Posts in Category: Papers

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

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

Katherine W Cook, Wei Xue, Peter Symonds, Ian Daniels, Mohamed Gijon, David Boocock, Clare Coveney, Amanda K Miles, Sabaria Shah, Suha Atabani, Ruhul H Choudhury, Poonam Vaghela, Daisy Weston, Rachael L Metheringham, Victoria A Brentville and Lindy G Durrant.
 
ABSTRACT: 
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. To determine the mechanism behind the therapy, immune cell infiltrates were analyzed using flow cytometry and therapy studies in the presence of myeloperoxidase (MPO) inhibitor and T-cell depletion performed. We assessed the T-cell repertoire to homocitrullinated peptides in patients with cancer and healthy donors using flow cytometry.
Results  Homocitrulline (Hcit) peptide vaccination stimulated strong CD4 T-cell responses and induced significant antitumor therapy in an established tumor model. The antitumor response was dependent on CD4 T cells and the effect was driven mainly via direct tumor recognition, as responses were only observed if the tumors were induced to express MHC-II. In vitro proliferation assays show that healthy donors and patients with cancer have an oligoclonal CD4 T-cell repertoire recognizing homocitrullinated peptides. Inhibition of cyanate generation, which mediates homocitrullination, by MPO inhibition reduced tumor therapy by the vaccine induced T cells (p=0.0018). Analysis of the tumor microenvironment (TME) suggested that myeloid-derived suppressor cells (MDSCs) were a potential source of MPO. The selected  B16 melanoma model showed MDSC infiltration and was appropriate to see if the Hcit vaccine could overcome the immunosuppression associated with MDSCs. The vaccine was very effective (90% survival) as the induced CD4 T cells directly targeted the homocitrullinated tumor and likely reversed the immunosuppressive environment.
Conclusion  We propose that MPO, potentially produced by MDSCs, catalyzes the buildup of cyanate in the TME which diffuses into tumor cells causing homocitrullination of cytoplasmic proteins which are degraded and, in the presence of IFNγ, presented by MHC-II for direct CD4 T-cell recognition. Homocitrullinated proteins are a new target for cancer vaccines and may be particularly effective against tumors containing high levels of MPO expressing MDSCs.
 

 

A novel bivalent DNA vaccine encoding both spike protein receptor-binding domain and nucleocapsid protein of SARS-CoV-2 to elicit T cell and neutralising antibody responses that cross react with variants

A novel bivalent DNA vaccine encoding both spike protein receptor-binding domain and nucleocapsid protein of SARS-CoV-2 to elicit T cell and neutralising antibody responses that cross react with variants

Brentville VA, Vankemmelbeke M, Metheringham RL, Symonds P, Cook KW, Urbanowicz R, Tsoleridis T, Coleman C, Chang K-C, Skinner A, Dubinina E, Daniels I, Shah S, Dixon JE, Pockley AG, Adams SE, Paston SJ, Daly JM, Ball J and Durrant LG.

ABSTRACT: The efficacy of vaccines targeting SARS-CoV-2 is becoming apparent now that the mRNA and adenovirus vector vaccines that have been approved for emergency use are showing promise. However, the longevity of the protective immune response and its efficacy against emerging variants remains to be determined. To improve longevity and future protection against variants, we have designed a DNA vaccine encoding both the SARS-CoV-2 spike (S) protein receptor-binding domain (RBD) and its nucleocapsid (N) protein, the latter of which is highly conserved amongst beta coronaviruses. The vaccine elicits strong pro-inflammatory CD4 Th1 and CD8 T-cell responses to both proteins, with these responses being significantly enhanced by fusing the nucleocapsid sequence to a modified Fc domain. We have shown that the vaccine also stimulates high titre antibody responses to RBD which efficiently neutralise in both a pseudotype and live virus neutralisation assay and show cross reactivity with S proteins from the emerging variants Alpha (B.1.1.7) and Beta (B.1.351). This DNA platform can be easily adapted to target variant RBD and N proteins and we show that a vaccine variant encoding the B.1.351 RBD sequence stimulates cross-reactive humoral and T-cell immunity. These data support the translation of this DNA vaccine platform into the clinic, thereby offering a particular advantage for targeting emerging SARS-CoV-2 variants.

 

Cancer Vaccines, Adjuvants, and Delivery Systems

Cancer Vaccines, Adjuvants, and Delivery Systems

Samantha J. Paston, Victoria A. Brentville, Peter Symonds and Lindy G. Durrant

ABSTRACT: 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. The development of therapeutic cancer vaccines has been disappointing with many early cancer vaccines that showed promise in preclinical models often failing to translate into efficacy in the clinic. In this review we provide an overview of the current vaccine platforms, adjuvants and delivery systems that are currently being investigated or have been approved. With the advent of immune checkpoint inhibitors, we also review the potential of these to be used with cancer vaccines to improve efficacy and help to overcome the immune suppressive tumor microenvironment.

 

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

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

Victoria A Brentville, Rachael L Metheringham, Ian Daniels, Suha Atabani, Peter Symonds, Katherine W Cook, Mireille Vankemmelbeke, Ruhul Choudhury, Poonam Vaghela, Mohamed Gijon, Ghislaine Meiners, Willem-Jan Krebber, Cornelis J M Melief, Lindy G Durrant

ABSTRACT: 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.

Engineering the human Fc-region enables direct cell killing by cancer glycan-targeting antibodies without the need for immune effector cells or complement

Fc-engineering cytotoxicity in cancer glycan-targeting mAbs

Engineering the human Fc-region enables direct cell killing by cancer glycan-targeting antibodies without the need for immune effector cells or complement

Mireille Vankemmelbeke, Richard S. McIntosh, Jia Xin Chua, Thomas Kirk, Ian Daniels, Marilena Patsalidou, Robert Moss, Tina Parsons, David Scott, Gemma Harris, Judith M. Ramage, Ian Spendlove and Lindy G. Durrant

ABSTRACT: Murine IgG3 glycan-targeting mAb often induces direct cell killing in the absence of immune effector cells or complement via a proinflammatory mechanism resembling oncotic necrosis. This cancer cell killing is due to non-covalent association between Fc regions of neighboring antibodies, resulting in enhanced avidity. Human isotypes do not contain the residues underlying this cooperative binding mode; consequently, the direct cell killing of mouse IgG3 mAb is lost upon chimerization or humanization. Using the Lewisa/c/x -targeting 88mAb, we identified the murine IgG3 residues underlying the direct cell killing and increased avidity via a series of constant region shuffling and subdomain swapping approaches to create improved ('i') chimeric mAb with enhanced tumor killing in vitro and in vivo. Constant region shuffling identified a major CH3 and a minor CH2 contribution, which was further mapped to discontinuous regions among residues 286-306 and 339-378 that, when introduced in 88hIgG1, recapitulated the direct cell killing and avidity of 88mIgG3. Of greater interest was the creation of a sialyl-di-Lewisa -targeting i129G1 mAb via introduction of these selected residues into 129hIgG1, converting it into a direct cell killing mAb with enhanced avidity and significant in vivo tumor control. The human iG1 mAb, termed Avidimabs, retained effector functions, paving the way for the proinflammatory direct cell killing to promote ADCC and CDC through relief of immunosuppression. Ultimately, Fc engineering of human glycan-targeting IgG1 mAb confers proinflammatory direct cell killing and enhanced avidity, an approach that could be used to improve the avidity of other mAb with therapeutic potential.

 

Monoclonal Antibody Targeting Sialyl-di-Lewisa– Containing Internalizing and Noninternalizing Glycoproteins with Cancer Immunotherapy Development Potential

Monoclonal Antibody Targeting Sialyl-di-Lewisa – Containing Internalizing and Noninternalizing Glycoproteins with Cancer Immunotherapy Development Potential

Silvana T. Tivadar, Richard S. McIntosh, Jia Xin Chua, Robert Moss, Tina Parsons, Abed M. Zaitoun, Srinivasan Madhusudan, Lindy G. Durrant and Mireille Vankemmelbeke

ABSTRACT: Tumor glycans constitute attractive targets for therapeutic antibodies. The sialylated glycocalyx plays a prominent role in cancer progression and immune evasion. Here, we describe the characterization of the mAb, FG129, which targets tumor-associated sialylated glycan, and demonstrate its potential for multimodal cancer therapy. FG129, obtained through BALB/c mouse immunizations with liposomes containing membrane glycan extracts from the colorectal cancer cell line LS180, is an mIgG1k that targets sialyl-di-Lewisa–containing glycoproteins. FG129, as well as its chimeric human IgG1 variant, CH129, binds with nanomolar functional affinity to a range of colorectal, pancreatic, and gastric cancer cell lines. FG129 targets 74% (135/182) of pancreatic, 50% (46/92) of gastric, 36% (100/281) of colorectal, 27% (89/327) of ovarian, and 21% (42/201) of non–small cell lung cancers, by IHC. In our pancreatic cancer cohort, high FG129 glyco-epitope expression was significantly associated with poor prognosis (P ¼ 0.004). Crucially, the glyco-epitope displays limited normal tissue distribution, with FG129 binding weakly to a small percentage of cells within gallbladder, ileum, liver, esophagus, pancreas, and thyroid tissues. Owing to glyco-epitope internalization, we validated payload delivery by CH129 through monomethyl auristatin E (MMAE) or maytansinoid (DM1 and DM4) conjugation. All three CH129 drug conjugates killed high-binding colorectal and pancreatic cancer cell lines with (sub)nanomolar potency, coinciding with significant in vivo xenograft tumor control by CH129-vcMMAE. CH129, with its restricted normal tissue distribution, avid tumor binding, and efficient payload delivery, is a promising candidate for the treatment of sialyl-di-Lewisa– expressing solid tumors, as an antibody–drug conjugate or as an alternative cancer immunotherapy modality.

Post-translational modifications such as citrullination are excellent targets for cancer therapy

Post-translational modifications such as citrullination are excellent targets for cancer therapy

V.A. Brentville, M. Vankemmelbeke, R.L. Metheringham, L.G. Durrant

ABSTRACT: Under conditions of cellular stress, proteins can be post-translationally modified causing them to be recognized by the immune system. One such stress-induced post-translational modification (siPTM) is citrullination, the conversion of arginine residues to citrulline by peptidylarginine deiminase (PAD) enzymes. PAD enzymes are activated by millimolar concentrations of calcium which can occur during apoptosis, leading to precipitation of proteins, their subsequent uptake by B cells and stimulation of antibody responses. Detection of anti-citrullinated protein antibodies (ACPAs) is a diagnostic of rheumatoid arthritis (RA), where immune complexes stimulate inflammation around the joints. More recently, autophagy has been shown to play a role in the presentation of citrullinated peptides on MHC class II molecules to CD4+ helper T cells, suggesting that citrullination may be a way of alerting immune cells to cellular stress.  Additionally, inflammation-induced IFNγ and concomitant MHC class II expression on target cells contributes to immune activation. Stressful conditions in the tumour microenvironment induce autophagy in cancer cells as a pro-survival mechanism. Cancer cells also over express PAD enzymes and in light of this the hypothesis that citrullinated peptides stimulate CD4+ T cell responses that would recognize these siPTM’s produced during autophagy has been investigated. The induction of potent citrullinated peptide-specific CD4 responses has been shown in both humans and HLA transgenic mouse models. Responses in mouse models resulted in potent anti-tumour responses against tumours expressing either constitutive or IFNγ-inducible MHC class II. The anti-tumour effect relied upon direct recognition of tumours by specific CD4 T cells suggesting that citrullinated peptides are attractive targets for cancer vaccines.

T cell repertoire to citrullinated self-peptides in healthy humans is not confined to the HLA-DR SE alleles; Targeting of citrullinated self-peptides presented by HLA-DP4 for tumour therapy

T cell repertoire to citrullinated self-peptides in healthy humans is not confined to the HLA-DR SE alleles; Targeting of citrullinated self-peptides presented by HLA-DP4 for tumour therapy

Victoria A Brentville, Peter Symonds, Katherine  W Cook, Ian Daniels, Tracy Pitt, Mohamed Gijon, Poonam Vaghela, Wei Xue, Sabaria Shah, Rachael E Metheringham, and Lindy Durrant

ABSTRACT: Post-translational modifications are induced in stressed cells which cause them to be recognised by the system. One such modification is citrullination where the positive charged arginine is modified to a neutral citrulline. We demonstrate most healthy donors show an oligoclonal CD4 response in vitro to at least one citrullinated vimentin or enolase peptide. Unlike rheumatoid arthritis patients, these T cell responses were not restricted by HLA-DRB1 shared epitope (SE) alleles, suggesting they could be presented by other MHC class II alleles. As HLA-DP is less polymorphic than HLA-DR, we investigated whether the common allele, HLA-DP4 could present citrullinated epitopes. The modification of arginine to citrulline enhanced binding of the peptides to HLA-DP4 and enhanced high-frequency CD4 responses in HLA-DP4 transgenic mouse models. Our previous studies have shown that tumours present citrullinated peptides restricted through HLA-DR4 which are good target for anti-tumour immunity. In this study, we show that citrullinated vimentin and enolase peptides also induced strong anti-tumour immunity (100% survival, p < 0.0001) against established B16 tumours d and against the LLC/2 lung cancer model (p = 0.034) both expressing HLA-DP4. Since most tumours do not constitutively express MHC class II molecules, models were engineered that expressed MHC class II under the control of an IFNγ inducible promoter. Immunisation with citrullinated peptides resulted in 90% survival (p < 0.001) against established B16 HHD tumour expressing IFNγ inducible DP4. These studies show that citrullinated peptides can be presented by a range of MHC class II molecules, including for the first time HLA-DP4, and are strong targets for anti-tumour immunity.

Current Strategies to Enhance Anti-Tumour Immunity (2018)

Current Strategies to Enhance Anti-Tumour Immunity (2018)

Katherine W. Cook, Lindy G. Durrant and Victoria A. Brentville

ABSTRACT: The interaction of the immune system with cancer is complex, but new approaches are resulting in exciting therapeutic benefits. In order to enhance the immune response to cancer, immune therapies seek to either induce high avidity immune responses to tumour specific antigens or to convert the tumour to a more pro-inflammatory microenvironment. Strategies, including vaccination, oncolytic viruses, and adoptive cell transfer all seek to induce anti-tumour immunity. To overcome the suppressive tumour microenvironment checkpoint inhibitors and modulators of regulatory cell populations have been investigated. This review summarizes the recent advances in immune therapies and discusses the importance of combination therapies in the treatment of cancers.