A clinically validated Drosophila S2 based vaccine platform for production of malaria vaccines

Drosophila S2 insect cell expression is less known than the extensively used Spodoptera or Trichoplusia ni (Hi-5) insect cell based Baculovirus expression system (BEVS). Nevertheless it has been used in research for almost 40 years. The cell line was derived from late stage Drosophila melanogaster (Fruit fly) embryos by Schneider in the 1970s, who named the cell line Drosophila Schneider line 2 (synonyms: S2, SL2, D.mel. 2). The system has been widely applied to fundamental research, where the availability of the whole genome sequence of Drosophila melanogaster (1, 2) and the S2 cells’ susceptibility to RNA interference methods (3, 4) have enabled genome wide RNAi screening and whole genome expression analysis techniques to be used to great effect. S2 cells have proved to be highly effective for the production of proteins from a great variety of protein classes (5), such as: viral proteins, toxins, membrane proteins, enzyme, etc. Recent publications have also shown the strength of the S2 system in expression of Virus Like Particles (VLPs) (6). ExpreS2ion has developed the ExpreS2, Drosophila S2 platform to achieve improved yields for difficult to express proteins. Furthermore, several technologies have been developed to improve the ease of use of the system, as well as enable fast and efficient screening of multiple constructs. S2 based production processes for two malaria vaccine clinical trails with The Jenner Institute, Oxford University (Rh5 (7,8), blood-stage malaria) and Copenhagen University (VAR2CSA (9) pregnancy associated malaria) have been developed. The placental malaria vaccine is currently in a phase Ia trail in Germany, and a Phase Ib trial in Benin. The blood-stage malaria vaccine is currently in Phase IIa trial and is expecting results by the end of 2018. Several transmission-blocking candidates have been identified over the years with some of the most prominent being pfs48/45, Pfs230C and Pfs25(10). Other vaccine targets focus on blood-stage malaria such as Rh5, PfRIPR and CyrPA. We will present data on the development of a high producing Pfs25 monoclonal cell line and the purification from said cell line,as well as expression data on a range of other malaria vaccine targets. This present the clinically validated ExpreS2 platform as a complete system for a wide range of malaria targeting vaccines. (1) Adams M.D. et al. Science 2000 287:2185-2195 (2) Ashburner M, et al. Genome Res. 2005 Dec;15(12):1661-7 (3) Neumüller RA, et al. Wiley Interdiscip Rev Syst Biol Med. 2011 Jul-Aug; 3(4):471-8 (4) D’Ambrosio M.V. et al. J. Cell Biol. Vol. 191 No. 3 471–478 (5) Schetz J.A. et al. Protein Expression in the Drosophila Schneider 2 Cell System, Current Protocols in Neuroscience, 2004 (6) Yang L. et al. J Virol. 2012, Jul;86(14):7662-76. (7) Wright K.E. et al. Nature, 2014 Nov 20;515(7527):427-30 (8) Hjerrild K.A. et al. Sci Rep. 2016 Jul 26;6:30357 (9) Nielsen M.A. et al. PLoS One. 2015 Sep 1;10(9):e0135406 (10) Chaturvedi N et al. Indian J Med Res. 2016 Jun;143(6):696-71

HER2 cancer vaccine optimization by combining Drosophila S2 insect cell manufacturing with a novel VLP-display technology

Breast cancer is a widespread oncology indication affecting more than 1.3 million people worldwide annually, 20%-30% of which are HER2 positive. HER2 is a tyrosine kinase receptor that is frequently overexpressed in several solid-tumor cancers (incl. breast, prostate, gastric, esophageal and osteosarcoma) where it denotes an aggressive phenotype, high metastatic rate, and poor prognosis. In a human context, passive HER2-targeted immunotherapy using monoclonal antibodies (mAb, e.g. Trastuzumab and Pertuzumab) has proven to be an effective treatment modality, which has dramatically improved clinical outcomes. Unfortunately, mAb therapy is very expensive and the repeated injections of high doses can be associated with severe side-effects that reduce efficacy. Vaccines are highly cost-effective, but overall progress in development of anti-cancer vaccines based on cancer-associated antigens (e.g. HER2) has been hampered by inherent immune-tolerogenic mechanisms rendering the immune system incapable of reacting against the body’s own cells/proteins (i.e. self-antigens). Consequently, many attempts to develop anti-cancer vaccines have failed in clinical trials due to insufficient immunogenicity. To circumvent this central issue, we have developed a proprietary virus-like particle (VLP)-based vaccine delivery platform. Notably, the VLP-platform is currently the only available technology to effectively facilitate multivalent “virus-like” display of large/complex vaccine antigens. This is key to overcome immune-tolerance and enable induction of therapeutically potent antibody responses directed against cancer-associated self-antigens. In this talk I will discuss the non-viral Drosophila S2 insect cell production system and how it was applied to the production of hHer2/neu antigen, including using advanced production methods such as perfusion for clinical material manufacture. Furthermore, I will present our data from a transgenic mouse model for spontaneous breast cancer development, where high-density display of the HER2 extracellular domain on the surface of virus-like particles (VLPs) enables induction of therapeutically potent anti-HER2 responses. Split-protein tag/catcher conjugation was used to facilitate directional covalent attachment of HER2 to the surface of icosahedral bacteriophage-derived VLPs, thereby harnessing the VLP platform to effectively overcome B-cell tolerance. Vaccine efficacy was demonstrated both in prevention and therapy of mammary carcinomas in HER2 transgenic mice. Thus, the HER2-VLP vaccine shows promise as a new strategy for treatment of HER2-positive cancer. The modular VLP system may also represent an effective tool for development of self-antigen based vaccines against other non-communicable diseases

The RNA polymerase II C-terminal domain : its phosphorylation and interaction with the mediator complex

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Prevention and Therapy of Metastatic HER-2+ Mammary Carcinoma with a Human Candidate HER-2 Virus-like Particle Vaccine

Vaccines are a promising therapeutic alternative to monoclonal antibodies against HER-2+ breast cancer. We present the preclinical activity of an ES2B-C001, a VLP-based vaccine being developed for human breast cancer therapy. FVB mice challenged with HER-2+ mammary carcinoma cells QD developed progressive tumors, whereas all mice vaccinated with ES2B-C001+Montanide ISA 51, and 70% of mice vaccinated without adjuvant, remained tumor-free. ES2B-C001 completely inhibited lung metastases in mice challenged intravenously. HER-2 transgenic Delta16 mice developed mammary carcinomas by 4–8 months of age; two administrations of ES2B-C001+Montanide prevented tumor onset for >1 year. Young Delta16 mice challenged intravenously with QD cells developed a mean of 68 lung nodules in 13 weeks, whereas all mice vaccinated with ES2B-C001+Montanide, and 73% of mice vaccinated without adjuvant, remained metastasis-free. ES2B-C001 in adjuvant elicited strong anti-HER-2 antibody responses comprising all Ig isotypes; titers ranging from 1–10 mg/mL persisted for many months. Antibodies inhibited the 3D growth of human HER-2+ trastuzumab-sensitive and -resistant breast cancer cells. Vaccination did not induce cytokine storms; however, it increased the ELISpot frequency of IFN-γ secreting HER-2-specific splenocytes. ES2B-C001 is a promising candidate vaccine for the therapy of tumors expressing HER-2. Preclinical results warrant further development towards human clinical studies