Preclinical evidences of safety of a new synthetic adjuvant to formulate with the influenza human vaccine: absence of subchronic toxicity and mutagenicity

GK-1 Induces Oxidative Stress, Mitochondrial Dysfunction, Decreased Membrane Potential, and Impaired Autophagy Flux in a Mouse Model of Breast Cancer

Breast cancer (BC) is the second most common cancer worldwide in women. During the last decades, the mortality due to breast cancer has progressively decreased due to early diagnosis and the emergence of more effective new treatments. However, human epidermal growth factor receptor 2 (HER2) and triple-negative breast cancer (TNBC) remain with poor prognoses. In our research group, we are proposing the GK-1 immunomodulatory peptide as a new alternative for immunotherapy of these aggressive tumors. GK-1 reduced the growth rate of established tumors and effectively reduced lung metastasis in the 4T1 experimental murine model of breast cancer. Herein, the effect of GK-1 on the redox state, mitochondrial metabolism, and autophagy of triple-negative tumors that can be linked to cancer evolution was studied. GK-1 decreased catalase activity, reduced glutathione (GSH) content and GSH/oxidized glutathione (GSSG) ratio while increased hydrogen peroxide (H₂O₂) production, GSSG, and protein carbonyl content, inducing oxidative stress (OS) in tumoral tissues. This imbalance between reactive oxygen species (ROS) and antioxidants was related to mitochondrial dysfunction and uncoupling, characterized by reduced mitochondrial respiratory parameters and dissipation of mitochondrial membrane potential (ΔΨm), respectively. Furthermore, GK-1 likely affected autophagy flux, confirmed by elevated levels of p62, a marker of autophagy flux. Overall, the induction of OS, dysfunction, and uncoupling of the mitochondria and the reduction of autophagy could be molecular mechanisms that underlie the reduction of the 4T1 breast cancer induced by GK-1.

Influence of adjuvants on the amount, specificity and functional activity of antibody response to human influenza vaccine in mice

It's been almost a century since immunologists started using adjuvants as tools to develop more effective vaccines. Despite the rising number of adjuvanted vaccines in the last decades, we still lack knowledge of the adjuvants' effects on antibody response. This study was aimed to test the effect of immunizing mice with the human Inactivated Influenza vaccine (IIV), either alone or combined with different widely used adjuvants on the specific antibody response induced. Differential levels of IgM and IgG subclasses were found with the different adjuvants tested. Higher levels of antibodies did not always correspond with a higher efficacy to interfere with the virus infectivity. Differences in neutralization properties are possibly mediated by the specificity of the repertoire of antibodies induced. The repertoire was studied using a phage display 7-mer peptide library to screen for epitopes/mimotopes recognized by serum pools from vaccinated mice. The selected phage clones included peptides that corresponded to conformational mimotopes since they have no homology with lineal sequences of the Influenza strains' proteins. Five peptides were identified as recognized by sera from mice immunized with the IIV vaccine alone, including peptides from the hemagglutinin stalk domain, and by sera from mice immunized with the vaccine plus the different adjuvants employed. Adjuvants elicited a more diverse repertoire of epitope-recognizing antibodies that recognized epitopes of the HA recombinant globular head. Mimotopes were theoretically located at the neutralizing antigenic sites of the globular head of Influenza A H1N1pdm09, Influenza A H3N2, and Influenza B hemagglutinin. This study illustrates how different adjuvants can modify the extent and quality of humoral immunity against the IIV vaccine and the effectiveness of vaccination.

Plant-made vaccines against parasites: bioinspired perspectives to fight against Chagas disease

Introduction: Three decades of evidence have demonstrated that plants are an affordable platform for biopharmaceutical production and delivery. For instance, several plant-made recombinant proteins have been approved for commercialization under good manufacturing practice (GMP). Thus far, plant-based vaccine prototypes have been evaluated at pre- and clinical levels. Particularly, plant-made vaccines against parasitic diseases, such as malaria, cysticercosis, and toxoplasmosis have been successfully produced and orally delivered with promising outcomes in terms of immunogenicity and protection. The experience on several approaches and technical strategies over 30 years accounts for their potential low-cost, high scalability, and easy administration.Areas covered: This platform is an open technology to fight against Chagas disease, one of the most important neglected tropical diseases worldwide.Expert opinion: This review provides a perspective for the potential use of plants as a production platform and delivery system of Trypanosoma cruzi recombinant antigens, analyzing the advantages and limitations with respect to plant-made vaccines produced for other parasitic diseases. Plant-made vaccines are envisioned to fight against Chagas disease and other neglected tropical diseases in those countries suffering endemic prevalence.

Helminth-derived peptide GK-1 induces Myd88-dependent pro-inflammatory signaling events in bone marrow-derived antigen-presenting cells

GK-1 is an immunomodulatory, 18-aa-long peptide that has been proved to promote the activation of mouse peritoneal macrophages and LPS-pulsed mouse bone marrow-derived dendritic cells (BM-DCs). This study is aimed to explore the mechanisms underlying the activation of these antigen-presenting cells (APCs) by GK-1. In our study, GK-1 up-regulated in vitro the expression of CD86 and CD40, and it increased the secretion of NO in bone marrow-derived macrophages (BMDMs). In BM-DCs, GK-1 upregulated the expression of MHC class II and CD86. Additionally, GK-1 was found to be involved in the phosphorylation of MAPK p38, JNK and ERK 1/2 and in Myd88-dependent activation of NF-κB in both antigen-presenting cell types. In vivo, GK-1 increased the secretion of IL-15, CCL2, and IL-6 through a Myd88-dependent mechanism. This study demonstrated that GK-1 promotes the activation and effector activity of APCs through a mechanism dependent on Myd88, probably involving a Toll-like receptor as a target.