The novel recombinant eukaryotic VRPIL4/6 plasmid, the secretory VR1020 vector containing fused pig IL-6
and IL-4 genes, was encapsulated with chitosan nanoparticles (CNP) prepared by use of ionotropic gelat ion
method and then used to inoculate intramuscularly forty 14-day-old piglets using 0.5, 1.0 or 1.5 mg/per animal,
which were simultaneously injected with inactivated Mycoplasma