MF59 and Pam3CSK4 Boost Adaptive Responses to Influenza Subunit Vaccine through an IFN Type I-Independent Mechanism of Action

Abstract

The innate immune pathways induced by adjuvants required to increase adaptive responses to influenza subunit vaccines are not well characterized. We profiled different TLR-independent (MF59 and alum) and TLR-dependent (CpG, resiquimod, and Pam3CSK4) adjuvants for the ability to increase the immunogenicity to a trivalent influenza seasonal subunit vaccine and to tetanus toxoid (TT) in mouse. Although all adjuvants boosted the Ab responses to TT, only MF59 and Pam3CSK4 were able to enhance hemagglutinin Ab responses. To identify innate immune correlates of adjuvanticity to influenza subunit vaccine, we investigated the gene signatures induced by each adjuvant in vitro in splenocytes and in vivo in muscle and lymph nodes using DNA microarrays. We found that flu adjuvanticity correlates with the upregulation of proinflammatory genes and other genes involved in leukocyte transendothelial migration at the vaccine injection site. Confocal and FACS analysis confirmed that MF59 and Pam3CSK4 were the strongest inducers of blood cell recruitment in the muscle compared with the other adjuvants tested. Even though it has been proposed that IFN type I is required for adjuvanticity to influenza vaccines, we found that MF59 and Pam3CSK4 were not good inducers of IFN-related innate immunity pathways. By contrast, resiquimod failed to enhance the adaptive response to flu despite a strong activation of the IFN pathway in muscle and lymph nodes. By blocking IFN type I receptor through a mAb, we confirmed that the adjuvanticity of MF59 and Pam3CSK4 to a trivalent influenza vaccine and to TT is IFN independent.

Development of a custom pentaplex sandwich immunoassay using Protein-G coupled beads for the Luminex® xMAP® platform

“…8). These data are consistent with previously published reports that show an increase in IP-10 and IL-1Ra expression in response to MF59 (Caproni et al, 2012;Mosca et al, 2008;Seubert et al, 2008), as well as increased CRP and IP-10 expression in response to influenza vaccination (Christian et al, 2011;Nakaya et al, 2011;Obermoser et al, 2013). IL-2Ra and sTNFRII remained at baseline levels in the serum, with no difference observed between the adjuvanted and non-adjuvanted animals in response to intramuscular immunisation.…”

A novel RNA‐based adjuvant combines strong immunostimulatory capacities with a favorable safety profile

“…Not only an increased cellularity of dLNs but also an enhanced activation of various cell types including B cells, T cells, migratory DCs, NK cells and NKT cells following the adjuvant injection was observed. Similar phenomenon was observed after the use of a TLR agonist such as R848 43 suggesting that RNAdjuvant 44,45 Using a murine model of HPV-16-induced cervical cancer we demonstrated that vaccination with low doses of the previously described HPV-E7-derived peptide containing both, a CTL epitope (E7 [49][50][51][52][53][54][55][56][57] ) and a Th epitope, 24 led to a complete eradication of established tumors in combination with RNAdjuvant V R . Similar results were obtained by Zwaveling and colleagues using E7 peptide combined with CpG.…”

The adjuvant MF59 induces ATP release from muscle that potentiates response to vaccination

“…The HI assay was carried out on individual sera taken 2 wk after the second immunization, as described elsewhere (17).…”

“…Four mice per group were killed 2 wk after immunization, and spleens were collected to assess the frequency and phenotype of Ag-specific CD4 + /CD44 + T cells induced by vaccination. The assay was performed as described elsewhere (17).…”

“…The strong adjuvant effect of MF59 (16,17) has been ascribed to its capability to induce an immunocompetent environment in the muscle, characterized by a rapid and transient influx of a large number of CD11b+ immune cells participating in antigen uptake and transport to draining lymph nodes (18)(19)(20)(21). To clarify the role of ATP in MF59-induced cell recruitment, mice were injected i.m.…”