A variant of Erysipelothrix rhusiopathiae surface protective antigen SpaA protein or of a shortened form of SpaA (ΔSpaA) in which a portion of SpaA protein is deleted for protection from Erysipelothrix rhusiopathiae infection and a process for preparing the same are provided. Introduction of amino acid substitution at a specific site in the amino acid sequence of SpaA or ΔSpaA protein provides a variant of SpaA or ΔSpaA protein which is immunogenic and is expressed in E. coli as inclusion bodies. The variant of SpaA or ΔSpaA protein of the present invention may easily be recovered and purified since it is expressed in E. coli as inclusion bodies.
