Immune responses generated by Lactobacillus as a carrier in DNA immunization against foot-and-mouth disease virus

• Published in: Vaccine Vol. 25; no. 5; pp. 902 - 911
• Main Authors: Li, Yun-Gang, Tian, Fu-Lin, Gao, Feng-Shan, Tang, Xiu-Shan, Xia, Chun
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.01.2007; Elsevier
• Subjects: Allergy and Immunology; Animals; Antibodies, Viral - blood; Applied microbiology; Bacterial Vaccines - immunology; Biological and medical sciences; Capsid Proteins - genetics; Capsid Proteins - immunology; DNA immunization; Female; Foot-and-mouth disease virus; Foot-and-Mouth Disease Virus - immunology; Fundamental and applied biological sciences. Psychology; Hypersensitivity, Delayed - etiology; Immunization; Lactobacillus; Lactobacillus - genetics; Lactobacillus acidophilus; Lactobacillus plantarum; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Microbiology; Miscellaneous; Plasmids; T-Lymphocytes - immunology; Tissue Distribution; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, DNA - immunology; Vaccines, Synthetic - immunology; Virology; DNA immunization; Foot-and-mouth disease virus; Lactobacillus; Virus; Aphthovirus; Lactic acid bacteria; Immune response; Picornaviridae; Bacteria; Lactobacillaceae; Veterinary; Genetic vaccine
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2006.09.034

Abstract To exploit Lactobacillus acidophilus as a carrier in DNA immunization against foot-and-mouth disease virus (FMDV), a recombinant eukaryotic expression plasmid (pRc/CMV2-VP1-Rep. 8014) harboring pRc/CMV2 vector, the FMDV VP1 gene, and a replication origin from Lactobacillus plantarum ATCC 8014 strain was constructed. To detect the VP1 protein, pRc/CMV2-VP1-Rep. 8014 was expressed in PK 15 cells and transfected into a L. acidophilus SW1 strain ( L. acidophilus SFMD-1). To evaluate the immunization effect of L. acidophilus SFMD-1, anti-FMDV VP1 antibody, T-cell proliferation, antigen-specific delayed-type hypersensitivity (DTH), and tissue distribution were investigated using intramuscular, intraperitoneal, intranasal, and oral administration delivery routes. The results showed that L. acidophilus SFMD-1 was able to elicit a detectable antibody level on day 21. The VP1 antibody levels induced by L. acidophilus SFMD-1 and commercial inactivated FMDV vaccine rose rapidly to 0.84 and 0.70, respectively, by day 42, then sustained a high level by day 49. The route of administration had an impact on the magnitude of the systemic antigen-specific IgG responses, with intramuscularly applied L. acidophilus SFMD-1 generating the greatest FMDV VP1 antibody response, followed by intraperitoneal, intranasal, and oral administration delivery routes. Using the T-cell proliferation assay, the stimulation index of a group immunized with L. acidophilus SFMD-1 reached 2.78 versus 5.08 in a group immunized with pRc/CMV2-VP1-Rep. 8014 plasmid. Mice immunized with L. acidophilus SFMD-1 were able to induce T-cell-mediated antigen-specific DTH. In addition, the VP1 gene was detected in the muscle, kidney, spleen, and heart, but not in the liver. The results demonstrate clearly that Lactobacillus as a carrier is a promising approach of DNA vaccination, and is a potentially guard against FMDV.