recognize allogeneic major histocompatibility complex (MHC) antigens, and that the majority of this response are not restricted by H‐2 antigens of the responding host. In contrast, the murine response against the xenogeneic HLA class I antigens is relatively weak. Moreover, a large proportion of the responding murine T cells do not recognize the HLA antigen per se but only in an H‐2‐restricted manner, probably as an HLA peptide bound to H‐2.

Considerable evidence suggests that in mice the T cell repertoire is selected by thymic H‐2 antigens. Therefore, we asked the question whether in transgenic mice expressing an HLA class I antigen the T cell repertoire would be shaped toward a more effective recognition of other HLA alleles. Normal C57BL/6 (B6) and HLA‐Cw3 ‐transgenic B6 mice were immunized with a B6‐derived cell line transfected with HLA‐A2. The resulting A2‐specific CTL were tested on L cells transfected with either A2 alone, which should identify the H‐2‐unrestricted CTL, and on L cells transfected with A2 plus H‐2b genes, which should identify the sum of H‐2b‐restricted and unrestricted CTL. Both bulk culture and limiting dilution experiments showed that the CTL precursor frequencies for A2‐specific CTL were not increased in the transgenic mice, and that both strains produced comparable proportions of H‐2b‐restricted and of unrestricted A2‐specific CTL. The B6.Cw3 mice seemed to respond less well to HLA‐A2 than the normal B6 mice, suggesting the possibility of tolerance for peptides shared by the Cw3 and A2 molecules. In conclusion, the T cells in the B6.Cw3 transgenic mice did not seem to be selected towards a stronger and more unrestricted recognition of an allo‐HLA antigen. The possible reasons are discussed.