Phase 1 Randomized, Placebo-Controlled, Dose-Escalating Study to Evaluate OVX836, a Nucleoprotein-Based Influenza Vaccine: Intramuscular Results.

BACKGROUND: OVX836 is a recombinant protein vaccine targeting the highly conserved influenza nucleoprotein (NP), which could confer broad-spectrum protection against this disease. METHODS: A randomized, placebo-controlled, double-blind, dose-escalating, single- center, first-in-human study was conducted in 36 healthy adults aged 18-49 years. Twelve subjects per cohort (9 vaccine and 3 placebo) received 2 OVX836 intramuscular administrations on days 1 and 28 at the dose level of 30 µg, 90 µg, or 180 µg. Safety and immunogenicity were assessed after each vaccination and for 150 days in total. RESULTS: OVX836 was safe and well tolerated at all dose levels, with no difference in solicited local and systemic symptoms, and unsolicited adverse events between the first and second administration, or between dose levels. All subjects presented pre-existing NP-specific immunity at baseline. OVX836 induced a significant increase in NP-specific interferon-gamma T cells and anti-NP immunoglobulin G at all dose levels after the first vaccination. The second vaccination did not further increase the response. There was a trend for a dose effect in the immune response. CONCLUSIONS: The safety and reactogenicity profile, as well as the humoral and cellular immune responses, encourage further evaluation of OVX836 in a larger Phase 2a study.

ß-Glucan-Induced Trained Immunity in Dogs.

Several observations in the world of comparative immunology in plants, insects, fish and eventually mammals lead to the discovery of trained immunity in the early 2010's. The first demonstrations provided evidence that innate immune cells were capable of developing memory after a first encounter with some pathogens. Trained immunity in mammals was initially described in monocytes with the Bacille Calmette-Guerin vaccine (BCG) or prototypical agonists like ß-glucans. This phenomenon relies on epigenetic and metabolic modifications leading to an enhanced secretion of inflammatory cytokines when the host encounters homologous or heterologous pathogens. The objective of our research was to investigate the trained immunity, well-described in mouse and human, in other species of veterinary importance. For this purpose, we adapted an in vitro model of trained innate immunity in dogs. Blood enriched monocytes were stimulated with ß-glucans and we confirmed that it induced an increased production of pro-inflammatory and anti-microbial compounds in response to bacterial stimuli. These results constitute the first demonstration of trained immunity in dogs and confirm its signatures in other mammalian species, with an implication of cellular mechanisms similar to those described in mice and humans regarding cellular epigenetics and metabolic regulations.