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Discover how PEPperPRINT Peptide Microarray products have been used in different fields of research.

A tumor-binding antibody with cross-reactivity to viral antigens

Campa, Michael J.; Gottlin, Elizabeth B.; Wiehe, Kevin; Patz, Edward F.
Cancer Immunol Immunother.
Feb 2025
**Background** We previously identified in non-small cell lung cancer (NSCLC) patients an autoantibody to complement factor H (CFH) that is associated with non-metastatic disease and longer time to progression in patients with stage I disease. A recombinant human antibody, GT103, was cloned from single B cells isolated from patients with the autoantibody. GT103 inhibits tumor growth and establishes an antitumor microenvironment. The anti-CFH autoantibody and GT103 recognize the epitope PIDNGDIT within the SCR19 domain of CFH. Here, we asked if this autoantibody could have originally arisen as a humoral response to a similar epitope in a viral protein from a prior infection. **Methods** Homologous viral peptides with high sequence identity to the core PIDNGDIT epitope sequence were identified and synthesized. NSCLC patient plasma containing anti-CFH autoantibodies were assayed by ELISA against these peptides. GT103 was assayed on a 4345-peptide pathogen microarray. **Results** Epitopes similar to the GT103 epitope are present in several viruses, including human metapneumovirus-1 (HMPV-1) that contains a sequence within attachment glycoprotein G that differs by one amino acid. Anti-CFH autoantibodies in NSCLC patient plasma weakly bound to an HMPV-1 peptide containing the epitope. GT103 cross-reacted with multiple viral epitopes on a peptide microarray, with the top hits being peptides in the human endogenous retrovirus-K polymerase (HERV-K pol) protein and measles hemagglutinin glycoprotein. GT103 bound the viral HMPV-1, HERV-K pol, and measles epitope peptides but with lower affinity compared to the GT103 epitope peptide. **Conclusion** These findings suggest that memory B cells against a viral target could have affinity matured to produce an antibody that recognizes a similar epitope on tumor cells and exhibits antitumor properties.

Targeting FLT3 by new-generation antibody-drug-conjugate in combination with kinase inhibitors for treatment of AML

Roas, Maike; Vick, Binje; Kasper, Marc-André; Able, Marina; Polzer, Harald; Gerlach, Marcus; Kremmer, Elisabeth; Hecker, Judith S.; Schmitt, Saskia; Stengl, Andreas; Waller, Verena; Hohmann, Natascha; Festini, Moreno; Ludwig, Alexander Edmund; Rohrbacher, Lisa; Herold, Tobias; Subklewe, Marion; Götze, Katharina S.; Hackenberger, Christian P.R.; Schumacher, Dominik; Helma-Smets, Jonas; Jeremias, Irmela; Leonhardt, Heinrich; Spiekermann, Karsten
Fms like tyrosine kinase 3 (FLT3) is often overexpressed or constitutively activated by internal tandem duplication (ITD) and tyrosine kinase domain (TKD) mutations in acute myeloid leukemia (AML). Despite the use of receptor tyrosine kinase inhibitors (TKI) in FLT3-ITD positive AML, the prognosis of patients is still poor and further improvement of therapy is required. Targeting FLT3 independent of mutations by antibody‑drug‑conjugates (ADCs) is a promising strategy for AML therapy. Here, we report the development and preclinical characterization of a novel FLT3‑targeting ADC, 20D9-ADC, which was generated by applying the innovative P5 conjugation technology. In vitro, 20D9‑ADC mediated potent cytotoxicity to Ba/F3 cells expressing transgenic FLT3 or FLT3-ITD, to AML cell lines and to FLT3-ITD positive patient derived xenograft AML cells. In vivo, 20D9‑ADC treatment led to a significant tumor reduction and even durable complete remission in AML xenograft models. Further, 20D9‑ADC demonstrated no severe hematotoxicity in in vitro colony formation assays using concentrations that were cytotoxic in AML cell line treatment. The combination of 20D9-ADC with the TKI midostaurin showed strong synergy in vitro and in vivo, leading to reduction of aggressive AML cells below the detection limit. Our data indicate that targeting FLT3 with an advanced new-generation ADC is a promising and potent antileukemic strategy, especially when combined with FLT3-TKI in FLT3‑ITD positive AML.

IFx-Hu2.0 phase I first in human study for unresectable melanoma for an intralesional “in-situ vaccine” approach.

Markowitz, Joseph; Shamblott, Michael; Brohl, Andrew Scott; Sarnaik, Amod; Eroglu, Zeynep; Khushalani, Nikhil I.; Chen, Pei-Ling; De-Aquino, Deanryan B.; Sondak, Vernon K.; Tarhini, Ahmad A.; Kim, Youngchul; Pilon-Thomas, Shari
e21542 Background: Many melanoma patients do not respond to anti-PD1 therapy due to lack of antigen specific responses. IFx-Hu2.0 (plasmid DNA encoding the streptococcal membrane protein, Emm55, contained within a cationic polymer) primes innate and antigen dependent responses in murine/equine melanoma models to produce an environment needed for checkpoint inhibitor efficacy. We describe the first in human study utilizing IFx-Hu2.0 in unresectable melanoma – NCT03655756. Methods: Melanoma patients (unresectable stage III/IV) had cutaneous lesions injected with IFx-Hu2.0 to test safety and feasibility. Patients were refractory to standard of care (anti-PD1, BRAF/MEK) or did not wish these treatments. 1-3 lesions (> 3 mm – 0.1 mg/0.2 mL) were injected, pre/post treatment biopsies obtained, and the primary endpoint of 5/6 patients without dose limiting toxicity (DLT) was assessed at 28 days. Retreatment was permitted. ≥2 lesions were needed: one for injection and uninjected lesion for biopsy. Tissue samples were analyzed for mRNA profiles, antigen responses (PEPperPRINT assay), and multiplex immunofluorescence (markers: CD3, CD8, FOXP3, PD1, PDL1, SOX10, DAPI). Results: The primary endpoint was met in 6 evaluable patients out of 7 enrolled. Observed toxicities included: G1-2 Injection site reactions – 5/7; G1 Bleeding – 1/7; G1-2 Pain – 2/7, G1 Lymphopenia – 1/7, G1 Pruritis – 1/7; with no ≥ G3 toxicities related to study drug observed. One G5 toxicity (Clostridium septicum infection 20 days post injection) was deemed unlikely related to study drug. 5/6 patients received 1 cycle prior to post-protocol immune-based therapy. One treatment naïve patient retreated once with IFx-Hu2.0 required no additional therapy > 9 months. Available paired tissue and plasma sampling revealed increased T cell infiltration into treated lesions, increase in IgM and IgG epitope recognition to melanoma associated antigens in the plasma (detected by PEPperPRINT assay), an increase in mRNA associated with innate immune responses in the injected lesion (CXCL13, LAG3, CXCL11, CXCL10, ICOS) and an adaptive immune response (IL-12, HLA-DRB5, WNT4, CD3D, Arg I) in uninjected lesions associated with downregulation of known melanoma antigens. Of 4 anti-PD1 refractory patients, three patients had clinical benefit to post-protocol retreatment with anti-PD1 based therapy (Stable Disease (SD) lasting > 2 years followed by surgical resection, Partial Response (PR) lasting > 9 months, PR subsequently surgical resected and rendered no evidence of disease). Conclusions: In this pilot study, intralesional IFx-Hu2.0 demonstrated a favorable safety profile. These data support encouraging immunological correlative responses and further study of IFx-Hu2.0 as a priming agent to enhance or restore sensitivity to immune checkpoint inhibitor therapy in melanoma. Clinical trial information: NCT03655756.

Single-Molecule Detection on a Protein-Array Assay Platform for the Exposure of a Tuberculosis Antigen

Schmidt, Ronny; Jacak, Jaroslaw; Schirwitz, Christopher; Stadler, Volker; Michel, Gerd; Marmé, Nicole; Schütz, Gerhard J.; Hoheisel, Jörg D.; Knemeyer, Jens-Peter
J. Proteome Res..
Jan 2011

Combinatorial Peptide Synthesis on a Microchip

Schirwitz, Christopher; Block, Ines; König, Kai; Nesterov, Alexander; Fernandez, Simon; Felgenhauer, Thomas; Leibe, Klaus; Torralba, Gloria; Hausmann, Michael; Lindenstruth, Volker; Stadler, Volker; Breitling, Frank; Bischoff, F. Ralf
Current Protocols in Protein Science.
Aug 2009
Microchips are used in the combinatorial synthesis of peptide arrays by means of amino acid microparticle deposition. The surface of custom-built microchips can be equipped with an amino-modified poly(ethylene glycol)methacrylate (PEGMA) graft polymer coating, which permits high loading of functional groups and resists nonspecific protein adsorption. Specific microparticles that are addressed to the polymer-coated microchip surface in a well defined pattern release preactivated amino acids upon melting, and thus allow combinatorial synthesis of high-complexity peptide arrays directly on the chip surface. Currently, arrays with densities of up to 40,000 peptide spots/cm2 can be generated in this way, with a minimum of coupling cycles required for full combinatorial synthesis. Without using any additional blocking agent, specific peptide recognition has been verified by background-free immunostaining on the chip-based array. This unit describes microchip surface modification, combinatorial peptide array synthesis on the chip, and a typical immunoassay employing the resulting high-density peptide arrays.

Particle-Based Synthesis of Peptide Arrays

Breitling, Frank; Felgenhauer, Thomas; Nesterov, Alexander; Lindenstruth, Volker; Stadler, Volker; Bischoff, F. Ralf
ChemBioChem.
Mar 2009
Lithographic methods allow for the combinatorial synthesis of >50,000 oligonucleotides per cm(2), and this has revolutionized the field of genomics. High-density peptide arrays promise to advance the field of proteomics in a similar way, but currently lag behind. This is mainly due to the monomer-by-monomer repeated consecutive coupling of 20 different amino acids associated with lithography, which adds up to an excessive number of coupling cycles. Combinatorial synthesis based on electrically charged solid amino acid particles resolves this problem. A color laser printer or a chip addresses the different charged particles consecutively to a solid support, where, when completed, the whole layer of solid amino acid particles is melted at once. This frees hitherto immobilized amino acids to couple all 20 different amino acids to the support in one single coupling reaction. The method should allow for the translation of entire genomes into sets of overlapping peptides to be used in proteome research.

High-density peptide arrays

Breitling, Frank; Nesterov, Alexander; Stadler, Volker; Felgenhauer, Thomas; Bischoff, F. Ralf
Mol. BioSyst..
Jan 2009
Arrays promise to advance biology by allowing parallel screening for many different binding partners. Meanwhile, lithographic methods enable combinatorial synthesis of >50 000 oligonucleotides per cm2, an advance that has revolutionized the whole field of genomics. A similar development is expected for the field of proteomics, provided that affordable, very high-density peptide arrays are available. However, peptide arrays lag behind oligonucleotide arrays. This review discusses recent developments in the field with an emphasis on methods that lead to very high-density peptide arrays.

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