Administration of Multivalent Influenza Virus Recombinant Hemagglutinin Vaccine in Combination-Adjuvant Elicits Broad Reactivity Beyond the Vaccine Components

Abstract

Combining variant antigens into a multivalent vaccine is a traditional approach used to provide broad coverage against antigenically variable pathogens, such as polio, human papilloma and influenza viruses. However, strategies for increasing the breadth of antibody coverage beyond the vaccine are not well understood, but may provide more anticipatory protection. Influenza virus hemagglutinin (HA) is a prototypic variant antigen. Vaccines that induce HA-specific neutralizing antibodies lose efficacy as amino acid substitutions accumulate in neutralizing epitopes during influenza virus evolution. Here we studied the effect of a potent combination adjuvant (CpG/MPLA/squalene-in-water emulsion) on the breadth and maturation of the antibody response to a representative variant of HA subtypes H1, H5 and H7. Using HA protein microarrays and antigen-specific B cell labelling, we show when administered individually, each HA elicits a cross-reactive antibody profile for multiple variants within the same subtype and other closely-related subtypes (homosubtypic and heterosubtypic cross-reactivity, respectively). Despite a capacity for each subtype to induce heterosubtypic cross-reactivity, broader coverage was elicited by simply combining the subtypes into a multivalent vaccine. Importantly, multiplexing did not compromise antibody avidity or affinity maturation to the individual HA constituents. The use of adjuvants to increase the breadth of antibody coverage beyond the vaccine antigens may help future-proof vaccines against newly-emerging variants.

Magnitude and breadth of antibody cross-reactivity induced by recombinant influenza hemagglutinin trimer vaccine is enhanced by combination adjuvants

“…The pyrimido-indole TLR4 a is less potent than the conventional MPLA agonist for TLR4, but is more suited for tri-agonist synthesis 25 , 39 . Plasma samples were obtained at days 10, 28, 43 and 103 for probing against an influenza protein microarray described previously 27 , which displayed 125 different monomeric full length HA (HA0) drift variants and 131 HA1 variants, spanning all 18 HA subtypes. Other than transient weight loss in the first 24 h after vaccination, the animals in each group showed normal increases in body weight (Supplementary Fig.…”

“…HA1 fragments contain the variable head domain and part of the more conserved stalk of the protein. Previous studies with this array format have shown that sera with reactivity to the full-length (HA0) may also recognize HA1, depending on whether there are antibodies present against the head 27 , 40 . IgG profiles to HA1 fragments are shown in Fig.…”

“…HA protein microarrays were fabricated as previously described 27 . Briefly, purified influenza HAs spanning 18 influenza A virus subtypes expressed in human or insect cells as either HA0 or HA1 molecules, were purchased from Sino Biological Inc. (Beijing, China).…”

“…No. 22858) according to the manufacturer’s instructions, as described previously 27 . Briefly, lyophilized HAs were reconstituted in 100 μL H 2 O (1 mg/mL) and 8 μL of 0.67 M borate buffer added.…”

Supramolecular Nanostructures for Vaccines

“…In a major, highly recommended review article, Irvine and coworkers considered that biotechnology combined with the nanomaterials science could bring about safer and more efficient vaccine formulations with major roles for the nanoparticles (NPs) [ 116 ]. In a fast moving field encompassing cancer nanotechnology [ 50 , 89 , 90 , 95 , 117 ], vaccinology against pathogenic viruses [ 61 , 62 , 96 , 97 , 98 , 99 , 100 , 106 , 118 ], and microbes such as bacteria [ 19 , 108 , 112 , 119 , 120 ], fungi [ 119 ], and parasites [ 22 , 120 , 121 , 122 , 123 , 124 ], elegant nanomaterials that are difficult to scale up for commercialization cannot become useful in clinics [ 116 , 125 ].…”