In Vivo Evaluation of PamCys-Modified Cancer-Testis Antigens as Potential Self-Adjuvanting Cancer Vaccines.

Peptide-based vaccines, formulated with an appropriate adjuvant, offer a versatile platform for targeted cancer immunotherapy. While adjuvants are usually coadministered for nucleic acid and protein vaccines, synthetic peptide antigens afford a more effective opportunity to covalently and regioselectively graft immunostimulatory motifs directly onto the antigen scaffold to yield self-adjuvanting vaccines. Herein, we explore the synthesis of two tissue-restricted cancer-testis antigens (CTAs); New York oesophageal cell carcinoma 1 (NY-ESO-1) and B melanoma antigen 4 (BAGE4), both carrying the toll-like receptor (TLR) agonist, PamCys.

Modi-2 a vaccine stimulating CD4 responses to homocitrullinated self epitopes as therapy for solid cancers.

Stresses within the tumour microenvironment can mediate post-translational modifications of self-proteins. Homocitrullination is the conversion of lysine to homocitrulline which generates neoepitopes and bypasses self-tolerance. In this study a vaccine targeting homocitrullinated antigens was assessed for stimulation of anti-tumour immunity.

Sparsely PEGylated poly(beta-amino ester) polyplexes enhance antigen specific T-cell response of a bivalent SARS-CoV-2 DNA vaccine.

DNA technology has emerged as a promising route to accelerated manufacture of sequence agnostic vaccines. For activity, DNA vaccines must be protected and delivered to the correct antigen presenting cells. However, the physicochemical properties of the vector must be carefully tuned to enhance interaction with immune cells and generate sufficient immune response for disease protection.

Vaccination with post-translational modified, homocitrullinated peptides induces CD8 T-cell responses that mediate antitumor immunity.

Background: Post-translational modification of proteins has the potential to alter the ability of T cells to recognize major histocompatibility complex (MHC) class -I and class-II restricted antigens, thereby resulting in altered immune responses. One such modification is carbamylation (homocitrullination) that results in the formation of homocitrulline (Hcit) residues in a non-enzymatic reaction of cyanate with the lysine residues in the polypeptide chain. Homocitrullination occurs in the tumor microenvironment and CD4-mediated immune responses to Hcit epitopes can target stressed tumor cells and provide a potent antitumor response in mouse models.

Immune responses to citrullinated and homocitrullinated peptides in healthy donors are not restricted to the HLA SE shared allele and can be selected into the memory pool.

Citrullination and homocitrullination are stress induced post-translational modifications (siPTMs) which can be recognized by T cells. Peripheral blood mononuclear cells isolated from healthy donors and rheumatoid arthritis (RA) patients were stimulated with nine siPTM-peptides. CD45RA/CD45RO depletion was employed to determine if peptide-specific responses are naïve or memory.

Citrullinated glucose-regulated protein 78 is a candidate target for melanoma immunotherapy.

Introduction: Post translational modification of proteins plays a significant role in immune recognition. In particular the modification of arginine to citrulline which is mediated by PAD enzymes is increased during cellular stress (autophagy) which permits the presentation of modified epitopes upon MHC class II molecules for recognition by CD4 T cells. Citrullination also occurs in tumour cells as a result of continuous environmental stresses and increased autophagy.

PAD-2-mediated citrullination of nucleophosmin provides an effective target for tumor immunotherapy.

Background: The enzymatic conversion of arginine to citrulline is involved in gene and protein regulation and in alerting the immune system to stressed cells, including tumor cells. Nucleophosmin (NPM) is a nuclear protein that plays key roles in cellular metabolism including ribosome biogenesis, mRNA processing and chromatin remodeling and is regulated by citrullination. In this study, we explored if the same citrullinated arginines within NPM are involved in gene regulation and immune activation.

Citrullinated Epitopes Identified on Tumour MHC Class II by Peptide Elution Stimulate Both Regulatory and Th1 Responses and Require Careful Selection for Optimal Anti-Tumour Responses.

Background: Somatic mutations or post-translational modifications of proteins result in changes that enable immune recognition. One such post-translational modification is citrullination, the conversion of arginine residues to citrulline. Citrullinated peptides are presented on MHC class II (MHCII) autophagy which is upregulated by cellular stresses such as tumourigenesis.

Homocitrullination of lysine residues mediated by myeloid-derived suppressor cells in the tumor environment is a target for cancer immunotherapy.

Background: Homocitrullination is the post-translational modification of lysine that is recognized by T cells.

Methods: This study identified homocitrullinated peptides from aldolase, enolase, cytokeratin and binding immunoglobulin protein and used human leukocyte antigen (HLA) transgenic mice to assess immunogenicity by enzyme-linked immunosorbent spot assay. Vaccine efficacy was assessed in tumor therapy studies using HLA-matched B16 melanoma expressing constitutive or interferon γ (IFNγ)-inducible major histocompatibility complex class II (MHC-II) as represented by most human tumors.

Cancer Vaccines, Adjuvants, and Delivery Systems.

Vaccination was first pioneered in the 18th century by Edward Jenner and eventually led to the development of the smallpox vaccine and subsequently the eradication of smallpox. The impact of vaccination to prevent infectious diseases has been outstanding with many infections being prevented and a significant decrease in mortality worldwide. Cancer vaccines aim to clear active disease instead of aiming to prevent disease, the only exception being the recently approved vaccine that prevents cancers caused by the Human Papillomavirus.

Combination vaccine based on citrullinated vimentin and enolase peptides induces potent CD4-mediated anti-tumor responses.

Background: Stress-induced post-translational modifications occur during autophagy and can result in generation of new epitopes and immune recognition. One such modification is the conversion of arginine to citrulline by peptidylarginine deiminase enzymes.

Methods: We used Human leukocyte antigen (HLA) transgenic mouse models to assess the immunogenicity of citrullinated peptide vaccine by cytokine Enzyme linked immunosorbant spot (ELISpot) assay.

Citrullinated α-enolase is an effective target for anti-cancer immunity.

Targeting post-translationally modified epitopes may provide a new strategy for generating tumor specific immune responses. Citrullination is the post-translational modification of arginine to citrulline catalyzed by peptidylarginine deaminase (PAD) enzymes. Presentation of citrullinated peptides on MHC-II has been associated with autophagy.

SCIB1, a huIgG1 antibody DNA vaccination, combined with PD-1 blockade induced efficient therapy of poorly immunogenic tumors.

Purpose: We have previously shown that supraoptimal signaling of high avidity T cells leads to high expression of PD-1 and inhibition of proliferation. This study was designed to see if this effect could be mitigated by combining a vaccine that stimulates high avidity T cells with PD-1 blockade.

Experimental Design: We investigated the anti-tumor effect of a huIgG1 antibody DNA vaccine (SCIB1) and PD-1 blockade.

SCIB2, an antibody DNA vaccine encoding NY-ESO-1 epitopes, induces potent antitumor immunity which is further enhanced by checkpoint blockade.

Checkpoint blockade has demonstrated promising antitumor responses in approximately 10-40% of patients. However, the majority of patients do not make a productive immune response to their tumors and do not respond to checkpoint blockade. These patients may benefit from an effective vaccine that stimulates high-avidity T cell responses in combination with checkpoint blockade.

Citrullinated Vimentin Presented on MHC-II in Tumor Cells Is a Target for CD4+ T-Cell-Mediated Antitumor Immunity.

Stressful conditions in the harsh tumor microenvironment induce autophagy in cancer cells as a mechanism to promote their survival. However, autophagy also causes post-translational modification of proteins that are recognized by the immune system. In particular, modified self-antigens can trigger CD4(+) T-cell responses that might be exploited to boost antitumor immune defenses.

Low and high molecular weight poly(L-lysine)s/poly(L-lysine)-DNA complexes initiate mitochondrial-mediated apoptosis differently.

Poly(L-lysine)s, PLLs, are commonly used for DNA compaction and cell transfection. We report that, although PLLs of low (2.9 kDa), L-PLL, and high (27.

A two-stage poly(ethylenimine)-mediated cytotoxicity: implications for gene transfer/therapy.

Poly(ethylenimine) (PEI) is a cationic macromolecule commonly used in gene transfer/therapy protocols with high transfection efficiency both in vitro and in vivo. PEI is also cytotoxic, but the molecular basis of its cytotoxicity is poorly understood. Here, we have demonstrated that branched (25 kDa) and linear (750 kDa) PEI can both induce membrane damage and initiate apoptosis in three clinically relevant human cell lines (Jurkat T cells, umbilical vein endothelial cells, and THLE3 hepatocyte-like cells).

Colorectal cancer cells induce lymphocyte apoptosis by an endothelial monocyte-activating polypeptide-II-dependent mechanism.

Endothelial monocyte-activating polypeptide-II (EMAP-II) was first isolated from cell growth medium conditioned by tumor cells, and is closely related or identical with the p43 component of the mammalian multisynthase complex. In its secreted form, EMAP-II has multiple cytokine-like activities in vitro, inducing procoagulant activity on the surface of endothelial cells, increasing expression of E- and P-selectins and TNF-R1, and directing migration of monocytes and neutrophils. EMAP-II has also been shown to induce apoptosis in endothelial cells, leading to the suggestion that it is a proinflammatory polypeptide with antiangiogenic activity.