Bacterial toxin's DNA vaccine serves as a strategy for the treatment of cancer, infectious and autoimmune diseases

Staphylococcal enterotoxin B as DNA vaccine against breast cancer in a murine model

Recently, many efforts have been made to treat cancer using recombinant bacterial toxins and this strategy has been used in clinical trials of various cancers. Therapeutic DNA cancer vaccines are now considered as a promising strategy to activate the immune system against cancer. Cancer vaccines could induce specific and long-lasting immune responses against tumors. This study aimed to evaluate the antitumor potency of the SEB DNA vaccine as a new antitumor candidate against breast tumors in vivo. To determine the effect of the SEB construct on inhibiting tumor cell growth in vivo, the synthetic SEB gene, subsequent codon optimization, and embedding the cleavage sites were sub-cloned to an expression vector. Then, SEB construct, SEB, and PBS were injected into the mice. After being vaccinated, 4T1 cancer cells were injected subcutaneously into the right flank of mice. Then, the cytokine levels of IL-4 and IFN-γ were estimated by the ELISA method to evaluate the antitumor activity. The spleen lymphocyte proliferation, tumor size, and survival time were assessed. The concentration of IFN-γ in the SEB-Vac group showed a significant increase compared to other groups. The production of IL-4 in the group that received the DNA vaccine did not change significantly compared to the control group. The lymphocyte proliferation increased significantly in the mice group that received SEB construct than PBS control group (p < 0.001). While there was a meaningful decrease in tumor size (p < 0.001), a significant increase in tumor tissue necrosis (p < 0.01) and also in survival time of the animal model receiving the recombinant construct was observed. The designed SEB gene construct can be a new model vaccine for breast cancer because it effectively induces necrosis and produces specific immune responses. This structure does not hurt normal cells and is a safer treatment than chemotherapy and radiation therapy. Its slow and long-term release gently stimulates the immune system and cellular memory. It could be applied as a new model for inducing apoptosis and antitumor immunity to treat cancer.

Study of Interactions between Antigens and Polymeric Adjuvants in Vaccines by Frontal Analysis Continuous Capillary Electrophoresis

Vaccine adjuvants are used to enhance the immune response induced by antigens that have insufficient immunostimulatory capabilities. The present work aims at developing a frontal analysis continuous capillary electrophoresis (FACCE) methodology for the study of antigen-adjuvant interactions in vaccine products. After method optimization using three cationic model proteins, namely lysozyme, cytochrome c, and ribonuclease A, FACCE was successfully implemented to quantify the free antigen and thus to determine the interaction parameters (stoichiometry and binding constant) between an anionic polymeric adjuvant (polyacrylic acid, SPA09) and a cationic vaccine antigen in development for the treatment for Staphylococcus aureus. The influence of the ionic strength of the medium on the interactions was investigated. A strong dependence of the binding parameters with the ionic strength was observed. The concentration of the polymeric adjuvant was also found to significantly modify the ionic strength of the formulation, the extent of which could be estimated and corrected.