Development of synthetic antigen vaccines for COVID-19.

The current pandemic called COVID-19 caused by the SARS-CoV-2 virus brought the need for the search for fast alternatives to both control and fight the SARS-CoV-2 infection. Therefore, a race for a vaccine against COVID-19 took place, and some vaccines have been approved for emergency use in several countries in a record time. Ongoing prophylactic research has sought faster, safer, and precise alternatives by redirecting knowledge of other vaccines, and/or the development of new strategies using available tools, mainly in the areas of genomics and bioinformatics. The current review highlights the development of synthetic antigen vaccines, focusing on the usage of bioinformatics tools for the selection and construction of antigens on the different vaccine constructions under development, as well as strategies to optimize vaccines for COVID-19.

Significant association between IL10-1082/-819 and TNF-308 haplotypes and the susceptibility to cervical carcinogenesis in women infected by Human papillomavirus.

Human papillomavirus (HPV) is responsible for high-grade cervical lesions and cervical cancer. The inflammation plays a key role in cervical cancer progression. In this context, studies propose an association between TNFα and IL10 SNPs and susceptibility to HPV infection. The present work aimed to investigate the possible association between IL10 and TNFα promoter polymorphisms and HPV infection in the cervical carcinogenesis risk in women from Brazil. A total of 654 samples was evaluated in this study. HPV detection was performed by PCR and HPV genotyping was performed by PCR and sequencing of positive MY09/11 PCR product. Genotyping of IL10 SNPs (rs1800871 and rs1800896) was performed by High Resolution Melt analysis. Genotyping of TNFα SNP (rs1800629) was performed by fluorogenic allele-specific probes. The distribution of TNF-308 (rs1800629) allelic (p = 0.03) and genotype (p = 0.03) frequencies and HPV-58 infection has showed a statistically significant difference between case and control groups for the assessed TNFα polymorphism. When it comes to TNFα (rs1800629) allelic and genotypic distribution and HPVs 18 and 31 infections, no statistically significant differences between case and control groups were observed for the studied TNFα polymorphism. The allelic and genotypic distribution of IL10-819 (rs1800871) and IL10-1082 (rs1800896) and HPV infection (HPVs 58, 18 and 31) has showed no statistically significant differences between case and control groups for the assessed IL10 polymorphisms. Furthermore, it was observed that haplotypes were associated with an increased cervical cancer risk in HPVs 16, 18 and 58-positive women. It was observed that women carrying the GTA and ATG haplotypes had 3.85 and 17.99-fold, respectively, increased cervical cancer susceptibility when infected by HPV-58. In women infected with HPV-16 and HPV-18, statistically significant results in women carrying the GTA and ATA haplotypes was observed. They had a 2.32 and 3.67-fold, respectively, increased cervical cancer susceptibility when infected by these two HPV types. The analysis of the haplotypes distribution in women infected with HPV-31 has showed no statistically significant results. Our study indicates that the association of genetic polymorphism in inflammation-related genes represents a risk to the susceptibility in the development of cervical cancer in women infected by HPVs 16, 18 and 58.

Current research into novel therapeutic vaccines against cervical cancer.

INTRODUCTION: Cervical cancer and cervical intraepithelial neoplasia (CIN) are well-known outcomes of a human papillomavirus (HPV) infection. Viral oncogenes expressions like E6, E7, and, recently recognized E5, lead to HPV-related malignant progression. Although HPV prevention by powerful vaccines against most frequent and oncogenic genotypes is feasible, current treatment against cervical neoplasia is distant from an ideal one. In addition, late diagnosis is commonly associated with a poor prognosis. On top of that, radiotherapy, chemotherapy, or surgery are less effective in high-grade lesions. Areas covered: Due to their peculiarities, HPV oncogenes represent an excellent target for cancer immunotherapy. Safety, efficacy, and potential immunogenicity are features achieved by DNA vaccines targeting HPV. The literature search has indicated that genetic immunotherapy is becoming a pharmacological tool and therapeutic option against cervical disease, as more and more DNA vaccines are reaching clinical trial phases. Expert commentary: Among some of the promising results, a phase II randomized trial showed a clinical activity of a nucleic acid-based vaccine in HPV16 or HPV18 positive CIN patients. The concept of a synergic combination of anti-HPV DNA vaccines with radiotherapy, chemotherapy, sophisticated delivery methods, immunomodulators or immune adjuvants opens a new and interesting perspective in cervical malignancy treatment.

A plant protein signal sequence improved humoral immune response to HPV prophylactic and therapeutic DNA vaccines.

Signal sequences (ss) play a critical role in the sorting of nascent secretory and membrane proteins. This function has been conserved from bacteria through eukaryotes, although ss appear diverse in length and amino acid composition. Sorting of proteins is also critical to instruct antigens for a proper immunological response. Thus, a plant ss was used to drive Human Papillomavirus (HPV) model antigens into the human secretory pathway: the HPV16 E7 oncoprotein, its chimera with the coat protein (CP) of the Potato Virus X (PVX), the first 200 amino acids of the HPV16 minor capsid protein L2 (known to harbour cross-reacting epitopes) and its chimera with E7 gene. These genes were used to transfect HEK-293 cells and to immunize C57BL/6 mice. The ss-provided genes were expressed, and proteins detected by immunofluorescence and immunoblotting. Mouse immunization with DNA constructs carrying the ss elicited a strong humoral response against both E7 and L2 and a weak cell-mediated immunity. To our knowledge this is the first demonstration that a signal sequence derived from a plant can modulate the sorting of a heterologous protein in mammalian cells. This activity in mammalian cells may be responsible for the observed increased humoral response to DNA-based vaccines that are generally weak inducers of IgG response. This might open new perspectives in the design of DNA vaccines, especially to counteract infections where a strong humoral response is needed.

HPV 16 E5 oncoprotein is expressed in early stage carcinogenesis and can be a target of immunotherapy.

HPV16 persistent infection is a well-known condition that precedes human cancer development. High risk HPV E5 proteins cooperate with E6/E7 oncogenes to promote hyper-proliferation of infected cells leading to possible cancer progression. Thus, presence of E5 viral transcripts could be a key marker of active infection and, in turn, a target of immunotherapy. Purpose of the study is to detect E5 transcripts in clinical samples and to explore the activity of novel anti-HPV16 E5 DNA vaccines. HPV transcripts were detected by PCR with specific primers encompassing the splice-donor sites of E5 transcript. For E5-based immunotherapies, 2 E5-based versions of DNA vaccines carrying whole E5 gene or a synthetic multiepitope gene were improved by fusion to sequence of PVX coat protein. These vaccines were challenged with a new luminescent animal model based on C3-Luc cell line. E5 transcripts were detected in clinical samples of women with HPV positive low-grade SIL, demonstrating the validity of our test. In C3 pre-clinical mouse model, vaccine candidates were able to induce a strong cellular immunity as indicated by ELISPOT assays. In addition, E5-CP vaccines elicited strong anti-tumor effects as showed by decreased tumor growth monitored by animal imaging. The tumor growth inhibition was comparable to those obtained with anti-E7 DNA vaccines. In conclusion, detection of E5 transcripts in clinical samples indicates that E5 is a possible target of immunotherapy. Data from pre-clinical model demonstrate that E5 genetic immunization is feasible, efficacious and could be utilized in clinical trials.

Anti-tumor effects of genetic vaccines against HPV major oncogenes.

Expression of HPV E5, E6 and E7 oncogenes are likely to overcome the regulation of cell proliferation and to escape immunological control, allowing uncontrolled growth and providing the potential for malignant transformation. Thus, their three oncogenic products may represent ideal target antigens for immunotherapeutic strategies. In previous attempts, we demonstrated that genetic vaccines against recombinant HPV16 E7 antigen were able to affect the tumor growth in a pre-clinical mouse model. To improve this anti-HPV strategy we developed a novel approach in which we explored the effects of E5-based genetic immunization. We designed novel HPV16 E5 genetic vaccines based on two different gene versions: whole E5 gene and E5Multi. The last one is a long multi epitope gene designed as a harmless E5 version. Both E5 genes were codon optimized for mammalian expression. In addition, we demonstrated that HPV 16 E5 oncogene is expressed in C3 mouse cell line making it an elective model for the study of E5 based vaccine. In this mouse model the immunological and biological activity of the E5 vaccines were assessed in parallel with the activity of anti-E7 and anti-E6 vaccines already reported to be effective in an immunotherapeutic setting. These E7 and E6 vaccines were made with mutated oncogenes, the E7GGG mutant that does not bind pRb and the E6F47R mutant that is less effective in inhibiting p53, respectively. Results confirmed the immunological activity of genetic formulations based on attenuated HPV16 oncogenes and showed that E5-based genetic immunization provided notable anti-tumor effects.