bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo blood monocyte migration to acute inflammatory reactions, IL-1 alpha, TNF-alpha, IFN-gamma, and C5a utilizes LFA-1, Mac-1, and VLA-4. The relative importance of each integrin.
Authors: Issekutz T B 
Published: December 2022

Abstract
The role of the monocyte integrins, Mac-1, LFA-1, and VLA-4, on the adhesion of rat blood monocytes to rat microvascular endothelial cells in vitro and the importance of these receptors in monocyte migration to inflammation in vivo were evaluated. Monocyte adhesion to cytokine (IL-1, IFN-gamma, and TNF-alpha)-stimulated endothelial cells was mediated by Mac-1, LFA-1, and VLA-4, but Mac-1 appeared to be less important than LFA-1 or VLA-4. After i.v. injection, large numbers of 51Cr-labeled blood monocytes migrated within 2 h to dermal inflammatory sites induced by C5a, IL-1 alpha, IFN-gamma, TNF-alpha, LPS, and poly inosinic:cytidylic acid. Anti-Mac-1 mAb treatment had no effect, whereas anti-LFA-1 inhibited migration to C5a and the cytokines by 20 to 40%. Blocking both Mac-1 and LFA-1 decreased monocyte accumulation by 50 to 70% to all stimuli. Anti-VLA-4 inhibited monocyte migration to IL-1 alpha, IFN-gamma, TNF-alpha, and LPS, but not to C5a. Combining anti-Mac-1 with anti-VLA-4 did not increase this inhibition, whereas blocking VLA-4 and LFA-1 together further suppressed (60-85%) migration. Combined treatment with mAb to all three integrins inhibited &gt; 98% of the monocyte migration to the inflammatory stimuli. In conclusion: 1) 51Cr blood monocytes can be used to quantify monocyte migration to inflammatory reactions in the rat. 2) Monocytes use Mac-1, LFA-1, and VLA-4 for in vitro adhesion and in vivo migration to cutaneous inflammation, and these integrins are essential for normal migration because blockade of all three virtually abolishes monocyte accumulation. 3) Mac-1 plays a less important role than LFA-1, as LFA-1 appears to substitute for Mac-1, and VLA-4 and LFA-1 can mediate much of the adhesion and migration. 4) The initiating inflammatory stimulus also modifies monocyte integrin usage, supporting the multistep combinatorial model of leukocyte extravasation.
The role of MHC class I molecules in the generation of endogenous peptide/MHC complexes.
Authors: Malarkannan S , Goth S , Buchholz D R , Shastri N 
Published: December 2022

Abstract
Cellular proteins undergo proteolysis to yield peptide/MHC class I complexes for display on the APC surface. During this process it is not clear whether MHC molecules bind to and stabilize independently generated peptides, or whether they are involved in the peptide cleavage events. In this study, we analyzed the role of MHC molecules in Ag processing by characterizing the naturally processed peptide analogues of OVA (OVA257-264, SL8) in APC. DNA constructs encoding SL8 precursors were transfected into cells that varied in their MHC expression. By HPLC fractionation of cell extracts and with sensitive T cell assays for both the processed SL8 and its minimal Met-SL8 (MSL8) precursor, we determined that expression of Kb MHC molecule was essential for detecting processed peptides in living cells. Curiously, although the translated MSL8 nonapeptide precursor itself could bind Kb as well as the SL8 octapeptide, and MSL8 was available to MHC, only the SL8 peptide was found in Kb cell extracts. The presence of naturally processed SL8, but not MSL8 peptide in Kb-expressing cells suggests that the precise identity of endogenously processed peptides is also strongly influenced by the MHC molecules.
Characterization of donor chimerism, alloreactive host T cells and memory cell development in thymi from mice resistant to neonatal transplantation tolerance.
Authors: Ruiz P , Nassiri M , Viciana A L , Padmanabhan J , Streilein J W 
Published: December 2022

Abstract
Certain B10 background mouse strains are resistant to tolerance induction after neonatal inoculation of class I/II MHC-disparate F1 hybrid cells. Despite initial thymic deletion of alloreactive cells, the majority (95%) of these mice reacquire the capacity to reject donor allografts. These current studies examined thymi of adult B10.S (H-2S/H-2E-) mice that neonatally received (B10.S x B10.A)F1 cells, before and after rejection or acceptance of B10.A (H-2k/d/H-2E+) skin grafts. Alloreactive thymic V beta 11+ and V beta 5+ T cells were often reduced in the injected recipients preceding allograft challenge. In some mice a single B10.A skin graft generated an increase in these T cell populations concurrent with allograft rejection. Injected mice that accepted B10.A skin grafts (i.e., tolerant) or that rejected two sequential B10.A grafts often had a reduction of these T cells. Thymic memory cells (CD44high+) were present before transplant in injected mice and reduced in the tolerant mice. Donor chimeric cells were identified in the majority of injected mice before transplant and diminished after B10.A graft application. A greater proportion of chimeric cells coexpressed CD11b or B220 in the tolerant mice. Thus, neonatally injected B10.S mice resistant to tolerance induction reacquire immunocompetent thymic T cells bearing characteristics of memory T cells that could mediate graft rejection. Finally, the initial presentation of chimeric cells (e.g., macrophages) that may efficiently present class I Ags through H-2E likely increases the possibility of adult tolerance.
Definition of a lamina propria T cell responsive state. Enhanced cytokine responsiveness of T cells stimulated through the CD2 pathway.
Authors: Targan S R , Deem R L , Liu M , Wang S , Nel A 
Published: December 2022

Abstract
This study was designed to compare cytokine release in lamina propria lymphocytes (LPLs) and PBLs activated by Abs against CD3, CD2, and CD28. LPL T cells were significantly more responsive to CD2 ligation than PBL, as determined by release of IFN-gamma, IL-2, IL-4, and TNF-alpha. Moreover, CD28 co-ligation in LPLs exaggerated CD2 &gt; CD3 dominance in cytokine induction. PHA-activated PBLs expressed more CD2 receptors than freshly isolated LPLs, but were less responsive to activation through CD2, indicating that postreceptor pathways in LPL may be adapted specifically to facilitate CD2-mediated cytokine secretion. Antiphosphotyrosine (APT) immunoblotting revealed inducible substrate phosphorylation during CD2, but not CD3, ligation in whole LPLs, as well as LPL-derived T cell lines. PBLs cocultured with an irradiated B cell line, Daudi, and IL-2 for 5 days attained a CD2-dominant cytokine-secretion pattern with identical tyrosine phosphorylation profiles as freshly isolated LPL or LPL T cell lines. PHA-activated PBLs did not produce these tyrosine phosphorylation profiles. This suggests that B lymphocytes in the lamina propria may contribute to a T cell differentiation process in which CD2, possibly by potentiation of its postreceptor pathway, becomes a prominent receptor for induction of cytokine secretion.
Conformation and ion channel activity of lymphotoxin at neutral and low pH.
Authors: Baldwin R L , Mirzabekov T , Kagan B L , Wisnieski B J 
Published: December 2022

Abstract
Lymphotoxin (LT or TNF-beta), a T cell-derived lymphokine with partial homology to TNF-alpha, was found to bind to dimyristoylphosphatidylcholine vesicles in a pH-dependent manner: binding increased with decreasing pH. Binding was not limited to surface association with phospholipid head groups because studies with a photoreactive membrane-restricted probe revealed protein penetration of the hydrocarbon core of the bilayer. Intramembranous photolabeling of the trimeric form of LT demonstrated maintenance of quaternary structure upon bilayer insertion. The efficiency of insertion was greatly enhanced with gel-phase bilayers compared with fluid phase bilayers even though the binding efficiency was much lower. Hence, binding and insertion represent two distinct physical processes. Intrinsic fluorescence and dye binding assays showed that the acid-facilitated membrane interactions stemmed from acid-induced changes in protein conformation. The acquisition of hydrophobic characteristics through these conformational changes supplies a physical explanation for LT conversion from a water-soluble form to a membrane-embedded structure. Moreover, the use of vesicle-embedded LT to prepare planar bilayers vs the addition of soluble LT subsequent to bilayer formation demonstrated that LT exhibits channel activity and that low pH-induced membrane insertion precedes and is distinct from expression of voltage-dependent ion gating. LT's ability to associate intimately with lipid vesicles and form ion channels mirrors the behavior of TNF-alpha. Thus, although LT and TNF-alpha are secreted by different cell types, the conservation of membrane binding, insertion, and channel-forming activities suggests a functional role in response induction.
Increased severity of experimental autoimmune encephalomyelitis in rats tolerized as adults but not neonatally to a protective TCR V beta 8 CDR2 idiotope.
Authors: Offner H , Malotky M K , Pope L , Vainiene M , Celnik B , Miller S D , Vandenbark A A 
Published: December 2022

Abstract
The ability of synthetic V region peptides to induce regulatory T cells and Abs in rodents and humans provides clear evidence that these idiotopes do not naturally induce tolerance. In this study, we investigated the ability of TCR V beta 8.2 peptides to experimentally induce specific T cell tolerance, as measured by loss of Ag-specific proliferation and delayed-type hypersensitivity responses, and by increased susceptibility to experimental autoimmune encephalomyelitis (EAE). We found that both neonatal and adult exposure to V beta 8.2-39-59 or V beta 8-44-54 peptides could induce efficient T cell tolerance, resulting in a significant inhibition of peptide-specific proliferative responses. In addition, neonatal tolerance resulted in a partial reduction in delayed-type hypersensitivity response and an inability to vaccinate against EAE after adult immunization with the tolerizing peptide. We further evaluated the contribution of naturally induced TCR-specific responses to EAE resistance induced by challenging neonatally or adult tolerized rats with myelin basic protein in adjuvant. The clinical course of EAE was not significantly altered in rats tolerized neonatally to V beta 8.2 peptides, but both the severity and incidence of mortality from EAE was increased in rats tolerized as adults with V beta 8.2 peptides conjugated to syngeneic splenocytes. These results demonstrate that V beta 8.2 peptides are tolerogenic as well as immunogenic. Moreover, the observation of different effects of neonatal vs adult tolerization on the course of EAE suggests either the emergence of additional protective idiotopes after neonatal tolerization and/or mechanistic differences in the two tolerance-inducing protocols. Most importantly, the enhancement of clinical EAE in rats tolerized as adults with V beta 8.2 peptides provides evidence for an innate regulatory role of the CDR2 idiotope in recovery from EAE.
Reconstitution of TCR alpha-chain expression in deletion mutants restores dinitrophenyl-specific/class I MHC-restricted suppressor molecule production.
Authors: Barbo J V , McCormack J E , Moorhead J W , Fairchild R L 
Published: December 2022

Abstract
A population of CD8+ T cells from dinitrobenzene sulfonate-primed mice produce soluble effector molecules that down-regulate the magnitude of dinitrophenol-specific contact hypersensitivity reactions. These soluble molecules express the binding specificity and serologic determinants of alpha/beta TCR. To examine the requirement for the TCR-alpha chain in the production of these molecules, we have cloned the alpha-chain gene used to encode the surface TCR of MTs 79.1, a T cell hybridoma producing a DNP/Kd-specific soluble suppressive molecule, and tested the ability of this gene to reconstitute the production of the regulatory molecule in TCR alpha-chain gene deletion mutants. Transfection and expression of the alpha-chain construct into an alpha-chain deletion mutant of the parental hybridoma that expressed the parental beta-chain gene resulted in reconstitution of both surface TCR expression and production of the soluble suppressive molecule. As with the molecule produced by the MTs 79.1 parental cells, the inhibitory activity produced by these alpha-chain gene transfectants was DNP-specific and expressed determinants bound by anti-V beta 8 Abs. Transfection of the alpha-chain gene construct into an alpha-/beta- chain gene deletion mutant did not restore the production of the soluble regulatory molecule. These results indicate that in addition to the TCR beta-chain gene, expression of the TCR alpha-chain gene is also required for the production of these molecules. Our results strongly support the hypothesis that some forms of immunosuppression are mediated by soluble forms of the TCR.
Human IL-3 receptor signaling: rapid induction of phosphatidylcholine hydrolysis is independent of protein kinase C but dependent on tyrosine phosphorylation in transfected NIH 3T3 cells.
Authors: Rao P , Kitamura T , Miyajima A , Mufson R A 
Published: December 2022

Abstract
Although tyrosine kinases are clearly activated after ligand engagement of the human IL-3R in both hematopoietic and nonhematopoietic cytoplasmic environments, a role for phospholipid hydrolysis and protein kinase C in IL-3R signal transduction is emerging. We have used NIH 3T3 cells transiently transfected with human IL-3R alpha- and beta-subunits to study phosphatidylcholine hydrolysis in response to human IL-3. We have found that NIH 3T3 cells expressing the complete human IL-3R respond to human IL-3 with a rapid and sustained increase in sn-1'2'-diacylglycerol. Accompanying this was a rapid increase in intracellular levels of phosphorylcholine. The protein kinase C inhibitor H-7, however, was not effective in inhibiting phosphatidylcholine hydrolysis in response to human IL-3 in NIH 3T3 cells expressing the human receptor. Thus the human IL-3R induces a rapid protein-kinase-C-independent hydrolysis induced by the murine receptor. Simultaneous with the increase in phosphatidylcholine hydrolysis induced by the murine receptor. Simultaneous with the increase in diacylglycerol levels was an increase in membrane-bound protein kinase C enzyme activity. Immunoblotting with isoform-specific Abs against protein kinase C showed that, whereas the zeta-isoform is constitutively membrane bound, the alpha-isoform of protein kinase C is translocated to the membrane in response to IL-3. Activation of phosphatidylcholine hydrolysis and protein kinase C activation required both alpha- and beta-receptor subunits. To determine the relationship of tyrosine phosphorylation to the activation of phosphatidylcholine hydrolysis and protein kinase C translocation, we used the specific and structurally unrelated tyrosine kinase inhibitors genistein and herbimycin. Both inhibitors effectively blocked human IL-3-induced tyrosine phosphorylation. In addition, both inhibitors blocked phosphatidylcholine hydrolysis and protein kinase C translocation. These data, combined with our previous report showing that c-jun induction by IL-3 is dependent on protein kinase C, suggest that, in hematopoietic and nonhematopoietic cells expressing the human IL-3R, phosphatidylcholine hydrolysis and protein kinase C are downstream effectors of tyrosine phosphorylation in the IL-3 signal transduction cascade resulting in immediate early response gene induction.
Superantigen-induced human CD4+ helper/killer T cell phenomenon. Selective induction of Th1 helper/killer T cells and application to tumor immunotherapy.
Authors: Kuge S , Miura Y , Nakamura Y , Mitomi T , Habu S , Nishimura T 
Published: December 2022

Abstract
Human CD4+ T cells activated with staphylococcal enterotoxin A (SEA) were fractionated by Percoll discontinuous density gradient centrifugation to enrich SEA-reactive CD4+ T cells. The SEA-reactive CD4+ T cells showed significant cytotoxicity, so-called superantigen-dependent cell-mediated cytotoxicity, against SEA-coated class II-positive tumor cells. During lysis of SEA-coated tumor cells, SEA-reactive CD4+ T cells produced high levels of IL-2 and IFN-gamma but not IL-4 in an Ag-specific manner. The skewing of human CD4+ T cells to Th1-type helper/killer T cells was also demonstrated when SEA-reactive CD4+V beta 5.3+ clonal T cells were cultured with SEA, but not with PHA or OKT3 mAb. Interestingly, the generation of SEA-reactive helper/killer T cells was negatively regulated by IL-4, but up-regulated by IL-12. The SEA-reactive CD4+ helper/killer T cells were able to generate from PBMC of tumor patients and could be expanded to 10(9) levels in a 7-day culture. The SEA-reactive CD4+ helper/killer T cells were specifically targeted to c-erbB-2 positive human colon cancer cells using SEA-conjugated-anti-c-erbB-2 mAb. These results initially demonstrated that SEA-activated human CD4+ T cells are a Th1 type of Th cell that has both helper and killer functions which may be useful for adoptive tumor immunotherapy in combination with SEA-conjugated antitumor mAb.
Interaction of human monocyte Fc gamma receptors with rat IgG2b. A new indicator for the Fc gamma RIIa (R-H131) polymorphism.
Authors: Haagen I A , Geerars A J , Clark M R , van de Winkel J G 
Published: December 2022

Abstract
Rat mAbs receive considerable interest for immunologic intervention in man. The rat IgG2b isotype has previously been found to be optimally active both in vivo and in vitro. We found that both a rat IgG2b CD3 mAb and a monovalent hybrid rat IgG2b-mouse IgG1 bispecific Ab triggered T cell activation in PBMC. Inhibition analyses with mAb blocking different human IgG Fc receptors (Fc gamma R) showed a dimorphic pattern. In donors expressing an Fc gamma RIIa-R/R131 allotype (previously defined on the basis of interaction with mouse (m) IgG1 as "high responder") anti-Fc gamma RI mAb 197 inhibited rat IgG2b induced T cell mitogenesis almost completely. In Fc gamma RIIa-H/H131 ("low responder" allotype) donors, however, both anti-Fc gamma RI mAb 197 and anti-Fc gamma RII mAb IV.3 were essential for optimal inhibition of mitogenesis. T cell proliferation experiments performed with the use of Fc gamma R-transfected fibroblasts as accessory cells showed the high affinity Fc gamma RIa (CD64) to interact with both rat IgG2b and rat IgG2b-mlgG1 hybrid CD3 mAb. The use of the two types of Fc gamma RIIa (CD32)-transfectants instead showed rat IgG2b CD3 mAb to interact solely with the IIa-H/H131 allotype. Interestingly, rat IgG2b-mlgG1 hybrid mAb did not interact effectively with this low affinity Fc gamma R. This suggests a requirement for only one rat IgG2b H chain for Fc gamma RIa-mediated binding, whereas two identical H chains seem to be necessary for proper interaction with Fc gamma RIIa. Ab-sensitized RBC-rosette experiments performed with the use of a rat IgG2b anti-NIP mAb confirmed the interaction pattern observed with rat CD3 mAb, supporting the phenomena to be isotype-, and not mAb-, dependent. These analyses point to a unique reactivity pattern for rat IgG2b Abs, interacting both with the high affinity Fc gamma RIa in all donors and Fc gamma RIIa of individuals expressing the IIa-H131 allotype.
Nonallergic individuals recognize the same T cell epitopes of Bet v 1, the major birch pollen allergen, as atopic patients.
Authors: Ebner C , Schenk S , Najafian N , Siemann U , Steiner R , Fischer G W , Hoffmann K , Szépfalusi Z , Scheiner O , Kraft D 
Published: December 2022

Abstract
The immune response toward allergens in nonallergic healthy individuals was investigated. To boost immune responses, two injections of birch pollen extract were administered to five nonallergic volunteers. T cell lines (TCL) with specificity for Bet v 1, the major birch pollen allergen, were established and analyzed for epitope specificity using overlapping peptides. Forty-nine T cell clones (TCC) specific for Bet v 1 were isolated from TCLs. Comparison with TCL and TCC established from birch pollen-allergic patients was performed. All TCC revealed the Th phenotype. Epitope specificities of TCL and TCC from nonatopics were identical to those found in allergic individuals. No association between MHC class II molecules and particular epitopes could be observed. In nonallergic as well as in allergic individuals, cytokine production in response to specific stimulation revealed a majority of Th-clones producing IL-4 and IFN-gamma. However, TCC derived from atopic individuals revealed a higher IL-4/IFN-gamma ratio. Immunoblot and ELISA revealed Bet v 1-specific IgG in nonallergic individuals before and after booster injections, but no IgE could be detected. High levels of Bet v 1-specific IgG and IgE could be detected in birch pollen-allergic patients. It can be concluded, that nonatopic and allergic individuals display the same repertoire of T cell specificities. In allergic individuals, the activation of allergen-specific TCC leads to a higher ratio of produced IL-4 vs IFN-gamma, which is responsible for enhanced IgE production.
Immunodominant framework region 3 peptide from TCR V beta 8.2 chain controls murine experimental autoimmune encephalomyelitis.
Authors: Kumar V , Tabibiazar R , Geysen H M , Sercarz E 
Published: December 2022

Abstract
Previous work has demonstrated the existence of regulatory circuitry that controls response to the dominant determinant Ac1-9 of myelin basic protein (MBP) which is highly restricted in TCR V gene usage to V beta 8.2 and V alpha 2.3. In particular, a CD4+ V beta 14+ regulatory T cell was shown to be a vital component of this circuit. In our work presented here, the peptide specificity of the response to V beta 8.2 peptides was examined. Five overlapping peptides, B1 through B5, were studied for their ability to induce a proliferative response: B2 (21-50), B4 (61-90), and B5 (76-101) each had this capacity in the B10.PL or (SJL x B10.PL)F1 mice. The determinant within the TCR peptide B5 appears dominant, whereas determinants within the B2 and B4 peptides are physiologically cryptic. Furthermore, only B5 could down-regulate the response to MBP Ac1-9 and significantly protect mice from MBP- or Ac1-9-induced EAE, whereas B2 or B4 treatment had no significant effect. Treatment of mice with B5 did not result in generalized deletion or inactivation of V beta 8.2+ T cells. The core residues of the B5 determinant lie within framework region 3 of the V beta 8.2 chain and do not include residues from the joining CDR3 region. Response to B5 was restricted by the I-Au MHC molecule. Furthermore, B5 only induced responses in mice with certain MHC alleles. It is evident that by specifically down-regulating the initial dominant response to Ac1-9, Ag-induced disease can be prevented. These data have implications for understanding induction of TCR-based regulation, as well as relevance to possible therapeutic approaches for oligoclonal responses in human autoimmune diseases.