PROTECTION AGAINST MYCOPLASMA-PULMONIS INFECTION BY GENETIC VACCINATION

The induction of an immune response against a foreign protein usually requires purification of that protein, which is injected into animals. The isolation of a pure protein is time consuming and costly. Recentl y, a technique called biolistic transformation (biological ballistic s ystem) microparticle injection, gene gun, or particle bombardment was developed. The basic idea is that the DNA or biological material coate d onto heavy tungsten or gold particles is shot into target cells or a nimals. We have vaccinated mice by introducing the gene (Mycoplasma pu lmonis DNA or a specific fragment) encoding a protein recognized by a protective monoclonal antibody directly into the skin or muscle of mic e by two methods: (i) using a hand-held form of the biolistic system t hat can propel DNA-coated gold microprojectiles (2 mu g of DNA) direct ly into the skin; (ii) using a conventional intramuscular injection of the DNA (100 mu g) into quadricep muscles of transfected mice. HeLa c ells were transfected in vitro by the gene gun or by the liposomal del ivery system. Indirect immuno-fluorescent antibody (IFA) assay of cult ure cells indicated that both methods could be successful. Production of antibody and cell-mediated immunity against M. pulmonis were monito red by assaying serum IFA and enzyme-linked immunosorbent assay (ELISA ), and delayed type hypersensitivity. In addition, macrophage migratio n inhibition and lymphocyte transformation to antigen in spleen cells were also tested. Both delivery systems induced humoral and cellular i mmunity, and vaccinated the mice against infection. Genetic immunizati on by using the gene gun saves time, money, and labor; moreover, this general method is also applicable to gene therapy.