The injection of plasmid DNA in mouse muscle results in lifelong persistence of DNA, gene expression, and humoral response.
The duration of the immune response against any vaccine is critical. The present study was performed to determine the stability of injected plasmid deoxyribonucleic acid (DNA), the duration of gene expression in mouse muscle, as well as the duration of the immune response generated in mice after injection of plasmid pSO2C1 harboring the cry11Bb gene of Bacillus thuringiensis serovar. medellin. The localization and the persistence of the inoculated gene were determined by in situ hybridization and polymerase chain reaction (PCR). The results demonstrated that plasmid DNA can persist in mouse muscle for up to 2 yr. Moreover, immunohistochemical analysis showed that Cry11Bb protein was expressed for the lifetime of the mice at a low but significant level. Finally, production of Cry11Bb-specific antibodies in mice injected with pSO2C1 was high and durable as significant antibody titers were observed up to 119 wk after injection of the plasmid. This persistent immune response is likely owing to the existence of a protein and/or DNA depot in the organism, which serves to maintain the immune response, acting as a secondary or booster immunization.
Armengol
Gemma
G
Biotechnology and Biological COntrol Unit, Corporación para Investigaciones Biológicas, AA 7378, Medellín, Colombia.
Ruiz
Lina Maria
LM
Orduz
Sergio
S
D000818:Animals; D000917:Antibody Formation; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D005786:Gene Expression Regulation; D005821:Genetic Techniques; D007109:Immunity; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D009132:Muscles / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D013997:Time Factors; D019444:Vaccines, DNA / Q000737:chemistry / Q000235:genetics
D001426:Bacterial Proteins; D001427:Bacterial Toxins; C115468:CRY11BB protein, Bacillus thuringiensis; D000939:Epitopes; D019444:Vaccines, DNA; D004247:DNA