bluuebunny/crossref_metadata_2025 huggingface dataset:
Human IL-13 production is negatively influenced by CD3 engagement. Enhancement of IL-13 production by cyclosporin A.
Authors: van der Pouw Kraan T C , Boeije L C , Troon J T , Rutschmann S K , Wijdenes J , Aarden L A
Published: December 2022

IL-13, a T cell-derived cytokine, shares many of its biologic activities with the Th2 cytokine IL-4, including induction of a class switch to IgE and anti-inflammatory properties. Its potential impact on development of Th2 responses makes it interesting to determine how the production of IL-13 is regulated and which cell types produce IL-13. In this work, we show that IL-13 is produced optimally by T cells when stimulated with a combination of anti-CD28 and PMA. Unexpectedly, additional ligation of the TCR complex with Abs to CD3 caused an approximately fivefold inhibition of IL-13 production. Moreover, this inhibition could be reversed by cyclosporin A (CsA). The effect of CsA did not depend on the presence of PMA; upon CD3 and CD28 stimulation, CsA equally enhanced IL-13 production. Both naive and memory CD4+ T cells and CD8+ T cells produced IL-13, and production in all cell types could be enhanced by CsA. In contrast to IL-13, IL-4 production was observed mainly in CD4+ memory cells, required costimulation through CD3, and was inhibited by CsA. The unusual regulation and relative abundance of IL-13 make it an important candidate to be controlled tightly by dose and type of TCR ligands. CsA is used widely to inhibit T cell function. The finding that IL-13 production is enhanced instead of diminished in the presence of CsA may explain the Th2-inducing effects of CsA in vivo.
TCRV beta 7+ Th2 cells mediate UVB-induced suppression of murine contact photosensitivity by releasing IL-10.
Authors: Yagi H , Tokura Y , Wakita H , Furukawa F , Takigawa M
Published: December 2022

In murine contact photosensitivity, a cutaneous delayed-type hypersensitivity reaction, preirradiation of the photosensitization site with UVB induced Ag-specific, afferent limb-acting, CD4+CD8- suppressor T cells (Ts). The present study examined usage of TCR V beta and production of immunosuppressive cytokines in Ts propagated in vitro. Spleen cells from UVB-preirradiated, 3,3',4',5- tetracholorosalicylanilide (TCSA)-photosensitized mice were stimulated with 3000-rad-irradiated lymph node cells (LNC) from TCSA/UVA-sensitized mice (LNCTCSA) in the presence of rIL-t. After several rounds of antigenic stimulation, a T cell line (B+TCL) consisted exclusively of CD3+CD4+CD8- V beta 7+ and V beta 13+ populations. Transfer to naive recipients of B+TCL treated with anti-V beta mAb plus complement revealed that the V beta 7+ cells suppressed both the in vivo and the in vitro aspects of contact photosensitivity to TCSA in an Ag-specific manner. The in vitro suppressive activity of B+TCL was neutralized by anti-IL-10 mAb, but not by anti-IL-4 mAb, indicating a crucial role of IL-10 in UBV-induced suppression. Upon stimulation with 3000-rad-irradiated-LNCTCSA, B+TCL released IL-4 and IL-10 but not IL-2, and V beta 7+ cells produced IL-10. The reverse transcriptase-PCR detected mRNA for IL-4 and IL-10 but not that for IL-2, IFN-gamma, or TGF-beta in B+TCL stimulated with or without concanavalin A. In accordance with the findings in B+TCL, spleen cells from UVB preirradiation plus TCSA/UVA mice contained V beta 7+ T cells that suppressed contact photosensitivity to TCSA and produced substantial amounts of IL-4 that provided a microenvironment for Th2 cell generation. We conclude that UVB preirradiation and photosensitization result in the generation of V beta 7+ Th2 cells that suppress contact photosensitivity by releasing IL-10. The dysfunction of effector Th1 cells underlying UVB suppression of delayed-type hypersensitivity seems to be due not only to altered APC function but also to counteraction of Th2 cells by Th1 cells.
Costimulation of fibronectin receptor promotes Fc gamma R-mediated rescue of IL-3-dependent bone marrow-derived cells from apoptosis.
Authors: Yoshikawa H , Sakihama T , Nakajima Y , Tasaka K
Published: December 2022

The IL-3-dependent murine bone marrow-derived cell line FDC-P2/185-4 (185-4) undergoes apoptosis when IL-3 is withdrawn from the culture medium. However, a high concentration of aggregated mouse IgG prevents apoptosis of 185-4 cells by an autocrine mechanism, producing IL-3. An analysis of flow cytometry revealed that 185-4 cells expressed Fc gamma RIII on their surface and that these effects of IgG are inhibited by anti-Fc gamma RIII mAb. These results indicated that the effect of IgG is mediated by low affinity Fc gamma RIII. In contrast, a low concentration of mouse IgG cannot prevent the apoptosis of 185-4 cells, but in the presence of fibronectin (FN), cell survival is prolonged. It is generally accepted that the interaction of cells with FN is mediated by several integrins such as alpha 5 beta 1 (VLA-5) or alpha 4 beta 1 (VLA-4), and analysis of flow cytometry showed that 185-4 cells express these integrins on their surface. Furthermore, these effects of FN are blocked specifically by RGD peptide or anti-VLA-4 mAb. These findings indicated that FN induces the costimulatory signal through integrin receptor and enhances the proliferative effect through Fc gamma RIII by a low concentration of IgG. The findings presented here suggested that the engagement of FN-integrin receptors on 185-4 cells increases the sensitivity of the cells for cellular activation of IgG. Since inflammatory cells in the microenvironment are surrounded by extracellular matrix proteins, it is possible that adhesion molecules play important roles in inflammatory states such as autoimmune diseases caused by increased levels of IgG.
A mannose 6-phosphate-containing N-linked glycopeptide derived from lysosomal acid lipase is bound to MHC class II in B lymphoblastoid cell lines.
Authors: Dustin M L , McCourt D W , Kornfeld S
Published: December 2022

Binding of peptides to MHC class II Ag generates ligands for TCR of Th lymphocytes. We have identified a novel class of peptides bound to MHC class II: mannose 6- phosphate (Man-6-P) containing glycopeptides from lysosomal enzymes. These species were identified in the process of characterizing mannose 6-phosphate/insulin-like growth factor II (M-6-P/IGF-II) receptor binding to the surface of B lymphoblasts. Surface iodination and Man-6-P/IGF-II receptor affinity chromatography implicated MHC class II as a carrier of Man-6-P-modified oligosaccharides. These oligosaccharides were found to be primarily associated with the bound peptide. Peptides eluted from the Man-6-P/IGF-II receptor-binding fraction of immunoaffinity-purified MHC class II from the Swei cell line contained a sequence derived from the propiece of lysosomal acid lipase. Partial sequences were also obtained for peptides from other HLA-DR alleles but none of these were attributable to known proteins. This study defines a novel approach for isolating rare glycan-modified peptides from MHC class II and demonstrates that very large secondary modifications are tolerated in peptides bound to MHC class II.
Interference between human herpesvirus 7 and HIV-1 in mononuclear phagocytes.
Authors: Crowley R W , Secchiero P , Zella D , Cara A , Gallo R C , Lusso P
Published: December 2022

Human herpesvirus 7 (HHV-7) uses CD4 as a cellular membrane receptor and thereby interferes with infection of CD4+ T cells by HIV-1. We studied the interactions between HHV-7 and a macrophage-tropic HIV-1 isolate (HIV-1BaL) in terminally differentiated human peripheral blood monocyte-derived macrophages, another critical target for infection by HIV-1 in vivo. Exposure of macrophages to HHV-7 alone yielded no signs of virus replication or cytopathic effects. Nevertheless, when macrophages were pre-exposed to either live or UV-inactivated HHV-7 and subsequently infected with HIV-1BaL, a significant dose-dependent inhibition of HIV-1 replication was documented. At day 7 postinfection, the average level of HIV-1 p24 Ag in cultures from five different donors was reduced by 91.7 +/- 8.3% by pretreatment with live HHV-7 and by 91.8 +/- 8.2% by pretreatment with UV-inactivated HHV-7. Moreover, the synthesis of HIV-1 proviral DNA in macrophages pretreated with HHV-7 was completely inhibited during the early stages after infection, suggesting that HHV-7 blocks HIV-1 at the level of interaction with the CD4 receptor. Consistent with this concept, both macrophage and CD4+ T cell cultures with pre-established HIV-1 infection were not susceptible to inhibitory effects of HHV-7. The proliferative response of PBMC to mitogens was only marginally inhibited by exposure to HHV-7 before mitogen stimulation, indicating that the inhibition of HIV-1 infection was not due to a negative effect on cell proliferation. These data demonstrate that HHV-7 is a powerful inhibitor of HIV-1 infection in cells of the mononuclear phagocytic lineage, despite its inability to replicate actively in such cells.
Vitamin A down-regulation of IFN-gamma synthesis in cloned mouse Th1 lymphocytes depends on the CD28 costimulatory pathway.
Authors: Cantorna M T , Nashold F E , Chun T Y , Hayes C E
Published: December 2022

Some infections deplete serum retinol, low retinol reduces immunity, and reduced immunity establishes susceptibility to further infection in a cyclical relationship that is poorly understood. We showed that when retinol was low, there was excessive Th1 cell IFN-gamma synthesis and inadequate Th2 cell IL-4 and IL-5 synthesis. The retinol metabolite retinoic acid inhibited the IFN-gamma stimulatory activity of APCs, enhanced Th2 cell differentiation, and inhibited Th1 cell IFN-gamma synthesis. Here we focus on the mechanism for retinoic acid inhibition of IFN-gamma synthesis in myelin basic protein-specific MM4 Th1 cells. Physiologic amounts of all-trans-retinoic acid directly and specifically down-regulated the MM4 Th1 cell IFN-gamma secretion rate in vitro without affecting cell growth, viability, or overall protein synthesis. All-trans-, 9-cis-, and 13-cis-retinoic acid, and the synthetic retinoid Ch55, inhibited IFN-gamma synthesis effectively, whereas retinaldehyde, retinol, and retinyl acetate did not. This pattern suggests retinoic acid receptor involvement in the inhibition mechanism. Retinoic acid did not inhibit when Th1 cells were activated only through the TCR/CD3 complex, with or without IL-2 costimulation. Retinoic acid inhibited IFN-gamma synthesis when the CD28 costimulatory pathway was activated in addition to the TCR/CD3 pathway, suggesting it blocks some step in the CD28 pathway. Retinoid probably acted to decrease IFN-gamma transcript accumulation by decreasing transcription because it did not decrease transcript stability. We suggest that unrestrained IFN-gamma synthesis is one key immunobiologic mechanism that accounts for poor antibody-mediated immunity in hypovitaminosis A, since IFN-gamma in relatively small amounts can limit Th2 cell growth and interfere with the B cell stimulatory functions of Th2 cell cytokines.
CD45 ligation induces programmed cell death in T and B lymphocytes.
Authors: Klaus S J , Sidorenko S P , Clark E A
Published: December 2022

Studies have shown an essential role for the CD45 protein tyrosine phosphatase in regulating Ag receptor-derived signals in lymphocytes. Co-ligating CD45 with the Ag receptor, however, can also inhibit receptor signaling, as manifest in T cells by the lack of IL-2 production and proliferation. We report that CD45 ligation alone induces apoptosis in normal T cells, and that death was greatly potentiated by cross-linking CD3. Normal B cells and T and B cell lines were also induced to die with insoluble CD45 mAb. CD45-induced cell death was blocked by inhibitors of protein tyrosine kinases and protein tyrosine phosphatases, but not by inhibitors of RNA or protein synthesis or by cyclosporin A. Morphologically, CD45-mediated apoptosis resembled death induced via CD95 (Fas), as evidenced by nuclear condensation and membrane blebbing, but did not cause DNA fragmentation into oligonucleosomes. Co-ligating CD45 and CD95 either enhanced or inhibited CD45-induced cell death, depending on the degree of CD45 and CD95 cross-linking. Finally, CD45 cross-linking induced its rapid association with the detergent-insoluble cell fraction, suggesting that it becomes linked to the cytoskeleton during CD45-induced apoptosis. These data show a novel role for CD45 in regulating lymphocyte death as well as proliferation.
Regulation of 3' IgH enhancers by a common set of factors, including kappa B-binding proteins.
Authors: Michaelson J S , Singh M , Snapper C M , Sha W C , Baltimore D , Birshtein B K
Published: December 2022

Targeted disruption of the p50 subunit of NF-kappa B resulted in isotype class switch defects resembling those observed in mice in which the downstream IgH enhancer 3'alpha E(hs1,2) was deleted. We postulated that kappa B binding proteins may regulate class switching by interacting with 3'alpha E(hs1,2) or with other IgH 3' enhancers with which 3'alpha E(hs1,2) synergizes. kappa B binding sites were identified in 3'alpha E(hs1,2) and 3' alpha-hs4, the distal 3' IgH enhancer. A kappa B binding site within 3'alpha E(hs1,2) contributes to at least half the activity of the enhancer in plasma cells, while the same kappa B binding site participates in the complex repression of the enhancer in B cells. In the case of 3'alpha-hs4, a kappa B binding complex activates the enhancer in pre-B, B cells and plasma cells. Additional binding sites within 3'alpha-hs4 for factors known to regulate 3'alpha E(hs1,2), including Oct-1 and BSAP, were identified, and their contribution to 3'alpha-hs4 regulation during B cell development was assessed. Oct-1 positively regulates the enhancer in pre-B and B cells, while BSAP is a repressor in pre-B cells and an activator at the B cell stage. These studies identify kappa B binding proteins as key modulators of 3'alpha E(hs1,2) and 3'alpha-hs4, and suggest coregulation of the two enhancers by a common set of factors.
Human mucosal addressin cell adhesion molecule-1 (MAdCAM-1) demonstrates structural and functional similarities to the alpha 4 beta 7-integrin binding domains of murine MAdCAM-1, but extreme divergence of mucin-like sequences.
Authors: Shyjan A M , Bertagnolli M , Kenney C J , Briskin M J
Published: December 2022

The mucosal vascular addressin, mucosal addressin cell adhesion molecule-1 (MAdCAM-1), is an Ig family adhesion receptor preferentially expressed by venular endothelial cells at sites of lymphocyte extravasation in murine mucosal lymphoid tissues and lamina propria. MAdCAM-1 specifically binds both human and mouse lymphocytes that express the homing receptor for Peyer's patches, the integrin alpha 4 beta 7. Functional expression cloning was used to isolate a cDNA from a macaque mesenteric lymph node library that encodes the homologue to murine MAdCAM-1. The macaque cDNA was subsequently used to clone the human homologue as well. Expression of human MAdCAM-1 RNA is restricted to mucosal tissues, gut-associated lymphoid tissues and spleen. Human MAdCAM-1 selectively binds both murine and human lymphocyte cell lines expressing alpha 4 beta 7. Human and macaque MAdCAM-1 have two Ig-like domains that are similar to the two amino-terminal integrin binding domains of murine MAdCAM-1. The conservation of sequences within the region homologous to the mucin/IgA domain of murine MAdCAM-1 is, however, much less apparent. These receptors exhibit considerable variation from murine MAdCAM-1 with respect to the length of the mucin-like sequence and the lack of a membrane proximal Ig (IgA-like) domain. The isolation of these different species of MAdCAM-1 demonstrates greater seleoffctive pressure for maintenance of amino acids involved in alpha 4 beta 7 binding than those sequences presumably involved in the presentation of carbohydrates for selectin binding.
A carbohydrate structure associated with CD15 (Lewis x) on myeloid cells is a novel ligand for human CD2.
Authors: Warren H S , Altin J G , Waldron J C , Kinnear B F , Parish C R
Published: December 2022

The T cell and NK cell adhesion molecule CD2 interacts with different ligands, viz, CD58, CD48, and CD59. Using a fluorescent multimeric construct of rCD2, we previously identified an additional CD2 ligand (CD2L) on the erythroleukemic cell line K562. CD2L bound to a different region of CD2 than known ligands and was N-glycosylation dependent. In this study we show that mAbs specific for the carbohydrate Ag Lewis x (CD15, Gal-beta 1-4 GlcNAc alpha 1-3Fuc) inhibit multimeric rCD2 binding to CD2L. CD2L is restricted in expression to myeloid cells, where it is co-expressed with CD58 on monocytes and is the dominant, if not sole, CD2 ligand on neutrophils. Sugar specificity studies show that CD2L is not CD15. Thus, whereas soluble Lewis x inhibits binding of CD15 mAb to K562 and neutrophils, binding of multimeric rCD2 is unaffected. Furthermore, multimeric rCD2 binding to K562 is inhibited by L-fucose and following treatment of K562 with an alpha 1-6 fucosidase, whereas these treatments do not inhibit the binding of CD15 mAb. Thus, it is likely that CD2L is a carbohydrate structure closely associated with, yet distinct from, CD15, which can be sterically blocked by CD15 mAb. Functional studies revealed that CD2L is probably an important CD2 ligand in the non-MHC-restricted NK cell killing of K562 target cells, since this activity was strongly inhibited by CD15 mAb. Collectively, this study indicates that a CD15 (Lewis x)-associated carbohydrate structure(s), which has previously been shown to be a selectin ligand, also may function as an important CD2 ligand on myeloid cells.
Transforming growth factor-beta 1 is the predominant paracrine inhibitor of macrophage cytokine synthesis produced by glomerular mesangial cells .
Authors: Kitamura M , Sütö T , Yokoo T , Shimizu F , Fine L G
Published: December 2022

Cross-communication between glomerular cells and infiltrating mononuclear cells plays an important role in the generation of or recovery from glomerular diseases. We found that cultured mesangial cells secrete a factor that inhibits production of proinflammatory cytokines by activated macrophages. Treatment of J774.2 macrophages with conditioned media from rat mesangial cells blunted the transcriptional induction of IL-1 beta, IL-6, and TNF-alpha by LPS. None of the media conditioned by other fibroblastic, epithelial, or endothelial cell lines exhibited the inhibitory effect. Media conditioned by normal rat glomeruli contained a similar inhibitory activity, which was enhanced in an acute model of mesangial proliferative glomerulonephritis. To identify the active component involved, we examined the expression of known macrophage deactivators IL-10, IL-13, and TGF-beta 1 in mesangial cells. Under the basal culture conditions, strong expression of TGF-beta 1 mRNA was observed, whereas expression of neither IL-10 nor IL-13 was detected. Immunoblot analysis and a specific bioassay detected the active form of TGF-beta 1 exclusively in the mesangial cell conditioned media. The inhibitory activity was enhanced by heat treatment, consistent with the known property of TGF-beta. A specific anti-TGF-beta 1 neutralizing Ab abolished the inhibitory effect exerted by the mesangial cell media, and exogenously added TGF-beta1 suppressed macrophage cytokine expression in a dose-dependent manner. These findings demonstrate that mesangial cells and isolated glomeruli secrete a factor which suppresses cytokine expression by activated macrophages, the active entity being identified as TGF-beta 1.
IL-13 induces phosphorylation and activation of JAK2 Janus kinase in human colon carcinoma cell lines: similarities between IL-4 and IL-13 signaling.
Authors: Murata T , Noguchi P D , Puri R K
Published: December 2022

We have recently reported that IL-13R may share a component with IL-4R. Here we report that both IL-4 and IL-13 share signaling events in human colon carcinoma cell lines (HT-29 and WiDr). IL-13 caused rapid phosphorylation of the three out of four members of the known Janus family of kinases (JAKs). We show that JAK2 kinase is rapidly phosphorylated and activated in response to IL-13. Within 1 min of activation, JAK2 was phosphorylated, and peaked in 10 min. In addition, IL-13 phosphorylated insulin response substrate-1, IL-4R p140, JAK1, and Tyk2, but not JAK3 kinase. IL-4 also stimulated all three kinases and substrates, but unlike in immune cells, IL-4 did not involve JAK3 activation for its signaling in colon cancer cell lines. Furthermore, JAK2 associated with the IL-4R p140 before and after stimulation with IL-13. Both IL-13 and IL-4 induced phosphorylation of IL-4 STAT (STAT6) but not STAT1, STAT3, or STAT5. 125I-IL-13 did not bind to colon cancer cell lines, but unlabeled IL-13 competed for the binding of 125I-IL-4. Our data suggest that IL-13 utilizes IL-4R and its signaling pathway, and JAK2 may play an important role in the function of IL-4R and IL-13R in colon cancer cells.
In vivo effects of chicken myelomonocytic growth factor: delivery via a viral vector.
Authors: York J J , Strom A D , Connick T E , McWaters P G , Boyle D B , Lowenthal J W
Published: December 2022

We have constructed a recombinant fowlpox virus (FPV) that expresses chicken myelomonocytic growth factor (cMGF). Administration of this construct (fp/cMGF) to 1-day-old chicks resulted in a marked and sustained increase in the number of circulating blood monocytes compared with chicks infected with the parental FPV strain (fp/M3). Blood monocyte numbers were elevated within 4 days of fp/cMGF infection, reached maximal levels at day 9, and returned to normal levels by day 16. During the peak response, approximately 35% of blood leukocytes were monocytes, compared with 4 to 7% in uninfected control birds. Infection with fp/M3 also resulted in a detectable increase in monocyte numbers; however, the effect was less dramatic. Compared with fp/M3, fp/cMGF consistently induced two- to threefold higher monocyte numbers, and the period of monocytosis was longer (10 vs 5 days). No other specific changes in white blood cell populations were observed. Associated with the increase in the number of monocytes was an increase in their state of activation, as measured by the ability to produce nitric oxide (NO) and to phagocytose latex beads. Blood monocytes from birds infected with fp/cMGF produced about 6 times as much NO per cell compared with monocytes from fp/M3-infected birds. Monocytes from normal birds failed to produce detectable levels of NO. Furthermore, cMGF treatment specifically induced enhanced phagocytic activity in blood monocytes. Overall, these results indicate that viral vectors are suitable for the delivery of biologically active cytokines and that they allow an assessment of cytokine activities in vivo.
Encephalitogenic epitopes of myelin basic protein, proteolipid protein, myelin oligodendrocyte glycoprotein for experimental allergic encephalomyelitis induction in Biozzi ABH (H-2Ag7) mice share an amino acid motif.
Authors: Amor S , O'Neill J K , Morris M M , Smith R M , Wraith D C , Groome N , Travers P J , Baker D
Published: December 2022

Myelin basic protein (MBP) and synthetic MBP peptides were screened for their ability to induce experimental allergic encephalomyelitis in Biozzi ABH (H-2Ag7) mice. In contrast to the failure of native MBP to induce experimental allergic encephalomyelitis, the use of overlapping MBP peptides revealed epitopes within MBP 12-26 and MBP 21-35, which induced mild disease. In comparison with disease induced by spinal cord homogenate or peptides of myelin oligodendrocyte glycoprotein (MOG) or proteolipid protein (PLP), the low incidence indicates that, at least in ABH mice, MBP is a minor encephalitogen. However, the data suggest the presence of a peptide core between MBP 21-26 (HARHGF), which contains similar elements to the previously defined encephalitogenic MOG 1-22 and PLP 56-70 peptides. The fine specificity of these epitopes was further investigated using frame-shifted peptides, which indicated cores between MOG 9-15 (GYPIRAL) and PLP 62-68 (NVIHAFQ). Based on these pathogenic peptides, a putative H-2Ag7 binding motif is suggested that contains a series of hydrophobic, basic, small, and large hydrophobic residues within a 6 to 7 amino acid core. The core and particular importance of these four residues in PLP 56-70 was confirmed in vitro using amino acid substitution studies. These findings support many of the predictions made by computer modeling of peptide:H-2Ag7 interactions. This may have relevance in the design of strategies in the treatment of experimental autoimmune diseases in animals that express this haplotype.
Structural elements controlling anti-DNA antibody affinity and their relationship to anti-phosphorylcholine activity.
Authors: Pewzner-Jung Y , Simon T , Eilat D
Published: December 2022

The heavy chains of the anti-DNA autoantibody D42, derived from an autoimmune NZB/NZW F1 mouse, and the anti-phosphorylcholine (PC) Ab 6G6, obtained from an immunized CBA/J mouse, are both encoded by the same VH11 (S107) germ-line gene. We have combined VH CDR3 exchange, site-directed mutagenesis, transfection of mutant hybridoma cells, and equilibrium affinity measurements of the expressed Abs to analyze the contribution of germ line-encoded genetic elements and somatic mutations to DNA binding affinity as well as to test the possibility that an anti-PC Ab can be converted to an anti-DNA Ab by somatic mutation. Our results indicate that the major contribution to DNA binding affinity is provided by the nonmutated rearranged configuration of the autoantibody and depends on the particular H/L chain pairing and the structure of the VH CDR3 gene segment. Two heavy chain somatic mutations increased the DNA binding affinity of the D42 anti-DNA Ab by about 10-fold. One of these mutations abolished PC binding of the 6G6 Ab, but did not convert it to an anti-DNA. These results suggest that activation of autoreactive B cells bearing germ-line-encoded Ag receptors may be required to initiate the affinity maturation of an anti-DNA response, and that B cells responding by somatic mutation to external Ags, such as PC, may be unable to contribute significantly to the high affinity immune response that is typical of disease-related anti-DNA autoantibodies.
CD2-induced apoptosis in activated human peripheral T cells: a Fas-independent pathway that requires early protein tyrosine phosphorylation.
Authors: Mollereau B , Deckert M , Déas O , Rieux-Laucat F , Hirsch F , Bernard A , Fischer A , Lynch D H , Charpentier B , Le Deist F , Senik A
Published: December 2022

Short-term activated peripheral T lymphocytes are susceptible to apoptotic cell death triggered by CD2 mAbs. The aim of this study was to examine whether the CD2-mediated pathway of apoptosis is linked to the Fas death pathway, as this is the case for CD3/TCR-triggered apoptosis in several models of T cells. Using T lymphocytes from patients harboring Fas gene mutations and displaying a profound defect in Fas signaling of cell death, we show that CD2- (but not CD3-) mediated apoptosis still proceeds normally. In normal activated T cells, CD3-mediated apoptosis is prevented by reagents that block the Fas/Fas-ligand interaction, namely soluble M3 (an antagonistic anti-Fas mAb) and soluble human Fas.Fc, a fusion protein able to bind released Fas-ligand. In contrast, CD2 signaling of apoptosis resists these blocking agents. Neither new protein synthesis nor the activation of calcineurin was required for CD2- and Fas-mediated apoptosis, suggesting that latent cytoplasmic "death" molecules were activated upon stimulation of the cells. In both cases, protein tyrosine kinases were transiently activated, as is exemplified by the autophosphorylation and exokinase activity of p56lck, yielding overlapping yet nonidentical profiles of protein tyrosine phosphorylation. Pretreating the cells with herbimycin A, before the addition of the apoptotic stimuli, almost completely inhibited CD2 transmembrane signaling of apoptosis, but left intact Fas-induced apoptosis. Our data suggest that CD2 is a Fas-independent cell death pathway that might contribute directly to the elimination of T cells expanding during an immune reaction.
CD28-mediated cytotoxicity by the human leukemic NK cell line YT involves tyrosine phosphorylation, activation of phosphatidylinositol 3-kinase, and protein kinase C.
Authors: Teng J M , Liu X R , Mills G B , Dupont B
Published: December 2022

The human leukemic cell line YT displays spontaneous cytotoxicity against CD80+ and/or CD86+ and ICAM-1+ target cells. In this work, we report that CD28-mediated cytotoxicity of YT involves tyrosine phosphorylation and activation of phosphatidylinositol (PI) 3-kinase, the Tec kinase Itk/Emt, and protein kinase C (PKC). YT mediates lysis of CD80+/CD86+ B lymphoblastoid cell lines and the murine mastocytoma p815 transfected with CD80 or CD86. The lysis was inhibited by two different Pi 3-kinase inhibitors, wortmannin and LY294002. The PKC inhibitors calphostin C and bisindolylmaleimide GF109203X also abolished YT-mediated cytotoxicity. Furthermore, exocytosis of cytolytic effector molecules was also inhibited by PI 3-kinase inhibitors and PKC inhibitors. PMA together with Ionomycin did not induce granule exocytosis or cytotoxicity by YT cells. Treatment of YT cells with PMA for up to 20 h, which depleted PMA-responsive PKC isoforms, had no effect on the CD28-mediated cytotoxicity. This cytotoxicity displayed by PMA-treated YT cells, however, could still be inhibited by Pi 3-kinase inhibitors and PKC inhibitors. Taken together, these results are consistent with a model in which activation of CD28 and LFA-1 induces tyrosine phosphorylation of the CD28 cytoplasmic domain, recruitment and activation of PI 3-kinase, as well as the Tec kinase Itk/Emt, and the activation of PMA-nonresponsive PKC isoenzymes. Activation of PI 3-kinase and PMA-nonresponsive PKC isoenzymes is shown to be involved directly in cytolytic granule release by YT cells.
Vasoactive intestinal peptide inhibits IL-4 production in murine T cells by a post-transcriptional mechanism.
Authors: Wang H Y , Xin Z , Tang H , Ganea D
Published: December 2022

Vasoactive intestinal peptide (VIP), a neuropeptide present in the peptidergic innervation of lymphoid organs and expressed in thymocytes and peripheral lymphocytes, modulates cytokine expression in T lymphocytes. VIP down-regulates the expression of IL-2 and IL-10 mRNA in T cells stimulated through the TCR-associated CD3 complex. In contrast, IL-4 production is inhibited at a post-transcriptional level. In this study, we investigate the molecular mechanisms involved in the inhibition of IL-4 production by VIP. At the protein level, the time courses for IL-2 and IL-4 inhibition by VIP are different, with IL-4 being affected approximately 24 h later than IL-2. Northern blots and competitive reverse-transcription PCR analysis confirm the post-transcriptional inhibition of IL-4 production in both murine spleen cells and thymocytes activated through the CD3 complex. VIP does not affect IL-4 secretion, and does not induce a rapid IL-4 reuptake. Exogenous rIL-2 completely reverses the inhibitory effect of VIP, suggesting that VIP inhibits IL-4 production indirectly as a consequence of IL-2 inhibition. Studies regarding the newly synthesized IL-4 protein show that although VIP and exogenous IL-2 do not affect the rate of IL-4 synthesis, VIP reduces significantly the stability of the newly synthesized IL-4 protein, and exogenous IL-2 can restore it to the levels observed in activated cells in the absence of VIP. These results explore the molecular mechanisms involved in the neuroendocrine regulation of cytokine production, and support the idea that neuropeptides released or produced in the local lymphoid microenvironment may participate in the intricate cytokine network controlling local immune responses.
The COI mitochondrial gene encodes a minor histocompatibility antigen presented by H2-M3.
Authors: Morse M C , Bleau G , Dabhi V M , Hétu F , Drobetsky E A , Lindahl K F , Perreault C
Published: December 2022

We found that (LP x C57BL/6)F1 mice could raise a CTL response against parental C57BL/6 cells. These CTLs recognized a maternally transmitted, H2-M3wt-restricted, minor histocompatibility Ag (MiHA) that is widely distributed among many strains of mice and encoded by the COI mitochondrial gene. The wild-type MiHA is the COI N-terminal hexapeptide. Sequencing the 5' end of the COI gene in LP and C57BL/6 mice showed that the LP allele arose by a T-->C transition in the third codon, which caused substitution of threonine for isoleucine. Molecular characterization of this MiHA and the demonstration that it is presented exclusively by H2-M3: 1) support the concept that differential expression of MiHA in MHC-identical animals is caused by polymorphism of the MiHA gene proper; 2) expand our knowledge of the repertoire of self-peptides naturally presented by H2-M3 and show that this MHC class I molecule can present short endogenous peptide ligands; and 3) suggest that mitochondrial DNA mutations that modify the repertoire of H2-M3-associated mitochondrial peptides are representative of mitochondrial DNA mutations in general.
Recombinant IL-10 and IL-10/Fc treatment down-regulate egg antigen-specific delayed hypersensitivity reactions and egg granuloma formation in schistosomiasis.
Authors: Flores-Villanueva P O , Zheng X X , Strom T B , Stadecker M J
Published: December 2022

In infection with the helminth Schistosoma mansoni, parasite eggs elicit a Th cell-mediated hepatic granulomatous inflammation that leads to scarring, portal hypertension, hemorrhage, and death. On the other hand, the cytokine IL-10 has been shown to decrease egg Ag-specific Th cell responses by down-regulating MHC class II as well as B7 costimulatory molecule expression on accessory cells. We now test the effect of IL-10 in vivo on models of egg Ag-specific hypersensitivity as well as on the natural disease. Systemic administration of IL-10 significantly inhibited delayed-type hypersensitivity reactions to egg Ag as well as primary and secondary granuloma formation to eggs embolized in the lung. However, significant inhibition of hepatic granuloma formation associated with the natural infection required the use of an IL-10/Fc fusion protein with a prolonged in vivo half-life. Lymph node cells from IL-10/Fc-treated mice produced less IL-2 and IFN-gamma, and more IL-4 and IL-10 than control cells, suggesting that reduced egg granuloma formation resulted primarily from down-regulation of Th1 responses. These results indicate that suitable administration of exogenous IL-10 can be effective in ameliorating immunopathologic damage associated with schistosomiasis.
Liver NK1.1+ CD4+ alpha beta T cells activated by IL-12 as a major effector in inhibition of experimental tumor metastasis.
Authors: Takeda K , Seki S , Ogasawara K , Anzai R , Hashimoto W , Sugiura K , Takahashi M , Satoh M , Kumagai K
Published: December 2022

We demonstrate herein evidence that IL-12-activated alpha beta T cells with intermediate TCR (NK1+ TCRint cells) in the liver inhibit metastases in the lung as well as in the liver metastases of i-v. injected tumors. IL-12 administration enhanced NK1 expression of NK1+ TCRint cells (NK1high) and increased CD4 weakly positive (CD4low) TCRint cells, while both CD4+ TCRint cells and double-negative TCRint cells were proportionally diminished. Accordingly, the major parts of NK1high TCRint cells are CD4low cells, and most of these cells are V beta 8+ cells. The cytotoxic assays of IL-12-stimulated hepatic mononuclear cells after treatment with respective Abs and complement in vitro and after sorting revealed that CD4low NK1high TCRint cells are cytotoxic effectors. When IL-12-stimulated hepatic mononuclear cells (but not splenocytes) were transferred into tumor-preinjected mice, EL-4 cell metastases in the liver as well as 3LL cell metastases in the lung were inhibited. The antimetastasis of hepatic mononuclear cells transfer was abrogated by the depletion of NK1+ cells, CD3+ cells, or CD4+ cells but not CD8+ cells before transfer. Moreover, transfer of these cells of nude mice into tumor-preinjected mice also inhibited metastases in both organs. Although NK1+ TCRint cells are nearly absent in the hepatic vein blood, a significant proportion of NK1high TCRint cells appeared by IL-12 administration. These results demonstrate that IL-12-stimulated liver NK1high TCRint cells, including extrathymic ones, are major effectors against tumor metastasis and suggest that the cells migrate and inhibit lung metastases.
Constitutive expression of B7-1 (CD80) on mouse keratinocytes does not prevent development of chemically induced skin papillomas and carcinomas.
Authors: Williams I R , Ort R J , Daley D , Manning L , Karaoli T , Barnhill R L , Kupper T S
Published: December 2022

Expression of the B7-1 (CD80) costimulatory molecule in a variety of tumor cell lines leads to an enhanced CD8+ T cell response to tumor Ags. We used transgenic mice constitutively expressing B7-1 on keratinocytes (K14/B7-1 line) to determine whether keratinocyte B7-1 expression would inhibit the development of papillomas and carcinomas following two-stage chemical carcinogenesis in skin. FVB inbred mice carrying the K14/B7-1 transgene and controls were initiated with 25 micrograms of 7,12-dimethylbenz[a]anthracene and promoted weekly with 5 micrograms of 12-O-tetradecanoylphorbol-13-acetate for 20 wk. Expression of the B7-1 transgene did not result in statistically significant decreases in the mean number of papillomas or carcinomas compared with controls. The incidence of carcinomas in both transgenic and control mice reached 90% or greater by 60 wk after initiation. Carcinoma cell lines established from the K14/B7-1 mice maintained expression of B7-1 and Kq. These B7-1 expressing carcinomas grew progressively following intradermal injection into syngeneic FVB mice, further demonstrating their inability to evoke protective tumor immunity. These same carcinoma cell lines were rapidly rejected by minor alloantigen-mismatched SWR mice, confirming their susceptibility to immune effector mechanisms. The failure of constitutive B7-1 expression on keratinocytes to prevent the growth of squamous cell papillomas and carcinomas may reflect the limited immunogenicity of tumors arising after initiation-promotion carcinogenesis. Our results in this transgenic model system are further evidence that B7-1 gene therapy alone may not be sufficient to induce protective immunity to some types of tumors.
Human skeletal myoblasts spontaneously activate allogeneic complement but are resistant to killing.
Authors: Gasque P , Morgan B P , Legoedec J , Chan P , Fontaine M
Published: December 2022

The complement (C) system has previously been implicated in several diseases of muscle. We here report that human myoblasts or rhabdomyosarcoma cell lines spontaneously activate C through the classical pathway, causing release of anaphylatoxins and coating of myoblasts with opsonic C fragments but without causing cell killing. Survival of myoblasts is a consequence of the abundant expression of the membrane C regulatory molecules MCP and CD59, and neutralization of CD59 renders cells susceptible to C killing. The decay-accelerating factor was expressed at a very low level. Myoblasts and rhabdomyosarcoma lines also abundantly express the fluid-phase regulators C1-inhibitor, factor H, C4 binding protein, S-protein, and clusterin and secrete a soluble form of CD59. Expression of membrane and fluid-phase regulators is enhanced by either IFN-gamma or TNF-alpha. Although myoblasts resist C killing, spontaneous activation of C on these cells may have important consequences in inflammatory diseases of muscle where the generation of anaphylactic and opsonic fragments will recruit and activate inflammatory cells. C activation on myoblasts may also have consequences for the use of these cells as vehicles for gene delivery. Inhibition of C using soluble complement receptor I (sCR1) efficiently protected myoblasts from C attack in vitro, and this agent, already being tested in therapy of several C-mediated diseases, might be of value in inflammatory muscle disease and in improving the efficiency of gene delivery.
Peptides derived from C-reactive protein inhibit neutrophil alveolitis.
Authors: Heuertz R M , Ahmed N , Webster R O
Published: December 2022

C-reactive protein (CRP) is the classic acute phase reactant in humans, with serum levels elevated up to 1000-fold after the onset of inflammation. CRP inhibits chemotaxis of complement (C5a)-, LTB4-, IL-8-, and FMLP-stimulated neutrophils in vitro, and rabbits and transgenic mice with elevated serum CRP levels exhibit diminished neutrophil infiltration and vascular permeability in models of chemotactic factor-induced alveolitis. To evaluate the mechanism of CRP inhibition on chemoattractant-induced neutrophil inflammation in vivo, experiments were performed in mice infused with peptides of human CRP shown to inhibit C5a- and FMLP-stimulated neutrophil chemotaxis in vitro. After direct tracheal instillation of FMLP, mice previously injected via the retro-orbital plexus with CRP peptide 77-82 or 201-206 showed significant reductions (up to 90%) of neutrophils in the bronchoalveolar lavage fluid compared with vehicle-treated mice. Both CRP peptides also significantly (up to 55%) inhibited the increase in alveolar total protein levels. Control injections of native rabbit CRP (3 microM) inhibited neutrophil influx by 93% and protein leak by 55% in mice intratracheally instilled with FMLP. Despite similar levels of inhibition, approximately 10-fold more peptide by weight than native CRP was required. These data suggest that CRP degradation products at sites of tissue injury, in particular CRP peptides 77-82 and 201-206, are anti-inflammatory and can diminish lung injury by a reduction in neutrophil influx and protein leakage into alveoli following FMLP-induced inflammation.
Internalization of Kit together with stem cell factor on human fetal liver-derived mast cells: new protein and RNA synthesis are required for reappearance of Kit.
Authors: Shimizu Y , Ashman L K , Du Z , Schwartz L B
Published: December 2022

Kit, the receptor for stem cell factor (SCF) and the product of the c-kit proto-oncogene, is expressed on fetal liver-derived mast cell progenitors when cultured with SCF. Decreased levels of Kit on the surface of human fetal liver-derived mast cells after exposure to recombinant human SCF were demonstrated by flow cytometry using the YB5.B8 mAb against Kit. Internalization of Kit along with SCF appears to be the principal means by which Kit is lost from the mast cell surface. Neither the beta 3-integrin CD51/CD61 (alpha v beta 3), nor the beta 1-integrins CD49d,e/CD29 (VLA-4 and -5) appeared to be internalized along with Kit-SCF complexes. Reappearance of Kit on day 28 fetal liver-derived mast cells is complete 3 days after exposure of the cells to SCF and is detectable by 2 days. Recovery requires new protein and new RNA synthesis, because Kit did not reappear if cycloheximide or actinomycin D was added to the cells. No substantial change in total Kit mRNA was detected during the resynthesis period, suggesting that post-transcriptional regulation of Kit production is involved. Internalization of Kit in mast cells exposed to soluble SCF may represent a negative regulatory mechanism for this receptor-ligand interaction and down-regulate mast cell properties such as degranulation to SCF.
Lack of IL-2 cytokine expression despite Il-2 messenger RNA transcription in tumor-infiltrating lymphocytes in primary human breast carcinoma: selective expression of early activation markers.
Authors: Coventry B J , Weeks S C , Heckford S E , Sykes P J , Bradley J , Skinner J M
Published: December 2022

Tumor-infiltrating lymphocytes (TIL) are found in most human infiltrating ductal breast carcinomas. In studies of other tumors, TIL were capable of activation by IL-2, both in vitro and in vivo, to produce selective tumor cytolysis. Specific TIL-mediated tumor cytolysis in human breast tumors has recently been reported. The large numbers of TIL within human breast cancers imply that an immune response is occurring, since many of these cells express HLA class II as a late activation marker. However, the degree of early activation of the native TIL in breast tumors has not been fully investigated. Early activation markers CD69, CD43, and CD38 together with the IL-2R (CD25) and IL-2 cytokine were examined using mAbs and tissue section immunohistology. In situ hybridization was used to detect IL-2 mRNA (IL-2 mRNA) in parallel with immunohistochemical localization of IL-2. The results revealed the expression of CD69, CD43, and CD38, but markedly low CD25 (IL-2R) and IL-2 protein expression by the TIL. This strongly indicates that the TIL are an activated population of T cells that shows a deficiency in IL-2 protein and IL-2R expression despite adequate levels of IL-2 mRNA. The mechanism for apparent inhibition of IL-2 production and IL-2R expression in the presence of IL-2 mRNA is currently unclear; however, this may explain the relative anergic state of native TIL.
Restricted V beta usage by T cells infiltrating rejecting human lung allografts.
Authors: DeBruyne L A , Lynch J P , Baker L A , Florn R , Deeb G M , Whyte R I , Bishop D K
Published: December 2022

TCR expression was evaluated in lung transplant patients to determine whether T cells infiltrating rejecting lung allografts employed restricted V beta elements. Serial bronchoalveolar lavage (BAL) specimens were obtained from six lung transplant recipients at approximately 3 wk, 6 wk, and 3 mo post-transplant. T cell lines were established by culturing lavage cells with irradiated donor splenocytes in the presence of low dose IL-2 for 3 wk, and TCR V beta usage was determined by quantitative reverse transcriptase-PCR. Patients were grouped into three categories based on TCR V beta profiles and the clinical status of the allograft. 1) In one patient, BAL-derived T cells expressed heterogeneous V beta repertoires at all time points evaluated. This patient did not experience graft rejection during the 16-mo period of observation, though respiratory infections were diagnosed. 2) In three patients, V beta usage by BAL-derived T cells was restricted during allograft rejection episodes, but was heterogeneous in the absence of rejection and during respiratory infections. In one of these patients, similar V beta repertoires were employed by BAL cells during multiple rejection episodes. 3) In two patients, restricted V beta usage by BAL-derived T cells was observed before and during rejection episodes. Collectively, these data illustrate that human lung allograft rejection, but not pulmonary infection, is associated with T cells expressing a limited number of V beta families. Restricted V beta usage by graft-reactive T cells may allow for the selective elimination of these cells using TCR-specific reagents, thereby promoting allograft-specific tolerance.