Optimizing a Multi-Component Intranasal Entamoeba Histolytica Vaccine Formulation Using a Design of Experiments Strategy

Abstract

Amebiasis is a neglected tropical disease caused by Entamoeba histolytica. Although the disease burden varies geographically, amebiasis is estimated to account for some 55,000 deaths and millions of infections globally per year. Children and travelers are among the groups with the greatest risk of infection. There are currently no licensed vaccines for prevention of amebiasis, although key immune correlates for protection have been proposed from observational studies in humans. We previously described the development of a liposomal adjuvant formulation containing two synthetic TLR ligands (GLA and 3M-052) that enhanced antigen-specific fecal IgA, serum IgG2a, a mixed IFNγ and IL-17A cytokine profile from splenocytes, and protective efficacy following intranasal administration with the LecA antigen. By applying a statistical design of experiments (DOE) and desirability function approach, we now describe the optimization of the dose of each vaccine formulation component (LecA, GLA, 3M-052, and liposome) as well as the excipient composition (acyl chain length and saturation; PEGylated lipid:phospholipid ratio; and presence of antioxidant, tonicity, or viscosity agents) to maximize desired immunogenicity characteristics while maintaining physicochemical stability. This DOE/desirability index approach led to the identification of a lead candidate composition that demonstrated immune response durability and protective efficacy in the mouse model, as well as an assessment of the impact of each active vaccine formulation component on protection. Thus, we demonstrate that both GLA and 3M-052 are required for statistically significant protective efficacy. We also show that immunogenicity and efficacy results differ in female vs male mice, and the differences appear to be at least partly associated with adjuvant formulation composition.

Small molecule metabolites: discovery of biomarkers and therapeutic targets

“…Metabolic processes study in vivo is important to determine multi-component characteristics of efficacy and guide the new drug development, or speed up drug discovery from natural products. 732 – 734 …”

Entamoeba histolytica: Membrane and Non-Membrane Protein Structure, Function, Immune Response Interaction, and Vaccine Development

“…Furthermore, the adjuvant's improved formulation could reduce parasite antigens in the colon by more than 80%, which helped to protect against disease. The dose and excipient composition of each vaccine formulation component was optimized using the statistical design of experiment (DOE) and desirability approach, according to recent studies by Abhyankar et al (2021) [1]. The optimization was conducted to maximize the desired characteristics while maintaining the physicochemical stability of the vaccine.…”

“…Amoebiasis is a parasitic infection caused by Entamoeba histolytica and constitutes an alarming public health concern in developing countries [1,2]. This parasite has recorded the highest rates of infection in Central and South America, Africa, and India [2,3].…”

The State of Art of Extracellular Traps in Protozoan Infections (Review)

“…It causes 40-100 thousand deaths every year and is the third-leading cause of human death due to parasitic infection. There are two stages in the life cycle of E. histolytica: the cyst stage is the infection stage, and the trophozoite stage is the proliferation stage (54)(55)(56).…”