title: Effects of immunization against a DNA vaccine encoding somatostatin gene (pGM-CSF/SS) by attenuated Salmonella typhimurium on growth, reproduction and lactation in female mice.
abstract: A novel somatostatin (SS) DNA vaccine (pGM-CSF/SS), delivered orally by attenuated Salmonella typhimurium (CSO22), was used to immunize female mice at 5, 7, and 11 wk of age; the objective was to investigate the humoral immune response and effects of this vaccine on growth, reproduction and lactation. The pGM-CSF/SS induced SS-specific antibodies, which peaked (3.69 ± 0.89; mean ± S.D) 4 wk after the first booster immunization. Compared with a saline-treated control group, body weight gain of a pGM-CSF/SS immunized group increased 30.3% (23.88 vs. 18.32 g, P < 0.05) during the growth period (from 2 wk after primary immunization to 4 wk after the first booster immunization). Immunized mice had higher plasma estradiol concentrations (84.10 ± 2.16 vs. 81.45 ± 2.12 pg/ml, P < 0.05) and a shorter estrous cycle (4.06 ± 0.75 vs. 5.33 ± 0.49 d, P < 0.05), but serum progesterone concentrations were not significantly affected. Since offspring produced by immunized mice gained weight faster (P < 0.05) in the first 2 wk of life (4.27 ± 0.62 and 7.81 ± 1.30 g in Weeks 1 and 2, respectively vs. 3.70 ± 0.23 and 7.14 ± 0.48 g), we inferred that pGM-CSF/SS could have a direct or indirect role in regulating lactation in mice. In conclusion, GM-CSF and CSO22 served as adjuvant and attenuated live vector, respectively, with efficient oral delivery of an SS DNA vaccine which successfully induced a humoral immune response and enhanced rate of weight gain. Furthermore, the DNA vaccine pGM-CSF/SS affected plasma estradiol concentrations and the estrous cycle, and seemed to enhance lactation performance of female mice.
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, China.
authors.forename: Li-Ya
authors.initials: LY
authors.lastname: Bai
authors.forename: Ai-Xin
authors.initials: AX
authors.lastname: Liang
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Han
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Huo
authors.forename: Li-Guo
authors.initials: LG
authors.lastname: Yang
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D030762:Estrous Cycle / Q000187:drug effects; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D056724:Immunity, Humoral; D007774:Lactation / Q000187:drug effects*; D051379:Mice; D012486:Salmonella typhimurium / Q000235:genetics*; D013004:Somatostatin / Q000235:genetics* / Q000276:immunology; D014613:Vaccines, Attenuated / Q000276:immunology / Q000494:pharmacology; D019444:Vaccines, DNA / Q000276:immunology / Q000494:pharmacology*; D015430:Weight Gain / Q000187:drug effects
chemical_list: D014613:Vaccines, Attenuated; D019444:Vaccines, DNA; D004958:Estradiol; D013004:Somatostatin; D013006:Growth Hormone