Genetically engineered orchemically purified soluble monovalent major histocompatiblity complex (MHC) molecules, which havepreviously beenusedtostudy Tcells, havenotblocked cytotoxic T-cell responses. Herewedescribe agenetically engineered divalent class IMHC molecule which inhibits lysis oftarget cells byalloreactive cytotoxic Tcells. This protein, H-2Kb/IgG, wasgenerated asafusion protein be- tween theextracellular domains ofamurine class Ipolypeptide, H-2Kb, andanimmunoglobulin heavy chain polypeptide. The chimeric protein hasserological andbiochemical characteris- tics ofboththeMHC andIgGpolypeptides. Nanomolar concentrations ofH-2Kb/IgG inhibited lysis ofH-2Kb_ expressing target cells notonlybyalloreactive H-2Kb-specific T-cell clones butalso byalloreactive H-2Kb-specific primary T-cell cultures. A direct binding assay showedhigh-affinity binding between theH-2Kb/IgG molecule andanH-2Kb_ specific alloreactive T-cell clone. Unlabeled H-2Kb/IgG dis- placed '25I-labeled H-2Kb/IgG fromTcells withanICss of1.2

A soluble divalent class Imajorhistocompatibili ty complex molecule inhibits alloreactive Tcells atnanomolar concentrations

Indoleamine 2,3-dioxygenase, immunosuppression and pregnancy

The Human MHC Project aims at comprehensive cataloging of peptides presented within the context of different human leukocyte antigens (HLA) expressed by cells of various tissue origins, both in health and in disease. Of major interest are peptides presented on cancer cells, which include peptides derived from tumor antigens that are of interest for immunotherapy. Here, HLA-restricted tumor-specific antigens were identified by transfecting human breast, ovarian and prostate tumor cell lines with truncated genes of HLA-A2 and HLA-B7. Soluble HLA secreted by these cell lines were purified by affinity chromatography and analyzed by nano-capillary electrospray ionization-tandem mass spectrometry. Typically, a large peptide pool was recovered and sequenced including peptides derived from MAGE-B2 and mucin and other new tumor-derived antigens that may serve as potential candidates for immunotherapy.

Analysis of endogenous peptides bound by soluble MHC class I molecules: a novel approach for identifying tumor-specific antigens.

The binding of soluble HLA class I (sHLA-I) molecules to CD8 on EBV-specific CTL induced up-regulation of Fas ligand (FasL) mRNA and consequent sFasL protein secretion This, in turn, triggered CTL apoptosis by FasL/Fas interaction Molecular analysis of the biochemical pathways responsible for FasL up-regulation showed that sHLA-I/CD8 interaction firstly induced the recruitment of src-like p56(lck) and syk-like Zap-70 protein tyrosine kinases (PTK) Interestingly, p59(fyn) was activated upon the engagement of CD3/TCR complex but not upon the interaction of sHLA-I with CD8 In addition, sHLA-I/CD8 interaction, which is different from signaling through the CD3/TCR complex, did not induce nuclear translocation of AP-1 protein complex These findings suggest that CD8- and CD3/TCR-mediated activating stimuli can recruit different PTK and transcription factors Indeed, the engagement of CD8 by sHLA-I led to the activation of Ca2+ calmodulin kinase II pathway, which eventually was responsible for the NF-AT nuclear translocation In addition, we found that the ligation of sHLA-I to CD8 recruited protein kinase C, leading to NF-kappaB activation Both NF-AT and NF-kappaB were responsible for the induction of FasL mRNA and consequent CTL apoptosis Moreover, FasL up-regulation and CTL apoptotic death were down-regulated by pharmacological specific inhibitors of Ca2+/calmodulin/calcineurin and Ca2+-independent protein kinase C signaling pathways These findings clarify the intracellular signaling pathways triggering FasL up-regulation and apoptosis in CTL upon sHLA-I/CD8 ligation and suggest that sHLA-I molecules can be proposed as therapeutic tools to modulate immune responses

Apoptosis of Antigen-Specific T Lymphocytes upon the Engagement of CD8 by Soluble HLA Class I Molecules Is Fas Ligand/Fas Mediated: Evidence for the Involvement of p56lck, Calcium Calmodulin Kinase II, and Calcium-Independent Protein Kinase C Signaling Pathways and for NF-κB and NF-AT Nuclear Translocation

https://onlinelibrary.wiley.com/doi/epdf/10.1111/ajt.15592

Deletion of donor-reactive T cell clones after human liver transplant.

Background. In vitro, soluble MHC (sMHC) antigens modulate and induce apoptosis in alloreactive and antigen-specific T cells, demonstrating their potency to regulate T cell-mediated immune responses. However, their efficacy to regulate immunological responses in vivo remains unclear. Here, we report that repetitive intraperitoneal injection of recombinant Lewis rat-derived MHC class I antigens in Dark Agouti (DA) rats modulates alloreactivity. Methods. RT1.Al (Lewis derived) genes were cloned into mammalian expression vectors, and RT1.Aa (DA derived) genes were used to transfect a rat myeloma cell line. RT1.Al molecules were injected intraperitoneally in DA recipients that subsequently underwent transplantation with Lewis-derived cardiac allografts. Results. Soluble class I antigens were secreted by the transfected cells and were shown to be heterodimeric, peptide-loaded, and conformationally folded. Injection of donor-derived soluble MHC significantly reduced the ability of recipient animals to mount a cytotoxic T-cell response to donor-derived tissue. More interestingly, this treatment significantly prolonged donor-graft survival and allowed 60% of treated animals to develop graft tolerance (>120 days), when donor sMHC were combined with a single subtherapeutic dosage of cyclosporine. Thymectomy of recipient animals before transplantation did not interfere with induction of peripheral tolerance. Conclusions. Donor-derived sMHC are potential tolerogens for down-regulating the cytotoxic T-cell response of animals that undergo transplantation. Thus, these data provide for the first time a rationale for the application of directly injected sMHC in vivo to down-regulate immunological responses and aid the induction of graft tolerance.

Donor-derived soluble MHC antigens plus low-dose cyclosporine induce transplantation unresponsiveness independent of the thymus by down-regulating T cell-mediated alloresponses in a rat transplantation model.

Background. Liver allografts transplanted between MHC-disparate mice, rats, and swine are spontaneously accepted in most strain combinations without requirement for immunosuppression. The underlying mechanism has, however, remained elusive. Here, we demonstrate that co-transplantation of donor-derived hepatocytes protect Lewis (RT1.A 1 ) cardiac allografts from acute and chronic rejection in DA (RT1.A a ) recipients indefinitely. Methods. Livers of donor Lewis rats were harvested and the hepatocytes separated from hepatic leukocytes by collagenase digestion and gradient separation. DA recipient animals were transplanted Lewis cardiac allografts and simultaneously intraportally infused either Lewis-derived hepatocytes or hepatic leukocytes. Recipient animals were either not further treated or received a single dosis of 15 mg/kg cyclosporine. Results. Donor hepatocytes alone significantly protected syngeneic cardiac allografts from rejection, whereas hepatic leukocytes failed to influence graft survival. In combination with cyclosporine, recipient cardiac allografts were indefinitely protected from rejection. Graft-infiltrating cells in tolerant animals presented as clusters of CD4 + T cells and stained mostly positive for interleukin-4, whereas graft-infiltrating cells in rejected allografts were predominantly positive for interferon-y. Adoptive transfer of splenocytes derived from tolerant animals protected Lewis cardiac allografts from rejection in DA recipients without immunosuppression. In contrast, hepatic leukocytes protected only 50% of the allografts from rejection. Conclusion. We propose that donor hepatocytes induce permanent engraftment of syngeneic allografts by establishing a Th2 type alloresponse that is transferable to new graft recipients. The results of this study demonstrate that liver parenchymal cells significantly mediate spontaneously liver-induced tolerance.

Co-transplantation of donor-derived hepatocytes induces long-term tolerance to cardiac allografts in a rat model.

Background. Soluble MHC class I molecules are ubiquitous in human body fluids, including serum, urine, sweat, and cerebrospinal fluid. However, their biological function has remained unresolved. Membrane-derived human soluble MHC molecules (soluble human leukocyte antigen; sHLA) have been shown to induce apoptosis in alloreactive cytotoxic T lymphocytes (CTL). Here we report the efficacy of recombinant soluble HLA-B7 (rsHLA-B7) to modulate T-cell function. Methods. Primers of HLA-B7 were designed to allow amplification of a cDNA lacking the transmembrane and cytoplasmic domains yielding a truncated gene. rsHLA-B7 molecules were expressed in the human myeloma cell line 721.221 and purified by affinity chromatography using the BB7.7 mouse monoclonal antibody. CTL were generated from peripheral blood lymphocytes derived from healthy blood donors by stimulation with irradiated Epstein Barr virus-transformed HLA-B7-positive B cells. CTL were preincubated with rsHLA-B7, and cytotoxicity and apoptosis were tested according to standard procedure. Results. A total of 2×10 6 cells/ml secreted 10 μg/ml rsHLA-B7 as determined by a conformation-dependent ELISA, suggesting that rsHLA-B7 do not require the transmembrane and cytoplasmic regions for proper folding. After purification by affinity chromatography, rsHLA-B7 induced apoptosis in anti-HLA-B7 CTL, but not in anti-HLA-A2-specific, CTL. As a consequence, allorecognition of target cells by the CTL was significantly blocked. Conclusion. Recombinant sHLA are sufficient binding cues for T cells, which efficiently induce apoptosis and block allorecognition of target cells by CTL. Thus, recombinant sHLA molecules may become a valuable new modality for specific immunological therapeutic intervention.

http://centerspan.org/pubs/transplantation/1998/1227/tr249801818o.pdf

Purified truncated recombinant HLA-B7 molecules abrogate cell function in alloreactive cytotoxic T lymphocytes by apoptosis induction.

Soluble, recombinant MHC class I molecules induce indefinite graft survival

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

M. Krönke

Author Tools

Chat about Author

Papers

Donor-derived soluble MHC antigens plus low-dose cyclosporine induce transplantation unresponsiveness independent of the thymus by down-regulating T cell-mediated alloresponses in a rat transplantation model.

Co-transplantation of donor-derived hepatocytes induces long-term tolerance to cardiac allografts in a rat model.

Purified truncated recombinant HLA-B7 molecules abrogate cell function in alloreactive cytotoxic T lymphocytes by apoptosis induction.

Soluble, recombinant MHC class I molecules induce indefinite graft survival