Næss, Lisbeth M., Vanderven, Hillary, Bryant-Bratlie, Danielle, Laake, Ida, Pleguezuelos, Olga, and Oftung, Fredrik (2025) FLU-v, a Broad-Spectrum Peptide-Based Influenza Vaccine, Induces NK Cell Activating IgG1 and IgG3 Subclass Antibodies in Humans. Vaccines, 13 (11). 1084.

Preview

PDF (Published Version) - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

Background/Objectives: FLU-v is a peptide-based broad-spectrum influenza vaccine proven to induce humoral and cellular immune responses in humans. In this study, FLU-v-specific IgG1 and IgG3 subclass antibodies, induced by adjuvanted or non-adjuvanted FLU-v vaccination in healthy adults participating in a phase II clinical study, were quantitated. The ability of these antibodies to induce NK cell activation was investigated. Methods: An ELISA was developed to quantify FLU-v-specific IgG1 and IgG3 antibodies in serum. A flowcytometric assay based on an NK cell line was used to evaluate NK cell activation by expression of degranulation marker CD107a. Results: In the adjuvanted FLU-v group, IgG1 and IgG3 seroconversion on day 42 was 88.5% and 86.5% compared to 53.4% and 29.3% in the non-adjuvanted FLU-v group, which was significantly different from the respective placebo groups (0–6.3%). Adjuvanted FLU-v vaccination induced a raise in median IgG1 and IgG3 levels from 435 and 167 ng/mL pre vaccination to 4422 and 2020 ng/mL 42 days post vaccination, representing a fold increase of 16.3 for IgG1 and 11.6 for IgG3, which was sustained on day 180 post vaccination (10.4-fold and 5.0-fold, respectively). Non-adjuvanted vaccination induced a more modest increase in IgG1 and IgG3 from 655 and 206 ng/mL pre vaccination to 1808 and 264 ng/mL 42 days post vaccination. A correlation between levels of FLU-v-specific IgG, IgG1, or IgG3 and their ability to induce NK cell activation was demonstrated. Conclusions: A single dose of adjuvanted FLU-v induced high levels of long-lasting antigen-specific IgG1 and IgG3 antibodies with NK cell-mediated effector functions relevant to protection against influenza disease.

Item ID:	89753
Item Type:	Article (Research - C1)
ISSN:	2076-393X
Copyright Information:	© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Date Deposited:	01 Dec 2025 22:41
FoR Codes:	32 BIOMEDICAL AND CLINICAL SCIENCES > 3204 Immunology > 320405 Humoural immunology and immunochemistry @ 50% 32 BIOMEDICAL AND CLINICAL SCIENCES > 3204 Immunology > 320402 Applied immunology (incl. antibody engineering, xenotransplantation and t-cell therapies) @ 50%
SEO Codes:	20 HEALTH > 2001 Clinical health > 200104 Prevention of human diseases and conditions @ 100%
Downloads:	Total: 2 Last 12 Months: 2
	More Statistics