Optimizing adjuvants for intradermal delivery of MenC glycoconjugate vaccine

Intradermal administration of the pneumococcal conjugate vaccine in mice results in lower antibody responses as compared to intramuscular administration

INTRODUCTION

Several studies have shown that intradermal vaccination leads to improved immune responses. In addition, lowering vaccine doses will reduce costs and therefore potentially increase coverage. To determine whether intradermal delivery enhances the antibody responses against the 13-valent pneumococcal conjugate vaccine (PCV13), we compared intradermally and intramuscularly vaccinated mice.

METHODS

Mice were immunized with PCV13, either intradermally or intramuscularly and CFU-counts in the nasal tissue were determined three or seven days after intranasal colonization with a serotype 4 clinical strain. Antibody concentrations against all thirteen polysaccharides were measured in blood and mucosal samples using a fluorescent-bead-based multiplex immunoassay.

RESULTS

Antibody levels in both serum and mucosal samples were higher in the intramuscularly vaccinated group as compared to the intradermally vaccinated group. No protection against S. pneumoniae intranasal colonization was observed for either vaccination route.

CONCLUSIONS

Intradermal vaccination was inferior to intramuscular immunization in inducing serotype-specific antibodies.

Mannosylation of LNP Results in Improved Potency for Self-Amplifying RNA (SAM) Vaccines

Mannosylation of Lipid Nanoparticles (LNP) can potentially enhance uptake by Antigen Presenting Cells, which are highly abundant in dermal tissues, to improve the potency of Self Amplifying mRNA (SAM) vaccines in comparison to the established unmodified LNP delivery system. In the current studies, we evaluated mannosylated LNP (MLNP), which were obtained by incorporation of a stable Mannose-cholesterol amine conjugate, for the delivery of an influenza (hemagglutinin) encoded SAM vaccine in mice, by both intramuscular and intradermal routes of administration. SAM MLNP exhibited in vitro enhanced uptake in comparison to unglycosylated LNP from bone marrow-derived dendritic cells, and in vivo more rapid onset of the antibody response, independent of the route. The increased binding antibody levels also translated into higher functional hemagglutinin inhibition titers, particularly following intradermal administration. T cell assay on splenocytes from immunized mice also showed an increase in antigen specific CD8⁺ T responses, following intradermal administration of MLNP SAM vaccines. Induction of enhanced antigen specific CD4⁺ T cells, correlating with higher IgG2a antibody responses, was also observed. Hence, the present work illustrates the benefit of mannosylation of LNPs to achieve a faster immune response with SAM vaccines and these observations could contribute to the development of novel skin delivery systems for SAM vaccines.

Immunogenicity and safety of intradermal delivery of hepatitis B booster vaccine using the novel drug delivery device VAX-ID™

BACKGROUND

Although intramuscular (IM) injection is still the most preferred method for vaccination, intradermal (ID) delivery may have several advantages over intramuscular and subcutaneous (SC), including an improved immune response and antigen dose sparing effect. However it is currently limited due to the difficulty in standardizing the injection technique often based on the Mantoux technique. Difficulties encountered using the Mantoux technique could be overcome by the use of alternative ID delivery systems that confer more uniform and standardized procedures. The aim of this study was to evaluate the performance of a newly developed intradermal injection device, VAX-ID™, via a proof-of-concept to assess the immunogenicity of a commercially available hepatitis B booster vaccination in healthy hepatitis B pre-immunised subjects. Additionally, device safety and tolerability was evaluated.

MATERIALS AND METHODS

Three different routes of administration were compared over 4 groups, each receiving hepatitis B vaccine antigen: (1) standard IM injection in the deltoid region (HBVAXPRO® 10 µg/1 ml), (2) ID injection in the proximal posterior area of the forearm according to the Mantoux technique, (3) with VAX-ID™ in one forearm, or (4) with VAX-ID™ in both forearms. For ID injections 0.11 cc, of which 0.01 cc is overfill, was drawn from a vial containing HBVAXPRO® 40 µg/1 ml. Immunogenicity and safety were followed-up at day 0, 14, 30 and 210.

RESULTS

A total of 48 subjects were included. All subjects showed an anamnestic response at 14 days post booster vaccination. Elevated titres persisted until end of follow-up at day 210. For the ID groups a 3 fold higher immune response at day 14 and day 30 was recorded compared to IM group. Local adverse events were more reported for ID compared to IM.

CONCLUSIONS

The investigated ID injection device VAX-ID™ proves to be a good alternative to offer ID vaccination.

Meningococcal Vaccines: Current Status and Emerging Strategies

Neisseria meningitidis causes most cases of bacterial meningitis. Meningococcal meningitis is a public health burden to both developed and developing countries throughout the world. There are a number of vaccines (polysaccharide-based, glycoconjugate, protein-based and combined conjugate vaccines) that are approved to target five of the six disease-causing serogroups of the pathogen. Immunization strategies have been effective at helping to decrease the global incidence of meningococcal meningitis. Researchers continue to enhance these efforts through discovery of new antigen targets that may lead to a broadly protective vaccine and development of new methods of homogenous vaccine production. This review describes current meningococcal vaccines and discusses some recent research discoveries that may transform vaccine development against N. meningitidis in the future.