bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcription, translation and secretion of interleukin 1 and tumor necrosis factor: effects of tebufelone, a dual cyclooxygenase/5‐lipoxygenase inhibitor
Authors: Sirko Steven P. , Schindler Ralf , Doyle Matthew J. , Weisman Steven M. , Dinarello Charles A.
Published: March 2007

We examined the effect of tebufelone, a dual cyclooxygenase (CO)/5‐lipoxygen‐ase (LO) inhibitor, on the synthesis, secretion and gene expression of interleukin (IL) 1β and tumor necrosis factor (TNF)‐α by human peripheral blood mono‐nuclear cells (PBMC). Basal concentrations of immunoreactive IL 1β and TNF‐α after 18–24 h, in the absence or presence of tebufelone (≤ 12.5 μM), were near the limit of detection (100 pg/ml). By contrast, preincubation (1 h) of cells, in amounts of tebufelone which decrease the formation of leukotriene (LT) B4, markedly enhanced (up to 500%) the synthesis of IL 1β and TNF‐α following lipopolysaccharide (LPS), heat‐killed Staphylococcus epidermidis or concanavalin A stimulation. Moreover, a disproportionate amount of the overall increase in IL 1(α and β) was secreted in contrast to the amount which remained cell associated, an effect unrelated to cell damage or leakage as tebufelone had no effect on either lactate dehydrogenase release by PBMC, or mitochondrial dehydrogenases of adherent monocytes as detected by enzymatic cleavage of the substrate 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide. There was no inverse correlation between the changes in prostaglandin (PG)E2 levels and TNF‐α or IL 1β synthesis, and when PG formation was maximally inhibited by preincubating the cells in indomethacin, tebufelone, added 1 h before the stimulus, continued to enhance the synthesis of IL 1β although not that of TNF‐α. The addition of the CO/5‐LO inhibitor 2 h after LPS stimulation, however, did not interfere with IL 1β synthesis, suggesting that tebufelone interacts with an early event(s) in the activation of PBMC. For IL 1β and TNF‐α, basal and stimulated (4 h post LPS) mRNA levels were not increased by tebufelone, despite a concomitant increase in the synthesis of IL1β. In conclusion, we have demonstrated that tebufelone enhances IL 1(α and β) and TNF‐α synthesis at concentrations which suppress leukotriene formation. These findings argue against a role of 5‐LO products as necessary intermediates of IL 1(α and β) and TNF‐α synthesis.
Immobilized anti‐CD5 together with prolonged activation of protein kinase C induce interleukin 2‐dependent T cell growth: evidence for signal transduction through CD5
Authors: Vandenberghe Peter , Ceuppens Jan L.
Published: March 2007

Monoclonal antibodies (mAb) identifying the CD5 antigen were used to stimulate human peripheral blood T lymphocytes. Three out of three anti‐CD5 mAb, 10.2, OKT1 and anti‐Leu‐1 induced vigorous proliferation of purified T cells in the presence of 1.6 nM phorbol 12‐myristate 13‐acetate (PMA). Immobilization of anti‐CD5 mAb on a solid support was necessary for the induction of a proliferative response. Neither 1.6 nM PMA, nor immobilized anti‐CD5 mAb were mitogenic as a sole stimulus. mAb identifying CD4, CD7, CD11a, CD18, and major histocompatibility complex class I molecules were not comitogenic with PMA. Anti‐CD5/PMA‐induced cell proliferation proceeded by an interleukin 2 (IL2)‐dependent mechanism, as was demonstrated by the cell surface expression of the p55 chain of the IL2 receptor (IL 2R), the production of IL2 and the inhibition of the proliferative response by anti‐IL2R mAb anti‐Tac. There was no strict requirement for detectable numbers of monocytes, although cell proliferation could be enhanced by the monocyte‐derived cytokines IL 1 and IL6. Phorbol 12, 13‐dibutyrate and mezerein could substitute for PMA in this activation pathway, but synthetic diacylglycerols and phorbol esters that do not activate protein kinase C (PKC) could not, indicating a need for prolonged activation of PKC. T cells activated by anti‐CD5/PMA are sensitive to inhibition by cyclosporin A (CsA) and by prostaglandin E2 (PGE2). This contrasts with anti‐CD28/PMA‐induced Tcell proliferation, which is resistant to CsA and PGE2. Cell surface expression of CD5 was strongly up‐regulated by PMA, whereas CD3 expression was down‐regulated. We conclude that T cell activation can be triggered by engagement of CD5 by immobilized anti‐CD5 mAb, combined with prolonged activation of PKC. These data support a role for CD5 as an independent signal transducing molecule.
Ilal Peyer's patch emigrants are predominantly B cells and travel to all lymphoid tissues in sheep
Authors: Reynolds John D. , Kennedy Laurie , Peppard Jane , Pabst Reinhard
Published: March 2007

The ileal Peyer's patch (PP) was selectively labeled with fluorescein isothiocyanate by extracorporeal perfusion in 7–12 week‐old lambs and the lymphocyte linege and fate of the emigrants was determined by fluorescence microscopy and flow cytometry. PP emigrants were found in all tissues examined, accounting for 10%–15% of ileal mesenteric lymph node (MLN), 1%–2% of jejunal MLN, jejunal PP, prescapular lymph node (PLN) and 3%–4% of spleen cells. All ileal PP emigrants enter the ileal MLN on their way to the circulation. Removal of the MLN prior to perfusion enabled emigrants to go directly to the circulation and extravasate in distant tissues faster than in intact animals. The ileal MLN might provide an additional level of regulation for ileal PP emigrants. The perfused ileal PP contained about 25 times more B cells than T cells. The emigrant cells found in different tissues included both T and B cells but came to reflect, although to a lesser degree, the B cell composition of the tissue from which they were derived. One day after perfusion the composition of PP emigrants was similar to that of the tissue within which they were found; the spleen was the exception with a bias towards B cells. By day 3 the ratio of B to T cells in the PP emigrants was 1 for jejunal MLN and PLN, 1.5 for ileal MLN and jejunal PP, and 4–5 for the spleen and blood. It was concluded that the PP‐derived T cells were recirculating T cells that were in the ileal PP at the time of perfusion. These cells emigrated rapidly and equilibrated such that they accounted for about 1.5% of the T cell pool in various tissues. Most PP‐derived B cells were probably produced in the PP. The greatest contribution (24.4%) that ileal PP emigrants made to the B cell pool of a tissue was with the ileal MLN through which they are obliged to pass. The contribution was lower but still very significant in blood (8.9%), spleen (6.8%), PLN (3.9%), jejunal MLN (3.5%) and jejunal PP (1.8%). There was no evidence that ileal PP emigrants made a greater relative contribution to either T or B cell populations in MLN or jejunal PP than to non‐gut‐associated sites. The B cells were distributed throughout the immune system, which is in accordance with the proposal that the ileal PP is a site of primary B cell genesis in sheep.
The accessory function of B lymphocytes is resistant to the adverse effects of UV radiation
Authors: Hertl Michael , Kaplan David R. , Fayen John D. , Panuska James R. , Ellner Jerrold J. , Elmets Craig A.
Published: March 2007

The effect of UV radiation on the accessory activities of B lymphoblastoid cell lines (B‐LCL) was investigated in three types of in vitro T lymphocyte proliferation assay, each of which differed in its accessory requirements. In contrast to monocytes whose accessory function was universally sensitive to UV radiation, B‐LCL were resistant to UV in oxidative mitogenesis and staphylococcal enterotoxin B assays, in which stimulus processing was not a requirement. Expression of membrane interleukin (IL) 1 and HLA‐DR antigens by B‐LCL and monocytes was not affected by UV, nor was surface membrane expression of intercellular adhesion molecule‐1 (ICAM‐1) on B‐LCL. These results were in marked contrast to monocytes in which there was a >65% reduction in ICAM‐1 expression. When UV‐irradiated B‐LCL were employed as antigen‐presenting cells for tetanus toxoid‐dependent T cell stimulation, a reduction in antigen‐presenting function was observed. However, pulsing of B‐LCL with tetanus toxoid prior to UV irradiation preserved their antigen‐ presenting capacity in this system also. These findings indicate that there is differential UV sensitivity among accessory cells which may be explained by different effects of UV radiation on antigen processing and adhesion molecule expression.
Fibronectin associated with infiltrating T lymphocytes. Evidence for in situ localization in biopsies and synthesis in vitro
Authors: Sundqvist Karl‐Gösta , Wanger Lena , Heimdahl Anders , Lönnqvist Berit , Hauzenberger Dan
Published: March 2007

Dermal and mucosal lymphocyte infiltrates in patients with lichen ruber planus and chronic graft‐vs.‐host disease exhibited reactivity with anti‐fibronectin antibodies. This reactivity was associated with the lymphocytes and localized pericellularly. In contrast, biopsy areas outside lymphocyte accumulations were relatively devoid of reactivity with anti‐fibronectin antibodies. Furthermore, the corresponding biopsies from healthy individuals or patients without lymphocyte infiltration showed negligible reactivity with anti‐fibronectin antibodies. The fibronectin associated with infiltrating lymphocytes in biopsies may be exogenous of non‐lymphoid origin. However, another possibility suggested by in vitro experiments is that this fibronectin is lymphocyte derived. Thus, during cultivation in vitro lymphocytes appear to synthesize a component with fibronectin‐like properties. Furthermore, a prerequisite for detection of this synthesis was that the cells were cultured in the presence of serum depleted of fibronectin. These results point to the possibility that fibronectin may play a role for lymphocyte interactions with tissues during infiltrative processes.
Evidence for regulation of naturally activated autoreactive B cells
Authors: Zöller Margot , Achtnich Martin
Published: March 2007

A large fraction of naturally activated B cells in the neonate displays degenerate specificity, including reactivity with autoantigens. Transgenic mouse models of autoreactive B cells are mainly concerned with monospecific B cells of high avidity, and the fate of naturally activated autoreactive B cells is still a matter of debate. To pursue this question further, we chose an IgM autoantibody with a recurrent idiotype (Id), i.e. Sp6, because transgenic mice expressing this IgM also were available. In a first approach monoclonal antibodies (mAb) derived from untreated, antigenically stimulated and transgenic mice were used to test whether there were indications for deletion or for Id regulation of naturally activated autoreactive B cells.

Over 90% of thymus and spleen cell derived hybridomas from 6‐day‐old Sp6‐transgenic mice were trinitrophenyl (TNP) reactive, carried the Sp6‐Id and bound to a panel of self antigens, including mouse albumin. We failed to obtain B cell hybridomas from the thymus of 28‐day‐old Sp6‐transgenic mice. Furthermore, we could not detect any mAb carrying an anti‐Sp6 Id, but Sp6 did weakly bind to itself. About 25% of mAb derived from control mice displayed degenerate specificity, the majority of them also were TNP reactive. The Sp6 Id was found at a low frequency and a comparable number of mAb carried an anti‐Sp6 Id. Prenatal manipulation at the antigen level (trinitrobenzenesulfonic acid treatment) led to a transient expansion of TNP‐ and autoreactive mAb. The number of mAb carrying the Sp6 Id was not increased, but mAb carrying an anti‐Sp6 Id were observed at high frequency. Those mAb also displayed degenerate specificity.

Since Sp6‐transgenic mice were perfectly healthy, it is concluded that this particular autoreactive antibody of degenerate specificity cannot be harmful for the developing organism, which may possibly be due to its self‐binding capacity. Furthermore, some process of down‐regulation was indicated by the absence of B cells expressing the transgene in the thymus of young adult mice. Autoreactivity of untreated and prenatally antigen‐treated mice was, in addition, regulated at the Id level. In particular, mAb recognizing the Id of Sp6 were significantly expanded in antigenically stimulated mice. The data were interpreted in the sense that autoreactive B cells appearing early during ontogeny were rather strictly controlled either by (functional) clonal deletion or by idiotypic connectivity.
T cell activation in the absence of interleukin 2 (IL 2) results in the induction of high‐affinity IL 2 receptor unable to transmit a proliferative signal
Authors: Proust Jacques J. , Shaper Nancy L. , Buchholz Meredith A. , Nordin Albert A.
Published: March 2007

Although interleukin 2 (IL2) clearly up‐regulates the expression of the p55 chain of the IL 2 receptor (IL 2R) little is known about its role in the induction of the high‐affinity IL 2R. Resting T lymphocytes were induced to express IL 2R under experimental conditions in which IL 2 production was not induced or was prevented. Under these conditions high‐ and low‐affinity IL 2R were easily demonstrated by Scatchard analysis. Northern blot analysis confirmed the accumulation of p55 specific mRNA and the absence of the IL 2 transcript. High‐affinity IL 2R induced in the complete absence of IL 2 were unable to transmit a proliferative response unless exposed to extremely high concentrations of IL 2. The addition of picomolar amounts of recombinant IL 2 or the initiation of endogenous IL 2 production during the induction period restored the functionality of high‐affinity IL 2R. Also, T cells induced to generate IL 2 displayed functional high‐affinity IL 2R even in the presence of monoclonal antibodies blocking extracellular IL 2 and IL 2R. These results indicate that the presence of IL 2 during the early phase of T cell activation is an absolute requirement for the induction of fully operational high‐affinity IL 2R and that low amounts of intracellular IL 2 are sufficient to confer functional properties to these receptors. The data also suggest that an intracellular as well as an extracellular high‐affinity structure, expressed as a consequence of cell activation, is responsible for conferring competence to the high‐affinity IL 2R involved in IL 2‐dependent proliferation.
The effect of interleukin 3 upon IgE‐dependent and IgE‐independent basophil degranulation and leukotriene generation
Authors: Kurimoto Yoshiyuki , de Weck Alan L. , Dahinden Clemens A.
Published: March 2007

Recent investigations have shown that the hematopoietic growth factor interleukin 3 (IL3) enhances histamine release of mature human basophils. Furthermore, basophils exposed to IL3 generate large amounts of leukotriene C4 in response to C5a, a basophil agonist which by itself is unable to promote lipid mediator formation. Also IL 3 renders the cells responsive to factors which do not otherwise induce basophil mediator release. Here we show in more detail how IL 3 affects the release of preformed and newly synthesized inflammatory mediators by basophils in response to antigen, anti‐IgE, N‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP) and C5a. In cells triggered by maximally effective concentrations of these agonists, IL 3 enhances histamine release, although it more profoundly affects leukotriene generation, in particular in response to stimuli which by themselves are inefficient or poor inducers of lipid mediator formation. This change in the mediator‐release reaction occurs at low IL 3 concentrations, over the same concentration range of IL 3 of 0.01–1.0 U/ml regardless of which triggering agent is used as a second signal. Pretreatment of basophils with IL 3 results in a left shift of the dose‐response curves for mediator release of both IgE‐dependent and IgE‐independent agonists by approximately one order of magnitude. IL 3 affects only the extent and not the time course of IgE‐independent peptide‐induced basophil degranulation. By contrast, histamine and leukotrienes are released more rapidly in response to IgE‐dependent stimulation after IL 3 priming. IL 3 also shortens the lag time and increases the rate of leukotriene generation in basophils triggered by FMLP. The priming process induced by IL 3 does not require extracellular calcium. Basophils exposed to IL 3 release significant amount of mediators in response to C5a, even in EDTA buffers without addition of Ca2+/Mg2+, indicating that in the presence of IL 3 the Ca2+‐dependent mediator release induced by C5a becomes partially Ca2+ independent. Thus, we find that IL 3 strongly affects the mediator profile, the amounts of mediators released, the dose‐response curves and the kinetic of the release reaction in basophils stimulated with diverse agonists. The data further support the hypothesis that IL 3 plays an important role in inflammatory processes, in particular in hypersensitivity reactions.
A new superfamily of lymphoid and melanoma cell proteins with extensive homology to Schistosoma mansoni antigen Sm23
Authors: Gaugitsch Helmut W. , Hofer Erhard , Huber Nathalie E. , Schnabl Eva , Baumruker Thomas
Published: March 2007

A novel cDNA clone termed R2 was isolated by subtractive hybridization of a cDNA library of phytohemagglutinin (PHA)/phorbol myristate acetate‐stimulated Jurkat cells and by rescreening a cDNA library of PHA‐stimulated peripheral blood lymphocytes. It hybridizes to a single mRNA species of about 2.2 kb, which is inducible in lymphoid cells and codes for a protein of 267 amino acids which contains four potential transmembrane domains. A computer‐aided comparison showed strong homology to four other membrane proteins, the pan B cell marker CD37, the pan leukocyte marker CD53, the melanoma antigen ME491 and surprisingly, the Schistosoma mansoni antigen Sm23. The four human proteins share a number of additional similarities in their overall structure. These include identical spacing of the transmembrane domains, similar hydro‐phobicity plots, possible N‐linked glycosylation sites of similar number and position as well as similar distribution of the cysteine residues. The majority of these characteristics are still conserved in the evolutionary most distant member of this family, the Schistosoma mansoni antigen Sm23. Here we introduce this new protein superfamily and characterize the inducible, lymphoid‐specific member R2.
Growth of Mycobacterium avium in human monocytes: identification of cytokines which reduce and enhance intracellular microbial growth
Authors: Denis Michel
Published: March 2007

Human monocytes were isolated by standard procedures and their ability to harbor growth of two virulent strains of Mycobacterium avium, TMC724 and TMC7479, was assessed in the absence or presence of cytokines. Both strains of mycobacteria, especially the M. avium TMC7479, grew progressively in untreated human monocytes. Inclusion of certain macrophage‐activating cytokines, such as interferon‐γ in the presence of indomethacin or 1,25(OH2)‐vitamin D3 (calcitriol) led to significant reductions in bacterial growth at 7 days post‐infection. Conversely, treatment of human monocytes with interleukin‐(IL) 1, macrophage‐colony stimulating factor or IL 3 led to an increased permissiveness of these cells for M. avium. Moreover, these cytokines were shown to increase dramatically extracellular M. avium growth in vitro in tissue culture medium. Further, inclusion of antibodies against IL 1β and IL6 in untreated infected monocytes monolayers led to a reduced growth of M. avium, suggesting that infected monocytes produce factors which enhance their susceptibility to M. avium. Overall, my findings suggest that cytokines may play a bidirectional role in atypical mycobacterial infections, by either increasing or decreasing resistance of the monocyte.
Avian CD4 and CD8 interact with a cellular tyrosine protein kinase homologous to mammalian p56lck
Authors: Veillette André , Ratcliffe Michael J. H.
Published: March 2007

Functional as well as immunochemical studies have indicated that chicken T lymphocytes express surface antigens homologous to mammalian CD4 and CD8. The results presented in this report demonstrate that the avian CD4 and CD8 homologs are physically associated with a cellular tyrosine protein kinase related to mammalian p56lck. Furthermore, they show that engagement of either avian CD4 or CD8 is associated with a rapid intracellular tyrosine phosphorylation signal, suggesting that the function of these surface molecules may be mediated through alterations of the associated tyrosine protein kinase. Taken together, these findings demonstrate that the associations of CD4 and CD8 with an intracellular tyrosine protein kinase are evolutionarily conserved, further enhancing the likelihood that they are critical for normal immune functions.
Mapping of the duplicated rabbit immunoglobulin χ light chain locus
Authors: Hole Nichola J. K. , Young‐Cooper Glendowlyn O. , Mage Rose G.
Published: March 2007

The rabbit has two isotypic forms of the immunoglobulin χ light chain, K1 and K2, which probably arose by duplication. In the normal rabbit, only traces of K2 light chains are produced. However, K2 levels are elevated in allotype‐suppressed rabbits and in the Basilea strain which does not produce K1 because of a K1 mRNA splice site mutation. Previous cloning and sequencing showed that each isotype has its own set of Jχ genes but it was not known whether the two isotypes utilize shared or separate sets of Vχ genes. In addition, although genetic linkage of allotypes associated with the K1 and K2 genes has been demonstrated, physical linkage had not been previously demonstrated by overlapping cosmid or phage clones. We used pulsed field and transverse alternating field electrophoresis to obtain megabase maps and to estimate the size of the duplication of the rabbit χ light chain locus. We found that the two Cχ genes are about 1 megabase apart. One explanation for the poor expression of K2, could be great physical distance from Vχ genes. However, we found that there are Vχ, Jχ and Cχ2 genes within a ∼ 105‐kb fragment. Thus, physical distance of Vχ from Cχ2 may not be the basis for poor K2 expression.
Preferrential rearrangement in normal rabbits of the 3′ VHa allotype gene that is deleted in Alicia mutants; somatic hypermutation/conversion may play a major role in generating the heterogeneity of rabbit heavy chain variable region sequences
Authors: Allegrucci Massimo , Young‐Cooper Glendowlyn O. , Alexander Cornelius B. , Newman Barbara A. , Mage Rose G.
Published: March 2007

The rabbit is unique in having well‐defined allotypes in the variable region of the heavy chain. Products of the VHa locus, (with alleles al, a2, and a3), account for the majority of the serum immunoglobulins. A small percentage of the serum immunoglobulins are a‐negative. In 1986, Kelus and Weiss described a mutation that depressed the expression of the Ig VH a2 genes in an a1/a2 rabbit. From this animal the Alicia rabbit strain was developed and the mutation was termed ali. We previously showed, using Southern analysis and the transverse alternating field electrophoresis technique, that the difference between the ali rabbit and normal is a relatively small deletion including some of the most 3′ VH genes. The most JH proximal 3′ VH1 genes in DNA from normal rabbits of a1, a2 and a3 haplotypes encode a1, a2 and a3 molecules respectively, and it has been suggested that these genes are responsible for allelic inheritance of VHa allotypes. The present study suggests that the 3′ end of the VH locus probably plays a key role in regulation of VH gene expression in rabbits because VH gene(s) in this region are the target(s) of preferential VDJ rearrangements. This raises the possibility that mechanisms such as somatic gene conversion and hypermutation are at work to generate the antibody repertoire in this species. Our data support the view that the 3′ VH1 gene may be the preferred target for rearrangement in normal rabbits, and for the normal chromosome in heterozygous ali animals. However, homozygous ali rabbits with a deletion that removed the a2‐encoding VH1 on both chromosomes do survive, rearrange other VH genes and produce normal levels of immunoglobulins as well as a significant percentage of B cells which bear the a2 allotype. This challenges the view that one VH gene, VH1, is solely responsible for the inheritance pattern of VHa allotypes.
Conserved V(D)J junctional sequence of cross‐reactive cytotoxic T cell receptor idiotype and the effect of a single amino acid substitution
Authors: Hirama Toshiyasu , Takeshita Sunao , Matsubayashi Yuji , Iwashiro Michihiro , Masuda Tohru , Kuribayashi Kagemasa , Yoshida Yataroh , Yamagishi Hideo
Published: March 2007

A dominant T cell population bearing the cross‐reactive idiotype of T cell antigen receptor (TcR) has been obtained using an anti‐TcR monoclonal antibody (mAb) developed in syngeneic mice. Forty‐four cytotoxic T cell (CTL) clones with reactivity to a mAb (N9 127) were selected out of 396 H‐2Db‐restricted CTL clones specific for FBL‐3 tumor antigen from C57BL/6 mice. These CTL clones were divided into two groups according to the blocking pattern of cytotoxic activities with mAb N9‐127. All eight CTL clones chosen from both groups expressed TcR with a specific combination of α and β chains (Vα1Jα112‐2/Vβ10Dβ2.1Jβ2.7), and the difference in the blocking susceptibility resided in a single amino acid substitution (Gly to Asp) in the D‐J joint of β chain. This provides direct evidence for the molecular basis of cross‐reactive idiotypes of TcR recognized by mAb.
Inhibition of B cell proliferation with anti‐CD19 monoclonal antibodies: anti‐CD19 antibodies do not interfere with early signaling events triggered by anti‐IgM or interleukin 4
Authors: Rigley Kevin P. , Callard Robin E.
Published: March 2007

The 95‐kDa antigen recognized by the anti‐CD19 panel of monoclonal antibodies is found on the surface of most cells of the B cell lineage. Anti‐CD19 antibodies inhibit B cell proliferation in response to anti‐Ig plus interleukin 4 (IL4), but enhance the response to mitogenic concentrations of either phorbol 12‐myristate 13‐acetate (PMA) or Epstein‐Barr virus. This dichotomy in the effect of anti‐CD19 antibodies suggested that the inhibitory action may be directed at the transmembrane signaling pathways utilized by anti‐IgM and IL4. To investigate this hypothesis, an attempt was made to determine the mechanism of signal transduction utilized by the CD19 antigen, and elucidate its effect on transmembrane signaling invoked by anti‐immunoglobulin and IL4. Binding of anti‐CD19 antibody to B cells did not promote activation of either the phosphoinositide or cAMP signaling pathways. In addition, anti‐CD19 antibody did not inhibit phosphatidylinositol bisphosphate (PIP2) hydrolysis induced by anti‐IgM or IL4, nor did it interfere with cAMP induction by IL4. We also found that anti‐CD19 antibody inhibited PMA plus calcium ionophore‐induced B cell proliferation. This evidence indicates that anti‐CD19 mAb interrupts the signaling cascade at a point distal to receptor‐mediated breakdown of PIP2 and/or activation of adenyl cyclase. This conclusion was fully consistent with experiments in which anti‐CD19 antibody was shown to inhibit DNA but not RNA synthesis, and the observation that anti‐CD19 antibody must be present between 6 h and 20 h after the initiation of the culture suggesting that anti‐CD19 mAb exerts its inhibitory effect in late G0 or G1, after the initial signaling events.
Immunobiological studies on experimental visceral leishmaniasis I. Changes in lymphoid organs and their possible role in pathogenesis
Authors: Saha Bhaskar , Nanda‐Roy Heramba , Pakrashi Anita , Chakrabarti Rohini Nandan , Roy Syamal
Published: March 2007

Studies were carried out to determine changes in lymphoid organs i. e. spleen, lymph node and bone marrow (BM) in progressive experimental visceral leishmaniasis. Mononuclear phagocytes in the BM were increased; spleens showed a hypercellularity coupled with a rise in parasite burden while secondary follicles with no apparent depletion of paracortex were seen in the lymph node. This enhanced proliferation of mononuclear phagocytes in the BM and probably their subsequent recruitment in the spleen could be induced in naive recipients by injecting nylon wool‐purified lymph node cells derived from infected mice together with sonicated leishmanial antigen(s). Similar changes could also be induced in the BM of naive recipients by injecting serum of infected mice. In control experiments where both donor and recipients were uninfected such changes were not apparent. A working hypothesis is proposed to delineate the role of lymphoid organs in the pathogenesis of experimental visceral leishmaniasis.
Na+/H+ antiporter has different properties in human B lymphocytes according to CD5 expression and malignant phenotype
Authors: Gaidano Gianluca , Caligaris‐Cappio Federico , Treves Silvia , Bussolino Federico , Pescarmona Gianpiero , Ghigo Dario , Bosia Amalia
Published: March 2007

In B chronic lymphocytic leukemia (B‐CLL) cells, lipopolysaccharide (LPS) and phorbol esters fail to activate the plasma membrane‐associated Na+/H+ anti‐porter and, subsequently, to elicit a rise in cytosolic pH. Since these events are thought to be a prerequisite for LPS‐induced proliferation of B normal lymphocytes, we analyzed the kinetic properties of Na+/H+ antiporter in B‐CLL cells as compared to both CD5− and CD5+ normal B lymphocytes. In the present work we report that Na+/H+ exchange rate after acid loading is drastically decreased in B‐CLL cells, as compared to normal CD5− B lymphocytes, although the antiporter affinity for external Na+ and internal H+ is not significantly different in both cell populations. Kinetic data account for a reduction in the number of operating antiport units in B‐CLL. The Na+/H+ antiporter of CD5+ normal B lymphocytes exhibits both an exchange rate and an ion affinity significantly higher than that observed in both CD5+ B‐CLL cells and CD5− B normal lymphocytes, thus suggesting a possible explanation for their activated phenotype.
Complementary roles for CD2 and LFA‐1 adhesion pathways during T cell activation
Authors: Moingeon Philippe E. , Lucich Jeanne L. , Stebbins Christopher C. , Recny Michael A. , Wallner Barbara P. , Koyasu Shigeo , Reinherz Ellis L.
Published: March 2007

The influence of T cell receptor (TcR) triggering on T cell adhesion function has been systematically investigated in the present studies; we show that the adhesion function of LFA‐1 is minimal in non‐activated T cells but is augmented within minutes following TcR‐mediated activation. In contrast, CD2 function is essentially optimal in non‐activated T cells and undergoes no detectable modification within 12 h of TcR stimulation. Protein kinase C activation augments LFA‐1 but not CD2 adhesion function and cyclic AMP reduces LFA‐1 adhesion without affecting CD2‐LFA‐3 interactions. Up‐regulation of the LFA‐1 pathway occurs in the absence of any detectable surface redistribution of this molecule, suggesting an activation dependent modification leading to a high‐affinity ICAM‐1 binding state. The TcR independence of CD2 adhesion function implies a critical role of the CD2 pathway in initiating cell‐cell interactions prior to TcR engagement and LFA‐1‐ICAM‐1 binding and underscores the complementary nature of the CD2 and LFA‐1 adhesion pathways during the immune response.
Expression and biological effects of high levels of serum IgE in ϵ heavy chain transgenic mice
Authors: Adamczewski Martin , Köhler Georges , Lamers Marinus C.
Published: March 2007

We have generated and examined transgenic mice carrying a rearranged immunoglobulin transgene coding for the heavy chain of an IgE antibody. These mice produce the secreted form of the recombinant ϵ heavy chain. Serum IgE levels were increased at least 100‐fold over control values. Transgenic ϵ mRNA was detected in spleen and thymus, not in liver and heart. Transgenic ϵ production in vitro was slightly up‐regulated by T cells, but not affected by interleukin 4 in vitro or Nippostrongylus infestation in vivo. The B cell and T cell compartments and antigen‐specific IgE, IgG1 and IgM responses as well as the increase in endogenous IgE after Nippostrongylus infestation in transgenic mice were normal. These data indicate that the presence of high levels of transgenic IgE did not induce class‐specific suppressive mechanisms. Transgenic IgE bound to Fcϵ receptor type I and Fcϵ receptor type II and mediated histamine release from mast cells in vitro and an allergic skin reaction in vivo. It inhibited an ovalbumin‐specific skin reaction in ovalbumin‐immunized transgenic mice only during the initial phases of the immune response. This result has a bearing on the feasibility of immune therapy of allergic diseases with substances that block binding of IgE to its receptors.
The MRC OX‐47 antigen is a member of the immunoglobulin superfamily with an unusual transmembrane sequence
Authors: Fossum Sigbj⊘Rn , Mallett Susan , Neil Barclay A.
Published: March 2007

The MRC OX‐47 monoclonal antibody recognizes a membrane antigen present at low levels on many lymphocytes but whose expression is markedly increased on activation with mitogens. cDNA clones for the OX‐47 antigen were isolated from an expression library and the protein sequence deduced. It contains a leader sequence giving a mature protein of 251 amino acids with a single putative transmembrane region, a cytoplasmic domain of 40 amino acids and an extracellular domain of 187 amino acids that contained two immunoglobulin‐like domains. The putative transmembrane sequence includes a glutamic acid residue within the hydrophobic sequence. The presence of acidic residues within the hydrophobic sequence of transmembrane sequences usually indicates association with other polypeptides and this is predicted for the OX‐47 antigen. A sequence of 37 amino acids that included all the transmembrane region was identical to that of the chicken HT7 antigen present on endothelium in brain and erythroblasts. The level of protein sequence identity in the Ig‐like domains was lower but HT7 is almost certainly the chicken homologue of the rat OX‐47 antigen. The ligand and function of the molecule are unknown. In addition to lymphoblasts the OX‐47 antigen was localized on a variety of other cell types including various immature cells, endothelia and cells with excitable membranes.
T cell proliferation induced by monoclonal antibodies to a phosphatidylinositol‐linked differentiation antigen of guinea pig lymphocytes
Authors: Schäfer Hubert , Burger Reinhard , Scheper Rick J. , Healey Don G. , Schenkel Johannes
Published: March 2007

Monoclonal antibodies (mAb) to differentiation antigens frequently influence the in vitro function of antigen‐bearing cells. We characterized a 32–36‐kDa membrane protein expressed on guinea pig lymphocytes and Langerhans cells. A series of independently derived mAb to this protein, now called guinea pig T cell activation antigen (gpTAA), induced strong proliferation of T cells in vitro. Cross‐linking of the mAb by a secondary antibody (rabbit anti‐mouse Ig) and costimulation with phorbol 12‐myristate 13‐acetate were required for activation. Treatment of the cells with phosphatidylinositol‐specific phospholipase C greatly reduced the amount of antigen expressed on the cell surface as measured by flow cytometry analysis. This finding indicates that the antigen is anchored to the cell membrane via phosphatidylinositol linkage as shown similarly for other membrane proteins with T cell activating properties, e.g. Thy‐1 and Ly‐6. The guina pig protein differs, however, in its molecular weight and tissue distribution from similar proteins identified in the mouse or in the rat system. Unlike Thy‐1, gpTAA is also expressed on B Lymphocytes and Langerhans cells. Considering the previously described involvement in cellular adhesion, and the functional characteristics reported here, gpTAA might represent a new species of differentiation antigen with T cell‐activating capacity.
Anti‐idiotypic antibodies to human anti‐gp120 antibodies bind recombinant and cellular human CD4
Authors: Corre Jean‐Philippe , Février Michèle , Thèze Jacques , Zouali Moncef , Chamaret Sophie
Published: March 2007

The presence of anti‐CD4 antibodies in sera of human immunodeficiency virus (HIV)‐seropositive individuals has been recently documented, but its origin remains unknown. To test the hypothesis that anti‐idiotypic antibodies to gp120, the HIV envelope glycoprotein with high affinity for CD4, mimic the configuration of gp120 and bind CD4, we performed two sets of experiments. First, we tested the possibility that anti‐CD4 antibodies present in sera of a proportion of HIV‐positive individuals exhibit variable region complementarity to autologous anti‐gp120 antibodies. We show here that affinity‐purified human anti‐gp160 antibodies recognize specifically autologous affinity‐purified anti‐CD4 antibodies. We also demonstrate that antibodies to CD4 competitively inhibit anti‐gp160 autologous antibodies binding to gp160. This implies that at least some anti‐CD4 antibodies are directed towards idiotypic motifs located on anti‐gp120 antibodies and that they may result from an anti‐idiotypic response to anti‐gp120 antibodies. In a second set of experiments, we examined the effect of anti‐idiotypic immunization of experimental animals against human anti‐gp120 antibodies. We found that anti‐idiotypic antibodies produced in a rabbit immunized against affinity‐purified human anti‐gp120 antibodies specifically recognize recombinant and cellular human CD4, and that this interaction is competitively inhibited by soluble CD4. The data support the concept of idiotypic mimicry whereby anti‐idiotypic antibodies produced against anti‐gp120 antibodies recognize CD4, the cellular receptor of HIV.
Molecular cloning of the cDNA coding for properdin, a positive regulator of the alternative pathway of human complement
Authors: Nolan Kathleen F. , Kaluz Stefan , Reid Kenneth B. M. , Dierich Manfred P. , Schwaeble Wilhelm
Published: March 2007

Northern blot analysis indicated that the mRNA for human properdin is approximately 1.5 kb long and that its level in U‐937 cells is increased by pretreating the cells with phorbol 12‐myristate 13‐acetate (PMA). Using a human genomic probe clones coding for human properdin were isolated from a λgt10 cDNA library derived from PMA‐treated U‐937 cells. The sequence of the 1474‐bp cDNA insert of the longest clone revealed an open reading frame of 1326 bp coding for the entire 442 amino acids of the mature form of human properdin and 67 bp coding for 22 amino acids of typical, but incomplete leader sequence. Polymerase chain reaction “RACE” experiments identified the start site ATG and revealed the complete, 27‐amino acid‐long, leader peptide sequence. Within the 81‐bp 3' non‐translated extension a polyadenylation signal was identified 41 bp downstream from the stop codon, TAA, and 12 bp upstream of a 19 nucleotide long poly(A) tail. The amino acid sequence of human properdin is clearly divided into three distinct regions: a 49 residue‐long N‐terminal region, a 32 residue‐long C‐terminal region and a middle region, covering residues 50 to 411, composed of six tandemly repeated thrompospondin repeat (TSR) motifs of the type first described in the adhesive glycoprotein thrombospondin and also known to be present in the C6, C7, C8α, C8β and C9 terminal components of complement. Human and mouse properdin sequences show a high (∼76%) degree of identity with almost complete conservation of the relatively large number of Cys (44) and Trp (20) residues.
Carbohydrate synthesis inhibitors decrease interleukin 1‐stimulated lymphocyte binding to endothelial cells
Authors: Renkonen Risto , Ustinov Jarkko
Published: March 2007

Lymphocyte extravasation (homing) is initiated when lymphocyte adheres to endothelial cells. All know protein structures involved in the lymphocyte binding located on the endothelial surface are heavily glycosylated. We asked therefore whether these carbohydrate motifs had a role in the lymphocyte homing. The relative importance of the N‐linked chains on biological effects mediated by glycoproteins can be studied with specific inhibitors of carbohydrate processing, i.e. 1‐deoxynojirimycin (DN), castonospermine (CAST), 1‐deoxymannojirimy‐cin (DMN) and swainsonine (SW), which produces different kinds of blocked carbohydrate chains. N‐linked carbohydrate chains are modified in the Golgi apparatus and in the final glycoprotein they can be either of high‐mannose‐, hybrid‐ or complex‐type motifs, having the same core structure but different terminal structures. We show here that when all N‐linked carbohydrates were cleaved off from the cell surface glycoproteins by treating endothelial cells with N‐glycosidase F interleukin 1‐induced lymphocyte binding was reduced almost to non‐stimulated control values. Treatment of endothelial cells with CAST led to generation of glycoproteins carrying high‐mannose‐type oligosaccharides, which are glucose capped with three glucose molecules on the chain. CAST treatment resulted in an 85% decrease in lymphocyte binding compared to interleukin 1‐induced levels. DMN treatment, resulting in accumulation of high‐mannose type oligosaccharides without any terminal glucoses on the cell surface, caused a similar inhibition of lymphocyte binding to that induced by CAST treatment. SW treatment, leading to accumulation of hybrid‐type glycoproteins, decreased only slightly the lymphocyte binding. These results suggest that carbohydrates indeed have a role in lymphocyte binding to endothelial cells.
Murine thymic nurse cell clone supports the growth of fetal thymocytes in the presence of interleukin 2
Authors: Doi Hideyuki , Nakagawa Satoshi , Hata Masahiro , Kasahara Shigeru , Itoh Tsunetoshi , Sakata Tsuneaki , Suzuki Ryuji , Nagata Kinya , Sugamura Kazuo , Nanno Masanobu
Published: March 2007

To investigate the role of thymic nurse cells (TNC) in activation and differentiation of fetal CD4−CD8− (double‐negative) thymocytes, we have co‐cultured murine fetal thymocytes (14–15 days of gestation) with an established murine TNC clone. We show here that TNC induced the growth of the fetal double‐negative thymocytes in the presence of recombinant interleukin 2 (rIL2). Activated fetal thymocytes markedly formed lymphocyte‐TNC complexes and proliferated extensively after 5 days in the co‐culture. The activated fetal thymocytes in this co‐culture condition remained double negative after 10 days in culture. None of them gave rise to phenotypically and functionally competent lymphocytes during this period. TNC alone and the supernatant of TNC had no effect on activation. The presence of both TNC and rIL2 was necessary for the growth of fetal thymocytes in our system. The proliferation of fetal thymocytes was inhibited by a monoclonal antibody against mouse IL2 receptors (IL2R). The fetal thymocytes could be maintained further in this co‐culture condition. The prolonged cultivation of fetal thymocytes resulted in the establishment of the fetal thymocyte line and its several clones. CD4 single‐positive cells of activated fetal thymocytes first appeared 14 days after the onset of culture and their number increased, whereas CD8+ cells or CD4CD8 double‐positive cells were not observed. These results indicate that fetal CD4−CD8− thymocytes underwent phenotypic change after long periods of culture. All established clones of fetal thymocytes are CD4 single positive showing lymphocyte‐TNC interactions but do not express CD3 complex. Northern blot analysis detected mRNA for the γ T cell receptor, but no messages for the δ, α or β T cell receptor. Chemical cross‐linking of 125I‐labeled IL2 revealed that the 90‐kDa band (presumably considered to be the IL2R β chain) was clearly present in IL2‐responsive fetal clones, whereas freshly isolated day 14–15 fetal thymocytes lacked the band.

Taken together, TNC might be involved in the differentiation and /or expansion of murine fetal thymocytes by inducing IL2R β chain, which forms the functional IL2R together with IL2R α chain and CD4, one of the T cell accessory molecules, on the cell surface through direct cell‐cell interaction.
Pulmonary epithelial T cells induced by viral infection express T cell receptors α/β
Authors: Openshaw J. M.
Published: March 2007

Cells were recovered from the lungs of mice by bronchoalveolar lavage before and after infection with respiratory syncytial (RS) virus. Uninfected mice yielded mostly macrophages, but after RS virus infection lymphocytes also appeared. Recovered cells were stained for CD4, CD8 and either CD3, T cell receptor (TcR) α/β or TcR γ/δ and analyzed by 3‐color flow cytometry. Both the CD4+CD8− and CD4−CD8+ subpopulations stained uniformly for CD3 and TcR α/β, while none stained for TcR γ/δ. Of the CD4−CD8− cells, about 5% stained for CD3 and TcR α/β during the first week after infection, although this figure increased during the second week. A small and variable fraction of this subset stained for TcR γ/δ. These results oppose the view that lymphocytes expressing TcR γ/δ predominate in initial epithelial immune responses to viral infections.
Contribution of the gene linked to the T cell receptor β chain gene complex of NZW mice to the autoimmunity of (NZB × NZW)F1 mice
Authors: Hirose Sachiko , Tokushige Katsutoshi , Kinoshita Kohji , Nozawa Shingo , Saito Juichi , Nishimura Hiroyuki , Shirai Toshikazu
Published: March 2007

We have investigated the contribution to the autoimmune disease of (NZB × NZW)F1 (NZB/W) mice made by the T cell receptor β (TcR β) chain gene complex, or genes linked to it, that are derived from the NZW strain. For this, we developed the NZW.TcR βNZB strain, a NZW congenic line carrying the TcR β of NZB type, and produced NZB × NZW.TcR βNZB (NZB/W.TcR βNZB)F1 mice. We compared the amounts of anti‐DNA and anti‐histone antibodies and also the severity of lupus nephritis in these mice with those in the original NZB/W F1 mice. We obtained evidence for significantly lower serum levels of autoantibodies to double‐stranded and single‐stranded DNA and histone, and a later onset and a lower incidence of proteinuria in the NZB/W.TcR βNZB F1 mice than in the original NZB/W F1 mice. These findings clearly indicate that the gene (s) within or closely linked to the TcR β chain gene complex on chromosome 6 of the NZW strain acts to intensify the feature of systemic lupus erythematosus in the NZB/W F1 strain. The significant relationship of this finding to the strict dependency of NZB/W F1 disease on the H2d/H2z heterozygosity is discussed.
Activation of a natural killer clone upon target cell binding via CD2
Authors: Nakamura Tetsuya , Takahashi Kazuhisa , Koyanagi Makoto , Yagita Hideo , Okumura Ko
Published: March 2007

The functional relevance of CD2‐mediated signal transduction in triggering T cell receptor/CD3‐independent natural killer cell cytotoxicity was investigated by introducing wild‐type CD2 or signaling‐deficient CD2 with truncated cytoplasmic region into a murine natural killer‐like large granular lymphocyte clone lacking CD2 and T cell receptor/CD3. The introduction of wild‐type CD2 led to CD2‐dependent binding and cytotoxicity against P815 target cells. In contrast, the introduction of mutant CD2 with truncated cytoplasmic region led to comparable P815 binding but reduced cytotoxicity as compared with the wild type. These results provide a direct evidence for CD2‐mediated triggering of NK cell cytotoxicity upon target cell binding.