bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noncognate contact-dependent B cell activation can promote IL-4-dependent in vitro human IgE synthesis.
Authors: Parronchi P , Tiri A , Macchia D , De Carli M , Biswas P , Simonelli C , Maggi E , Del Prete G , Ricci M , Romagnani S 
Published: December 2022

Abstract
We have previously shown that IL-4 is an essential mediator for the synthesis of human IgE in vitro. In this study we demonstrate that prior physical contact with T cells is required by B cells to synthesize IgE in response to IL-4. Both autologous and allogeneic freshly prepared T cells were consistently able to support IL-4-dependent IgE synthesis, provided that they were added to B cells together with, or before, the addition of IL-4. In addition, most CD4+, as well as a proportion of CD8+, PHA-induced T cell clones (TCC) established from two HLA-DR incompatible donors, supported, in the presence of exogenous IL-4, the synthesis of IgE in B cells from the majority of individuals tested including both donors of cloned T cells. An alloreactive TCC able to produce IL-4 in response to HLA-DR4+ B cells and to induce HLA-DR4+ B cells to synthesize IgE, acquired the ability to support IgE synthesis by B cells lacking the appropriate alloantigen provided that exogenous IL-4 was added. Although the ability of freshly prepared T cells to support IgE synthesis was consistently abrogated by fixation with paraformaldehyde (PF), such a treatment variably affected the IgE-inducing ability of TCC. Preactivation with anti-CD3 before treatment with PF maintained or even enhanced the ability of TCC to support IL-4-dependent IgE synthesis. More importantly, preactivation with anti-CD3, followed by fixation with PF, enabled TCC, apparently devoid of IgE-inducing activity in unfixed condition, to support IL-4-dependent IgE synthesis. Taken together these data suggest that at least two signals are involved in the triggering of human B cells to IgE production: the first is delivered by a T-B cell contact and the second by IL-4. The physical signal delivered by T cells does not necessarily consist of cognate interaction. Non-cognate contact-dependent induction of B cells to IgE synthesis in response to IL-4 appears to be related to molecule(s) distinct from the TCR/CD3 complex, but fully expressed on the membrane of TCR/CD3-activated T cells.
Tumor allograft rejection is mainly mediated by CD8+ cytotoxic T lymphocytes stimulated with class I alloantigens in cooperation with CD4+ helper T cells recognizing class II alloantigens.
Authors: Tomita Y , Mayumi H , Eto M , Nomoto K 
Published: December 2022

Abstract
Presence of the three major pathways (self-Ia restricted, allo-K/D restricted, and allo-Ia restricted pathways) in generating class I-restricted CTL has been reported. The present study was conducted in order to clarify which of the three is the main pathway in mediating tumor allograft rejection. One million EL-4 tumor cells derived from C57BL/6 (B6;H-2b) were inoculated into the various strains of mice that were genetically different from B6. Class I (K/D) Ag-disparate but IA Ag-matched B6.C-H-2bm1 (bm1;Kbm1, IAb, IE-, Db) mice or B10.A (5R) (5R; b, b, k, d) mice could not reject 1 x 10(6) EL-4 tumor cells in spite of the strong generation of CTL against the B6 Ag, suggesting the inability of the self-Ia restricted pathway and the allo-K/D restricted pathway in rejecting tumor allografts. The strains of mice being capable of rejecting EL-4 tumor were disparate from B6 mice in both class I and class II (IA) Ag, suggesting the importance of the allo-Ia restricted pathway in rejecting tumor allografts. To generate CTL against Kb Ag via the allo-Ia restricted pathway in the bm1 mice, 2 x 10(7) B6.H-2bm12 (bm12; b, bm12, -, b) spleen cells were injected into the bm1 mice as a supplementary source of allogeneic APC that possibly raise CTL through CD4+ Th cells of bm1 origin. These bm1 mice became capable of rejecting 1 x 10(6) EL-4 tumor cells. The same was observed in the combination of bm12----B10.A (5R) (b, b, k, d) mice. To further elucidate the role of the class II restricted CD4+ Th cells, anti-CD4 antibody was repeatedly i.v. administered into the C3H/He (C3H; H-2k) or the DBA/2 (DBA; H-2d) mice on days 0, 1, and 4. Injection of anti-CD4 antibody led 1 x 10(6) EL-4 tumor cells to grow and kill the C3H and DBA mice. These results suggest that the main effector CTL pathway involved in tumor allograft rejection is allo-Ia restricted pathway where CD8+ precursor CTL were stimulated by the class II-restricted CD4+ Th cells.
The use of peptide analogs with improved stability and MHC binding capacity to inhibit antigen presentation in vitro and in vivo.
Authors: Lamont A G , Powell M F , Colón S M , Miles C , Grey H M , Sette A 
Published: December 2022

Abstract
The identification of a core region for OVA 323-339, which is critical in determining binding to IAd, has enabled us to generate a series of analog peptides in which this core region was extended at both the N and C termini with different amino acid residues. When assessed for binding capacity, several peptides were shown to have increased affinity for IAd compared with the parent sequence, and in addition, some peptides had acquired binding specificities for class II MHC haplotypes not present for OVA 323-339. These peptides were next examined for their ability to inhibit T cell responses in vitro and in vivo. The correlation between binding and the ability to inhibit T cell activation in vitro was good. However, when assessed in vivo, it was clear that high Ia binding was not sufficient in itself to define the inhibitory capacity of a given peptide. That this discrepancy was due to differences in degradation of the core-extended peptides was suggested by 1) results from an inhibition of Ag presentation assay, in which the pulse period with Ag and inhibitor was extended to 20 h; and 2) direct analysis of peptide stability by using reverse phase HPLC. Finally, by protecting the peptide from degradation with N- and C-terminal substitutions of D-amino acids, the inhibitory capacity of an unstable core-extended peptide in vitro could be greatly enhanced. These data indicate that the core extension approach may be one method by which antagonists for MHC class II molecules may be generated.
Inhibition by anti-HLA class II monoclonal antibodies of monoclonal antibody OKT3-induced T cell proliferation. Studies at the mRNA level.
Authors: Racioppi L , Moscarella A , Ruggiero G , Manzo C , Ferrone S , Fontana S , Zappacosta S 
Published: December 2022

Abstract
mAb to monomorphic determinants of HLA class II Ag have been shown to inhibit monocyte-dependent OKT3-induced T cell proliferation, indicating that MHC class II molecules play a regulatory role also in Ag nonrestricted, CD3-induced T cell proliferation. This effect involves several steps in the process of T cell activation and proliferation, including IL-1 beta, IL-6, and IL-2 secretion and IL-2R alpha expression. In the present study, we analyzed the effect of an anti-HLA class II mAb (Q5/6) on the mRNA expression of genes related to monocyte and T cell activation. mRNA levels for early (early c-myc, c-fos) and late (late c-myc, N-ras, c-myb) genes involved in T cell activation were determined as well as mRNA levels for IL-1 beta, IL-6, IFN-gamma, IL-2, and IL-2R alpha. The kinetics of mRNA induction for ICAM-1 was also investigated. The results show that in T lymphocytes the expression of c-fos and early c-myc mRNA was unaffected by mAb Q5/6, whereas the c-myb and N-ras mRNA levels were strongly diminished as well as those of IL-2, IL-2R alpha, and IFN-gamma mRNA. An early increase of ICAM-1 mRNA was partially inhibited. In monocytes, a marked reduction of IL-1 beta and IL-6 mRNA was found. It is concluded that the HLA class II determinant involved in the inhibition mechanism can be engaged in the control of IL-1 beta and IL-6 mRNA levels and constitute an accessory signal up-regulating IL-2 and IL-2R alpha gene activation, through a pathway not affecting c-myc and c-fos expression.
IgG antibodies from patients with bullous pemphigoid bind to localized epitopes on synthetic peptides encoded by bullous pemphigoid antigen cDNA.
Authors: Rico M J , Korman N J , Stanley J R , Tanaka T , Hall R P 
Published: December 2022

Abstract
Bullous pemphigoid (BP) is an autoimmune blistering disease characterized in part by the presence of tissue-bound and circulating antibodies specific for basement membrane zone proteins, the BP Ag. The purpose of the present study was to determine seroreactivity of patients with BP to six nonoverlapping synthetic peptides representing sequences in the carboxyl domain of the recently cloned 230-kDa BP Ag. Sera from 40 patients with BP, 57 normal subjects, and 18 patients with other autoimmune blistering skin diseases were examined in an ELISA for binding to six synthetic peptides varying between 17 and 19 amino acids in length. The binding of IgG from patients with BP to three synthetic peptides, P1-2, P1-1, and P3-1, was significantly different from that seen in the normal controls (p less than 0.001, Fisher's exact test). Affinity-purified anti-P1-2 antibody from a patient with BP bound in a characteristic linear band to the epidermal side of 1 M NaCl split skin and immunoprecipitated the native 230-kDa BP Ag. Serum IgG antibodies from a rabbit immunized with a BP fusion protein that contains the sequences for P1-1 and P1-2, bound on ELISA to P1-2 but not to P1-1. These data suggest that multiple epitopes on the 230-kDa BP Ag are recognized by circulating autoantibodies in patients with this disease, and that an epitope encoded within the synthetic peptide P1-2 is expressed on the native molecule and may be relevant in the generation of an immune response both in man and in an animal model.
Selective in vivo inhibition of T cell activation by class II MHC-binding peptides administered in soluble form.
Authors: Muller S , Adorini L , Juretic A , Nagy Z A 
Published: December 2022

Abstract
A synthetic peptide corresponding to residues 53-61 of hen egg white lysozyme, as well as its N-succinyl C-amide, inhibit in vivo priming for T cell responses when administered in soluble form, in osmotic minipumps implanted s.c., 1 day before immunization. The inhibition exhibits MHC selectivity that corresponds to the binding specificity of these peptides for class II MHC molecules in vitro. Approximately fourfold higher doses of soluble competitor are required than of competitor in CFA-depot, in order to achieve comparable levels of inhibition. The inhibition of priming to a nonimmunodominant T cell determinant requires lower doses of soluble competitor than the suppression of priming to a dominant T cell determinant. The soluble competitors do not appear to induce class II MHC-restricted T cell response against themselves.
Evidence for a new HLA determinant that causes T cell activation without costimulation.
Authors: Mittler R S , Fifer C A , Burbach P , Edinger K , Kiener P A 
Published: December 2022

Abstract
We describe the requirements for T cell activation by a mAb termed 4-10 that recognizes a novel determinant on MHC class I molecules. The determinant recognized by mAb 4-10 appears on resting T cells of all individuals tested (n greater than 30). Unlike previously described anti-class I mAb, 4-10 was shown to be directly mitogenic for T cells obtained from more than 20 normal donors. In order for 4-10 to exert its mitogenic effect on purified T cell populations it must be immobilized on a solid support. Immobilization of 4-10 can be circumvented if low numbers of adherent cells are added to the T cell cultures. mAb 4-10 preferentially activates the CD8+ T cell subset as judged by the fact that CD8+ T cells preferentially down-regulated their TCR after 4-10 activation and because CD4+ T cell activation with 4-10 requires approximately five times the concentration of mAb needed to reach comparable levels of activation observed with CD8+ T cells. We further observed that simultaneous cross-linking of class I and CD8 Ag by using 4-10 and anti-CD8 mAb almost completely abrogated the proliferative response of T cells when anti-CD8 was presented in immobilized form. In contrast, similar cross-linking with 4-10 and anti-CD4 diminished the response by about 20%. We also found that other anti-class I mAb were able to synergize in the activation of T cells with mAb 4-10 in a dose-dependent manner.
Alteration in H chain V region affects complement activation by chimeric antibodies.
Authors: Horgan C , Brown K , Pincus S H 
Published: December 2022

Abstract
Chimeric antibodies to the synthetic polypeptide (Tyr, Glu)-Ala-Lys ((T,G)-A-L) were used to examine C activation by human IgG1. Two IgG1 antibodies, which contained mouse L chains and H chains with mouse V domains and human C domains, differed only in their VH domain. Ag binding and C activation by these antibodies were analyzed by ELISA. When limiting amounts of Ag were used in the assays, the antibodies required different quantities of Ag for optimal binding, suggesting that the antibodies bind to different epitopes on the (T,G)-A-L molecule. However, when competitive inhibition assays were performed with an optimal concentration of Ag, there were no differences in relative binding affinities for (T,G)-A-L or dissociation characteristics of the antibodies. C activation was examined at optimal Ag concentration to ensure equivalent binding of two IgG1 antibodies to Ag. After combination with immobilized Ag, these two antibodies bearing different V regions exhibited marked differences in the binding of C components C1q and C3d. When present in equal amounts in the assay, antibody 10B activated C and bound more C1q and C3d than antibody B11. These results indicate that V region differences can affect C activation by IgG.
Inhibition of neutrophil migration by tumor necrosis factor. Ex vivo and in vivo studies in comparison with in vitro effect.
Authors: Otsuka Y , Nagano K , Nagano K , Hori K , Oh-ishi J , Hayashi H , Watanabe N , Niitsu Y 
Published: December 2022

Abstract
Coincubation of neutrophils with TNF inhibited the chemoattractant-directed migration of neutrophils under agarose and enhanced their migration in the multiwell chemotaxis chamber. To assess the physiological significance of these differing in vitro TNF effects, ex vivo and in vivo investigations were performed using animal models. Neutrophils from the peripheral blood of rabbits preadministered systemic TNF showed impaired ability to migrate toward chemoattractants in vitro. In addition, systemic TNF administration suppressed zymosan-activated plasma-induced local accumulation of leukocytes in mouse skin. The results indicate that circulating TNF may act as a suppressor for local inflammatory reaction.
Synthetic peptide immunogens eliciting antibodies to Plasmodium falciparum sporozoite and merozoite surface antigens in H-2b and H-2k mice.
Authors: Rzepczyk C M , Csurhes P A , Lord R , Matile H 
Published: December 2022

Abstract
Peptides representing conserved (MSA2/1A and MSA2/1B) and variant (MSA2/2, MSA2/6 and MSA2/7) regions of the merozoite surface Ag 2 (MSA2) of Plasmodium falciparum (FCQ-27/PNG isolate) were coupled to either peptide NP(NANP)5NA or peptide C(NANP)6 both of which contained the core sequence (NANP)n. The coupling was done via the N-terminus of one peptide and a cysteine residue on either terminus of the other. BL/10 (H-2b) and B10.BR (H-2k) mice were immunized with these MSA2-(NANP)n conjugates. The mice were also immunized with the unconjugated MSA2 peptides and with NP(NANP)5NA and C(NANP)6. Antibody responses were evaluated by 1) ELISA, in which the MSA2 peptides and C(NANP)6 were used as Ag; 2) immunofluorescence assays (IFAT) against intact sporozoites and merozoites; and 3) immunoblotting experiments against solubilized P. falciparum blood stage proteins. High titer antibodies to (NANP)n were elicited in both BL/10 and B10.BR mice after immunization with all the conjugates except MSA2/7-(NANP)n which gave only a very limited response in B10.BR mice. These antibodies recognized unfixed sporozoites. The conjugates also elicited antibodies to MSA2 as shown by ELISA, IFAT, and immunoblotting except for mice immunized with MSA2/1B-(NANP)n where an anti-MSA2 response was only detectable by immunoblotting. Immunization with unconjugated MSA2 peptides showed that MSA2/2 was immunogenic in both BL/10 and BR.10 mice, with MSA2/6 and MSA2/7 being immunogenic only in BL/10 mice. The antibodies elicited recognized both merozoites and the MSA2 protein. However, the antibody titers were lower overall than those seen when these peptides were used in the conjugated form. No anti-MSA2 antibodies were detected after immunization with MSA2/1A and MSA2/1B. Immunization of mice with the peptide NP(NANP)5NA produced antibodies in BL/10 (H-2b) mice only, and the immunogenicity of this preparation was poor. In contrast, C(NANP)6 produced a strong antibody response in both mouse strains. The antibodies elicited by NP(NANP)5NA and C(NANP)6 recognised sporozoites in IFAT. The MSA2 peptides studied (or their derivatives) were previously shown to be recognized by human T cells. Their immunogenic potential shows promise in that complex anti-P. falciparum responses can be elicited with simple synthetic immunogens based on these peptides.
The molecular configuration and ultrastructural locations of an IgG Fc binding site in human colonic epithelium.
Authors: Kobayashi K , Hamada Y , Blaser M J , Brown W R 
Published: December 2022

Abstract
Previously, we discovered a binding site for the Fc region of IgG in human small intestinal and colonic mucosa. The binding site (Fc gamma IBS) appeared to be primarily associated with goblet cells, to consist of greater than 200,000 Da and 78,000 Da components, and to be distinct from leukocyte FcR. In the present work, we used mAb made to colonocyte IgG-binding material to more accurately define the molecular structure and cellular locations of the Fc gamma IBS. In immunoblot and fast protein liquid chromatography analysis, the mAb revealed that the Fc gamma IBS consists of a 110,000- to 140,000-Da component in addition to the two components previously recognized. The greater than 200,000 component may be the critical component for IgG binding, inasmuch as mAb to it but not to the other two components inhibited binding of IgG to colonic sections in vitro. Used in immunoelectron microscopy, the mAb documented that the Fc gamma IBS is present in the endoplasmic reticulum of goblet cells, in the cytoplasmic matrix separating secretory granules of goblet cells, and within the granules themselves; occasionally it has the appearance of being secreted into the intestinal lumen with mucus. The Fc gamma IBS could not be solubilized from colonocyte homogenates by three different detergents, which suggests that it exists in complex with cytoskeletal elements. We speculate that the Fc gamma IBS aids in immunologic protection of the intestine by facilitating interaction between intestinal mucus and antigenic material in the lumen.
Inhibition of epidermal Langerhans cell function by low dose ultraviolet B radiation. Ultraviolet B radiation selectively modulates ICAM-1 (CD54) expression by murine Langerhans cells.
Authors: Tang A , Udey M C 
Published: December 2022

Abstract
Immunosuppressive effects of low levels of ultraviolet B (UVB) radiation on cutaneous immune responses have been attributed to deleterious effects of UVB radiation on epidermal Langerhans cells (LC). To determine how UVB radiation modulates LC function we examined the effect of in vitro UVB exposure on LC accessory cell activity and surface phenotype. Exposure of BALB/c murine epidermal cells to low dose (less than or equal to 200 J/m2) UVB radiation in vitro inhibited their ability to support the mitogenic response of unstimulated, accessory cell-depleted splenic T cells to anti-CD3 mAb. LC accessory cell activity was also inhibited when LC were exposed to UVB radiation in situ, although several-fold higher doses of UVB radiation were required to achieve complete inhibition of LC function. This dose-dependent inhibition was mediated through a direct effect on LC that could not be reversed by IL-1 or IL-6 alone or in combination, or granulocyte-macrophage-CSF. TNF-alpha did not inhibit LC accessory cell function in this assay and anti-TNF-alpha neutralizing antibodies did not reverse the inhibitory effects of UVB radiation. UVB irradiated LC failed to participate in the anti-CD3-dependent clustering that normally occurs between T cells and LC during the proliferative response of murine T cells to anti-CD3 mAb, suggesting that UV radiation may interfere with accessory cell function by preventing intercellular adhesion. Two-color flow cytometric studies revealed low levels of the ICAM-1 on freshly isolated LC and some keratinocytes. ICAM-1 expression on LC increased 15 to 20-fold within the first 24 h in vitro and continued to increase during a 72-h culture period. The integrin LFA-1 was not identified on freshly isolated or cultured LC but was detected on responding T cells. Prior exposure of LC to UVB radiation (50 or 100 J/m2) inhibited the increase in ICAM-1 expression that normally occurs in vitro by up to 70% whereas surface levels of class II MHC Ag, CD45 and Fc-gamma receptors were not affected. Blocking studies revealed that anti-CD3 induced T cell proliferation and T cell-LC cluster formation was inhibited by both anti-LFA-1 and anti-ICAM-1 mAb suggesting that ICAM-1 expressed on LC must bind to LFA-1 on T cells to facilitate proliferative responses of T cells to anti-CD3 mAb. We conclude that the in vitro inhibitory effects of low dose UVB radiation on LC accessory function may result because UVB radiation prevents upregulation of ICAM-1 expression by LC in culture.(ABSTRACT TRUNCATED AT 250 WORDS)
Cytokines in chronic inflammatory arthritis. VI. Analysis of the synovial cells involved in granulocyte-macrophage colony-stimulating factor production and gene expression in rheumatoid arthritis and its regulation by IL-1 and tumor necrosis factor-alpha.
Authors: Alvaro-Gracia J M , Zvaifler N J , Brown C B , Kaushansky K , Firestein G S 
Published: December 2022

Abstract
Granulocyte-macrophage CSF (GM-CSF) is a potent stimulator of macrophages and neutrophils and is produced by rheumatoid arthritis (RA) synovium. We now report studies that identify some of the synovial cells and cytokines responsible for local GM-CSF production and gene expression in RA. GM-CSF was assayed by ELISA in supernatants from cultured RA fibroblast-like synoviocytes stimulated with various cytokines (IL-1 beta, TNF-alpha, macrophage-CSF, IFN-gamma, IL-6, and TGF-beta). Immunoreactive GM-CSF was detected in IL-1 beta and TNF-alpha-stimulated cultures, but not in cells cultured in medium or stimulated with any of the other cytokines. IL-1 and TNF-alpha had a synergistic effect on GM-CSF production. GM-CSF gene expression by fibroblast-like synoviocytes was analyzed by ribonuclease protection assay, Northern blot analysis, and in situ hybridization. Both IL-1 beta and TNF-alpha induced GM-CSF mRNA accumulation, with a maximum effect after 4 h of stimulation. We then studied GM-CSF production by macrophage-like synoviocytes (MLS) isolated from fresh synovial specimens by flow microfluorimetry. Fresh MLS spontaneously secreted the cytokine and exogenous IL-1 beta or TNF-alpha had no effect. After 1 wk in culture, additional stimulation with IL-1 beta or TNF-alpha was required for GM-CSF production. Finally, in situ hybridization performed on freshly isolated subpopulations of synovial cells, identified GM-CSF RNA transcripts in MLS.