The stimulating index of T lymphocyte proliferation in SPF chickens immunized with either pFDNA-PLGA-NPs, pVAX1-F (o), or Blank NP.

Values are presented as mean ± S.D. of five experiments in each group. Values within the same column with the different lower case letter in the superscript are significantly different (p<0.05; Student's t-test), and with the different upper case letter in the superscript are extremely significant different (p<0.01; Student's t-test). The stimulation indices of chickens immunized with the pFDNA-PLGA-NPs by either i.m, i.n. or i.n./i.m. were extremely significantly higher than those of chickens immunized with the plasmid DNA pVAX1-F (o), or with blank PLGA-NPs (p<0.01), and the chickens immunized with the pFDNA-PLGA-NPs either i.n. or i.n./i.m. had significantly higher stimulation indices than the chickens immunized with the pFDNA-PLGA-NPs i.m at the fourth week post immunization (p<0.05).