bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of a functional chimeric Ig-MHC class II protein.
Authors: Zwirner J , Weissenhorn W , Karlsson L , Becker A , Rieber E P , Riethmüller G , Weiss E H , Peterson P A , Widera G 
Published: December 2022

Abstract
We have generated a chimeric protein molecule composed of the alpha- and beta-chains of the MHC class II I-E molecule fused to antibody V regions derived from anti-human CD4 mAb MT310. Expression vectors were constructed containing the functional, rearranged gene segments coding for the V region domains of the antibody H and L chains in place of the first domains of the complete structural genes of the I-E alpha- and beta-chains, respectively. Cells transfected with both hybrid genes expressed a stable protein product on the cell surface. The chimeric molecule exhibited the idiotype of the antibody MT310 as shown by binding to the anti-idiotypic mAb 20-46. A protein of the anticipated molecular mass was immunoprecipitated with anti-mouse IgG antiserum. Furthermore, human soluble CD4 did bind to the transfected cell line, demonstrating that the chimeric protein possessed the binding capacity of the original mAb. Thus, the hybrid molecule retained: 1) the properties of a MHC class II protein with regard to correct chain assembly and transport to the cell surface; as well as 2) the Ag binding capacity of the antibody genes used. The generation of hybrid MHC class II molecules with highly specific, non-MHC-restricted binding capacities will be useful for studying MHC class II-mediated effector functions such as selection of the T cell repertoire in thymus of transgenic mice.
Protease inhibitors interfere with the transforming growth factor-beta-dependent but not the transforming growth factor-beta-independent pathway of tumor cell-mediated immunosuppression.
Authors: Huber D , Philipp J , Fontana A 
Published: December 2022

Abstract
Tumor cells have been reported to exert inhibitory effects on the activation of T lymphocytes in vitro. We show that the IL-2-stimulated proliferation of a Th cell line is suppressed when the T cells are cocultured with human glioblastoma and melanoma cell lines. The use of two Th cell clones that differ in their responsiveness to growth-inhibition by transforming growth factor-beta (TGF-beta) and the analysis of tumor cell-derived supernatants as well as of TGF-beta 1/TGF-beta 2 gene expression allowed to distinguish two pathways of tumor-induced immunosuppression. Glioblastoma cells exert their immunosuppressive effects by producing biologically active TGF-beta 2, whereas the immunosuppressive state induced by melanoma cells is TGF-beta-independent and requires direct contact between tumor cell and T cell. The TGF-beta-dependent immunosuppression is down-regulated by various protease inhibitors and up-regulated by estradiol via modulation of the production of biologically active TGF-beta 2 by glioblastoma cells leaving total activatable TGF-beta 2 unaffected. No such modulation is functional for the TGF-beta-independent pathway of immunosuppression. We conclude that the production of active TGF-beta by tumor cells is regulated at a posttranslational level by the coordinated action of several proteolytic enzymes.
Multiple cytolytic mechanisms displayed by activated human peripheral blood T cell subsets.
Authors: Smyth M J , Norihisa Y , Ortaldo J R 
Published: December 2022

Abstract
It has been proposed that CTL-mediated cytotoxicity may involve multiple lytic mechanisms. We have examined both the antibody-redirected cytolytic potential and the direct cytotoxicity of purified human peripheral blood high buoyant density CD4+ and CD8+ T cells activated with IL-2 and anti-CD3 mAb. TNF-sensitive and TNF-resistant targets and various metabolic inhibitors were used to compare the antibody-redirected cytotoxicity of T cell subsets and discern the role of potential lytic mediators. In a 4-h assay against several different nitrophenyl-modified targets, the heteroconjugated antibody (anti-CD3-anti-nitrophenyl) redirected cytolytic potential of 72-h activated CD4+ T cells was inhibited by the continuous presence of actinomycin D, cycloheximide, and EGTA, but not mitomycin C, cyclosporin A, or cholera toxin (CT). Conversely, only CT and EGTA inhibited the antibody-redirected cytolytic potential of activated CD8+ T cells. Despite both CD4+ and CD8+ T cell subsets expressing granzymes, pore-forming protein, TNF-beta, and TNF-alpha, these T cell subsets displayed distinct pathways of antibody-redirected lysis against TNF-sensitive and TNF-resistant targets, even in the presence of anti-TNF antibodies. In addition, these same effector T cell subsets were also directly cytotoxic (in the absence of heteroconjugated antibody) against TNF-sensitive targets in an 18-h assay. Indeed, this direct cytotoxicity was completely abrogated by anti-TNF-alpha antibody and was sensitive to the metabolic inhibitors (cyclosporin A, CT, cycloheximide, and actinomycin D), all of which blocked CD4+/CD8+ T cell TNF-alpha production. Therefore, both CD4+ and CD8+ T cells were demonstrated to utilize antibody and lymphokine-mediated lytic mechanisms. CD4+ and CD8+ effector subsets were demonstrated to lyse the same TNF-sensitive target by these two different mechanisms. Although it cannot be excluded that the redirected lytic mechanisms of both CD4+ and CD8+ effectors share common elements, it is likely that other important events in this cytolytic process are fundamentally distinct between these subsets of T cells.
Expression and function of insulin-like growth factor receptors on anti-CD3-activated human T lymphocytes.
Authors: Johnson E W , Jones L A , Kozak R W 
Published: December 2022

Abstract
The pattern of expression of receptors for insulin-like growth factors (IGF-I and IGF-II) and insulin was studied on monocyte-depleted human peripheral blood T cells activated via anti-CD3. Binding assays demonstrated the sequential appearance of receptors for IGF-I, IGF-II, and insulin on activated T cells. IGF-IR appeared early, their expression reaching maximum levels at or before the peak of cellular proliferation. IGF-IIR expression generally followed that of the IGF-IR and was more transient, with increases and decreases in expression paralleling the rise and decline of cellular proliferation. Insulin receptor expression remained low throughout the activation time course. The identity of the IGFR on anti-CD3-activated T cells was confirmed in affinity cross-linking experiments. These data demonstrated a 135,000 Mr peptide that specifically binds radiolabeled IGF-I and corresponds to the alpha subunit of the type I IGF-IR, and a 260,000 Mr peptide that specifically binds radiolabeled IGF-II and corresponds to the type II IGFR. We have additionally found that IGF-I and IGF-II (in nanomolar concentrations) produce as much as a threefold enhancement of T cell proliferation early in the activation process, correlating with the early appearance of IGF-IR. The effect of both IGF appeared to be mediated through the type I receptor, since an antibody (alpha IR3), which blocks binding to the alpha subunit of this receptor, inhibited enhancement by up to 83%. Furthermore, we have found expression of IGF-IR on T cells after activation to be associated with both CD4+ and CD8+ T cell subpopulations. These observations provide a foundation for investigating the contribution of IGF in regulating T cell proliferation, differentiation, and effector function.
Tyrosine phosphorylation of phospholipase C-gamma 2 upon cross-linking of membrane Ig on murine B lymphocytes.
Authors: Hempel W M , Schatzman R C , DeFranco A L 
Published: December 2022

Abstract
When membrane Ig (mIg) on the surface of B lymphocytes is cross-linked using anti-Ig antibodies, the enzyme phospholipase C (PLC) is activated to cleave inositol phospholipids. Tyrosine kinase inhibitors have been reported to inhibit this event. Therefore, we investigated the effect of cross-linking of mIg on the state of tyrosine phosphorylation of PLC activity in two murine B cell lines and in normal resting mouse B cells. Proteins from lysates of stimulated or unstimulated cells were immunoprecipitated with an antiphosphotyrosine antibody and subsequently assayed for PLC activity. Treatment of the B cell line WEHI-231 with anti-IgM led within 15 to 30 s to a 10- to 20-fold increase in tyrosine-phosphorylated PLC activity. Inositol trisphosphate generation by WEHI-231 cells stimulated under the same conditions demonstrated similar kinetics. Normal resting B cells treated with anti-IgM or anti-IgD demonstrated 2.5- and 4-fold increases, respectively, of tyrosine-phosphorylated PLC activity. To identify the isozyme of PLC that was phosphorylated, we immunoprecipitated PLC-gamma 1 or PLC-gamma 2 with specific antibodies and assessed the amount of tyrosine phosphorylation of these proteins by antiphosphotyrosine immunoblotting. Treatment of WEHI-231 or Bal17 cells with anti-IgM induced an increase in PLC-gamma 2 tyrosine phosphorylation over background levels. There was no detectable tyrosine phosphorylation of PLC-gamma 1 in treated or untreated WEHI-231 cells, whereas anti-IgM-treated Bal17 cells did exhibit low but detectable levels of tyrosine phosphorylation of PLC-gamma 1. In normal resting mouse B cells, there was no detectable PLC-gamma 1, but PLC-gamma 2 was abundant. These observations suggest that PLC-gamma 2 is a significant substrate for the mIg-activated protein tyrosine kinase and may be responsible for mediating mIg stimulation of inositol phospholipid hydrolysis in murine B cells.
Type II collagen-induced murine arthritis: induction of arthritis depends on antigen-presenting cell function as well as susceptibility of host to an anticollagen immune response.
Authors: Seki N , Sudo Y , Mizuhara H , Orito K , Imasaki A , Ono S , Hamaoka T , Senoh H , Fujiwara H 
Published: December 2022

Abstract
Two sets of ((resistant x susceptible) F1----parent) and (parent----F1) chimeric mice were prepared. In the chimeric combinations involving BALB/c and DBA/1 mice, all (F1----F1) chimeras developed arthritis as well as potent anticollagen responses after immunization with collagen, whereas all (F1----BALB/c) and (BALB/c----F1) chimeras induced neither arthritis nor immune responses. This type of F1 T cells could be activated with APC from DBA/1 but not from BALB/c mice. Thus, the failure of the [F1 in equilibrium with BALB/c] chimeras to mount anticollagen responses was due to a defect at the APC level. Another arthritis-resistant strain, C57BL/6, exhibited adequate APC function, but reduced T cell responsiveness, representing an intermediate responder. In the chimeric combinations involving C57BL/6 and DBA/1 mice, (F1----F1) and (C57BL/6----C57BL/6) chimeras developed very high and very low incidence of arthritis, respectively. (C57BL/6----F1) chimeras developed an appreciable incidence of arthritis under conditions in which this group of chimeras generated intermediate levels of anticollagen responses. In contrast, (F1----C57BL/6) chimeras developed low incidence of disease despite induction of strong responses. Moreover, cells from collagen-immunized (F1----C57BL/6) chimeras, when transferred into T cell-depleted B cell mice of F1 or C57BL/6 strain, produced comparable immune responses in both groups but induced much more severe arthritis in F1 than in C57BL/6 recipients. These results indicate that: i) two types of arthritis-resistant strains can be identified, each of which has anticollagen APC defect as a low responder and reduced T cell responsiveness as an intermediate responder and ii) a discrepancy between the degree of anticollagen responses and clinical arthritis is attributed to the differential susceptibility to anticollagen immune responses.
Structural and functional analysis of monomorphic determinants recognized by monoclonal antibodies reacting with the HLA class I alpha 3 domain.
Authors: Tanabe M , Sekimata M , Ferrone S , Takiguchi M 
Published: December 2022

Abstract
To identify mAb reacting with the HLA class I alpha 3 domain, 14 mAb recognizing monomorphic determinants expressed on HLA-A, B, and C Ag or restricted to HLA-B Ag were screened in indirect immunofluorescence with mouse L cells expressing HLA-B7/H-2Kb chimeric Ag. mAb CR1S63, CR10-215, CR11-115, and W6/32 were found to react with the HLA class I alpha 3 domain in addition to the alpha 2 domain. mAb Q1/28 and TP25.99 were found to react only with the HLA class I alpha 3 domain. The determinants recognized by the six mAb were mapped on the HLA class I alpha 3 domain by indirect immunofluorescence staining of L cells expressing H-2Kb Ag containing different segments of the HLA-B7 alpha 3 domain chimerized with the H-2Kb alpha 3 domain. mAb TP25.99 reacts with chimeric Ag containing the HLA-B7 184 to 199 stretch, mAb CR10-215 and CR11-115 react with chimeric Ag containing the HLA-B7 184 to 246 stretch, mAb CR1S63 and Q1/28 react with chimeric Ag containing the HLA-B7 184 to 256 stretch, and mAb W6/32 reacts with chimeric Ag containing the whole HLA-B7 alpha 3 domain. Functional analysis using human CD8 alpha-bearing mouse H-2Kb-specific T cell hybridoma cells (HTB-Leu2) showed that only mAb TP25.99 inhibited IL-2 production by HTB-Leu2 cells stimulated with L cells expressing KbKbB7 Ag. This inhibition may occur because of the spatial proximity of the determinant defined by mAb TP25.99 to the CD8 alpha binding loop and/or because of change(s) in the conformation of the CD8 alpha binding loop induced by the binding of mAb TP25.99 to the HLA class I molecule. Furthermore, mAb TP25.99 inhibited the cytotoxicity of CD8-dependent and CD8-independent CTL clones. These results indicate that mAb TP25.99 has unique specificity and functional characteristics. Therefore it represents a valuable probe to characterize the role of the HLA class I alpha 3 domain in immunologic phenomena.
Epitope mapping of Streptococcus mutans SR protein and human IgG cross-reactive determinants, by using recombinant proteins and synthetic peptides.
Authors: Gangloff S , M'Zoughi R , Lett E , Scholler M , Baer J , Pini A , Ogier J , Klein J P 
Published: December 2022

Abstract
alpha-Hemolytic oral streptococci are known to possess a family of cell surface cross-reactive proteins termed Ag I/II, having a molecular mass of approximately 180 to 210 kDa. These proteins are implicated in bacterial adherence to various oral tissues, and we showed recently that the SR protein, an I/II Ag-related protein, from Streptococcus mutans OMZ 175 serogroup f possesses Ag mimicry with human IgG. In this study, regions of the SR protein encoding the cross-reactive epitope(s) were analyzed by expressing selected restriction fragments from the cloned sr gene. The three SR-derived polypeptides reacted in ELISA with anti-SR rabbit IgG, whereas only the two polypeptides located along the carboxyl-terminal two thirds of the SR protein reacted with anti-human IgG rabbit IgG. In order to locate more precisely the human IgG-cross-reactive region, we synthesized six peptides, on the basis of the recently determined complete nucleotide sequence of the sr gene. Among these peptides, peptide 2, corresponding to the alanine-rich repeating amino-terminal region, peptide 3, located in the three tandem proline-rich regions, and peptide 6, located near the cell wall-spanning region, were the most interesting in term of antigenicity and immunogenicity. Anti-peptide 2, 3, and 6 rabbit IgG reacted with free SR and with cell wall-associated SR. Peptide 1, located near the amino terminus, was poorly immunogenic. Peptides 4 and 5, located in the putative human IgG-cross-reactive region, were immunogenic; however, anti-peptide 4 rabbit IgG reacted only weakly with SR or human IgG, whereas anti-peptide 5 rabbit IgG reacted strongly with SR and human IgG, and peptide 5 was recognized by anti-SR and anti-human IgG rabbit IgG. These results confirm the cell surface accessibility of this epitope and its potential participation in eliciting, in rabbits, anti-SR IgG cross-reactive with human IgG.
Characterization of HTLV-I in vivo infected T cell clones. IL-2-independent growth of nontransformed T cells.
Authors: Höllsberg P , Wucherpfennig K W , Ausubel L J , Calvo V , Bierer B E , Hafler D A 
Published: December 2022

Abstract
Mononuclear cells from subjects infected with human T lymphotrophic virus type I (HTLV-I) display a unique ability to proliferate in vitro in the absence of mitogens or exogenous growth factors. Subjects who have developed an HTLV-I-associated myelopathy (HAM) show an even higher degree of spontaneous proliferation concomitant with transcription of the HTLV-I provirus. The mechanism underlying HTLV-I-induced T cell activation was investigated by characterizing a series of HTLV-I-infected T cell clones generated from the blood of subjects with HAM. Approximately 15% of the T cell clones generated were HTLV-I infected as determined by polymerase chain reaction and Southern blotting. Infected T cell clones displayed altered growth kinetics as they continued to incorporate tritiated thymidine 7 to 14 days after stimulation, a time when noninfected T cell clones had returned to a resting state. This was not due to transformation as all the T cell clones required periodic restimulation with mitogens and feeder cells for continued growth. Although HTLV-I-infected T cell clones showed increased expression of the IL-2 receptor p55 chain, the spontaneous clonal proliferation was not inhibited by anti-IL-2 receptor mAb. Moreover, the spontaneous clonal proliferation was insensitive to cyclosporin A and FK 506 while being highly sensitive to rapamycin, which is known to inhibit IL-2-mediated signaling. Together these results demonstrate that IL-2 is not required for the HTLV-I-induced spontaneous clonal proliferation and further suggest that HTLV-I may induce signaling pathways replacing an IL-2 receptor signal proximal to the site of action of rapamycin.
Cloning and expression of murine IL-12.
Authors: Schoenhaut D S , Chua A O , Wolitzky A G , Quinn P M , Dwyer C M , McComas W , Familletti P C , Gately M K , Gubler U 
Published: December 2022

Abstract
Human IL-12 (NK cell stimulatory factor, cytotoxic lymphocyte maturation factor) is a heterodimeric cytokine that can act as a growth factor for activated human T and NK cells, enhance the lytic activity of human NK/lymphokine-activated killer cells, and stimulate the production of IFN-gamma by resting human PBMC. Because in our hands, human IL-12 did not elicit similar responses in murine lymphocytes, we have cloned and expressed the murine IL-12 subunit cDNA in order to obtain recombinant protein for murine studies. Comparison of the predicted amino acid sequences of the murine subunits with their human counterparts revealed that the p40 subunits are more highly conserved than the p35 subunits (70% vs 60% identity, respectively). The sizes of the p35 and p40 subunit mRNA were estimated to be 1.5 kb and 2.6 kb, respectively. RNA blot analysis showed that p35 mRNA was expressed in lymphoid tissues (spleen, thymus) and nonlymphoid tissues (lung, brain), whereas p40 mRNA expression was only detected in lymphoid cells. Incubation of splenocytes with pokeweed mitogen did not significantly affect p35 mRNA levels, however, it resulted in a decrease of p40 mRNA. Coexpression of the murine p35 and p40 cDNA clones in COS cells resulted in the secretion of IL-12, which was active in human and mouse T cell proliferation, murine NK cell activation, and murine IFN-gamma induction assays. Transfection of each subunit cDNA alone did not result in measurable secreted IL-12 activity. A hybrid heterodimer consisting of murine p35 and human p40 subunits retained bioactivity on murine cells; however, the combination of human p35 and murine p40 was completely inactive on murine cells. These results indicate that the observed inability of human IL-12 to act on murine cells is largely determined by the p35 subunit.
Functional nerve growth factor receptors on human B lymphocytes. Interaction with IL-2.
Authors: Brodie C , Gelfand E W 
Published: December 2022

Abstract
In addition to its neurotrophic activity, nerve growth factor (NGF) has been shown to interact with cells of the immune system. We have characterized the effects of NGF on human B cell proliferation and the regulation of NGF receptor expression on these cells. Nerve growth factor receptors were expressed on all tonsillar and peripheral blood B cells and this expression was increased upon activation of the cells. NGF augmented the mitogenic effect of the T-independent B cell mitogen, Staphylococcus aureus Cowan I strain, and provided a progression signal to competent B cells. The proliferative response was augmented when the progression signal provided by NGF was combined with that provided by IL-2 but not with IL-4. One effect of the interaction between NGF and IL-2 appears to occur at the receptor level, because each of these ligands increased the expression of the receptor for the other ligand, whereas IL-4 was without effect. These results demonstrate the expression of functional receptors on human B lymphocytes, the involvement of NGF in immuno-regulation, and indicate that NGF may act as a B cell growth factor.
Mast cell mediators prostaglandin-D2 and histamine activate human eosinophils.
Authors: Raible D G , Schulman E S , DiMuzio J , Cardillo R , Post T J 
Published: December 2022

Abstract
Airway damage secondary to eosinophil activation is thought to contribute to the development of asthma. Using the fluorescent dye FURA-2 to measure the concentration of cytosolic calcium, we found that supernatants from anti-IgE-stimulated human lung mast cells increased cytosolic calcium in human eosinophils. We then examined the major mast cell mediators (histamine, PGD2, platelet-activating factor (PAF), eosinophil chemotactic factor of anaphylaxis (ECF-A), leukotriene (LT)C4 and LTB4) for their ability to increase cytosolic calcium in eosinophils. We found that both PAF (5 x 10(-9) to 5 x 10(-6) M) and PGD2 (two of five donors responsive at 1 x 10(-9) M) were potent stimuli for calcium mobilization. LTB4 (10(-8), 10(-7) M) and histamine were also active, although higher concentrations of histamine were required to see a response (3 x 10(-7) to 10(-5) M). LTC4, val-ECF-A, and ala-ECF-A were inactive. The effects of PGD2 and histamine were specific for eosinophils, although LTB4 and PAF increased calcium in both neutrophils and eosinophils. The histamine-induced increase in intracellular calcium was not blocked by the H1 or H2 antagonists pyrilamine or cimetidine (10(-4) M), respectively; however, the response to 10(-6) M histamine was completely blocked by the specific H3 antagonist thioperamide (10(-6) M). To evaluate the relative contribution of these stimulatory mast cell mediators on the calcium mobilizing activity in supernatants from anti-IgE-stimulated human lung mast cell (HLMC), we examined the effect of supernatants from HLMC pretreated with indomethacin and/or the 5-lipoxygenase pathway inhibitor MK886. These supernatants were added to FURA-2-loaded eosinophils that had been preincubated with thioperamide and/or the PAF antagonist WEB-2086. We found that the increase in eosinophil calcium in response to supernatants from anti-IgE-stimulated-HLMC was totally inhibited only when the mast cells were challenged in the presence of indomethacin and MK886, and the eosinophils were preincubated with thioperamide. WEB-2086 had little effect. When we examined the effect of these mediators on eosinophil secretory function, we found that PGD2 (not histamine) primed eosinophils for enhanced release of LTC4 in response to the calcium ionophore A23187. We conclude that the activation of eosinophils by PGD2 and other mast cell products may contribute to airways inflammation that is characteristic of asthma.