Functional expression of the costimulatory molecule B7 on accessory cells for MHC class I-restricted immune responses

1031 Background: DS-8201a, a HER2-targeting antibody–drug conjugate (ADC), with a topoisomerase I inhibitor, exatecan drivative (DX-8951 derivative, DXd) has been shown to have antitumor effects in preclinical xenograft models and clinical trials, but the involvement of the immune system in the antitumor efficacy of DS-8201a has not been elucidated yet. Methods: The antitumor efficacy of DS-8201a individually and in combination with an anti-PD-1 antibody was determined in a syngeneic mouse model with human HER2-expressing CT26.WT (CT26.WT-hHER2) cells. Mice whose tumors had been cured by DS-8201a treatment were rechallenged with CT26.WT-hHER2 cells; their splenocytes were co-cultured with CT26.WT-hHER2 or CT26.WT-mock cells, and IFN-g secretion by these cells was determined. To investigate effects of DXd and DS-8201a on dendritic cells (DCs), the expression of DC markers on bone marrow derived DCs (BMDCs) and intratumoral DCs was analyzed by flow cytometry. Furthermore, MHC class I and PD-L1 expression on tumor cells was analyzed. Results: At a weekly dosage of 10 mg/kg, DS-8201a showed significant antitumor effects in the mouse model. Mice whose tumors had been cured by DS-8201a treatment rejected the rechallenge with CT26.WT-hHER2 cells, and splenocytes from these mice were activated by both CT26.WT-hHER2 and CT26.WT-mock cells. In the mouse model, DS-8201a treatment raised a population of intratumoral DCs (CD45+CD11c+MHC class II+) and increased DC expression of CD86, a DC activation marker; DXd also up-regulated CD86 expression on BMDCs in vitro. Furthermore, DS-8201a up-regulated PD-L1 and MHC class I expression on tumor cells. Notably, antitumor effects of the combination of DS-8201a with an anti-PD-1 antibody were better than those of monotherapy. Conclusions: DS-8201a elicits immune responses via mechanisms other than cytotoxic effects on tumor cells. This finding suggests additional benefits of combining DS-8201a with an immune checkpoint inhibitor (ICI). The combination of DS-8201a and an anti-PD-1 antibody was effective in tumor suppression, indicating that DS-8201a may be successfully combined with an ICI in human clinical applications.

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NLRC5: a key regulator of MHC class I-dependent immune responses

Nature Reviews Immunology ◽

10.1038/nri3339 ◽

2012 ◽

Vol 12 (12) ◽

pp. 813-820 ◽

Cited By ~ 143

Author(s):

Koichi S. Kobayashi ◽

Peter J. van den Elsen

Keyword(s):

Immune Responses ◽

Mhc Class I ◽

Class I

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Sendai Virus Fusion Protein-Mediates Simultaneous Induction of MHC Class I/II-Dependent Mucosal and Systemic Immune Responses Via the Nasopharyngeal-Associated Lymphoreticular Tissue Immune System

The Journal of Immunology ◽

10.4049/jimmunol.167.3.1406 ◽

2001 ◽

Vol 167 (3) ◽

pp. 1406-1412 ◽

Cited By ~ 49

Author(s):

Jun Kunisawa ◽

Tsuyoshi Nakanishi ◽

Ichiro Takahashi ◽

Akiko Okudaira ◽

Yasuo Tsutsumi ◽

...

Keyword(s):

Immune System ◽

Immune Responses ◽

Fusion Protein ◽

Mhc Class I ◽

Sendai Virus ◽

Class I ◽

Virus Fusion ◽

Simultaneous Induction ◽

Lymphoreticular Tissue

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An Efficient and Versatile Mammalian Viral Vector System for Major Histocompatibility Complex Class I/Peptide Complexes

Journal of Virology ◽

10.1128/jvi.76.23.11982-11988.2002 ◽

2002 ◽

Vol 76 (23) ◽

pp. 11982-11988 ◽

Cited By ~ 14

Author(s):

Ai Kawana-Tachikawa ◽

Mariko Tomizawa ◽

Jun-ichi Nunoya ◽

Tatsuo Shioda ◽

Atsushi Kato ◽

...

Keyword(s):

Major Histocompatibility Complex ◽

Immune Responses ◽

Mhc Class I ◽

Class I ◽

Vector System ◽

Specific Ctls ◽

Histocompatibility Complex ◽

Peptide Complexes ◽

Hiv 1 ◽

Made In

ABSTRACT We report a Sendai virus (SeV) vector system for expression of major histocompatibility complex (MHC) class I/peptide complexes. We cloned the extracellular domain of a human MHC class I heavy chain, HLA-A*2402, and human β-2 microglobulin (β2m) fused with HLA-A*2402-restricted human immunodeficiency virus type 1 (HIV-1) cytotoxic T-lymphocyte (CTL) epitopes (e-β2m) in separate SeV vectors. When we coinfected nonhuman mammalian cells with the SeVs, naturally folded human MHC class I/peptide complexes were secreted in the culture supernatants. Biotin binding peptide sequences on the C terminus of the heavy chain were used to tetramerize the complexes. These tetramers made in the SeV system recognized specific CD8-positive T cells in peripheral blood mononuclear cells of HIV-1-positive patients with a specificity and sensitivity similar to those of MHC class I tetramers made in an Escherichia coli system. Solo infection of e-β2m/SeV produced soluble e-β2m in the culture supernatant, and cells pulsed with the soluble protein were recognized by specific CTLs. Furthermore, when cells were infected with e-β2m/SeV, these cells were recognized by the specific CTLs more efficiently than the protein pulse per se. SeV is nonpathogenic for humans, can transduce foreign genes into nondividing cells, and may be useful for immunotherapy to enhance antigen-specific immune responses. Our system can be used not only to detect but also to stimulate antigen-specific cellular immune responses.

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The effect of co-expression costimulatory molecule CD80 on uptake of antigen peptide-MHC class I-GFP complex by specific T cells

International Journal of Oncology ◽

10.3892/ijo.30.6.1389 ◽

2007 ◽

Author(s):

Xia Liu ◽

Leilei Zhang ◽

Xingqian Zhang ◽

Hai Yu ◽

Xiaoping Zhao ◽

...

Keyword(s):

T Cells ◽

Mhc Class I ◽

Costimulatory Molecule ◽

Class I ◽

Costimulatory Molecule Cd80 ◽

Antigen Peptide ◽

Molecule Cd80

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Dipeptides catalyze rapid peptide exchange on MHC class I molecules

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1418690112 ◽

2014 ◽

Vol 112 (1) ◽

pp. 202-207 ◽

Cited By ~ 29

Author(s):

Sunil Kumar Saini ◽

Heiko Schuster ◽

Venkat Raman Ramnarayan ◽

Hans-Georg Rammensee ◽

Stefan Stevanović ◽

...

Keyword(s):

Immune Responses ◽

Mhc Class I ◽

Molecular Mechanisms ◽

Peptide Binding ◽

Class I ◽

Peptide Ligand ◽

Cell Monitoring ◽

Epitope Discovery ◽

Peptide Exchange ◽

Mhc Class I Molecules

Peptide ligand selection by MHC class I molecules, which occurs by iterative optimization, is the centerpiece of immunodominance in antiviral and antitumor immune responses. For its understanding, the molecular mechanisms of peptide binding and dissociation by class I molecules must be elucidated. To this end, we have investigated dipeptides that bind to the F pocket of class I molecules. We find that they accelerate the dissociation of prebound peptides of both low and high affinity, suggesting a mechanism of action for the peptide-exchange chaperone tapasin. Peptide exchange on class I molecules also has practical uses in epitope discovery and T-cell monitoring.

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Characterization of Cellular Immune Responses to a Recombinant Idiotype Vaccine by ELISPOT and Identification of MHC Class I-Restricted T Cell Epitopes by Peptide Mapping.

Blood ◽

10.1182/blood.v104.11.1409.1409 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1409-1409 ◽

Cited By ~ 1

Author(s):

Cristina M. Bertinetti ◽

Hendrik Veelken

Keyword(s):

T Cell ◽

Immune Responses ◽

B Cell ◽

Mhc Class I ◽

B Cell Lymphoma ◽

Class I ◽

Fab Fragment ◽

Cellular Immune Responses ◽

Idiotype Vaccine ◽

Cellular Immune

Abstract Induction of tumor-specific immune responses by idiotype vaccination is a promising strategy for biological therapy of indolent B cell lymphomas. In a previous report, we have described immune responses in a subset of patients participating in a phase I clinical trial primarily designed to demonstrate safety and efficacy of a recombinant idiotype vaccine (Veelken et al., ASH abstract #3342, 2003). In this trial, B-NHL patients who had relapsed after standard chemotherapy received repetitive intradermal vaccinations with recombinant idiotype Fab fragment derived from their tumor mixed with lipid-based adjuvant and concurrent subcutaneous GM-CSF at the same site. We now present the final analysis of cellular immune responses in this cohort. Peripheral blood lymphocytes (PBL) were obtained prior to and on various time points during and after vaccinations. Cryopreserved PBL were stimulated twice by autologous dendritic cells (DC) exposed to the autologous Fab protein for cross-presentation as MHC class I-bound peptides. INFγ-secreting cells were subsequently quantified by ELISPOT with Fab-presenting DC. Alternatively, freshly thawed PBL were directly assayed with recombinant Fab by ELISPOT without prestimulation. An increase in the frequency of Fab-responding PBL was detected in 7 of 15 evaluable patients with the prestimulation assay and in 4 of 10 patients by direct quantitation, resulting in a combined cellular response rate of 53% (9 of 17). A cellular immune response showed a trend for correlation with extended progression-free survival (p=0.08). T cell responses were predominantly idiotype-specific since lesser or no increases in IFNγ-secreting cells were detected against light chain- and VH family-matched control Fabs. Interestingly, a much higher base-line reactivity was observed against the control Fabs in comparison to the patient’s lymphoma Fab in four patients, pointing to the possibility of tumor-specific anergy in lymphoma patients that can at least be partially corrected by active immunization. In an effort to identify the MHC class I-presented idiotype-derived peptides, potential binding motifs were defined by reverse immunology with the SYFPEITHI algorithm (www.syfpeithi.de). Ten candidate peptides from the variable and constant region of an immune responder’s idiotype heavy chain were synthesized and evaluated with post-vaccination PBL by ELISPOT without prestimulation. A peptide derived from the CDR2 region showed a significantly higher response compared to an unrelated peptide control (p=0.0013). Additional peptides derived from the FWR1, CDR1, and CDR2 also showed a significant stimulation, but only in comparison to a no peptide control. ELISPOT offers a valuable tool to monitor cellular immune reponses and demonstrates successful induction of tumor immunity in pretreated, tumor bearing and immunosuppressed B cell lymphoma patients. Supported by Deutsche Krebshilfe

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