The co-vaccination effects of BCG and Poly I:C on the development of T cell subsets in neonatal BALB/c mice
Objective To explore the effects of BCG and Poly I:C co-vaccination on the development of spleen T cell subsets of neonatal BALB/c mice. Methods Neonatal BALB/c mice were inoculated with BCG and/or Poly I:C intraperitoneally within 2-3 d after birth. Four weeks later, spleen cells of mice were isolated and the percentage of CD3+ CD8+ IFN-γ+,CD3+ CD8-IFN-γ+,CD3+ CD8+ IL-4+,CD3+ CD8- IL-4+,CD4+ Foxp3+ T cells,which represent Tc1,TH1,Tc2,TH2,Treg cells,respectively,were tested by flow cytometry at single cell level,and the ratios of TH 1/TH 2 and Tc1/Tc2 were calculated. Results The percentages of TH1 and Tc1 cells of BCG-vaccinated mice,Poly I:C-vaccinated mice and BCG plus Poly I:C-vaccinated mice were significantly higher than that of control mice(P＜0.05 or P＜0.01),and there was no difference among the three vaccinated group. The ratios of TH1/TH2 and total IFN-γ/IL-4 of the three vaccinated groups were higher than that of control group,but not the ratio of Tc1/Tc2. The TH1/TH2 ratio of BCG plus Poly I:C-vaccinated group was higher than that of BCG-vaccinated group(P＜0.05).The percentages of Trge cells showed no difference among the four groups(P＞0.05). Conclusion BCG and Poly I:C co-vaccination can significantly increase the number of Tc1 and TH 1 cells and TH 1/TH2 ratio in spleen cells. BCG and Poly I:C vaccination may have a synergistic effect on TH 1/TH2 ratio of spleen cells in neonataI mice. The percentage of CD4+ Foxp3+ T cells among four groups showed no significant difference. 
 
Key words: 
BCG; Polyinosine-polycytidylic acid; T cell subsets; Regulatory T cells