Fig. 7.

CoPoP/PHAD liposomes for multivalent immunization. In total, 8 HA and 2 NA types of recombinant antigens were used to immunize mice with 5 ng per dose of each of the 10 antigens (50 ng total) following incubation with CoPoP/PHAD (A) or Alum (B). HAI and MNT assays were performed using sera collected from vaccinated mice. (C) Against H1N1 strain A/California/07/2009pdm09, both formulations achieved comparable HAI titers, while neutralization indicated significant neutralization by antibodies elicited with CoPoP/PHAD. (D) Against H5N1-derived strain A/Vietnam/1203/2004 (H5N1), also known as HALo, the serum antibodies from the same CoPoP/PHAD vaccinated animals significantly improved both HAI and neutralization over alum. (E) Mice challenged with 5 × LD₅₀ HALo exhibit reduced body weight loss when vaccinated with CoPoP/PHAD bound with heterologous H5 HA from A/gyrfalcon/Washington/41088–6/2014 (H5N8) or multiplex 8HA/2NA antigens. (F) Mice vaccinated with heterologous H5 achieved 100% survival, while two of five mice in multiplex group survived to the end of the challenge period. CoPoP/PHAD with H5 or 8HA/2NA mix each provided significant increase in survival over alum adjuvanted counterparts. Data expressed in geometric mean ± geometric SD. Statistical analysis was performed for C and D with unpaired t test, E with one-way ANOVA with Dunnett’s comparison CoPoP/PHAD only, and F with log-rank test. * indicates P < 0.05, ** indicates P < 0.01.