Cytochlor

Influenza A virus (IAV) vaccines offer little protection from mismatched viruses with antigenically distant hemagglutinin (HA) glycoproteins. We sought to determine if a cationic lipid/DNA complex (CLDC) adjuvant could induce heterosubtypic protection if added to a whole inactivated IAV vaccine (WIV).

Adult rhesus macaques (RMs) were vaccinated and at 2 weeks boosted with either an H1N1-WIV or an H3N2-WIV, with and without CLDC adjuvant. Four weeks postboost, animals were challenged with an H1N1 IAV matched to the H1N1-WIV vaccine.

After challenge, viral RNA (vRNA) levels in the trachea of control RMs and RMs vaccinated with the unadjuvanted H1 or H3 WIV vaccines were similar. However, vRNA levels in the trachea of both the H1-WIV/CLDC- and the H3-WIV/CLDC-vaccinated RMs (P < 0.01 and P < 0.05, respectively) were significantly lower than in unvaccinated control RMs. Heterosubtypic protection in H3-WIV/CLDC RMs was associated with significantly higher levels of nucleoprotein (NP) and matrix-1-specific immunoglobulin G antibodies (P < 0.05) and NP-specific nonneutralizing antibody-dependent natural killer cell activation (P < 0.01) compared with unprotected H3-WIV RMs.

Addition of the CLDC adjuvant to a simple WIV elicited immunity to conserved virus structural proteins in RMs that correlate with protection from uncontrolled virus replication after heterosubtypic influenza virus challenge.

Because of their ideal size and temperament, rabbits are commonly used in polyclonal antibody production. Immunostimulatory adjuvants-such as Freund complete and incomplete adjuvants as well as various proprietary products-trigger a robust immune response, which increases antibody concentrations. However, these adjuvants can cause excessive soft tissue reactions, prompting concerns regarding animal wellbeing. This study assessed the safety and efficacy of cationic liposome- oligonucleotide complexes (CLDC) as an alternative adjuvant to conventional adjuvants. On days 0 and 14, 15 female New Zealand white rabbits were vaccinated subcutaneously with 15 μg ovalbumin mixed with either CLDC, Freund adjuvant (day 0, complete; day 14, incomplete), or a proprietary adjuvant (n = 5 per group). Antibody titers were measured by direct ELISA on days 0, 14, and 28. Rabbits were palpated daily for lesion development, and all lesions were measured. Rabbits in all groups developed a significant antibody response to ovalbumin over 28 d. However, the differences between groups were not statistically significant. No rabbits in the CLDC group developed skin lesions, whereas 80% of rabbits that received Freund adjuvant and 100% of those that received the proprietary product developed skin lesions. This study demonstrates that CLDC may be a valuable and effective alternative adjuvant for polyclonal antibody production in rabbits-one that avoids the palpable injection-site lesions often seen with other adjuvants.