Ponente
Descripción
StII, a pore-forming protein (PFP) isolated from the marine anemone Stichodactyla heliantus, co-encapsulated in liposomes with a model antigen, has been explored as a vaccine candidate to enhance antigen-specific cytotoxic T lymphocyte (CTL) response. The results obtained in our group suggest that the high capacity to stimulate such CTL response by this formulation does not depend exclusively on the pore-forming activity of this PFP. Interestingly, the response is dependent on the activation of TLR4 in the antigen-presenting cells (APCs) (Laborde et al., 2017 and 2021). The activation of the APCs by this PFP may be due to its direct interaction with TLR4 or to signaling cascades triggered by its binding to the lipid membrane. In order to count on a laboratory tool to deepen into this phenomenon and on a non-cytotoxic variant of StII to improve the vaccine platform, we designed the mutant StIIW110.114A_Y111A (StII3A) by bioinformatic tools. The objective of the present work is to conformationally and functionally characterize StII3A and to study its immunomodulatory properties. By the use of different techniques, we demonstrated that StII3A loses the lipid binding capacity and pore-forming activity while keeping the conformation of the wild-type protein. This mutant was able to induce maturation of APCs and to enhance the antigen-specific effector TCD8+ response. The results suggest the immunomodulatory properties of StII are based on a protein-protein interaction and that StII3A is a promising candidate to improve the vaccine platform.
