title: PCEP enhances IgA mucosal immune responses in mice following different immunization routes with influenza virus antigens.
abstract: BACKGROUND
  We previously demonstrated that polyphosphazenes, particularly PCEP, enhance immune responses in mice immunized subcutaneously and intranasally. The objective of the present study was to investigate the efficacy of polyphosphazenes as adjuvants when delivered through different routes of vaccine administration.
  
  
  METHODS
  BALB/c mice were immunized through intranasal, subcutaneous, oral and intrarectal delivery with vaccine formulations containing either influenza X:31 antigen alone or formulated in PCEP. Serum and mucosal washes were collected and assayed for antigen-specific antibody responses by ELISA, while splenocytes were assayed for antigen-specific cytokine production by ELISPOT.
  
  
  RESULTS
  Intranasal immunization with PCEP+X:31 induced significantly higher IgA titers in all mucosal secretions (lung, nasal, and vaginal) compared to the other routes. Serum analysis showed that all mice given the PCEP+X:31 combination showed evidence of enhanced IgG2a titers in all administered routes, indicating that PCEP can be effective as an adjuvant in enhancing systemic immune responses when delivered via different routes of administration.
  
  
  CONCLUSIONS
  We conclude that PCEP is a potent and versatile mucosal adjuvant that can be administered in a variety of routes and effectively enhances systemic and local immune responses. Furthermore, intranasal immunization was found to be the best administration route for enhancing IgA titers, providing further evidence for the potential of PCEP as a mucosal adjuvant.
authors.affiliation: Vaccine & Infectious Disease Organization/International Vaccine Center, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N 5E3, Canada.
authors.forename: Nelson F
authors.initials: NF
authors.lastname: Eng
authors.affiliation: Vaccine & Infectious Disease Organization/International Vaccine Center, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N 5E3, Canada.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Garlapati
authors.affiliation: Vaccine & Infectious Disease Organization/International Vaccine Center, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N 5E3, Canada.
authors.forename: Volker
authors.initials: V
authors.lastname: Gerdts
authors.affiliation: University of Alberta, 3-7 University Hall, Edmonton, Alberta, T6G 2J9, Canada.
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Babiuk
authors.affiliation: Vaccine & Infectious Disease Organization/International Vaccine Center, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N 5E3, Canada.
authors.forename: George K
authors.initials: GK
authors.lastname: Mutwiri