title: Comparison of in vivo Adjuvanticity of Liposomal PO CpG ODN with Liposomal PS CpG ODN: Soluble Leishmania Antigens as a Model.
abstract: OBJECTIVE
  CpG oligodeoxynucleotides (CpG ODNs) have been shown to have potent immunostimulatory adjuvant activity for a wide range of antigens. Due to susceptibility of phosphodiester CpG ODNs (PO CpG) to nuclease degradation, nuclease-resistant phosphorothioate CpG ODNs (PS CpG) were currently utilized in an in vivo model. In this study, according to some recently reported drawbacks with PS CpG, the adjuvant potential of liposomal PO CpG as a substitute for PS CpG was evaluated.
  
  
  METHODS
  Soluble Leishmania antigens (SLA) as a model antigen and distearoylphosphatidylcoline (DSPC) as a neutral lipid were employed to prepare liposomes. Susceptible BALB/c mice received buffer, SLA, Lip-SLA, Lip-SLA-PS CpG, Lip-SLA-PO CpG, SLA+PS CpG, or SLA+PO CpG subcutaneously 3 times with 3 weeks intervals and then were challenged with Leishmania major's live promastigotes. Blood and spleen samples were analyzed to determine the level and type of antibodies and cytokines. The number of live parasites in the spleen of immunized mice was determined. Moreover, the lesion size progress was assessed weekly by footpad swelling measurement.
  
  
  RESULTS
  The results showed that mice immunized with Lip-SLA-PS CpG or Lip-SLA-PO CpG developed a significantly smaller footpad swelling, higher level of anti SLA IgG antibodies before and after challenge, and lower spleen parasite burden compared with the control groups. However, there was no significant difference between mice received Lip-SLA-PS CpG and those received Lip-SLA-PO CpG.
  
  
  CONCLUSIONS
  The results demonstrated that liposomal PO CpG ODN could be used instead of PS CpG ODN to overcome the possible drawbacks.
authors.affiliation: Nanotechnology Research Centre, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Ensieh
authors.initials: E
authors.lastname: Golali
authors.forename: Mahmoud Reza
authors.initials: MR
authors.lastname: Jaafari
authors.forename: Ali
authors.initials: A
authors.lastname: Khamesipour
authors.forename: Azam
authors.initials: A
authors.lastname: Abbasi
authors.forename: Zahra
authors.initials: Z
authors.lastname: Saberi
authors.forename: Ali
authors.initials: A
authors.lastname: Badiee
keywords: CpG ODNs; Leishmaniasis; Liposome; SLA; Vaccine