bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional markers of the major histocompatibility gene complex of snakes
Authors: Farag Magda Adly , Ridi Rashika El
Published: March 2007

In optimal seasonal conditions, outbred adult snakes Psammophis sibilans displayed the major immunological functions related, in mammals, to the presence of the major histocompatibility gene complex (MHC). Thus, out of 30 snake random pairs that exchanged skin transplants 72.9% rejected their allograft in an acute or subacute manner. Strongly significant proliferative response was recorded in 67.3% of 168 separate one‐way mixed leukocyte reaction (MLR) cultures. Lymphocytes from 6/11 snakes immunized by skin allografting displayed, after secondary stimulation in vitro, cell‐mediated lympholysis (CML) in vitro of 51Cr‐labeled lymphoblasts derived from the donor snake. Finally, cytotoxic alloantibodies were readily generated after snake priming with skin allograft and blood cells.

Snakes did not only exhibit the major cell‐ and humoral‐mediated immune functions, but these functions appeared to be linked with the degree of MLR disparity. Thus, animals with different MLR rejected skin allografts acutely and produced cytotoxic effector cells. In contrast, MLR‐identical animals rejected the skin allograft of their partner chronically and failed to produce killer cells in CML. This significant positive correlation between MLR disparity, graft rejection and CML suggests that the responsible antigens are encoded, as in other vertebrates, by the same genetic system, the MHC.
Resistance to murine cutaneous leishmaniasis is mediated by TH1 cells, but disease‐promoting CD4+ cells are different from TH2 cells
Authors: Moll Heidrun , Röllighoff Martin
Published: March 2007

A limiting dilution system has been used for quantitative analysis of antigen‐reactive T cells producing interleukin (IL)2, IL4 and interferon (IFN)‐γ in the course of murine infection with Leishmania major. The precursor frequencies of CD4+ cells with the potential for production of IFN‐γ, which has been associated with TH1 cells, are much higher in resistant than in susceptible mice, whereas the reverse is found for CD4+ cells secreting IL4 which have been classified as TH2 cells. Our results allow a better understanding of the relative contribution of these cell types at various stages of disease and can be summarized as follows: (a) secretion of IL4 can be demonstrated in short‐term clonal cultures of CD4+ cells from L. major‐infected mice, (b) CD4+ cells releasing IL2, suggested to be a characteristic of TH1 cells that predominate in resistant mice, can also be detected in susceptible mice at any time of infection, (c) both IL2 and IL4 are released by the progeny of individual T cells from susceptible mice and (d) the kinetics of precursor frequencies in genetically susceptible mice protected against the disease by prophylactic treatment are different from those of congenitally resistant mice, thus indicating that the development of lymphokine‐producing T cells and the establishment of protective immunity may be regulated differently in those mice. The data suggest that resistance to disease is correlated with the presence of IFN‐γ‐producing TH1 cells, while susceptibility is associated with CD4+ cells that do not segregate into the TH1 or TH2 subset but display an overlapping pattern of lymphokine activities.
Participation of a dominant cytotoxic T cell population defined by a monoclonal antibody in syngeneic anti‐tumor responses
Authors: Matsubayashi Yuji , Hirama Toshiyasu , Morioka Atsuo , Iwashiro Michihiro , Masuda Tohru , Uchino Haruto , Takeshita Sunao , Yamagishi Hideo , Udono Heiichiro , Mieno Masahiro , Nakayam Eiichi , Shiku Hiroshi , Uenaka Akiko , Kuribayashi Kagemasa
Published: March 2007

Cytotoxic T lymphocyte (CTL) clones against a syngeneic Friend virus‐induced erythroleukemia (FBL‐3) were generated in C57BL/6 (B6) mice. A monoclonal antibody (mAb, N9‐127) was then raised from spleen cells of a B6 mouse immunized syngenically against one of these CTL clones. This mAb detected the epitope (127Ep) of the T cell antigen receptor (TcR) on the immunizing CTL clone in tests of immunoprecipitation, specific blocking and proliferation, and induction of TcR‐mediated nonspecific lysis of the clone. In addition, more than 10% of the FBL‐3‐specific CTL clones isolated independently from B6 mice were 127Ep+. Further investigations revealed that up to 30% of B6 anti‐FBL‐3 T cell blasts from mixed lymphocyte tumor cell cultures were positive for this epitope, and that its expression was confined to CD8+ T cells. This epitope was not detected in naive lymphoid cells from the spleen, lymph nodes or thymus or in T cell clones specific for tumors other than FBL‐3. The FBL‐3‐specific CTL clones were next grouped into 127Ep+ and 127Ep− clones. Sequence analyses of the CTL clone used for immunization showed the rearrangements of Vα1Jα112‐2 and Vβ10Dβ2.1Jβ2.7. Southern blot analysis of all the 127Ep+ CTL clones examined showed the same DNA rearrangement bands of both the TcR α and β genes. These findings suggested that mAb N9‐127 recognized the shared determinant of the TcR molecule which was expressed by the dominant CTL population in the response to FBL‐3.
The neutrophil‐activating proteins interleukin 8 and β‐thromboglobulin: in vitro and in vivo comparison of NH2‐terminally processed forms
Authors: van Damme Jo , Rampart Marc , Conings René , Decock Benny , van Osselaer Nancy , Willems Jean , Billiau Alfons
Published: March 2007

Isolation of the human neutrophil activating protein (NAP) interleukin 8 (IL 8) from leukocytes has revealed that it is structurally related to β‐thromboglobulin (βTG) from platelets. Both these proteins occur as natural mixtures of multiple forms, differing from each other by unequal truncation at the NH2 terminus. In this study we have compared IL8 and βTG forms for in vitro and in vivo neutrophil activation. In contrast to IL8, none of the βTG forms were found to exert granulocyte chemotactic activity in vitro, as measured in the agarose assay. However, fractions rich in the most extensively processed forms of βTG (e.g. NAP‐2) as well as pure NAP‐2 did induce lactoferrin release from granulocytes, whereas fractions containing only the longer forms (e.g. connective tissue‐activating peptide III) were inactive. In order to observe this in vitro effect, about 10‐fold less IL8 (10 nM) than NAP‐2 was required. In the presence of a vasodilatator substance low doses (2–20 pmol) of IL8 and the shorter forms of βTG caused granulocyte accumulation and plasma leakage in rabbit skin whereas the longer forms of βTG again failed to do so. Finally, granulocytosis induction following i.v. injection was found to occur with NAP‐2. At the maximal dose tested (250 pmol), this in vivo effect of NAP‐2 was less pronounced than that of IL8. In the case of IL8, NH2‐terminal processing did not seem to affect granulocyte stimulatory activity. It should be noted, however, that the extent of processing of IL8 is less than that occurring with βTG. It can be concluded that the platelet factor βTG, structurally related to the monokine IL8, can also play a role in neutrophil activation during inflammatory reactions.
Binding of monomeric immunoglobulins by bone marrow‐derived mononuclear phagocytes; its modulation by interferon‐γ
Authors: Keller Robert , Keist Ruth , Bazin Hervé , Joller Peter , van Der Meide Peter H.
Published: March 2007

The ability of resting and activated rat bone marrow‐derived mononuclear phagocytes (BMMΦ) to bind monomeric rat, mouse, and human IgG was determined by means of flow cytometry. Rat IgG2b bound with high affinity (Kd ≅ 3 × 10−9); binding was optimal at 4°C and was only little affected by trypsin treatment. The other IgG bound with only low affinity (rat IgG2a, mouse and human IgG) or not at all to rat BMMΦ (rat IgG1, rat IgG2c). The binding of rat IgG2b was not affected by the presence of a surplus of low‐affinity binding IgG, and vice versa, indicating that high‐ and low‐affinity IgG bind to different sites. Binding of high‐ and low‐affinity IgG as well as expression of MHC class II molecules and of tumoricidal activity by BMMΦ was markedly enhanced by rat interferon‐γ in low concentration (0.1 to 1.0 IU IFN‐γ/ml). On the other hand, heat‐killed Corynebacterium parvum organisms, that were equally potent in triggering tumoricidal activity, neither enhanced the binding of IgG nor the expression of MHC class II molecules by BMMΦ, suggesting that these abilities are not necessarily closely related phenomena.
Exposure of female mice to type II collagen reduces susceptibility to collagen‐induced arthritis in offspring
Authors: van Vollenhoven Ronald F. , Thorbecke G. Jeanette , Siskind Gregory W.
Published: March 2007

The effect of exposure of female DBA/1 mice to collagen II (CII) prior to breeding on the susceptibility of their offspring to CII‐induced arthritis (CIA) was investigated. It was found that female offspring, born within 3 months after exposure of the mothers to CII, had a significantly reduced incidence of CIA, following immunization with CII. Just prior to this immunization, no anti‐CII could be detected in the offspring. Offspring born more than 3 months after exposure of the mothers to CII showed no differences in susceptibility to induction of CIA, if optimal conditions for induction were used. However, when suboptimal conditions for induction of CIA were used, offspring of females that had been exposed to CII developed less severe arthritis and had a delayed onset of arthritis as compared with controls. It is concluded that exposure of female mice to CII prior to mating results in changes in the immune response to CII in the offspring, leading to a subtle decrease in susceptibility to CIA.
The influence of S17 stromal cells and interleukin 7 on B cell development
Authors: Cumano Ana , Dorshkind Kenneth , Gillis Steven , Paige Christopher J.
Published: March 2007

A clonal assay was used to study different stimuli involved in the progression of fetal liver B cell precursors to mature B lymphocytes.

In this report we replaced fetal liver heterogenous feeder cells by a recombinant growth factor, interleukin 7 (IL 7), and a clonal stromal cell line, S17. Under those conditions we could clone 1 in 10 B220+ B cell precursors from fetal liver and the cells could differentiate to a mitogen‐responsive, immunoglobulinsecreting stage. We found that IL 7 stimulates proliferation of B220+ precursors but is not sufficient to support maturation of those precursors to a stage of mitogen responsiveness. We show further that the cell line S17 does not produce IL 7 at functionally detectable level but provides support for B cell maturation. We conclude that this cell line supplies an exogenous stimulus required by B cell precursors to become mature lymphocytes. We describe therefore two stages in pre‐B cell development: (a) IL 7‐dependent proliferation and (b) S17‐dependent maturation to mitogen reactivity. Further studies demonstrate that S17 has a profound effect on B cells by increasing the clonal efficiency of lipopolysaccharide‐responsive cells to nearly 1:1 B cell in the spleen of adult C57BL/6 mice.
A new surface antigen on intraepithelial lymphocytes in the intestine
Authors: Kilshaw Peter J. , Murant Susan J.
Published: March 2007

A new surface molecule has been discovered on mouse intestinal intraepithelial lymphocytes (IEL) using a rat anti‐mouse IEL monoclonal antibody, M290. It was expressed at high levels on nearly all IEL and on a majority of T cells in the gut lamina propria. M290 stained, with lower intensity, a small minority of T cells in other lymphoid tissues. Expression was biased towards the CD8+ subset. Stimulation of peripheral T cells with mitogens did not induce expression of the new antigen but addition of transforming growth factor β to stimulated T cells had a marked inductive effect. Sodium dodecyl sulfate‐polyacrylamide gel electrophoretic analysis of IEL surface components precipitated with M290 showed principal bands at 135, 120, 28 and 24 kDa (reduced) and 135, 100, 24 and 21 kDa (nonreduced). Precipitation with antibodies to integrin subunits showed that the new molecular complex was not a member of the β1, β2, or β3 integrin families although all of these were represented on IEL. A 13‐amino acid N‐terminal sequence obtained from the 120‐kDa β subunit of the antigen prepared from an M290+ Thybridoma (MTC‐1) did not show homology with integrins. Pulse‐chase studies using MTC‐1 cells showed that the 135‐kDa α subunit was derived from a 147‐kDa precursor. The function of this new molecular complex is not yet known.
Induction of antibody synthesis by CD4+ T cells: IL 5 is essential for induction of antigen‐specific antibody responses by TH2 but not TH1 clones
Authors: Dekruyff Rosemarie H. , Mosmann Rim R. , Umetsu Dale T.
Published: March 2007

Murine B cells stimulated with lipopolysaccharide (LPS) and interleukin (IL) 4 produce IgG1 and IgE, but synthesize IgG2a when stimulated with LPS and interferon‐γ. The cytokines, however, that regulate immunoglobulin (Ig) synthesis induced in normal B cells under antigen‐driven major histocompatibility complex (MHC)‐restricted conditions in the absence of potent B cell mitogens have not been fully elucidated. We and others have shown that under cognate MHC‐restricted conditions, CD4+ T cell clones of the TH1 subset, which produce IL 2 and interferon‐γ, and T cell clones of the TH2 subset, which produce IL 4 and IL 5, are both capable of inducing anti‐trinitrophenyl IgG plaque‐forming cells. In this report we have examined in further detail the cytokine requirements for the induction of Ig synthesis in B cells cultured directly with TH1 and TH2 T cell clones.

Using (a) TH2 clones that varied in the amount of IL 5 secreted, (b) a neutralizing monoclonal antibody against IL 5 and (c) T cell clones pretreated with cyclosporin A to inhibit cytokine secretion, we found that IL 5 was essential for induction of IgG1 synthesis by TH2 but not TH1 T cells. Although we demonstrated that IL 2 could actually up‐regulate the synthesis of IL 5 by TH2 clones, the induction of IgG synthesis by TH2 clones was entirely independent of IL 2. In contrast, induction of IgG1 synthesis by TH1 clones was absolutely dependent upon the presence of IL 2 and was not affected by the presence of IL 5. Thus, these studies demonstrate the idea that at least two independent pathways exist for the induction of IgG1 synthesis, and that one of these pathways is IL 4/IL5 dependent and the other IL 2 dependent.
Molecular associations on the T cell surface correlate with immunological memory
Authors: Dianzani Umberto , Luqman Mohammad , Rojo Jose , Yagi Junji , Baron Jody L. , Woods Andrea , Janeway Charles A. , Bottomly Kim
Published: March 2007

Different isoforms of CD45 are expressed on naive and memory CD4 T cells in the mouse, as revealed by an antibody to a set of isoforms of CD45 that utilize exon B, called CD45RB. Cloned TH1 and TH2 lines also differ for expression of isoforms detected by this antibody. Differential expression of CD45 isoforms correlates with different behavior of cell surface molecules involved in transmembrane signal transduction. On naive T cells, CD4, CD45 and the CD3/T cell receptor complex behave as independent entities. On memory T cells, these three molecules are stably associated on the T cell surface. Furthermore, on TH2 cells, which express intermediate levels of CD45RB, CD4 is stably associated with CD45 isoforms other than CD45RB, but this complex is not associated with the CD3/T cell receptor. These results lead us to propose that immunological memory in CD4 T cells consists of an altered structure of the T cell's specific signal transduction apparatus controlled by low‐molecular weight CD45 isoforms. This altered receptor structure would allow the more sensitive triggering of the T cell characteristic of memory cells. The organization of multimolecular signal transduction systems may be a general means by which cells alter their physiological behavior, allowing the acquisition of new phenotypic characteristics.
Suppression of B cell activation by cyclosporin A, FK506 and rapamycin
Authors: Wicker Linda S. , Boltz Robert C. , Matt Victoria , Nichols Elizabeth A. , Peterson Laurence B. , Sigal Nolan H.
Published: March 2007

The effects of the immunosuppressants cyclosporin A (CsA), FK506 and rapamycin have been compared using murine B cells activated with a variety of mitogens. FK506 is a macrolide antibiotic that has been recently shown to inhibit T cell activation by a mechanism that appears similar to that of CsA. Rapamycin is a macrolide structurally related to FK506 whose mechanism of T cell suppression appears to be distinct from that of FK506 and CsA. While CsA and FK506 were found to preferentially inhibit B cell activation caused by stimuli which induce a rise in intracellular calcium, rapamycin partially inhibited activation by all stimuli tested, including those which are not associated with a calcium flux. All three compounds were found to inhibit cell cycle progression within the G1 phase; however, the rapamycin‐sensitive event within G1 was completed earlier than the G1 events inhibited by CsA and FK506. In addition, inhibition of anti‐IgM‐activated B cells with CsA and FK506, but not with rapamycin, resulted in cell death. These data suggest that although CsA, FK506 and rapamycin are all inhibitors of B cell activation, the inhibitory activity of rapamycin can be clearly distinguished from that of CsA and FK506.

Although the suppressive effects of CsA and FK506 on B cell proliferation were nearly identical in this study, their biological activities were distinguishable since FK506, but not CsA, could antagonize rapamycin‐mediated suppression.
Protective methylation of immunoglobulin and T cell receptor (TcR) gene loci prior to induction of class switch and TcR recombination
Authors: Burger Christa , Radbruch Andreas
Published: March 2007

Methylation of the Sγ1 switch region and Cγ1 constant region gene from the immunoglobulin heavy chain locus and of the Jβ2 and Cβ regions from the T cell receptor β chain (TcRβ) locus is compared here in murine germ‐line cells, nonlymphoid cells and lymphocytes. In germ‐line cells and in lymphocytes prior to recombination all four regions show strong methylation, i.e. most MspI sites are methylated. After activation of lymphocytes, demethylation is observed for those regions which are activated for recombination, at specific sites 5′ of Sγ1 in B cells activated with bacterial lipopolysaccharide and interleukin 4, and for Jβ2 in thymocytes. In nonlymphoid cells, where these regions cannot be used for recombination, considerable demethylation is observed for all four regions analyzed as compared to lymphocytes. The result implies an important role for methylation of recombinatorial regions. Methylation may be involved in protecting them from uninduced recombination, thus allowing regulated expression of distinct genes in lymphocyte ontogeny.
Functional characterization of the antibody‐mediated protection against blood stages of Plasmodium falciparum in the monkey Saimiri sciureus
Authors: Groux Hervé , Perraut Ronald , Garraud Olivier , Poingt Jean Philippe , Gysin Jürg
Published: March 2007

The squirrel monkey Saimiri sciureus is one of the World Health Organization recommended experimental models of Plasmodium falciparum blood stage infection. Anti‐malaria antibodies developed by this host after a drug‐controlled infection play an important part in the acquired protection against the P. falciparum blood stages. Futhermore, the use of two anti‐Saimiri immunoglobulin (Ig) monoclonal antibodies (mAb) has permitted the differentiation between protective (mAb 3A2/G6) and non‐protective (mAb 3E4/H8) antibodies, as shown by transfer experiments to recipient monkeys infected with blood stage parasites. In the present study we have established that protection conferred by the 3A2/G6+ protective Ig preparation is strictly associated with an in vitro opsonic activity. Such an opsonic activity is not detectable in the 3E4/H8+ non‐protective Ig population. In addition, results indicate that the 3E4/H8+ non‐protective Ig population competes with protective opsonic 3A2/G6+ Ig antibodies when co‐incubated with parasitized red blood cells. Thus, it follows that protection can be directly correlated to the quantitative and qualitative fluctuation of the two Ig populations. When challenged with 1 × 108 P. falciparum‐infected Saimiri red blood cells parasitemia occurred in 5 out of 12 Saimiri who were lacking detectable 3A2/G6+ opsonic antibodies in their sera. By employing antibodies against the human Fc receptor for IgG (FcγR) in an in vitro phagocytic assay, we have been able to show that the principal receptor is FcγRIII. Finally, we also show that in contrast to the situation in man, this receptor is present on circulating monocytes. These findings could lead to a different strategy in designing malaria vaccine candidates and also allow the possibility of predicting the outcome of immunization trials in Saimiri monkeys.
Generation of hen egg lysozyme‐specific and major histocompatibility complex class I‐restricted cytolytic T lymphocytes: recognition of cytosolic and secreted antigen expressed by transfected cells
Authors: Forquet Fréderique , Calin Véronique , Trescol‐Biemont Marie‐Claude , Kanellopoulos Jean , Mottez Estelle , Kourilsky Philippe , Rabourdin‐Combe Chantal , Gerlier Denis
Published: March 2007

Syngeneic cells exogenously supplied with hen egg lysozyme (HEL) or endogenously synthesizing HEL were used as antigen‐presenting cells to induce major histocompatibility complex class I‐restricted cytotoxic T lymphocytes (CTL). Immunization of C57BL/6 mice followed by repeated stimulation of their splenocytes in vitro with trypsinized HEL peptides led to the generation of CTL lines specific for trypsinized HEL peptides and restricted by H‐2Kb. Immunization of C3H mice with a mixture of soluble native HEL and irradiated syngeneic spleen cells followed by in vitro stimulation of immune spleen cells with soluble HEL could in a few cases result in HEL‐specific CTL able to kill syngeneic transfectant L cells secreting HEL (HELs) or expressing cytosol‐targeted HEL (HELc). The use of HELs or HELc transfectant L cells as in vivo and in vitro immunogens was a potent way for eliciting HEL‐specific polyclonal CTL. These CTL and two CD8+ clones were found to be H‐2Kk restricted and specific for the 1‐17 N‐terminal HEL peptide. In addition, the anti‐HEL CTL could also exhibit a significant cross‐reactivity against unsensitized and HEL‐untransfected targets expressing the K restriction element. This cross‐reactivity was likely due to recognition of unidentified HEL mimicking peptides (self‐derived ?) presented by the MHC class I (H‐2Kb or H‐2Kk) molecule used as the restriction element for the specific recognition of HEL. The CTL raised after immunization with HELs or HELc transfectant cells were found to recognize both the HELs and HELc transfectant cells even though HEL was not detected in the latter after a 2‐ or 5‐min radiolabeling pulse. Recognition of both HELs and HELc transfectant cells by a given CTL clone suggests that HEL subjected to two separate processing pathways, each depending on the initial subcellular localization, can ensure the generation of similar MHC class I peptide complexes.
Leukocyte function‐associated antigen 1 (LFA‐1) is a signaling molecule for cytoskeletal changes in a human T cell line
Authors: Kelleher Dermot , Murphy Anne , Cullen Derek
Published: March 2007

The HuT 78/2 clone is a human T cell clone which has an activated phenotype. When this line was stimulated with immobilized antibody to LFA‐1, the majority of cells developed dendritic processes. These processes were demonstrated to contain cytoskeletal elements including microtubules and intermediate filaments. Phorbol myristate acetate synergized with and prolonged this effect. Thus, the LFA‐1 molecule may function as a signaling molecule for cytoskeletal reorganization in a human T cell clone.
Microenvironmental organization and stromal cell associations of B lymphocyte precursor cells in mouse bone marrow
Authors: Jacobsen Karen , Osmond Dennis G.
Published: March 2007

B lymphocyte precursor cells expressing B220 glycoprotein have been examined in mouse bone marrow (BM) by the in vivo binding of monoclonal antibody (mAb) 14.8 visualized by light and electron microscope radio autography. Young mice were injected intravenously with 125I‐labeled mAb 14.8 and then perfused to remove unbound antibody. Quantitative analysis of radioauto graphic sections of femoral BM revealed many labeled mAb 14.8‐binding cells which were situated both singly and in groups throughout the extravascular BM parenchyma. Groups of large 14.8+ cells were located in patchy areas in the peripheral regions of the BM near the endosteum. These cells were shown to include proliferating precursor B cells by using mice given vincristine sulfate to stop cells in metaphase and mice treated from birth with anti‐IgM antibodies to delete mature B lymphocytes. Electron microscopy revealed clusters of 14.8+ cells intimately associated with the processes of stromal reticular cells. Other 14.8+ cells were in close contact with macrophages; in some instances the intervening cell membranes were indistinct and the macrophages contained 14.8+ material in their cytoplasm. In addition, 14.8+ small lymphocytes were highly concentrated within the lumen of some sinusoids. The present method of detecting B lineage precursor cells in situ has led to a working model of the microenvironmental organization of primary B cell genesis in vivo. The model proposes (a) a centrally directed sequence of differentiation initiated by early precursor cells situated peripherally near the surrounding bone; (b) close associations between precursor B cells and stromal reticular cells; (c) deletion of ineffective B cells by macrophages, and (d) an intravascular maturation phase before B lymphocytes are finally delivered into the blood stream.
Molecular cloning and characterization of WP34, a phosphorylated human lymphocyte differentiation and activation antigen
Authors: Kumar Kadiyala R. , McIntyre Bradley W. , Krensky Alan M.
Published: March 2007

An absorbed antiserum was made by incubating a cytotoxic T lymphocyte immune antiserum with the T cell leukemia HPB‐ALL, thus removing reactivity to known lymphocyte function‐associated antigens. This antiserum was used to screen a cDNA expression library and isolate a novel human lymphocyte cDNA clone designated WP34. WP34 transcript is expressed in functional T cells and a variety of hematopoietic cell lines and tissues, including fetal liver and thymus, but not in HPB‐ALL or any non‐hematopoietic cell lines or tissues tested. The WP34 protein is an acidic, phosphorylated molecule with a pI of 4.5 and molecular mass of 50 kDa. WP34 protein expression is absent in resting peripheral blood lymphocytes but can be induced with antigen stimulation, while the transcript is constitutively expressed. Sequence analysis indicates that WP34 is the human homologue of the recently described murine molecule LSP1.
Glucocorticoids inhibit the production of IL 6 from monocytes, endothelial cells and fibroblasts
Authors: Waage Anders , Slupphaug Geir , Shalaby Refaat
Published: March 2007

We have examined the effect of dexamethasone (DM) and cortisol on the production of interleukin (IL)6 from the murine macrophage cell line RAW 264.9, human monocytes, human endothelial cells and the human fibroblast cell line FS4. In RAW 264.9 cells DM in the concentration range 10−9 M to 10−6 M inhibited the lipopolysaccharide (LPS)‐induced production of IL 6 by 10% to 90%. Cortisol had a similar effect, but was about 25 times less potent than DM. Also, when 10−6 M of DM was added to the cultures after addition of LPS, it completely inhibited the residual 24‐h production of IL 6. Corresponding to the effect on IL 6 production, DM (10−6 M) reduced the mRNA levels for IL 6 in the RAW 264.9 cells. The glucocorticoid analogue RU 486 competes with DM and cortisol for the glucocorticoid receptor and reversed the inhibitory effect of DM, demonstrating that DM exerts its effect via the glucocorticoid receptor. DM also had an inhibitory effect on LPS‐stimulated IL 6 production in freshly isolated human monocytes, and on IL 1‐stimulated IL 6 production in human endothelial cells and FS4 fibroblasts. These results demonstrate that DM via a receptormediated mechanism inhibits IL 6 production at the transcriptional level, and this may contribute to the anti‐inflammatory and immunosuppressive effect of glucocorticoids.
Decreased accessory cell function of macrophages after infection with human immunodeficiency virus type 1 in vitro
Authors: Ennen Joachim , Seipp Inka , Norley Stephen G. , Kurth Reinhard
Published: March 2007

Peripheral blood monocytes from human immunodeficiency virus (HIV)‐infected individuals or AIDS‐related complex/AIDS patients ex vivo exhibit distinct alterations in some but not all immune functions. In studies presented here, monocytes from healthy donors were infected with HIV 1 in vitro and co‐cultures with autologous uninfected T lymphocytes were set up. The monocyte/macrophage (MΦ)‐dependent T cell function was determined by measurement of proliferative and secretory [interleukin (IL)2, interferon‐γ] responses to lectin (phytohemagglutinin), mitogen (anti‐CD3 monoclonal antibody), or recall antigen (tetanus toxoid, tuberculin). Accessory function of MΦ was normal after HIV infection when optimal amounts (10%–20%) were added to the T lymphocytes. However, HIV infection of MΦ significantly decreased T cell proliferative responses and secretion of IL 2 when supplemented at limited dilution (0.5%‐5%), although interferon‐γ production was not affected. Whereas the lipopolysaccharide‐triggered MΦ production of IL 1 was not impaired by HIV 1 infection, there was a significant decrease in this response when anti‐CD3 monoclonal antibody or tetanus toxoid were used to trigger the peripheral blood mononuclear cells. The impairment of proliferation of T lymphocytes in the presence of HIV 1‐infected MΦ could be overcome by addition of exogenous IL 1. Taken together, these data clearly show that the mononuclear phagocytedependent enhancement of stimulated T cell proliferation and lymphokine secretion is decreased when the restricted numbers of monocytes/MΦ are HIV 1 infected. There are, therefore, two possible roles of MΦ in HIV infection and progression to disease. First, as a reservoir and vehicle for dissemination of the virus, and second, as an immune cell whose essential functions are impaired by infection.
Expression of CD4 can confer major histocompatibility complex class II‐associated superantigen reactivity upon a T cell receptor derived from a CD8‐dependent cytotoxic T lymphocyte clone
Authors: Wallace Valerie A. , Ohashi Pamela S. , Hengartner Hans , Mak Tak W.
Published: March 2007

It has been shown that reactivity against major histocompatibility complex (MHC) class II‐associated Mlsa determinants is mainly mediated by CD4+ Vβ6+ T cells. 3F9 is a CD8+ CTL clone which is specific for the alloantigen H‐2Db. While 3F9 is Vβ6+, it is not Mlsa reactive, presumably because it does not express CD4. 3F9 utilizes the same T cell receptor (TcR) VαVβ combination as LB2, a CD4+ T helper clone specific for chicken red blood cells (cRBC)/I‐Ab and yet differs from LB2 in the junctional sequences in both TcR chains. CD4+CD8− and CD4−CD8− hybridomas expressing the 3F9 TcR were tested for reactivity against Mlsa and cRBC/I‐Ab. Only the CD4+CD8− hybridomas were Mlsa reactive, and antibody inhibition studies revealed that this reactivity was both CD4 and MHC class II dependent. Therefore the expression of the CD4 molecule can make an MHC class I‐restricted TcR Mlsa reactive. Neither type of hybridoma reacted against cRBC, thus the main difference in the antigen reactivity between 3F9 and LB2 lies in the TcR junctional regions.
Autoimmune reactions to heat‐shock proteins in pristane‐induced arthritis
Authors: Thompson Stephen J. , Rook Graham A. W. , Brealey Richard J. , Zee Ruurd Van Der , Elson Christopher J.
Published: March 2007

The development of arthritis induced in mice by intraperitoneal injection of the non‐antigenic mineral oil, 2,6,10,14‐tetramethylpentadecane (pristane), was shown to depend on an intact immune response possibly to a heat‐shock protein (hsp) in the synovium. Initial experiments suggested that some crucial event in the development of arthritis takes place early after pristane injection. First, irradiated pristane‐treated mice failed to develop arthritis unless they were reconstituted with spleen cells from normal donors within 25 days of irradiation. Second, mice irradiated up to 50 days after pristane injection, but not later, did not develop arthritis. Evidence for the involvement of an immune response to heat‐shock protein (hsp) comes from the finding that mice injected with mycobacterial 65‐kDa hsp prior to pristane challenge had a reduced incidence of arthritis in contrast to animals pre‐immunized with the E. coli hsp equivalent GroEL or with bovine serum albumin. Other experiments revealed that T cells from mice with gross morphologically defined arthritis proliferated strongly to hsp65 and to normal joint antigens, whereas T cells from animals treated with pristane which did not develop arthritis gave much smaller responses. Mice which developed arthritis also had elevated levels of anti‐hsp65 IgG in comparison with non‐arthritic animals. These findings strongly suggest that autoimmune reactions to an antigen which cross‐reacts with hsp65 are generated in pristane‐induced arthritis. It is considered that the autoimmune response is directed to a synovial antigen and that pre‐immunization with hsp65 protects the animals from the development of pristane‐induced arthritis by altering the specificity or quality of the immune response to this antigen.
Interferon‐gamma gene and protein are spontaneously expressed by the porcine trophectoderm early in gestation
Authors: Lefèvre Françcois , Martinat‐Botté Françcoise , Guillomot Michel , Zouari Kamel , Charley Bernard , Bonnardière Claude La
Published: March 2007

The nature and the source of the antiviral activity found in the reproductive tract of pregnant gilts early in gestation were analyzed. Two antigenically distinct antiviral activities were found in uterine flushings and in supernatants of conceptus‐conditioned culture medium between days 12 and 20 of gestation, using Madin Darby bovine kidney cells and vesicular stomatitis virus as a challenge in the antiviral bioassay. One component was antigenically identified as interferon‐γ (IFN‐γ). Northern blot analysis of conceptus poly(A)+ RNA with a human IFN‐γ cDNA probe revealed two mRNA of 1.3 and 1.4 kb. In addition, immunoprecipitation of metabolically labeled conceptus secretory proteins with an antiserum raised against purified porcine rIFN‐γ resulted in four bands in sodium dodecyl sulfate‐polyacrylamide gel electrophoresis, with molecular mass 18.5 to 24.5 kDa. Pre‐electrophoresis incubation of the immunoprecipitate with glycopeptidase F, which removes N‐linked carbohydrates, yielded a single band of 16.5 kDa. Finally, staining of ultrathin sections by indirect immunofluorescence using the same antiserum to rIFN‐γ revealed that all cells of extra‐embryonic trophectoderm contained intensely fluorescent granules in their apical cytoplasm. Neither endoderm nor embryonic cells stained positive. These results clearly show that IFN‐γ, known so far as a T or NK cell‐derived lymphokine, is spontaneously and intensively secreted by the porcine trophectoderm, an embryonic tissue not related to the hematopoietic lineage. They also suggest that the implanting conceptus, at least in the porcine species, could play an active role in immune interactions with the mother.
Prostaglandin E2 as a selective stimulator of antigen‐specific IgE response in murine lymphocytes
Authors: Ohmori Hitoshi , Hikida Masaki , Takai Toshiyuki
Published: March 2007

Anti‐2,4,6‐trinitrophenyl (TNP) IgE antibody response was elicited by stimulating TNP‐keyhole limpet hemocyanin‐primed murine spleen cells with the same antigen in vitro. The released anti‐TNP IgE was assayed by antigen‐ and isotype‐specific enzyme immunoassay developed in our laboratory. When prostaglandin E2 (PGE2) was added to the lymphocyte culture at 10−7 M, anti‐TNP IgE response was augmented two‐ to fourfold. Interestingly, PGE2 did not affect the production of anti‐TNP antibodies belonging to other isotypes including IgM, IgG1, IgG2a, IgG2b, IgG3 and IgA. Moreover, PGE2 showed neither enhancing nor interleukin 4‐replacing activities in the polyclonal IgE response by B cells stimulated with lipopolysaccharide and interleukin 4. When endogenous prostaglandin synthesis was inhibited by 10−6 M indomethacin, the anti‐TNP IgE response, but not the corresponding IgG response, was suppressed by 30%‐60%. These results suggest a potential role of PGE2 in the up‐regulation of the antigen‐specific IgE response.
Phosphotyrosine phosphatases are involved in reversion of T lymphoblastic proliferation
Authors: Iivanainen Antti V. , Lindqvist Christer , Mustelin Tomas , Andersson Leif C.
Published: March 2007

Resting T lymphocytes can be activated by mitogens or antigens to become T blasts, which revert spontaneously both in vivo and in vitro in extended cultures to secondary, memory T lymphocytes. We have studied the role of phosphotyrosine phosphatases (PTPase) in the reversion of lymphoblasts in extended, phytohemagglutinin‐stimulated cultures of human T lymphocytes. Membrane‐associated PTPase activity is high in resting T cells, but decreased during mitogen‐induced blast transformation. When the blasts were reverting to lymphocytes, the PTPase activity increased more than twofold concomitantly with an elevated surface expression of CD45. When T blasts from phytohemagglutinin‐activated cultures were kept in the presence of sodium orthovanadate, an inhibitor of PTPase, they maintained their lymphoblastic proliferation and did not revert to resting lymphocytes. This was accompanied by retention of a 48‐kDa phosphotyrosine‐containing protein. Our data indicate an important role for PTPase in the transition of lymphocytes from an activated to a resting stage.
Newly generated thymocytes are not refractory to deletion when the α/β component of the T cell receptor is engaged by the superantigen staphylococcal enterotoxin B
Authors: Jenkinson Eric J. , Kingston Rosetta , Owen John J. T.
Published: March 2007

It has been reported that, following the initial expression of the T cell receptor (TcR) α/β, newly generated thymocytes pass through a developmental window characterized by ineffective coupling between the α/β and CD3 components resulting in resistance to deletion (negative selection). However, we now provide evidence that the TcR α/β on developing thymocytes is capable of delivering deletional signals in response to the superantigen staphylococcal enterotoxin B (SEB) as soon as the receptor is expressed. We also show that if TcR+ thymocytes are allowed to mature in organ cultures of embryonic thymus before SEB is added, they respond by proliferation giving rise to blast cells of CD4−CD8−, CD4+CD8− or CD4−CD8+ phenotypes.
Tolerogenicity of thymic epithelium
Authors: Webb Susan R. , Sprent Jonathan
Published: March 2007

To attempt to resolve the controversy on the role of thymic epithelial cells (TEC) in tolerance induction, athymic mice were grafted with allogeneic day‐14 fetal thymuses treated with deoxyguanosine in vitro. The data indicate that the tolerogenicity of TEC varies considerably according to the antigen and the subpopulation of T cells studied. For cytotoxic CD8+ cells responding to H‐2 class I antigens, TEC induce minimal tolerance. For proliferative responses of CD4+ cells, by contrast, TEC induce significant tolerance to H‐2 class II antigens but no detectable tolerance to Mls3 antigens.
A mechanism of activation of the alternative complement pathway by the classical pathway: protection of C3b from inactivation by covalent attachment to C4b
Authors: Meri Seppo , Pangburn Michael K.
Published: March 2007

In this work we studied the role of the classical pathway complement component C4b in the activation of the alternative pathway. It was found that nascent C3b attaches with high efficiency to C4b and that C3b in C4bC3b complexes is protected from inactivation by factors H and I. Activation of C3 by factors B and D in the presence of Mg2+ ions and excess C4b led to 35% incorporation of nascent C3b into C4bC3b complexes in the fluid phase. In comparison, when human IgG was tested as an acceptor under similar conditions, only 12% of generated C3b was incorporated into IgGC3b complexes. The half‐life time of dissociation of C3b from purified C4bC3b complexes was approximately 2.3 h at 37°C. C4b in these complexes protected C3b from inactivation as effectively as any known alternative pathway activator. Thus, C3b bound to C4b was tenfold more stable than free C3b or C3b bound to a nonactivating surface. In comparison, the protection provided by attachment to human IgG was only 67% of that of C4b. The results provide an explanation for observations of alternative pathway recruitment following classical pathway activation and for the stability of the classical pathway C5 convertase on surfaces which do not provide protection for C3b from factors H and I.
Autoimmune T cell recognition of human acetylcholine receptor: the sites of T cell recognition in myasthenia gravis on the extracellular part of the α subunit
Authors: Oshima Minako , Ashizawa Tetsuo , Pollack Marilyn S. , Zouhair Atassi M.
Published: March 2007

Autoimune T cell lines were prepared from peripheral blood lymphocytes of five myasthenia gravis patients by passage in vitro with an equimolar mixture of 18 overlapping synthetic peptides corresponding to the entire extracellular region (residues α1‐210) of the α subunit of human acetylcholine receptor (AChR). The proliferative responses of the human AChR‐specific T cell lines to each of the individual peptides were determined. It was found that the profiles of the peptides recognized by the T cells were different among the five T cell lines, consistent with genetic control operating at the recognition site level. However, other regulatory influences may play important roles in the triggering of the autoimmune responses. These results suggest that the pathogenesis of this autoimmune disease is variable at the cellular‐molecular level.
Immunological heterogeneity of autoreactive T lymphocytes against the nicotinic acetylcholine receptor in myasthenic patients
Authors: Zhang Y. , Schluep M. , Frutiger S. , Hughes G. J. , Jeannet M. , Steck A. , Barkas T.
Published: March 2007

The response of human T lymphocytes against the nicotinic acetylcholine receptor (AChR) was studied in five patients with myasthenia gravis (MG) and in six healthy donors using either native Torpedo AChR or recombinant protein derived from the mammalian AChR α subunit (X4, residues 6–216 of mouse AChR α subunit). The present study demonstrates that (a) AChR‐specific T helper cell lines can be generated from MG patients [either from peripheral blood lymphocytes (PBL) or from thymocytes] as well as from PBL of normal controls, (b) lymphocytes from MG patients, but not from controls, recognize the mammalian AChR but not the Torpedo receptor, (c) in humans, the HLA‐DR2‐associated T cell epitope is probably located in the region of residues 162–216 of the AChR α subunit and (d) there is a considerable heterogeneity of autoreactive T cell responses: (i) Tcell lines from different HLA‐type donors have distinct epitope profiles; (ii) the epitope specificity of the PBL‐derived T cell line is different from that of the thymocyte‐derived line; (iii) the epitope specificities of patient‐derived T cell lines are different from those generated from normal controls who share the same HLA phenotype.
Selective induction of autocytotoxic activity through the CD3 molecule
Authors: Bensussan Armand , Leca Gérald , Corvaïa Nathalie , Boumsell Laurence
Published: March 2007

In the present study we show that when certain major histocompatibility complex‐alloreactive CD8+ T cell clones with natural killer‐like activity are stimulated through their CD3 molecules, in the absence of significant cross‐linkage (as provided by Fab' fragments of OKT3 antibodies) they lose their interleukin 2 response. This is attributable to an induction of a nonspecific autocytolytic activity. These results suggest that activation of this process in some cytotoxic cells leads to an overall decrease in CTL activity and constitutes a possible mechanism of suppression of the immune response.
Cyclosporin A inhibits the interleukin 2 receptor α chain gene transcription but not its cell surface expression: the α chain stability can explain this discrepancy
Authors: Hémar Agnès , Dautry‐Varsat Alice
Published: March 2007

The effect of the immunosuppressor cyclosporin A (CsA) on the expression of interleukin (IL) 2 receptors was investigated in a human T cell line IARC301 which constitutively expresses such receptors. This cell line also spontaneously secretes IL 2 which supports its autocrine growth. We have previously shown that CsA prevents the constitutive transcription of the IL 2 gene in these cells. Here we show that as soon as 4 h after CsA addition, the transcription of the gene encoding the α chain (p55) of IL 2R was inhibited. IL 2 can transiently increase the expression of this gene. CsA did not prevent this transient IL 2‐dependent induction of IL 2Rα, but could still partially inhibit it. Once IL 2 induction was over, CsA exerted its full inhibition. Thus, CsA does not seem to inhibit IL 2Rα gene transcription simply by inhibition of IL 2 synthesis. However, no modification of IL 2Rα expression on the cell surface could be detected after 48 h in the presence of CsA. This discrepancy between the effect of CsA on IL 2Rα expression as probed at the mRNA or the protein level can be accounted for by the stability of the IL 2Rα protein after synthesis. Indeed, the half‐life of IL 2Rα chain is longer than 40 h. This suggests that the α chain, after it is endocytosed together with the β chain as a component of high‐affinity IL 2R, might recycle back to the cell surface.
Complement alternative pathway activation and control on membranes of human lymphoid B cell lines
Authors: Caudwell Valérie , Porteu FrançOise , Calender Alain , Pangburn Michael K. , Halbwachs‐Mecarelli Lise
Published: March 2007

Membrane regulatory molecules normally prevent complement activation by autologous cells, therefore we compared the membrane control system of human lymphoid cell lines which activate or not human complement through the alternative pathway (AP). Membrane expression of decay‐accelerating factor (DAF), membrane cofactor protein (MCP), complement receptors (CR)1, CR2 and H was measured either by radioimmunoassay or enzyme‐linked immuno‐sorbent assay on cell lysates. Soluble extracts of isolated membranes were tested functionally for their ability to accelerate the decay of C3bBb C3‐convertase and allow the cleavage of C3b by factor I. Both regulatory functions were detected in solubilized membranes of Ramos cells, which do not activate the AP, as well as on the potent AP activator, Raji. Raji cells were found to express CR2, DAF and MCP molecules, while MCP was the only known regulatory protein detected on Ramos cells which expressed neither CR1, nor CR2, H or DAF. The I‐cofactor activity of both Raji and Ramos cells was immunoprecipitated by anti‐MCP, but the decay‐accelerating activity was not adsorbed by anti‐DAF nor by any of the available antibodies. Two EBV genome‐negative cell lines (BJAB, BL41) were tested before and after in vitro conversion by EBV. As previously shown, EBV‐converted cell lines activate the AP more efficiently than EBV− cell lines. At the same time, EBV superinfection induces an increase of both AP regulatory functions of cell membranes and enhances the expression of DAF, MCP and CR2. The results of this study show that complement activation by lymphoid cell lines is not related to an impaired autologous control of these cells, but that the expression of regulatory molecules increases together with the appearance of activating structures on the cell surface. Our results also suggest the occurrence of a new factor involved in the decay‐accelerating activity on BL lines.