title: Oral and intranasal administration of somatostatin DNA vaccine mediated by attenuated Salmonella enterica serovar Typhimurium to promote growth of piglets.
abstract: An attenuated strain of Salmonella typhimurium has been used as a carrier for oral and intranasal genetic immunization. Here, we evaluate the efficacy of a vaccine strain of S. typhimurium. CSO22 (pGM-CSF/SS, plasmid granulocyte-macrophage colony-stimulating factor/somatostatin) expressing two copies of SS genes. A total of 115 piglets, aged 2 months old, were either orally or intranasally immunized against the vaccine strain CSO22 (pGM-CSF/SS) with three dosages (5 × 10(10) colony forming units (CFU), 5 × 10(9) CFU and 5 × 10(8) CFU). For oral immunization, the specific anti-SS antibodies were detected in the immunized piglets. The levels of SS antibodies in the high-dose immunized group (5 × 10(10) CFU) were significantly higher than that in the phosphate buffered saline immunized group (P < 0.01) and 40% of animals were positive in SS antibodies in the high-dose immunized group. Moreover, the weight gain of the high-dose group was increased by 20.86%, 10.26% and 15.30% during 4, 8 and 12 weeks, respectively, after immunization in comparison to the control. For intranasal immunization, the growth of the low-dose group was increased by 10.23% in the whole test period (12 weeks). In conclusion, our results suggest that the recombinant strain could elicit anti-SS antibodies and improve the growth performance of immunized piglets, and that the oral immunization program is better than the intranasal program.
authors.affiliation: Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: X B
authors.initials: XB
authors.lastname: Liu
authors.forename: A X
authors.initials: AX
authors.lastname: Liang
authors.forename: X G
authors.initials: XG
authors.lastname: Feng
authors.forename: A Z
authors.initials: AZ
authors.lastname: Guo
authors.forename: C Y
authors.initials: CY
authors.lastname: Ke
authors.forename: S J
authors.initials: SJ
authors.lastname: Zhang
authors.forename: L G
authors.initials: LG
authors.lastname: Yang