bluuebunny/crossref_metadata_2025 huggingface dataset:
IL-2 knockout recipient mice reject islet cell allografts.
Authors: Steiger J , Nickerson P W , Steurer W , Moscovitch-Lopatin M , Strom T B
Published: December 2022

The IL-2 pathway is portrayed often as central to allograft rejection. To test this hypothesis, we studied IL-2-deficient mice as allograft recipients. IL-2 gene knockout (KO) mice reject islet allografts and demonstrate a classical mononuclear leukocytic infiltrate, containing CD4+ and CD8+ T cells, surrounding and invading the islet allografts. Moreover, allograft rejection in the IL-2 KO mouse is associated with intragraft expression of certain cytokine and CTL attack molecule genes (e.g. IFN-gamma, IL-4, IL-7, IL-10, and granzyme B). In separate experiments, IL-2 KO mice generated CTLs in response to in vivo challenge with allogeneic tumor cells. Although IL-2 KO mice reject allografts in vivo, spleen cells from immunologically naive IL-2 KO mice exhibit a diminished proliferative response to mitogens in vitro that could be restored largely by exogenous IL-2, IL-4, or IL-7. The paradoxical ability to execute graft rejection in vivo despite near absent T cell proliferative responses in vitro may result from the expression of IL-7 in vivo, but not in vitro. Con A-stimulated bulk spleen cell cultures derived from IL-2 KO mice were essentially devoid not only of IL-2 but also IL-7 gene transcripts. These data indicate that 1) IL-2 is not the sole T cell growth factor capable of supporting allograft rejection and 2) expression of IL-4, but not IL-2, during the allograft response does not lead inevitably to tolerance.
CD28-B7 costimulatory blockade by CTLA4Ig prevents actively induced experimental autoimmune encephalomyelitis and inhibits Th1 but spares Th2 cytokines in the central nervous system.
Authors: Khoury S J , Akalin E , Chandraker A , Turka L A , Linsley P S , Sayegh M H , Hancock W W
Published: December 2022

We studied the contribution of the CD28-B7 costimulatory T cell activation pathway to the pathogenesis of experimental autoimmune encephalomyelitis in the Lewis rat model. Systemic administration of CTLA4Ig suppressed clinical disease and was effective even when CTLA4Ig was delayed until day 10 postimmunization, a time when pathologic disease is evident. This protection was not reversible by systemic administration of high doses of IL-2. Detailed immunohistologic studies showed that CTLA4Ig therapy resulted in suppression of the inflammatory response with inhibition of Th1 (IL-2 and IFN-gamma) and sparing of Th2 (IL-4, IL-10, and IL-13) cytokines in the central nervous system. These results indicate that the CD28-B7 T cell costimulatory pathway plays an important role in experimental autoimmune encephalomyelitis, a Th1-mediated disease, and suggest that blockade of this costimulatory pathway protects against active disease by causing a state of immune deviation towards Th2 function. The ability of CTLA4Ig to treat animals with pathologically established disease may have important clinical implications for patients with multiple sclerosis.
Prostaglandin E2 at priming of naive CD4+ T cells inhibits acquisition of ability to produce IFN-gamma and IL-2, but not IL-4 and IL-5.
Authors: Katamura K , Shintaku N , Yamauchi Y , Fukui T , Ohshima Y , Mayumi M , Furusho K
Published: December 2022

We investigated the effect of prostaglandin E2 on the acquisition of cytokine-producing ability by naive CD4+ T cells in human cord blood. Naive CD4+ T cells were stimulated for 3 days with mouse monoclonal anti-CD3 Ab, then washed and expanded in IL-2-containing medium for 3 more days. These activated T cells produced IL-2, IL-4, IL-5, and IFN-gamma upon stimulation with PMA and ionomycin. PGE2 added at priming of naive T cells inhibited the production of IL-2 and IFN-gamma, but not of IL-4 and IL-5, in a dose-dependent manner. This change in the cytokine production profile induced by PGE2 was maintained in T cells restimulated with anti-CD3 in the absence of PGE2, expanded by IL-2, and stimulated with PMA and ionomycin. The mRNA expression of IFN-gamma and IL-2, but not that of IL-4, was also decreased in these cells. Forskolin and dibutyryl cAMP had a similar effect. PGE2 must exist at an early stage of T cell activation to inhibit priming for IL-2 and IFN-gamma production. PGE2 also showed this effect, even in the presence of exogenous IFN-gamma, at the primary stimulation. These results indicate that PGE2 inhibits the acquisition of the ability to produce IL-2 and IFN-gamma by acting directly on naive T cells. Our results suggest that PGE2 plays a role in facilitating the development of the Th2-type cytokine production profile.
Alterations in cytokine and antibody production following chemical sympathectomy in two strains of mice.
Authors: Kruszewska B , Felten S Y , Moynihan J A
Published: December 2022

It is becoming clear that immune responses are subject to modulation by the sympathetic nervous system. We examined the effect of chemical sympathectomy (to ablate peripheral sympathetic nerve fibers) on cytokine and Ab production in two strains of mice that are known to differ in their response to a variety of pathogens and in the dominant types of cytokines produced. C57Bl/6J mice produce a strong cell-mediated response, characterized by production of IL-2 and IFN-gamma, whereas BALB/cJ have a dominant humoral response, with production of IL-4 and IL-10. Animals were denervated by injection with 6-hydroxydopamine and immunized with keyhole limpet hemocyanin, and spleens were removed at various times after immunization. Denervation significantly increased the keyhole-limpet-hemocyanin-stimulated in vitro proliferation and IL-2 and IL-4 production by splenocytes from both strains. The increases were prevented by pretreatment with desipramine, which blocks the uptake of 6-hydroxydopamine into the nerve fibers and subsequent nerve fiber destruction. Serum titers of IgM, IgG, IgG1, and IgG2a were also enhanced in the C57Bl/6J strain; BALB/cJ mice had a small increase in IgG1 only. These results suggest that one function of splenic innervation and transmitter release may be to modulate T helper cytokines, thereby partially regulating immune effector function. Our evidence is consistent with a model of immune regulation in which removal of sympathetic nervous system input enhances at least some parameters of immune responses.
Mucosal adjuvant effect of cholera toxin in mice results from induction of T helper 2 (Th2) cells and IL-4.
Authors: Marinaro M , Staats H F , Hiroi T , Jackson R J , Coste M , Boyaka P N , Okahashi N , Yamamoto M , Kiyono H , Bluethmann H , Fujihashi K , McGhee J R
Published: December 2022

Despite pathophysiologic effects including diarrhea, cholera toxin (CT) is a potent mucosal immunogen and adjuvant. We investigated the influence of CT on T helper (Th)-type 1 (Th1) and Th2 cell-regulated Ag-specific B cell isotype and IgG subclass Ab responses elicited when the toxin was co-administered orally with different protein Ags. When mice were orally immunized with tetanus toxoid (TT) and CT as adjuvant, this regimen induced TT-specific secretory IgA responses in the gastrointestinal tract as well as serum IgG, including IgG1 and IgG2b subclasses, and IgA responses. This oral regimen also induced TT- and CT-B-specific IgE responses. In addition, CT also elicited adjuvant effects for Ag-specific IgG1, IgE, and IgA responses when two other protein Ags, OVA and hen egg white lysozyme, were given by the oral route. Quantitative reverse transcriptase-PCR was performed to assess levels of mRNA for Th1 (IFN-gamma) and Th2 (IL-4) cytokine expression in TT-stimulated CD4+ T cell cultures. Both Peyer's patches and splenic CD4+ T cells expressed markedly increased levels of IL-4-specific message, but did not result in changes in IFN-gamma mRNA expression. To determine whether the route of immunization influenced IgE responses, mice were immunized s.c. with TT and CT as adjuvant. Significant increases in total and TT-specific IgE Abs were induced when CT was co-administered. Taken together, these results show that CT acts as a mucosal adjuvant to enhance Th2-type responses and in particular, the IL-4 produced results in a characteristic Ab isotype pattern associated with this cytokine.
Stimulation of thymocytes before and after positive selection results in the induction of different NF-kappa B/Rel protein complexes.
Authors: Moore N C , Girdlestone J , Anderson G , Owen J J , Jenkinson E J
Published: December 2022

Positive selection triggers the differentiation of immature CD4+8+TCRlow thymocytes into TCRhigh single-positive CD4+ or CD8+ cells and is associated with major changes in gene expression. However, little is known about the DNA binding factors controlling these fundamental changes. Here we have examined NF-kappa B/Rel subunit expression and DNA-binding activity in developing thymocytes before and after the induction of positive selection. We show that positive selection is accompanied by the strong up-regulation of c-rel mRNA expression and the constitutive activation of p50/p65 and p50/c-Rel NF-kappa B/Rel complexes, confirming the activation-like status of cells undergoing positive selection. Moreover, CD69+ cells that have initiated positive selection (but not their preselection CD4+8+TCR- precursors) respond to stimulation by the preferential activation of c-Rel-containing DNA-binding complexes. Because the different NF-kappa B/Rel dimers have distinct transcriptional activities and binding site preferences, this preferential activation of c-Rel-containing DNA-binding complexes may well have implications for the changes in gene expression and functional response associated with positive selection.
Differentiation to T helper cells in the thymus. Gradual acquisition of T helper cell function by CD3+CD4+ cells.
Authors: Vanhecke D , Verhasselt B , Debacker V , Leclercq G , Plum J , Vandekerckhove B
Published: December 2022

We investigated at which point during thymocyte differentiation functions were acquired that are characteristic for mature Th cells. Differentiation from CD3+CD69-, CD4+CD8+ double-positive (DP) cells to terminally differentiated CD3+, CD4+CD8- single-positive (SP) cells was broken down into six discrete stages that were purified by four-color sorting: CD69-CD3+DP (stage 0), CD69+CD27-DP (stage 1), CD69+CD27-CD4+SP (stage 2), CD27+CD1+CD4+SP (stage 3), CD1-CD45RO+CD4+SP (stage 4), and CD1-CD45RO-CD4+SP cells (stage 5). Phenotypically, these stages seem to describe consecutive steps in differentiation from immature stage 0 to the terminally matured stage 5. Functionally, the capacity to proliferate on IL-2 after stimulation was absent in CD69- stage 0 cells, but was acquired gradually during stages 1 to 4. Clonal expandability and the capacity to respond to stimulation with the production of cytokines were acquired later and rather abruptly by CD1- stage 4 and 5 cells. Activation markers such as CD69 expression and in vivo IL-2 gene transcription came up simultaneously at the DP stage and peaked at stage 3 to 4. These data suggest that functional maturation of Th cells occurs over an extended period in differentiation, stages 1 to 4, and coincides with a gradual increase in activation markers. After completion of functional differentiation, at stage 5, in vivo IL-2 mRNA transcription and CD69 expression are down-regulated, and the cells become functionally resting naive T cells expressing CD45RA+.
Interference of distinct invariant chain regions with superantigen contact area and antigenic peptide binding groove of HLA-DR.
Authors: Vogt A B , Stern L J , Amshoff C , Dobberstein B , Hämmerling G J , Kropshofer H
Published: December 2022

In the endoplasmic reticulum, MHC class II alpha beta dimers associate with the trimeric invariant chain (li), generating a nine-subunit (alpha beta li)3 complex. In the presence of li, the peptide binding groove is blocked, so that loading with self or antigenic peptides can only occur after proteolytic removal of li in specialized post-Golgi compartments. The class II-associated invariant chain peptide region of li (about residues 81-104) is known to mediate binding to class II molecules and blockade of the groove, but this does not exclude additional contact sites for li. Using a set of overlapping li peptides and recombinant soluble li, we demonstrate here that a large segment of li encompassing approximately residues 71 to 128 interacts with HLA-DR molecules. The N- and C-terminal regions of this li segment appear to bind outside the peptide groove to the contact area for the staphylococcal superantigen Staphylococcus aureus enterotoxin B on the alpha 1 domain. The core region of this segment (residues 95-108) prevents binding of antigenic peptides, probably by interaction with the peptide groove. Occupation of the groove with antigenic peptides abolishes binding not only of the core region, but also that of those li peptides that bind outside the groove. These findings suggest the existence of distinct conformational states of class II molecules, with li binding preferentially to one form.
Identification of an HLA-A11-restricted epitope from the tandem repeat domain of the epithelial tumor antigen mucin.
Authors: Doménech N , Henderson R A , Finn O J
Published: December 2022

Epithelial cell mucin encoded by the MUC-1 gene is overexpressed and aberrantly glycosylated on pancreatic, breast, and ovarian cancers as well as on multiple myelomas. It is recognized by patients' Ab and by T cells derived from tumor-draining lymph nodes. The T cell recognition is not MHC restricted and is specific for an epitope previously localized to the immunodominant tandem repeat region of the native mucin molecule. In search of possible MHC-restricted epitopes in the same immunodominant region, we synthesized a panel of overlapping, nine-amino acid long peptides spanning the MUC-1 tandem repeat and first examined their binding to specific human MHC class I molecules using two independent flow cytometry-based assay systems. This approach identified one peptide, p9-17 (STAPPAHGV), that bound to HLA-A1, -A2.1, -A3, and -A11. Measurements of the affinity of binding to each of these alleles, using a quantitative molecular binding assay, indicated that only the relative binding affinity to HLA-A11 was close to immunogenic values. We tested the immunogenicity of p9-17 in vitro. We detected a secondary T cell response specific for p9-17 in lymph nodes from an HLA-A11 breast cancer patient. Moreover, CTL specific for p9-17 peptide could be generated from PBL in several healthy HLA-A11 donors by primary in vitro stimulation.
The role of monocyte chemotactic protein-1 (MCP-1) in the recruitment of monocytes and CD4+ T cells during a pulmonary Cryptococcus neoformans infection.
Authors: Huffnagle G B , Strieter R M , Standiford T J , McDonald R A , Burdick M D , Kunkel S L , Toews G B
Published: December 2022

Cryptococcus neoformans is acquired via the respiratory tract and is the leading cause of fatal mycosis in AIDS. Development of a T cell-mediated pulmonary inflammatory response is critical for clearance of this pathogen; however, the chemotactic factors that mediate inflammatory cell recruitment into the lungs have not been identified. In the present study, the bronchoalveolar lavage (BAL) fluid levels of the C-C chemokine monocyte chemotactic protein-1 (MCP-1) and the recruitment of inflammatory cells both increased following pulmonary infection with C. neoformans. The kinetics of MCP-1 production in the lungs correlated most closely with the recruitment of CD4+ T cells and monocytes/macrophages. Administration of neutralizing anti-MCP-1 Abs in vivo reduced the BAL fluid levels of MCP-1, decreased the recruitment of both macrophages (> 95%) and CD4+ T cells (76 +/- 9%), and inhibited cryptococcal clearance. Although no in vitro neutrophil or B cell chemotactic activity has been reported for MCP-1, recruitment of these leukocytes was also decreased in anti-MCP-1-treated mice (most likely an indirect effect of reducing the number of CD4+ T cells and macrophages). Neutralization of MCP-1 also resulted in decreased BAL fluid levels of TNF-alpha and IL-6. This is the first demonstration of a role for MCP-1 in clearance of an infection, and provides direct evidence that MCP-1 plays a critical role in the T cell-dependent immune response to C. neoformans.
Increased susceptibility of fas mutant MRL-lpr/lpr mice to staphylococcal enterotoxin B-induced septic shock.
Authors: Mountz J D , Baker T J , Borcherding D R , Bluethmann H , Zhou T , Edwards C K
Published: December 2022

MRL-lpr/lpr mice are defective in the fas Ag/APO-1 apoptosis gene (CD95). Using the hepatotoxin D-galactosamine (D-GalNH2), we demonstrate that MRL-lpr/lpr mice have an increased susceptibility to staphylococcal enterotoxin B (SEB)-induced lethal shock, which causes them to exhibit the septic shock-like behaviors of fur ruffling and listlessness, and death occurs within 8 to 18 h. SEB susceptibility is greater in V beta 8.2 TCR transgenic MRL-lpr/lpr mice than in nontransgenic mice. In studies designed to elucidate the molecular pathways of SEB-induced septic shock, we found that C57Bl/6.Ab0/Ab0, MHC class II-deficient "C2D" mice, but not C57Bl/6-(+/+) mice, are nonresponsive to challenge with SEB. C2D mice, backcrossed with the fas mutation resulting in double-knockout C2D;lpr/lpr mice, are more susceptible to challenge with SEB/D-GalNH2. The LD50s for C57Bl/6.C3H-gld/gld "fas ligand-mutant mice" challenged with SEB/D-GalNH2 were comparable to C57Bl/6.MRL-lpr/lpr and MRL-lpr/lpr mice, suggesting that reciprocal mutations in either fas or fas ligand increases susceptibility to bacterial superantigens (SAGs). SEB-induced lethal shock can be reversed by treatment with Abs to V beta 8 TCR, MHC class II Ia+, IL-2, and TNF-alpha, by the immunosuppressant cyclosporin A, or by treatment with carbocyclic nucleoside analogues. These data indicate that SAG-induced septic shock is dependent on interactions with the TCR and MHC class II Ags, and they also suggest a critical role for a functional fas and/or fas ligand in resistance to SAG-induced septic shock.
High level monocyte chemoattractant protein-1 expression in transgenic mice increases their susceptibility to intracellular pathogens.
Authors: Rutledge B J , Rayburn H , Rosenberg R , North R J , Gladue R P , Corless C L , Rollins B J
Published: December 2022

We have constructed transgenic mice in which the mouse mammary tumor virus long terminal repeat controls the expression of murine monocyte chemoattractant protein-1 (MCP-1). Several independently derived lines of transgenic mice constitutively expressed MCP-1 protein in a variety of organs. Protein extracts from these organs had substantial in vitro monocyte chemoattractant activity that was neutralized by an anti-MCP-1 Ab, indicating that transgenic MCP-1 protein is biologically active. However, no transgenic mouse at any age displayed monocyte infiltrates in MCP-1-expressing organs. Two transgenic lines had circulating MCP-1 levels of 13 to 26 ng/ml, which is a concentration sufficient to induce maximal monocyte chemotaxis in vitro. These transgenic lines showed a 1 to 1.5 log greater sensitivity to infection with Listeria monocytogenes and Mycobacterium tuberculosis. A third transgenic line had lower serum levels of MCP-1 and was resistant to L. monocytogenes. The results suggest that this transgenic model is one of monocyte nonresponsiveness to locally produced MCP-1 due to either receptor desensitization or neutralization of a chemoattractant gradient by high systemic concentrations of MCP-1. Regardless of the mechanism, the data indicate that constitutively high levels of MCP-1 expression do not induce monocytic infiltrates, and that MCP-1 is involved in the host response to intracellular pathogens.
Neutrophil inhibitory factor prevents neutrophil-dependent lung injury.
Authors: Barnard J W , Biro M G , Lo S K , Ohno S , Carozza M A , Moyle M , Soule H R , Malik A B
Published: December 2022

Neutrophil inhibitory factor (NIF) is a recently cloned 41-kDa protein from the canine hookworm that binds CD11b/CD18 and inhibits CD11b/CD18-dependent neutrophil adhesion. We evaluated NIF's effects on neutrophil-dependent lung injury in guinea pigs. Pulmonary vascular endothelial CD54 (ICAM-1) was induced in buffer-perfused lungs by 90-min exposure to 1000 U/ml TNF-alpha. Human neutrophils (2 x 10(7)) were added to the perfusate and activated by 5 x 10(-9) PMA; in some lungs, the neutrophils were pretreated with NIF (100 nM) before their addition to the perfusate. Lung injury was assessed by wet:dry weight ratio, and neutrophil uptake by lung myeloperoxidase (MPO) activity. HUVEC exposed to TNF-alpha for 90 min were assayed for neutrophil adhesion, and we compared PMA-stimulated neutrophil adhesion to endothelial cells and fibrinogen-coated plates. PMA-induced pulmonary edema (lung wet:dry ratio increased from 8.8 +/- 0.7 to 18.8 +/- 4.4) was inhibited by NIF (10.0 +/- 1.0). Lung MPO activity concomitantly decreased from 17.1 +/- 6.1 to 8.7 +/- 1.8 U/mg dry lung tissue in the NIF-treated group, similar to controls (6.9 +/- 2.0). Endothelial monolayer experiments confirmed that NIF reduced neutrophil adherence (basal adhesion of 11 +/- 3% increased to 30 +/- 5% with TNF-alpha pretreatment of endothelial cells, an increase that was reduced to 10 +/- 4% with NIF). Moreover, NIF prevented PMA-induced neutrophil adhesion to fibrinogen, a CD11b/CD18-dependent event, but produced a smaller decrease in adherence to endothelial cells, which also involves CD11a/CD18 integrins. These studies indicate that NIF prevents neutrophil-dependent lung vascular injury by inhibiting neutrophil adhesion to the TNF-alpha-activated endothelium.
Stimulation of CD40 with purified soluble gp39 induces proinflammatory responses in human monocytes.
Authors: Kiener P A , Moran-Davis P , Rankin B M , Wahl A F , Aruffo A , Hollenbaugh D
Published: December 2022

CD40 is a glycoprotein of about 50 kDa that plays a crucial role in B cell growth and differentiation. It is found on the surface of B cells, follicular dendritic cells, monocytes, and some endothelial, epithelial, and carcinoma cells. Engagement of CD40 with anti-CD40 mAbs, gp39 expressed on the cell surface or soluble forms of gp39, primes B cells to efficiently respond to subsequent stimulatory signals leading to B cell proliferation, differentiation, and isotype switching. Peripheral monocytes also express CD40 on the cell surface and expression in increased following treatment with IFN-gamma. Using a soluble murine CD8/human gp39 fusion protein (sgp39) we have found that CD40 plays a crucial role in the regulation of monocyte function. Stimulation of human peripheral monocytes with sgp39 induced homotypic aggregation and significantly increased the expression of several cell-surface proteins including CD54, MHC class II, CD86, and CD40. Soluble gp39 also dramatically enhanced monocyte survival, preventing the onset of apoptosis that normally occurs upon withdrawal of serum. Finally, in the absence of any costimulatory molecules, sgp39 stimulated monocytes to produce TNF-alpha, IL-1 beta, IL-6, and IL-8. These results suggest that ligation of CD40 on human monocytes induces phenotypic changes that would be expected to influence T cell activation by the monocyte and also to enhance or prolong inflammatory responses.
TGF-beta enhances macrophage ability to produce IL-10 in normal and tumor-bearing mice.
Authors: Maeda H , Kuwahara H , Ichimura Y , Ohtsuki M , Kurakata S , Shiraishi A
Published: December 2022

In the present study, we demonstrate that TGF-beta is capable of enhancing macrophage ability to produce IL-10 in normal and EL4 tumor-bearing mice. We found the increase in IL-10 in ascitic fluid and IL-10 mRNA expression in macrophages in parallel with the TGF-beta level and tumor progression. The macrophage production of IL-10 in the tumor-bearing mice was significantly enhanced without LPS stimulation in vitro, compared with normal controls. To clarify the mechanism wherein increased IL-10 production was induced, anti-TGF-beta or anti-IL-10 Abs were administered to EL4-bearing mice. Administration of anti-TGF-beta Ab led to a reduction in the IL-10 contents in ascitic fluid of tumor-bearing mice; however, anti-IL-10 Ab administration did not prevent the increase in TGF-beta contents. Enhanced IL-10 production and mRNA expression of macrophages from the tumor-bearing mice were also reduced by anti-TGF-beta Ab administration. Both anti-TGF-beta and anti-IL-10 Ab administration restored the TNF-alpha production by macrophages in EL4-bearing mice. In normal macrophages, in vitro pretreatment with TGF-beta 1 potentiated IL-10 production, and when natural TGF-beta 1 was administered to normal mice, the recovered peritoneal macrophages showed enhanced IL-10 production. Based on the above findings it can be concluded that TGF-beta enhances macrophage ability to produce IL-10, which sheds a new light on the role of TGF-beta in the immune system.
Classical complement pathway activation on nucleated cells. Role of factor H in the control of deposited C3b.
Authors: Ollert M W , David K , Bredehorst R , Vogel C W
Published: December 2022

The restriction of alternative complement pathway activation in fluid phase or on nonactivator surfaces has been described as the major physiologic function of the complement regulatory protein factor H. In this study, we provide evidence that factor H is also a restriction factor of classical pathway activation on the surface of nucleated cells. We found that C3b was rapidly converted to inactivated C3b (iC3b) on human SK-MEL-93-2 melanoma cells after classical pathway activation with the murine monoclonal IgG3 Ab R24 directed against the disialoganglioside surface Ag GD3. The SK-MEL-93-2 cells are nonactivators of the alternative pathway and express neither CR1 (CD35) nor the C3b-cleaving protease p65. The cells are further characterized by the expression of only moderate amounts of DAF (CD55) and approximately 5 x 10(3) MCP (CD46) molecules/cell. FACS analysis and direct quantitation using [125I]factor H revealed high level binding of factor H to the melanoma cells (5.6 x 10(6) molecules/cell) during classical pathway activation. The binding of factor H could be inhibited under conditions that inactivate the classical complement pathway (EGTA and heat treatment), but not by factor B depletion of the serum, demonstrating that classical pathway activation was responsible for factor H binding. Treatment of factor B-depleted serum with neutralizing concentrations of polyclonal anti-factor H resulted in the prolonged presence of intact C3b on the cells and a significantly reduced generation of iC3b. The increased amount of C3b on these cells correlated with a 2.65-fold greater rate of cell death. In contrast, the increase in cell death effected by neutralizing concentrations of anti-CD46 or anti-CD55 Ab was only 0.13- or 0.35-fold, respectively. In addition, the supplementation of serum with purified factor H decreased the extent of lysis of the cells. Collectively, these data provide experimental evidence that factor H, through its cofactor activity for C3b degradation, is involved in the restriction of the classical pathway of complement on the surface of nucleated cells, a function that to date has been exclusively attributed to the membrane regulatory proteins CD35 and CD46.
An important role for the chemokine macrophage inflammatory protein-1 alpha in the pathogenesis of the T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis.
Authors: Karpus W J , Lukacs N W , McRae B L , Strieter R M , Kunkel S L , Miller S D
Published: December 2022

Experimental autoimmune encephalomyelitis (EAE) is a CD4+ T cell-mediated, inflammatory demyelinating disease of the central nervous system (CNS) that serves as a model for the human demyelinating disease, multiple sclerosis. A critical event in the pathogenesis of EAE is the entry of both Ag-specific T lymphocytes and Ag-nonspecific mononuclear cells into the CNS. In the present report we investigated the role of two C-C chemokines (macrophage inflammatory protein-1 alpha (MIP-1 alpha) and monocyte chemotactic protein-1) and a C-x-C chemokine (MIP-2) in the pathogenesis of EAE. Production in the CNS of MIP-1 alpha, but not that of MIP-2, a rodent homologue of IL-8, or monocyte chemotactic protein-1, correlated with development of severe clinical disease. Administration of anti-MIP-1 alpha, but not that of anti-monocyte chemotactic protein-1, prevented the development of both acute and relapsing paralytic disease as well as infiltration of mononuclear cells into the CNS initiated by the transfer of neuroantigen peptide-activated T cells. Ab therapy could also be used to ameliorate the severity of ongoing clinical disease. Anti-MIP-1 alpha did not affect the activation of encepahlitogenic T cells as measured by cytokine secretion, surface marker expression, and ability to adoptively transfer EAE. These results demonstrate that MIP-1 alpha plays an important role in directing the chemoattraction of mononuclear inflammatory cells in the T cell-mediated autoimmune disease, EAE.
Effects of recombinant dimeric TNF receptor on human inflammatory responses following intravenous endotoxin administration.
Authors: Suffredini A F , Reda D , Banks S M , Tropea M , Agosti J M , Miller R
Published: December 2022

Effects of dimeric TNF receptor (p80) Fc (TNFR:Fc) on acute phase responses were evaluated in 18 volunteers given endotoxin (4 ng/kg i.v.). Subjects were randomized to receive either placebo (n = 6), low dose TNFR:Fc (10 mg/m2 i.v., n = 6), or high dose TNFR:Fc (60 mg/m2 i.v., n = 6). TNFR:Fc blocked plasma TNF bioactivity (p = 0.001) and increased, in a dose-ordered fashion, TNF immunoactivity (p < 0.001). TNFR:Fc decreased secondary cytokine levels including IL-1 beta (p = 0.007), IL-8 (p < 0.001), IL-1 receptor antagonist (p < 0.001), granulocyte-CSF (p = 0.03), and growth regulated peptide-alpha (p = 0.001) but not macrophage inflammatory protein-1 alpha or IL-10. Low dose, but not high dose, TNFR:Fc blunted or delayed the release of epinephrine and cortisol (p < or = 0.026). Despite the absence of plasma TNF bioactivity, high dose TNFR:Fc was less immunosuppressive than low dose TNFR:Fc as measured by cytokine and stress hormone responses. Endotoxin-related symptoms were not altered by TNFR:Fc and the febrile response was delayed but not diminished (p = 0.004). Increases in cardiac index (72 +/- 19%) and heart rate (60 +/- 10%) and decreases in systemic vascular resistance index (47 +/- 7%) were unaltered by TNFR:Fc. These data suggest that the inflammatory response to endotoxin can escape from high levels of circulating TNF-blocking activity and redundant pathways, independent of circulating TNF, can sustain inflammation and clinical responses caused by acute endotoxemia.
Oligoclonal expansion of CTLs directed against a restricted number of dominant minor histocompatibility antigens in hemopoietic chimeras.
Authors: Brochu S , Baron C , Hétu F , Roy D C , Perreault C
Published: December 2022

To understand how T cells respond to allogeneic minor histocompatibility Ags (MiHAs), we studied the fate of Thy-1.1+ lymphocytes, as well as their TCR usage and functional activity, in irradiated LP (Thy-1.2+) recipients transplanted with a mixture of C57BL/6 (Thy-1.2+) hemopoietic progenitors supplemented with either low or high numbers of B6.PL lymphocytes (Thy-1.1+). Mice transplanted with low numbers of T cells experienced a dramatic expansion (> or = 10(5)-fold) of donor Thy-1.1+/CD8+ cells during the first 15 days post-transplant. Flow-cytometric analysis and sequencing of junctional nucleotide sequences showed that the nature of this expansion was oligoclonal and involved primarily one or a few clones using V beta 5.1 or V beta 8.1 TCR elements. Expanded T lymphocyte populations displayed MHC-restricted cytotoxicity for a restricted number of MiHAs, that were found in only two peaks following fractionation of LP MiHAs by reverse-phase HPLC. Expansion of donor T cells was limited to the spleen, and short-lived in these recipients that became healthy long-term chimeras without any signs of graft-vs-host disease (GVHD). In contrast, mice transplanted with high numbers of T cells (GVHD+) showed proliferation of Thy-1.1+ donor cells not only in the spleen, but also in the thymus, and recipients died rapidly of GVHD. These results show that: 1) in the MiHA-incompatible transplantation setting, lack of GVHD cannot be explained simply by the absence of antihost T cell responses, 2) GVHD+ recipients present a massive thymic infiltration by donor mature T lymphocytes, and 3) antihost T cell responses are oligoclonal in nature and targeted to only a few MiHAs. These findings shed new light on the pathogenetic mechanisms involved in GVHD and on the selection of the T cell repertoire involved in response to immunodominant MiHAs.
Triggering of a sustained calcium response through a p56lck-dependent pathway by exogenous ganglioside GM1 in human T lymphocytes.
Authors: Gouy H , Debré P , Bismuth G
Published: December 2022

Various biologic effects induced by free external gangliosides, including cell-signaling events, have been described in several cell systems. We show in this report that free monosialoganglioside GM1, following its rapid and saturable binding to the cell membrane of human Jurkat T cells, triggers in a few seconds a sustained elevation of the intracellular free calcium concentration. It also induces in parallel the early tyrosine phosphorylation of numerous proteins, including phospholipase C gamma-1. Parallel experiments performed with asialo-GM1 or the ceramide part of the molecule do not reproduce these effects, demonstrating the prominent role played by the sialylated part of the ganglioside. A marked conversion of the T cell-specific tyrosine kinase p56lck to a slow migrating 60-kDa form is also found following GM1 addition. It is accompanied in the same time by an increased kinase activity in p56lck immunoprecipitates. Finally, the marked calcium response and tyrosine phosphorylations triggered by GM1 cannot be observed in a p56lck-negative T cell variant. Together these results demonstrate that the monosialoganglioside GM1 can behave as an authentic activation molecule on human T lymphocytes, likely through a p56lck tyrosine kinase-dependent pathway.
Cross-linking of CD45 on NK cells stimulates p56lck-mediated tyrosine phosphorylation and IFN-gamma production.
Authors: Xu X , Chong A S
Published: December 2022

The cross-linking of low-affinity Fc gamma RIIIA on NK cells with specific mAbs or aggregated IgG stimulates both cytotoxic activity and cytokine production. In addition, the interaction of NK cells with certain tumor cells can also stimulate cytokine production and cytotoxic activity. The identity of the molecules on the tumor cell or NK cells involved in this stimulation currently has not been defined. We have reported previously that cross-linking of CD45 and the CD45RO isoform on IL-2-activated NK cells or the NK cell line NK3.3 results in the stimulation of IFN-gamma production. We report here that this effect is specific, because cross-linking of CD45 does not stimulate the expression of cytotoxic activity. Consistent with studies suggesting that cross-linking of CD45 results in reduced phosphatase activity, inhibition of tyrosine phosphatase activity by pharmacologic means also resulted in enhanced tyrosine kinase activity and, ultimately, increased IFN-gamma production. Biochemical analyses and immunofluorescence studies suggest that the tyrosine kinase associated with CD45 is p56lck and that cross-linking of CD45 results in the activation of p56lck. Thus, CD45 may regulate p56lck kinase, which initiates the cascade of intracellular tyrosine phosphorylation events that lead to IFN-gamma transcription and secretion in NK 3.3 cells.
Multiple lineages of tumors express a common tumor antigen, P1A, but they are not cross-protected.
Authors: Ramarathinam L , Sarma S , Maric M , Zhao M , Yang G , Chen L , Liu Y
Published: December 2022

Whether tumors of different lineages share common Ags is a critical issue for understanding anti-tumor immune responses and for designing Ag-specific tumor immunotherapy. Because of lack of cross-protection among individually derived tumors, it has been proposed that tumor Ags are specific for individual tumors. Here we show that lack of cross-protection is not due to lack of a shared tumor Ag. Thus, a plasmocytoma J558 transfected with the costimulatory molecule B7 activates a cross-reactive CTL response in vivo. The major Ag recognized by the cross-reactive CTL is P1A, which is expressed in mastocytoma P815, plasmocytoma J558, and fibrosarcoma Meth A. Surprisingly, no significant cross-protection can be detected among P1A-expressing tumors after immunization with either P1A-expressing or B7-transfected P815 cells. Our results demonstrate that multiple lineages of tumors are not cross-protected even though they share a tumor Ag that can be recognized by CTL. These results have important implications for tumor immunotherapy.
Pulmonary surfactant protein A mediates enhanced phagocytosis of Mycobacterium tuberculosis by a direct interaction with human macrophages.
Authors: Gaynor C D , McCormack F X , Voelker D R , McGowan S E , Schlesinger L S
Published: December 2022

During initial infection with Mycobacterium tuberculosis, bacteria that reach the distal airspaces of the lung are phagocytosed by alveolar macrophages in the presence of pulmonary surfactant. Here we have examined the role of surfactant-associated protein A (SP-A) in phagocytosis of the virulent Erdman strain of M. tuberculosis by human monocyte-derived macrophages (MDMs) and human alveolar macrophages (HAMs). Macrophage monolayers incubated with soluble SP-A from alveolar proteinosis patients (APP SP-A4) and recombinant rat SP-A (SP-Ahyp) demonstrated enhanced adherence of M. tuberculosis, 82 +/- 17% and 49 +/- 18%, respectively. Removal of SP-A from monolayers by washing before adding bacteria did not diminish the enhanced adherence. Fluorescence microscopy demonstrated that washed monolayers contained intracellular rather than surface-bound SP-A. These studies indicated a direct interaction between SP-A and the macrophage in mediating enhanced adherence of M. tuberculosis. Consistent with this interpretation, macrophage monolayers formed on human or rat SP-A (substrate SP-A) demonstrated enhanced adherence of M. tuberculosis to their apical surface (APP SP-A and native rat SP-A increased M. tuberculosis adherence by 102 +/- 16% and 102 +/- 25%, respectively). Electron microscopy demonstrated increased numbers of phagocytosed bacteria in APP SP-A-treated MDM cross-sections. SP-A proteins devoid of carbohydrate failed to enhance M. tuberculosis adherence to macrophages. In contrast, heat-denatured APP SP-A enhanced adherence of bacteria equivalent to that of intact glycoprotein. Thus, the carbohydrate moieties of SP-A appear to be critical in the SP-A-macrophage interaction. Finally, mannan and anti-mannose receptor Ab completely inhibited the enhanced phagocytosis of M. tuberculosis observed with APP SP-A, providing evidence for up-regulation of macrophage mannose receptor activity. These studies implicate SP-A as an important modulator of alveolar macrophage function that results in an enhanced potential for M. tuberculosis to gain access to its intracellular niche.
Chemically detoxified lipid A precursor derivatives antagonize the TNF-alpha-inducing action of LPS in both murine macrophages and a human macrophage cell line.
Authors: Tanamoto K
Published: December 2022

The chemically synthesized disaccharide precursor of lipid A (406) has been demonstrated to reduce its activity in mice by an order of 10(5) or more by replacing the hydroxyl groups with succinyl or acetyl residues. In the present study, these chemically detoxified synthetic lipid A precursors were found to antagonize the LPS action of inducing TNF-alpha in both murine peritoneal macrophages and in human monocyte-macrophage cell line THP-1. These preparations were found to antagonize the induction of TNF-alpha in murine macrophages by both stimulants of LPS and untreated 406, which acts as an agonist in the murine system, in a dose-dependent manner. Complete inhibition by succinylated 406 occurred at 10-fold excesses of the antagonist. Succinylated precursor also antagonized the TNF-alpha-inducing action of LPS in human cell line THP-1. The precursor itself also exhibited antagonism in this assay. The activity of the succinylated 406, however, was much more potent than that of the unmodified precursor. These derivatives do not inhibit either the Limulus gelation activity of LPS, or the induction of TNF-alpha in macrophages by zymosan, indicating that the inhibition is not caused by molecular interaction and that the inhibition is specific to LPS action. These findings suggest common features in murine macrophage and human monocytic cell receptors. They also suggest the importance of the substituents on the hydroxyl groups of 3-hydroxy fatty acids of the nonreducing glucosamine of lipid A for the activity and for transformation to the antagonistic structure.
Endogenous IL-10 protects mice from death during septic peritonitis.
Authors: van der Poll T , Marchant A , Buurman W A , Berman L , Keogh C V , Lazarus D D , Nguyen L , Goldman M , Moldawer L L , Lowry S F
Published: December 2022

IL-10 production during endotoxic shock is part of a protective mechanism that involves IL-10-induced inhibition of TNF synthesis. We sought to determine the role of IL-10 in septic peritonitis induced by cecal ligation and puncture (CLP). CLP led to a rapid induction of IL-10 mRNA in various organs of C57BI/6 mice. In liver, IL-10 mRNA was detectable within 1 h following CLP, while in spleen and lungs, IL-10 mRNA was detected from 2 to 4 h and onward. IL-10 protein became detectable in plasma 2 h after CLP, reaching peak concentrations after 12 h (12.7 +/- 5.7 ng/ml). Pretreatment (-2 h) with anti-IL-10 mAb resulted in higher plasma TNF levels following CLP when compared with mice treated with control mAb. Plasma IL-1 activity and IFN-gamma remained undetectable in virtually all mice. Anti-IL-10 enhanced mortality after CLP (p < 0.05 by log-rank test). Addition of anti-TNF mAb did not influence the increased mortality associated with anti-IL-10 treatment. Septic peritonitis is associated with sustained production of IL-10 in various organs, which serves to protect the host against lethality.
Human dendritic Langerhans cells generated in vitro from CD34+ progenitors can prime naive CD4+ T cells and process soluble antigen.
Authors: Caux C , Massacrier C , Dezutter-Dambuyant C , Vanbervliet B , Jacquet C , Schmitt D , Banchereau J
Published: December 2022

Earlier studies have concluded that fresh Langerhans cells (LC) are able to capture and process native Ags, whereas cultured LC have lost these functions while acquiring the capacity to prime naive T cells. Herein we studied the functions of human dendritic/Langerhans cells (d-Lc) generated in vitro by culturing CD34+ hemopoietic progenitor cells in the presence of granulocyte-macrophage CSF (GM-CSF) + TNF-alpha. Less than 50 d-Lc were found to strongly stimulate the proliferation of 2.5 x 10(4) allogeneic naive CD4+ T cells. Furthermore, six to 50 d-Lc induced half-maximal proliferation of naive syngeneic CD4+ cord blood T cells, in the presence of picomolar concentrations of superantigens. During the alloreaction, the CD4+ T cells were expanded up to 100-fold within two successive stimulation cycles with the same d-Lc, and the recovered T cells were specific for the d-Lc alloantigen. HLA-matched tetanus toxoid (TT)-specific T cell clones were found to proliferate in response to TT presented by CD1a+ d-Lc. Finally, electron microscopy demonstrated that CD1a+ d-Lc were able to capture an Ag (gold-labeled Igs) through receptor-mediated endocytosis. Thus, in vitro generated d-Lc can prime naive T cells and process native Ags, a property that might eventually prove useful for priming Ag-specific naive T cells for cellular immunotherapy.
Anatomical environment as a determinant in viral immunity.
Authors: Doherty P C
Published: December 2022

The immune response is not monolithic. The phenotype of immunity is modulated by the range of environments that lymphocytes experience as they passage through, or lodge for a time in, both secondary lymphoid tissue and other organ systems. Although we are constrained to think in terms of the homogeneity characteristic of the tissue culture flask, the cellular events in particular in vivo sites can vary considerably. The profiles found for accessible "windows" such as the blood, tonsil, or spleen do not necessarily reflect the totality of the host response. The theme of anatomically related divergence in the effector and memory phases of immunity is developed here, using examples from experiments with viruses.
Antigen-dependent clonal expansion of a trace population of antigen-specific CD4+ T cells in vivo is dependent on CD28 costimulation and inhibited by CTLA-4.
Authors: Kearney E R , Walunas T L , Karr R W , Morton P A , Loh D Y , Bluestone J A , Jenkins M K
Published: December 2022

The importance of CD28 costimulation to a primary T cell response in vivo was assessed in an adoptive transfer system where a small population of peptide-specific CD4+ TCR transgenic T cells can be physically tracked. Ag-dependent clonal expansion of the transgenic T cells in draining lymph nodes was blocked by cyclosporin A and required a CD28 signal that was completely inhibited by CTLA-4-Ig or a combination of anti-B7-1 and anti-B7-2 mAbs, but not by either Ab alone. In vivo treatment with the combination of anti-B7-1 and anti-B7-2 mAbs also blocked conversion of the Ag-specific T cells to the activated phenotype. In contrast, anti-CTLA-4 Fab greatly enhanced the in vivo clonal expansion of the Ag-specific T cells. These results suggest that Ag-driven proliferation and phenotype conversion of naive CD4+ T cells is dependent on CD28-derived signals and is inhibited by CTLA-4.
Latent membrane protein-1 induces cyclin D2 expression, pRb hyperphosphorylation, and loss of TGF-beta 1-mediated growth inhibition in EBV-positive B cells.
Authors: Arvanitakis L , Yaseen N , Sharma S
Published: December 2022

The normal cell cycle is regulated by several molecules, such as the tumor-suppressor protein pRb, the G1 cyclins, the cyclin-dependent kinases, and their inhibitors. These regulators are targeted by negative growth regulatory signals, such as that provided by TGF-beta. Here, we show that the presence of either wild-type EBV or its transforming latent membrane protein-1 (LMP-1) results in the loss of TGF-beta 1-mediated growth inhibition in human B cells. Chemical cross-linking with 125I-labeled TGF-beta 1 showed an essentially normal TGF-beta receptor profile in EBV-positive and EBV-negative Burkitt's lymphoma cell lines, and these receptors were shown to be functional in transducing signals, as evidenced by the TGF-beta 1-mediated modulation of junB gene expression. However, TGF-beta 1 did not induce dephosphorylation of pRb in EBV (or LMP-1)-positive cells as opposed to EBV-negative cells, suggesting a dichotomy in the TGF-beta 1 signaling pathway leading to separable gene regulatory and growth inhibitory responses. Furthermore, LMP-1 was found to induce the expression of cyclin D2; normal B cells or EBV-negative Burkitt's lymphoma cells do not express D-type cyclins. Taken together, these data point to a potential mechanism underlying EBV-mediated B cell transformation whereby constitutive induction of key cell cycle regulators by LMP-1 can lead to pRb hyperphosphorylation and uncontrolled cell proliferation.