Gao et al studied promotion of immunity of mice to P. multocida and hog cholera vaccine by pig interleukin-6 gene and CpG motifs and concluded that VR1020 plasmid containing pig interleukin-6 gene on chitosan nanoparticles (VPIL6C) could better promote the immunity and resistance of mice against pasteurellosis than conventional bivalent vaccine and facilitate the development of effective adjuvant to enhance the immunity of animal against infection 27. The gene discussed is IL6; the disease is infection.