Microcrystalline Cellulose for Delivery of Recombinant Protein-Based Antigen against Erysipelas in Mice.

The study describes the development of a vaccine using microcrystalline cellulose (Avicel PH-101) as a delivery carrier of recombinant protein-based antigen against erysipelas. Recombinant SpaA, surface protective protein, from a gram-positive pathogen was fused to a cellulose-binding domain (CBD) from endoglucanase II through a S3N10 peptide. The fusion protein (CBD-SpaA) was expressed in and was subsequently bound to Avicel PH-101. The antigenicity of CBD-SpaA bound to the Avicel was evaluated by enzyme-linked immunosorbent (ELISA) and confocal laser scanning microscope (CLSM) assays. For the examination of its immunogenicity, groups of mice were immunized with different constructs (soluble CBD-SpaA, Avicel coated with CBD-SpaA, whole bacterin of (positive control), and PBS (negative control)). In two weeks after immunization, mice were challenged with 1x10 CFU of and Avicel coated with CBD-SpaA induced protective immunity in mice. In conclusion, this study demonstrates the feasibility of microcrystalline cellulose as the delivery system of recombinant protein subunit vaccine against infection in mice.