title: Low hemagglutinin antigen dose influenza vaccines adjuvanted with AS03 alter the long-term immune responses in BALB/c mice.
abstract: We investigated the long-term immune profiles of dose-sparing, AS03-adjuvanted vaccines compared to a traditional high-dose, unadjuvated influenza vaccine formulation. BALB/c mice received 2 IM injections of influenza A/Uruguay/716/2007 (H3N2) split vaccine antigen: high-dose (HD) (3 µg hemagglutinin (HA)/dose) or low-dose (LD) formulations (0.03 µg or 0.003 µg HA) with AS03 and were followed to 34 weeks post-boost (pb). We examined serologic responses, spleen and bone marrow (BM) HA-specific antibody-secreting cells (ASCs) by ELISpot, influenza-specific cytokine/chemokine production in re-stimulated splenocytes by multiplex ELISA, and antigen-specific CD4+ T cells that express cytokines (IL-2, IFNγ, TNFα and IL-5) by flow cytometry. All formulations elicited robust serum antibody titers that persisted for at least 34 weeks. The number of antigen-specific ASCs in the spleen and BM were higher in the 2 LD +AS03 groups, but despite having fewer ASCs, the average spot size in the HD-unadjuvanted group was larger at later time-points, suggesting greater antibody production per cell. Striking differences in the long-term profiles induced by the different vaccine formulations may contribute to these different ASC profiles. The HD-unadjuvanted vaccine elicited strong Th2 cytokines during the first 6 weeks pb but LD+AS03 groups generated broader, more durable responses at later timepoints. Finally, the 0.03 µg HA+AS03 group generated the greatest number of antigen-specific CD4+ T cells and the highest percentage of poly-functional cells that expressed 2 or more cytokines. Although all of the tested vaccines induced durable antibody responses, we show that different vaccine formulations (dose-sparing, adjuvant) generate distinct long-term immune profiles. Furthermore, our data suggest that the different profiles may be generated through unique mechanisms.
authors: a Department of Experimental Medicine , Research Institute of the McGill University Health Centre , Montreal , Québec , Canada.
authors: Karen K
authors: KK
authors: Yam
authors: a Department of Experimental Medicine , Research Institute of the McGill University Health Centre , Montreal , Québec , Canada.
authors: Angela
authors: A
authors: Brewer
authors: a Department of Experimental Medicine , Research Institute of the McGill University Health Centre , Montreal , Québec , Canada.
authors: Virginie
authors: V
authors: Bleau
authors: b GSK Vaccines , Laval , Québec , Canada.
authors: Édith
authors: É
authors: Beaulieu
authors: b GSK Vaccines , Laval , Québec , Canada.
authors: Corey P
authors: CP
authors: Mallett
authors: a Department of Experimental Medicine , Research Institute of the McGill University Health Centre , Montreal , Québec , Canada.|c Vaccine Study Centre , Research Institute of the McGill University Health Centre , Montreal , Québec , Canada.
authors: Brian J
authors: BJ
authors: Ward
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D004338:Drug Combinations; D058501:Enzyme-Linked Immunospot Assay; D005260:Female; D005434:Flow Cytometry; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000008:administration & dosage* / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007273:Injections, Intramuscular; D008807:Mice, Inbred BALB C; D011136:Polysorbates / Q000008:administration & dosage*; D013185:Squalene / Q000008:administration & dosage*; D024502:alpha-Tocopherol / Q000008:administration & dosage*
chemical_list: D016207:Cytokines; D004338:Drug Combinations; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D011136:Polysorbates; D013185:Squalene; C550253:AS03 adjuvant; D024502:alpha-Tocopherol
keywords: AS03; adjuvant; antibody-secreting cells; chemokine; cytokine; dose-sparing; hemagglutination inhibition; influenza; long-term immune response; microneutralization; vaccine