I have some problems with injecting C57Bl6 mice with a CpG solution to get a IFNa response.
So far I tried 2 different mixes of 25ug of CpG (ODN 1585, custom made) complexed in DOTAP (from Roth) injected intravenously.
Mix A was made as follows:
- dissolve 25ug CpG in 100ul PBS
- add 100ul PBS to 50ul (=50ug) DOTAP
incubated for 5 min separately
After incubation CpG was added dropwise to DOTAP and incubated for 20 more minutes (RT)
Mixed well and 200ul injected i.v.
- 75ug CpG
- 15ul PBS
- 22.5ul DOTAP
Mix together and incubate for 15 min RT
Add 487.5ul PBS, mix and inject i.v. in mice
The CpG was dissolved in RNAse free water
I took blood at T-0, T=2, T=6, T=8 but did not see an elevated response compared to T=0.
Does anyone have some hints or critical points that I should keep in mind?