bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of T cell receptors on resident murine dendritic epidermal T cells
Authors: Steiner Georg , Koning Frits , Elbe Adelheid , Tschachler Erwin , Yokoyama Wayne M. , Shevach Ethan M. , And Georg Stingl , Coligan John E.
Published: March 2007

Cell lines derived from Thy‐1 dendritic epidermal cells (Thy‐1DEC) display a marked heterogeneity in T cell receptor (TcR) expression including CD3‐associated α/β, Cγ2/δ or Cγ2/δ and Cγ4/δ TcR. In order to investigate whether this heterogeneity is primarily imposed by in vitro culture conditions or, alternatively, is already present within the epidermis, we studied TcR expression by Thy‐1 DEC in situ and on freshly isolated epidermal cell suspensions greatly enriched for Thy‐1DEC. Immunolabeling experiments showed that resident Thy‐lDEC are CD45, Thy‐l, CD3, TcR Vβ8−, CD5−, CD4− CD8−, CD25− lymphocytes. Immunoprecipitation of lysates from 1251‐surface‐labeled Thy‐1DEC‐enriched epidermal cells with anti‐CD3 ε, anti‐Cγ 1,2,3 and anti‐Cγ4 antibodies, respectively, and subsequent analysis of the precipitates by two‐dimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis revealed only CD3‐associated 35 kDa/45 kDa γ/δ heterodimers. The demonstration of TcR heterodimers on resident Thy‐1DEC strongly implies that these cells are functional T cells. The selective expression of Cγ1/δ (C57BL/6) and Cγ1/δ or Cγ2/δ (C3HkIe) TcR makes these cells useful for the study of γ/δ TcR function.
T cell response to myoglobin: a comparison of T cell clones in high‐responder and low‐responder mice
Authors: Gorai Itsuo , Aihara Michiko , Bixler Garvin S. , Zouhair Atassi M. , Walden Peter , Klein Jan
Published: March 2007

Mice carrying the H‐2b haplotype (e.g., inbred strains C57BL/6 and C57BL/10) are low responders to sperm whale myoglobin when tested in the T cell proliferation assay. Their response is improved by the removal of the Ly‐2 cells from the lymph node population, but it still remains significantly lower than that of cells from high‐responder strains (e.g., DBA/2, H‐2d). To determine whether T cells from the low and high‐responder mice recognize the same or different epitopes on the immunizing antigen, we obtained sets of T cell clones from both strains and tested them against peptides representing different regions of the myoglobin molecule, as well as against myoglobins from species other than the sperm whale. Four types of T cell clones were obtained from the DBA/2 mice: 3 types responded to the peptide 107–120 (9 clones altogether), and 1 type responded to the peptide 133–149 (4 clones altogether). The 3 types responding to the peptide 107–120 could be distinguished by their response to horse myoglobin or by the restriction of the response (Ad vs. Ed). Similarly, 5 types of T cell clones were obtained from the C57BL/6 mice: 2 types responded to the peptide 10–22 (1 type, but not the other, responded to horse myoglobin); 1 type responded to the peptide 133–149; and 2 types did not respond to any of the peptides used (1 type, but not the other, responded to dog myoglobin). All 5 types (13 clones altogether) were presumably Ab restricted. These results demonstrate the diversity of epitopes in single antigenic regions and show equivalent heterogeneity of T cell repertoires in high and low responder mice. Attempts to demonstrate specific T cell suppression in the low responder mice failed; only partial, nonspecific suppression was observed.
Cyclic AMP‐mediated alteration of the CD2 activation process in human T lymphocytes. Preferential inhibition of the phosphoinositide cycle‐related transduction pathway
Authors: Bismuth Georges , Theodorou Ioannis , Gouy Helene , Gouvello Sabine Le , And Main Bernard , Debré Patrice
Published: March 2007

Activation of human T lymphocytes via the CD2 molecule produces an enhanced turnover of phosphatidylinositol (PI) cycle‐related phospholipids accompanied by the increased production of diacylglycerol (DG) and phosphorylated derivatives of inositol (IP). In this report we demonstrate that increased levels of intracellular cyclic AMP induced in human T lymphocytes by prostaglandin E2 or dibutyryl cAMP antagonize these early biochemical events of the CD2 activation process. Thus, a substantial inhibition of the CDZinduced increase in 32P‐phosphatidic acid and 32P‐PI values is observed. In parallel, both the DG production and the IP release triggered by the CD2 signal are strongly reduced contrasting with an almost conserved Ca2+ response. We also report here that cAMP does inhibit the CDZinduced proliferation in a dose‐dependent manner while the proliferation generated independently of DG and 1P production by a combination of Ca2+ ionophore A23187 and 12–0‐tet‐radecanoylphorbol 13‐acetate is not affected. These results therefore suggest that (a) intracellular cAMP levels may participate in the regulation of the PI cycle‐related transduction pathway involved in the activation process of human T lymphocytes via the CD2 molecule; (b) the observed CAMP‐mediated functional inhibitory effects are mainly related to an alteration of this cellular transduction signal; and (c) considering the putative critical second messenger role in the T cell proliferative response of DG and IP, respectively thought to activate the protein kinase C and to raise the intracellular free Ca2+, the lowering of DG production may be the key event responsible for this CAMP‐mediated effect.
B cell‐stimulating activity of lymphoid cell membrane fractions*
Authors: Sekita Ken‐Ichi , Straub Cedric , Hoessli Daniel , Zubler Rudolf H.
Published: March 2007

We had previously found that a mutagenized subline of the mouse thymoma EL 4 very efficiently stimulates B cells via direct cell‐cell contact, thereby inducing the responsiveness of B cells to cytokines. In the present study, we investigated whether this effect could also be mediated by plasma membranes of EL 4 (and other) cells. By equilibrium centrifugation of cell homogenates, four cell membrane fractions of different densities were obtained. These were tested for (a) stimulation of B cell proliferation in conjunction with EL4 supernatant as source of cytokines, and (b) enhancement of B cell proliferation at suboptimal concentration of lipopolysaccharide. It turned out that all membrane fractions from a variety of T lineage cells (mutant EL4, parent EL4, BW5147, P198 thymomas, normal T cells) and B lineage cells (BCL1 lymphoma, X63Ag8 cytoplasma, normal B cells) exhibited similar B cell stimulating activity in both assays. Interleukin 1 activity was not detected in the membrane fractions. Heat treatment abolished all activity showing that protein at least was involved. Either protease treatment or extraction with detergent abolished the activity of subcellular fractions rich in intracellular membranes but not that of fractions most enriched in surface membranes. Finally, erythrocyte membranes also displayed B cell‐stimulating activity sensitive to protease and detergent extraction. In contrast, and in confirmation of a previous study, liver cell membrane was inhibitory in the B cell proliferation assay with lipopolysaccharide.

In conclusion, the effects of cell membranes did not reflect the unique activity of intact mutant EL 4 cells. However, with respect to our data it is conceivable that membrane proteins with relatively nonspecific activity and wide distribution among lymphoid cells could play a role in T cell help together with molecules specialized in cell adhesion and cell triggering.
Major histocompatibility complex class I molecules of nonhuman primates
Authors: Watkins David I. , Kannagi Mari , Stone Marc E. , Letvin Norman L.
Published: March 2007

The usefulness of nonhuman primates in immunologically relevant research has until now been limited by difficulties in characterizing the major histocompatibility (MHC) gene products of these species. We have now biochemically characterized the MHC‐encoded class I molecules from four different species of nonhuman primates using antibodies directed against human MHC class I structures and one‐dimensional isoelectric focusing (1‐D IEF). We demonstrated the functional relevancy of this technique of MHC typing by generating virus‐specific cytotoxic T cells and assaying their cytotoxic activity against a panel of virus‐transformed cells that expressed the same or differing class I structures. Only virus‐infected cell lines expressing MHC class I antigens identical to those of the cytotoxic T lymphocyte population were lysed. This simple method of MHC class I typing using 1‐D IEF will be useful in immunological research involving nonhuman primates and in nonhuman primate colony management.
Clonal analysis of human T lymphocytes infiltrating the liver in chronic active hepatitis B and primary biliary cirrhosis
Authors: Meuer Stefan C. , Moebius Ulrich , Manns Michael M. , Dienes Hans P. , Ramadori Guiliano , Hess Georg , Hercend Thierry , Buschenfelde Karl‐Hermann Meyer Zum
Published: March 2007

Human T lymphocytes infiltrating the liver in chronic active hepatitis B (CAH‐B) and primary biliary cirrhosis were isolated from liver biopsy cores, cloned by limiting dilution technique and expanded in vitro. Phenotypic and functional analysis demonstrates that this tissue infiltrate represents a heterogeneous cell population. However, when compared to peripheral blood lymphocytes of the same patients, a marked enrichment for T8 cytotoxic T cells was found to exist at a local site in both types of chronic liver disease. These data provide support for the notion that liver cell injury in CAH‐B and PBC may be mediated by a common immunologic mechanism likely executed by cells of the T lineage.
Analysis of human lymphocyte protein expression I. Identification of subpopulation markers by two‐dimensional polyacrylamide gel electrophoresis
Authors: Willlard‐Gallo Karen E. , Houck David W. , Loken Michael R.
Published: March 2007

This study provides new knowledge on the changes in protein expression that differentiate the functionally and phenotypically different cells of the human immune system. Purification by flow cytometry of normal lymphocytes (both T and B cells), monocytes and granulocytes, combined with high‐resolution two‐dimensional polyacrylamide gel electrophoresis, revealed reproducible qualitative and quantitative changes between these cell populations. Characteristic profiles of marker proteins for each cell type were identified. Determination of markers for T lymphocyte subpopulations was achieved by the comparative analysis of normal T cells separated on the basis of CD4 and CD8 expression in combination with the analysis of cells from patients with T cell chronic lymphocyte leukemia. These results suggest that the modulation or regulation of proteins is very strictly controlled in lymphoid differentiation, and that several quantitative and a few qualitative differences can give rise to completely different phenotypes. Thus, instead of detecting numerous random differences among lymphocyte protein patterns, rather stringent regulation of protein expression in each subpopulation was found.
GENETIC ANALYSIS OF EXTRATHYROIDAL FEATURES OF OBESE STRAIN (OS) CHICKENS WITH SPONTANEOUS AUTOIMMUNE THYROIDITIS
Authors: Kroemer Guido , Faessler Reinhard , Hála Karel , Boeck Guenther , Schauenstein Konrad , Brezinschek Hans‐Peter , Neu Nikolaus , Dietrich Hermann , And Rosanna Jakober , Wick Georg
Published: March 2007

The Obese strain (OS) of chickens, which is afflicted with Hashimoto‐like spontaneous autoimmune thyroiditis (SAT), displays elevated T cell proliferation, interleukin (IL) 2 production and IL2 receptor expression upon mitogen stimulation, and defects in the neuroendocrine control of the immune system including elevated corticos‐teroid‐binding globulin (CBG) and a deficient increase of serum corticosterone (CN) upon cytokine injection. Recently this strain has further been shown to harbor retrovirus‐related sequences (endogenous virus no. 22, ev22) absent in healthy control strains. To determine the number of genes responsible for SAT‐associated immunodysregulation and to unravel possible ev22 associations, we analyzed the above immune and endocrine parameters in F1 hbrids and backcrosses of the autoimmune OS B15B15 with healthy inbred CB B12B12 chickens.

OS‐like T cell hyperproliferation and IL2 hypersecretion in response to both con‐canavalin A and phytohemagglutinin were transmitted as autosomal dominant traits and co‐segregated in backcross animals. In vivo hyporesponse of the OS to the cor‐ticosterone‐inducing effect of cytokine preparations was inherited dominantly and the elevated CBG serum levels recessively. None of these traits appeared to be major histocompatibility complex (MHC) linked. However, while T cell abnormalities and elevated CBG serum levels were not associated with the autosomal ev22 locus, in vivo hyporesponsiveness to glucocortocoid‐inducing cytokines co‐segregated with this OS‐specific provirus.

These results add to the concept of SAT as a polyetiological and plurigenetic disease and do not support our previous hypothesis that T cell hyperreactivity and immunoen‐docrine dysfunction might be functionally related.
COMPARISON OF THE STRUCTURE OF THE MURINE INTERLEUKIN 2 (IL 2) RECEPTOR ON CYTOTOXIC AND HELPER T CELL LINES BY CHEMICAL CROSS‐LINKING OF 125I‐LABELED IL 2
Authors: Well Brian Fox , Taylor David , Ryffel Bernhard
Published: March 2007

The structure of the murine interleukin 2 receptor (IL2R), on a cytotoxic (CTLL) and a helper (HT2) cell line, has been studied by a combination of chemical cross‐linking with 125I‐labeled IL2 and immunoprecipitation with an anti‐receptor monoclonal antibody (7D4). In CTLL cells both methods detected the major 57‐kDa IL2‐binding protein and in addition the cross‐linking studies revealed the presence of a 70–75‐kDa protein associated with the high‐affinity receptor. In the HT2 cell line, however, immunoprecipitation studies revealed three additional proteins of 18, 22 and 37 kDa to the expected 50‐kDa receptor protein. Again cross‐linking studies demonstrated the presence of a 70–75‐kDa protein, which was not immunoprecipitable with the 7D4 antibody. The low molecular polypeptides in HT2 cell were associated with the low‐affinity receptor and represented most likely breakdown products of the 50‐kDa protein. Whereas the 18‐ and 22‐kDa proteins were involved in ligand binding, the 37‐kDa fragment carried the epitope recognized by the 7D4 antibody. Comparative studies with two IL2R antibodies, PC61 and 7D4, revealed that only PC61 inhibited the formation of the IL2 α/β chain complex, although both antibodies reportedly prevent the biological response to IL2. It is speculated that the 37‐kDa fragment, which reacts with the 7D4 antibody, might be involved in IL2 signal transduction. Finally there was no evidence for the existence of a high molecular weight component of the IL2R, previously described as γ chain.

In summary, the two‐chain structure of the IL2R has been confirmed for both murine cell lines with some heterogeneity of the α chain. The possibility was raised that a 37‐kDa fragment of the α chain plays a role of in signal transduction.
Application of recombinant granulocyte‐macrophage colony‐stimulating factor has a detrimental effect in experimental murine leishmaniasis
Authors: Greil Johann , Bodendorfer Barbara , And Martin RÖLlinghoff , Solbach Werner
Published: March 2007

The purpose of this study was to evaluate the effect of recombinant granulocyte‐macrophage colony‐stimulating factor (rGM‐CSF) on BALB/c mice infected s.c. with the intracellular pathogen Leishmania major. Daily i.p. application of 1 μ rGM‐CSF for 21 days following the infection led to an aggravated course of the disease in most animals. In no case was a therapeutic effect observed. In vitro analysis revealed that the parasite burden was approx. 2‐ to 7‐fold higher in the infected lesions, in the lymph nodes draining the infection and in the spleens of rGM‐CSF‐treated animals than in tissues from nontreated mice. L. major‐infected macrophages obtained from chronically infected mice proliferated in the presence of rGM‐CSF in vitro without gaining antiparasitic effector function. However, antiparasitic effector function increased and macrophage growth was inhibited in the presence of recombinant interferon‐γ (IFN‐γ). These data indicate that rGM‐CSF‐induced macrophage proliferation alone is not sufficient to overcome infections with intracellular pathogens like L. major, since simultaneous activation of macrophages by IFN‐γ is required.
Functional discrimination between interleukin 6 and interleukin 1
Authors: Helle Maarten , And Leonie Boeije , Aarden Lucien A.
Published: March 2007

In this study we have investigated the specificity of bioassays in which interleukin (IL)1 and/or IL6 are active. The thymocyte assay cannot be used to discriminate between IL1 and IL6; both monokines are active in this assay. Moreover the detection limit for both IL1 and IL6 is around 100 pg/ml. IL6 activity can be measured with a murine hybridoma cell line (B9). The detection limit for human as well as murine IL6 is about 0.5 pg/ml. The assay is specific for IL 6 and is not influenced by a variety of other cytokines except for murine IL4 which shows some activity in this assay. IL1 can be measured specifically with D10 cells. The detection limit for IL1α and IL1β is around 1 pg/ml whereas IL6 is not active in this assay at all. Upon stimulation by IL1 and/or IL2 D10 cells produce IL6. However, this IL6 does not seem to be involved in the proliferation of these cells.
Heterogeneity in the molecular defect leading to the leukocyte adhesion deficiency
Authors: Dimanche‐Boitrel Marie‐Thérèse , Guyot Anne , De Saint‐Basile Geneviéve , Fischer Main , And Claude Griscelli , Lisowska‐Grospierre Barbara
Published: March 2007

Leukocyte adhesion deficiency (LAD) is a recessive autosomal disease characterized by life‐threatening recurrent bacterial infections, by defective functions of leukocytes and by deficient membrane expression of leukocyte adhesion glycoproteins. These proteins, LFA‐1, Mac‐1 and p150,95, are α/β1 heterodimers composed of different a chains and of a common β chain. Patients with the severe phenotype of the disease completely lack the three glycoproteins on cell surface. Previous studies showed a conserved synthesis of the LFA‐1 α chain precursor in cytosol of patients' cells and an inconstant presence of the β chain precursor. When present, precursors are in free form and not associated to α/β complexes in the cells of patients with the severe phenotype. The availability of the β chain cDNA probe allowed us to examine the β chain gene expression in the lymphoblastoid cell lines of 4 patients. On the basis of the results obtained both at protein and RNA levels we can distinguish 3 types of mutations characterized by (a) barely detectable β subunit messenger RNA and un‐detectable β precursor, (b) decreased level of β subunit mRNA and undetectable β precursor and (c) normal β subunit mRNA level and detectable p precursor of normal size.
Dilsulfide‐linked receptors for mitogenic lectins on piglet lymphocytes
Authors: Chilson Oscar P. , Kelly‐Chilson Anne E.
Published: March 2007

The interaction between leucoagglutinating phytohemagglutinin (L‐PHA), con‐canavalin A (Con A), soybean agglutinin (SBA) and lentil lectin (LcH) with disulfide‐linked cell surface receptors & lymphocytes from mesenteric lymph nodes of 3‐day piglets (PMLN) was investigated. Surface radioiodinated PMLN lymphocytes were lysed with buffer containing Nonidet‐P40. The lysates were adsorbed on lectin‐agarose derivatives (or bovine serum albumin‐agarose). Eluates from the lectin‐agar‐ose derivatives were analyzed by one‐dimensional or two‐dimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis both under reducing and non‐reducing conditions. Among the various lectin‐binding polypeptides, L‐PHA recognizes a single 92‐kDa disulfide‐linked moiety in piglet lymphocyte lysate, comprised of polydisperse 52‐kDa subunits. In addition to this apparent homodimer, SBA, Con A and LcH bind a much less prominent 82‐kDa heterodimer comprised of 47‐kDa and 37‐kDa polypeptides; these molecules are not observed in eluates of L‐PHA. Binding of the 92‐ and 82‐kDa molecules by LcH is inhibited by methyl‐a‐D‐man‐noside. These results indicate that there are two lectin‐binding disulfide‐linked glycoproteins on lymphocytes from 3‐day piglets which bind preferentially to potent mitogens. The electrophoretic properties of these molecules, under both reducing and nonreducing conditions, as well as their lectin‐binding properties are very similar to those observed for antigen receptor molecules on lymphocytes from other species.
Role of CD2 cross‐linking in cytoplasmic calcium responses and T cell activation
Authors: Ledbetter Jeffrey A. , Rabinovitch Peter S. , Hellström Ingegerd , Hellström Karl Erik , Grosmaire Laura S. , June Carl H.
Published: March 2007

The relationship between the increase of intracellular free Ca2+ concentration ([Ca2+],) in resting T cells after stimulation with monoclonal antibody (mAb) to CD2 (E rosette receptor) and the subsequent proliferation response was investigated. Although the Combination of 9.6 plus 9‐1 mAb to CD2 was both mitogenic and induced an increase in [Ca2+]i, cross‐linking of an individual CD2 mAb on the cell surface induced an increase in [Ca2+]i without directly stimulating T cell proliferation. The [Ca2+]i response from cross‐linking an individual mAb was not epitope dependent,since 21 of 21 mAb to CD2 were effective when cross‐linked with a polyclonal goat anti‐mouse Ig second step. The kinetics of calcium mobilization was highly dependent upon the procedure for cross‐linking, since the binding of biotinconjugated 9.6 mAb followed by avidin gave a large and rapid response, whereas cross‐linking of 9.6 with an anti‐x mAb, 187.1, caused a minimal response, and the cross‐linking of 9.6 followed by a polyclonal goat anti‐mouse Ig gave an intermediate response. In addition, ligation of CD2 by rosetting with sheep red blood cells alone was sufficient to cause increased [Ca2+]i. In functional studies only the procedures associated with minimal CD2 cross‐linking induced proliferation of resting T cells in combination with interleukin (IL) 2. The proliferation also required IL1 or accessory cells. Cross‐linking 9.6 on the cell surface also enhanced proliferation in the presence of phorbol myristate acetate or a CD28 mAb, 9.3, under conditions that were accessory cell independent. In contrast to the proliferation following stimulation with 9.6 plus 9−1, the combination of 9.6 plus 9‐1 F(ab′)2 fragments lost mitogenic activity. The 9.6 plus 9‐1 F(ab′)2 combination was similar to 9.6 cross‐linking in that either could induce responsiveness to recombinant IL2 or CD28 mAb 9.3. The combination of 9.6 plus 9‐1 F(ab′)2 fragments was still able to increase [Ca2+]i in T cells with slow kinetics. Together these results suggest that the binding of mAb to CD2 under conditions that cause a slow rather than a rapid increase in [Ca2+]i is associated with T cell activation. Furthermore, they suggest that in studies of T cell activation, sheep eryth‐rocyte rosette formation should not be used to isolate T cells since rosetting may effect [ca2+]i.
Transforming growth factor‐β2 down‐regulates HLA‐DR antigen expression on human malignant glioma cells.
Authors: Zuber Patrick , Kuppner Maria C. , Tribolet Nicolas De
Published: March 2007

Transforming growth factor‐β (TGF‐β) is known to have a potent inhibitory influence on several immune functions. It has recently been demonstrated that TGF‐β2 is identical to the glioblastoma‐derived T cell suppressor factor (G‐TsF). In the present study, human malignant glioma cell lines were incubated with various concentrations of TGF‐β2. An optimal concentration of 1 ng/ml TGF‐β2 produced a partial but significant decrease of HLA‐DR (class II) surface antigen expression on glioma cells expressing this antigen, as well as decreased levels of HLA‐DR‐specific mRNA. The surface expression of other HLA‐related molecules, such as HLA‐ABC (class I) and β2‐microglobulin, was not influenced by TGF‐β2. The suppressive effect of TGF‐β2 on HLA‐DR expression, both at the surface antigenic and cytoplasmic mRNA levels, could be completely overcome by adding relatively high concentrations (500 U/ml) of interferon (1FN)‐γ to the culture system. However, TGF‐β2 inhibited the enhancement of HLA‐DR surface expression produced by low concentrations of IFN‐γ on some cells which initially did not express these antigens. These results show that TGF‐β2 can act as a regulator of HLA‐DR antigen expression on human glioma cells.
Lymphokine mRNA and T cell multireceptor mRNA of the Ig super gene family are reciprocally modulated during human T cell activation
Authors: Paillard Florence , Sterkers Ghislaine , Bismuth Georges , Gomard Elisabeth , Vaquero Catherine
Published: March 2007

The expression of genes, implicated in T cell proliferation as well as those coding for the three chains of the T cell receptor (TcR) and for the CD4 and CD8 molecules, has been investigated during activation of various T cell populations maintained in long‐term culture. We show that a minimal activation signal, capable of inducing inter‐leukin 2 (IL2) receptor expression without the expression of IL2 and interferon‐γ, was not associated with a down‐regulation of the messengers coding for the T cell multireceptor molecules. In contrast, a strong activation signal via the TcWCD3 complex or via the CD2 molecule resulted in a reciprocal transient up‐regulation of the messengers implicated in T cell proliferation and a down‐regulation of the messengers encoding the molecules of the TcR complex of the immunoglobulin super gene family.
Expression of CD23 antigen is not necessary for human 12‐kDa B cell growth factor‐mediated B cell proliferation*
Authors: Vazquez Aime , Mills Syivia , And Surenda Sharma , Maizel Abby L.
Published: March 2007

In an attempt to understand the relationship between the CD23 antigen and the human 12‐kDa B cell growth factor (BCGF) receptor, we have undertaken studies to define the biological efficacy of 12‐kDa‐BCGF on CD23+ (Raji) and CD23− (P3HR1) human Burkitt B cell lines. Our results show that recombinant 12‐kDa‐BCGF can induce efficient [3H]thymidine incorporation and proliferation in cells of either phenotype. These results strongly suggest that a functional receptor for the 12‐kDa‐BCGF may exist independently of the CD23 molecule.
Unusual expression of CD2 in sheep: implications for T cell interactions
Authors: Mackay Charles R. , Hein Wayne R. , Brown Marion H. , Matzinger Polly
Published: March 2007

The CD2 adhesion/activation molecule on the surface of mammalian T lymphocytes binds to a ubiquitous receptor, LFA‐3. We show that CD2 in sheep differs significantly in its expression from CD2 in humans, and this most likely relates to the high level of expression of the sheep LFA‐3 molecule. In sheep, in contrast to man, CD2 was weakly expressed on peripheral T cells and thymocytes. Moreover, a large subset of T cells identified by the monoclonal antibody T19 and considered to be γ δ receptor‐bearing T cells completely lacked the CD2 molecule. T19+ cells constituted up to 50% of peripheral blood T cells in lambs, and 20–30% of T cells in older sheep, whereas the CD4+ and CD8+ subsets, which are both CD2+, constituted relatively small subsets in peripheral blood. Only those T cells which did express CD2 adhered as “rosettes” to dendritic cells, and the localization of CD2 to the membrane junction indicated that CD2 was critical for this adhesion. However, CD2 adhesion was not necessary for CTL‐mediated killing of allogeneic target cells, since T19+ cells generated in bulk mixed lymphocyte culture were extremely efficient at killing appropriate target cells. Some of the behavioral differences between T19+ and CD4+/CD8+ subsets might be explained by the presence or absence of CD2. The results also indicate that the expression of CD2 (and LFA‐3) may differ markedly between species.
Effect of recombinant human interleukin 4 on spontaneous in vitro human IgE synthesis*
Authors: Yang Xiao‐Dong , De Weck Alain L. , Stadler Beda M.
Published: March 2007

Recombinant human interleukin 4 (IL4) alone enhanced the spontaneous IgE synthesis in cultures of peripheral blood leukocytes (PBL) from atopic patients as well as from nonatopic individuals, suggesting the existence of preactivated PBL sensitive for IL4. Preactivated cells were also obtained by stimulation with Staphyloccus aureus strain Cowan I (SAC). However, co‐stimulation of PBL by IL4 with SAC or anti‐IgM antibody and pokeweed mitogen did not result in an enhanced IgE synthesis. Optimal IL4 concentrations for the induction of IgE synthesis coincided with optimal proliferative responses in PBL. The effect of IL4 was not isotype specific, and in terms of protein even more IgG and IgM antibodies were formed. The effect of IL4 on IgE synthesis was counteracted by very low concentrations of interferon‐γ (IFN‐γ), suggesting that both IL 4 and IFN‐γ might be decisive cytokines for the human in vitro IgE synthesis.
Activation of the phosphatidylinositol metabolic pathway by low molecular weight B cell growth factor
Authors: Renard Dominique , Petit‐Koskas Elisabeth , Gé Elisabeth , Dugas Bernard , Poggioli Josiane , Kolb Jean‐Perre
Published: March 2007

The possible role of phosphatidylinositol breakdown in the induction of proliferation of human activated B cells by low molecular weight B cell growth factor (LMW‐BCGF) was examined. LMW‐BCGF was found to induce a rapid rise in the concentration of inositol trisphosphate (InsP3) in [3H]inositol‐loaded B cell blasts, obtained by prior anti‐μ antibody activation. A concomitant decrease in the concentration of phosphatidylinositol 4,5‐bisphosphate could be detected at the same time. Maximum generation of InsP, occurred within 15–30 s after the addition of the LMW‐BCGF ligand to the activated B cells, then was followed by a slow decrease and return to control values. The amount of InsP3 generated by phosphatidylinositol hydrolysis was dependent on the concentration of LMW‐BCGF. This effect was only detected in B cells already preactivated by a first signal such as anti‐μ antibody and not in resting unstimulated B cells. In contrast, under similar conditions, interleukin 2, another B cell growth‐promoting lymphokine, did not alter the rate of formation of the various phosphatidylinositol breakdown products. An augmentation of the [Ca2+], concentration was also detected in activated B cells upon addition of LMW‐BCGF and this increase could be blocked by TMB‐8, a specific inhibitor of endoplasmic reticulum calcium release. Hydrolysis of phosphoinositides thus represents an essential component in the mechanism of transduction of the signal provided by LMW‐BCGF.
Xid mice fail to express an anti‐dextran immune response but carry α(1‐3)dextran‐specific lymphocytes in their potential repertoire
Authors: Selinka Hans‐Christoph , Bösing‐Schneider Rita
Published: March 2007

Even after repeated immunizations with α(1‐3)dextran (Dex) male (CBA/N × BALB/ c)F1 mice fail to produce specific antibodies whereas nondefective female littermates express an idiotype‐positive anti‐Dex immune response. This failure of xid mice to express serum anti‐Dex immunoglobulins is not only limited to immunization with the thymus‐independent (TI‐2) antigen Dex, since immunization with anti‐idiotypic antibodies against Dex‐specific idiotypes does not overcome this defect. When xid lymphocytes are cultured in the presence of mitogens, in vitro anti‐Dex responses are markedly reduced. We show here that α(1‐3)Dex‐specific hybridomas can be established by fusion of splenic lymphocytes from xid mice to Spy2/0 myeloma cells. Therefore, these mice do carry the potential to generate B cells specific for Dex. All hybridoma antibodies were found to be of IgM isotype, bearing the λ light chain typical for δ(1‐3)Dex‐specific antibodies. Whereas monoclonal anti‐Dex antibodies obtained from spleen cell hybridomas from female littermates showed variable idiotope patterns, hybridoma proteins from the immune‐defective NBF1‐xid mouse expressed only a limited pattern of Dex‐specific idiotopes, suggesting that these hybridomas derived from a common precursor.
Cloned T helper cells reverting to a resting state develop increasing sensitivity in their antigen‐mediated interaction with accessory cells
Authors: Huhn Helga , Reske‐Kunz Angelika B. , Rüde Erwin
Published: March 2007

A cloned murine T cell line, KIII5, specific for the polypeptide poly‐L(Tyr,Glu)‐poly‐D,L‐Ala–poly‐L‐Lys [(T,G)‐A–L] was compared at different stages after antigenic stimulation with respect to the conditions required for the reinduction of growth by varying concentrations of antigen presented on different types of accessory cells (AC). We show that the dose of antigen necessary for inducing half maximal proliferation in the presence of splenic AC shifts to considerably lower concentrations when the T cell blasts revert to a resting state (100 μg/ml on day 7 to 10 μg/ml on day 21–35). During the same time period the expression of interleukin 2 (IL2) receptor and the reactivity to IL2 decline. However, no direct correlation between the increasing sensitivity to antigen and the decreasing reactivity to IL2 appears to exist. With peritoneal AC “early” T cells (day 7) did not respond to (T,G)‐A–L at all, but in the course of “aging” responsiveness increased and finally reached the same level as in the presence of splenic AC, although at a higher antigen dose (100 μg/ml on day 35–45). Furthermore, the antigen‐induced proliferation of “aging" T cells became more resistant to inhibition both by anti‐L3T4 and anti‐T cell receptor antibodies. Two alternative interpretations of these data are possible: antigen‐activated T cells, while gradually reverting to a resting state, interact more avidly with antigen‐presenting cells or the triggering threshold of the T cells is decreasing.
Autoreactive T cells in mercury‐induced autoimmunity. Demonstration by limiting dilution analysis
Authors: Rossert JéǑMe , Pelletier Lucette , And RéGine Pasquier , Druet Philippe
Published: March 2007

Mercuric chloride is responsible in Brown‐Norway rats for an autoimmune disease that is autoregulated. Previous studies have shown that this agent induces T cell‐dependent polyclonal B cell activation in these rats. Evidence has also been obtained for the existence of autoreactive T cells which play a role in the evolution of this process. In the present study, limiting dilution analysis was used to demonstrate that (a) frequent autoreactive T helper cells which proliferate in the presence of T cells from HgCI2‐injected rats are present from day 4; (b) frequent auto‐anti‐Ia T helper cells which recognize normal B cells as well as B cells from HgCIinjected rats appear from day 6; and (c) less frequent T suppressor cells which could play a role in auto‐regulation emerge from day 14.
Cross‐linking of membrane IgM on B CLL cells: dissociation between intracellular free Ca2+ mobilization and cell proliferation
Authors: Hivroz Claire , Grillot‐Courvalin Catherine , Labaume Sylvaine , And Roger Miglierina , Brouet Jean‐Claude
Published: March 2007

It has been shown previously that chronic lymphocytic leukemia (CLL) B cells are frozen at different stages of activation with unique requirements for proliferation. Although most B CLL cells express surface IgM, anti‐γ antibodies are able to trigger only some of them to proliferate and/or respond to B cell growth factor (BCGF) or interleukin 2 (IL2), as normal B cells

In this report we extend these observations using three different monoclonal antibodies (mAb) to human y chain (one mitogenic in soluble form for normal B cells, the two others mitogenic only when coupled on Sepharose 4B beads). Cells from only 3 out of 11 B CLL patients proliferated in the presence of either mitogenic anti‐μ. When the early events following surface Ig cross‐linking, such as calcium mobilization (by flow cytometry on indo‐1‐labeled cells), were studied all three mAb in soluble form were able to induce a similar increase in the intracellular free calcium concentration ([Ca2+Ii); analogous to [Ca2+], rise after the mitogenic F(ab′)2 anti‐μ stimulation. This response was seen only in 8 out of the 12 CLL B cells studied. All B CLL cells, however, proliferate in response to a combination of phorbol ester 12,13‐dibutyrate (PBt2) and ionomycin. Therefore, three patterns of response to sIg cross‐linking by anti‐μ could be distinguished: cells from 4 out of 12 cases proliferate and mobilize Ca2+ upon anti‐y triggering (behaving like resting B lymphocytes); in 4 other cases anti‐μ lead to Ca2+ mobilization without cell proliferation; in the last 4 cases neither Ca2+ mobilization, IP3 generation (in the one case studied) nor cell proliferation are observed although these cells do proliferate directly in response to growth factors. Moreover, anti‐μ stimulation in this group leads to increased proliferation in response to BCGF and IL2 suggesting an anti‐Ig signaling independent of inositol phosphate metabolism. These results are interpreted in terms of differential anti‐μ signaling on B cells at different stages of activation.
Ly‐6C is a monocyte/macrophage and endothelial cell differentiation antigen regulated by interferon‐gamma
Authors: Jutila Mark A. , Kroese G. M. , Jutila Kathy L. , Stall Alan M. , Fiering Steve , Herzenberg Leonore A. , And Ellen Lakey Berg , Butcher Eugene C.
Published: March 2007

Using a new Ly‐6C‐specific antibody (Monts‐1) we show that this class of antigens are differentially expressed on monocytes/macrophages and endothelial cells. Recently elicited peritoneal exudate Mac‐1+ mononuclear cells, as well as Mac‐1+ mononuclear cells in the bone marrow and in the peripheral blood, express high levels of Ly‐6C. Ly‐6C+ mononuclear Mac‐1+ cells are absent in normal uninflamed skin, but are present in high numbers in skin lesions 3 days after the s.c. injection of lipopolysaccharide, concanavalin A or complete Freunďs adjuvant. In addition, large Ly‐6C+ mononuclear cells are predominant in chronic granulomas induced by complete Freunďs adjuvant. Resident macrophages in a variety of tissues express low levels or in many cases do not express Ly‐6C. Two out of three monocyte‐like cell lines are Ly‐6C+, whereas macrophage‐like cell lines are negative. Ly‐6C+ monocytes/macrophages lose the Ly‐6C antigen within 24 h after in vitro culture. Ly‐6C‐ cultured monocytes and Ly‐6C‐ monocyte‐like cell lines, but not fully differentiated macrophages and macrophage‐like cell lines, can be induced to express the Ly‐6C antigen by interferon‐γ. A population of small vessel endothelial cells in diverse tissues also express high levels of Ly‐6C. The present findings suggest that the Ly‐6C antigen family, shown by others to be involved in T cell activation, may have more general importance in immune responses and cellular differentiation than previously appreciated.
Demonstration of two distinct forms of released low‐affinity type interleukin 2 receptors
Authors: Josimovic‐Alasevic Olivera , Herrmann Thomas , Diamantstein Tibor
Published: March 2007

The release of interleukin 2 (IL2)‐binding proteins, derived from the 55‐kDa low‐affinity IL2 receptor (IL2R; L chain), has been observed for virtually all L chain‐bearing cells in either humans, the mouse or the rat. Based on the characterization of the released human L chain as a molecule 10 kDa smaller than the cell surface receptor, either proteolytic cleavage or differential splicing of the L chain‐encoding mRNA have been suggested as mechanisms underlying the receptor release. Combining affinity labeling of the L chain with l25I‐labeled IL 2 and immunoprecipitation with L chain‐specific monoclonal antibodies applied for the detection of soluble mouse IL 2R revealed the existence of two classes of soluble receptors, one being of the same size as cell surface expressed L chain, the other of 45‐kDa apparnent molecular mass. These findings raise the possibility of mechanisms of receptor release other than those discussed for human L chain.
CD4+CD8+ thymocytes develop into CD4 or CD8 single‐positive cells in athymic nude mice*
Authors: Tamauchi Hidekazu , Tamaoki Norikazu , Habu Sonoko
Published: March 2007

A differentiation pathway from CD4+CD8+ cells to CD4+CD8− or CD4−CD8+ cells was investigated in athymic nude mice. Using fluorescence‐activated cell sorter, CD4+CD8+ cells were sorted out from AKR thymocytes (H‐2k, Thy‐1.1) stained with two monoclonal antibodies against CD4 and CD8 (anti‐L3T4 and anti‐Ly‐2). These CD4+CD8+ AKR thymocytes were injected i.v. into CBA or C3H nude mice (H‐2k, Thy‐1.2) which had received 650 rads and had been reconstituted with syngeneic nude bone marrow cells. The lymph node cells of the nude recipients at 4 wks post‐thymocyte transfer were shown to contain 50% AKR‐derived Thy‐1.1+ cells. The majority of the Thy‐1.1+ cells were found to express either CD4 or CD8 alone but not to express both CD4 and CD8. These findings indicate that CD4+CD8+ thymocytes can develop into CD4+CD8− and CD4−CD8+ single‐positive cells in extrathymic tissues.
Activation of rat complement by soluble and insoluble rat IgA immune complexes
Authors: Rits Michel , Hiemstra Pieter S. , Bazin Hervé , Van Es Leendert A. , Vaerman Jean‐Pierre , Daha Mohamed R.
Published: March 2007

The ability of rat monoclonal IgA, specific for 2,4‐dinitrophenyl (DNP), to activate the complement (C) system of the rat was investigated using aggregated IgA or IgA immune complexes (IC). IgA was coated onto a solid phase, and tested for its capacity to bind C3 upon incubation at 37°C in normal rat serum (NRS) in the presence of Mg‐EGTA. Binding of C3 was observed dependent on the dose of dimeric (d‐), polymeric (p‐) and secretory IgA tested. In contrast, little C3 fixation was observed in this system with monomeric (m‐) rat IgA or with mouse m‐ and d‐IgA (MOPC315). Soluble and insoluble rat IgA IC were prepared using dinitrophenylated rat serum albumin (DNP8RSA) as antigen (Ag), and assessed for C activation. It was shown that insoluble IC (immune precipitates; IP) containing m‐, d‐ or pIgA of rat origin activate the alternative pathway of rat C, as demonstrated by their capacity to induce C consumption in NRS in the presence of Mg‐EGTA. When p‐ and m‐IgA IP were compared for their capacity to activate C, it was found that p‐IgA activated C four times as efficiently as m‐IgA IP (at 2 mg/ml).

Soluble rat IgA IC were prepared in an excess of DNP8RSA, fractionated by gel filtration on Sepharose 6B, and analyzed for C activation and antibody (Ab)/Ag ratio. In contrast to m‐IgA IP, soluble m‐IgA did not activate C. On the other hand soluble d‐IgA IC activated C dependent on their concentration and size: at a concentration of 0.1 mg/ml high‐molecular weight d‐IgA IC with a high Ab/Ag ratio were four times as efficient as low‐molecular weight IC with a low Ab/Ag ratio, and twice as efficient as IP prepared at equivalence. To demonstrate the induction by IgA of the assembly of the terminal membrane attack complex, trinitrophenyl (TNP)‐conjugugated rat red blood cells (TNP‐RRBC) coated with d‐ or p‐IgA were shown to be lysed in NRS in the presence of Mg‐EGTA. No lysis of m‐IgA‐coated TNP‐RRBC was observed. The results in this study demonstrate that both soluble and insoluble rat IgA IC activate the alternative pathway of homologous rat C. Alternative pathway activation by soluble rate IgA IC is dependent on the size of the IC. The degree of polymerization of the IgA Ab itself also influences C activation.
Back‐stimulation of B lymphocytes binding to helper T cell surface antigens
Authors: Martinez‐A. Carlos , Bandeira Antonio , Toribio Maria Luisa , Coutinho António , Marcos Miguel Angel , Pereira Pablo
Published: March 2007

Helper T cells directed to B cell surface determinants activate their “targets” into polyclonal antibody production in vitro and in vivo, but B cells which bind to epitopes on the helper cell surface are preferentially induced. Furthermore, “anti‐helper” B cell activation also occurs by “back‐stimulation”, that is even when the responding B lymphocytes are not specific targets for the inducing helper cells, as long as these are simultaneously activated by appropriate interactions with presenting cells. In our experimental systems, this is the only condition where “bystander” activation can be recorded. These findings suggest mechanisms of auto‐antibody production associated with unrelated helper cell activity in vivo.
HIV‐specific T lymphocyte immunity in mice immunized with a recombinant vaccinia virus
Authors: Michel Frédérique , Hoffenbach Angès , Lanlade‐Demoyen Pierre , Guy Bruno , Girard Marc , Lecocq Jean‐Pierre , Wain‐Hobson Simon , Kieny Marie‐Paule , Plata Fernando
Published: March 2007

Infection by the human immunodeficiency virus (HIV) induces T cell immunity in humans, chimpanzees and macaques. The protective value of this immune response is not clear. We have consequently developed a murine experimental system to study HIV‐specific CD4 and CD8 T lymphocyte immunity in vitro and in vivo. BALB/c, DBA/2 and C3H/He mice were immunized with vaccinia virus (VV) recombinant VV‐11.39 which expresses the gp160 glycoprotein of HIV‐1. Primary and secondary cytotoxic T lymphocyte response to HIV were detected with histocompatible mouse target cells transfected with the HIV‐1 env gene. Killer cells were positive for the Thy‐1 and Ly‐2 (CD8) T cell markers, and were restricted by class IH‐2 histocompatibility antigens. Immunological memory specific for HIV‐1 envelope antigens was clearly induced by vaccination with W‐11.39: spleen cells from mice vaccinated 4 weeks or more prior to assay generated CD4 and CD8 T lymphocyte responses following stimulation in vitro with HIV envelope antigens. The intensity of these responses increased with consecutive vaccinations, indicating that HIV‐specific precursor T cell pools were progressively amplified. Finally, DBA/2 mice vaccinated with VV‐11.39 developed protective immunity against a syngeneic tumor which expresses HIV‐1 env antigens, leading to accelerated tumor rejection and increased survival.
Multiple T helper cell epitopes of the circumsporozoite protein of Plasmodium berghei
Authors: Romero Pedro J. , Tam James P. , Schlesingera David , Clavijo Pedro , Gibson Helen , Barr Philip J. , Nussenzweig Ruth S. , Nussenzweig Victor , Zavala Fidel
Published: March 2007

The present findings establish the lack of genetic restriction of the humoral immune response to sporozoites of Plasmodium berghei, corraborating earlier observations that mice of different strains can be protected by immunization with irradiated sporozoites. Most, if not all, anti‐sporozoite antibodies are directed against the repetitive B cell epitope of the circumsporozoite (CS) protein. However, neither a peptide containing a dimer of this repeat (17.1), nor a peptide polymer containing multiple repeats induced an antibody response in mice of different H‐2 and different genetic backgrounds.

A yeast‐derived recombinant, containing the repeat domain and part of the surrounding amino and carboxy‐terminal regions of the P. berghei CS protein, induces very different levels of antibody in mice of diverse H‐2 haplotypes. H‐2j mice are high responders and the immunized mice are extensively protected against sporozoite challenge. The lymph node cells of the H‐2j mice (but not from other strains) proliferated in the presence of peptide N, contained in the amino terminal region of the CS recombinant. Additional H‐%‐restricted T cell epitopes have been identified in amino and carboxy‐terminal regions of the CS protein, and mice of most of the strains recognized multiple T cell epitopes.

Two peptides representing T cell epitopes were synthesized in tandem with a peptide representing the B cell epitope, and were assayed for T helper activity in vivo. The antibody response of mice, primed by a single injection of sporozoites, was boosted very effectively by the administration of peptide N+17.1 or peptide B‐4 +17.1. The B‐4 T cell epitope is located in the carboxy‐terminal region of the CS protein and is recognized by mice of at least four different H‐2 haplotypes.

These observations demonstrate that the immune response to the CS protein of P. berghei is not genetically restricted and that it contains several T cell epitopes, some of which can function as helper epitopes. In addition, they show that a synthetic sporozoite vaccine can boost the immune response to sporozoites.