Human Monoclonal Antibodies Broadly Neutralizing against Influenza B Virus

Abstract

Influenza virus has the ability to evade host immune surveillance through rapid viral genetic drift and reassortment; therefore, it remains a continuous public health threat. The development of vaccines producing broadly reactive antibodies, as well as therapeutic strategies using human neutralizing monoclonal antibodies (HuMAbs) with global reactivity, has been gathering great interest recently. Here, three hybridoma clones producing HuMAbs against influenza B virus, designated 5A7, 3A2 and 10C4, were prepared using peripheral lymphocytes from vaccinated volunteers, and were investigated for broad cross-reactive neutralizing activity. Of these HuMAbs, 3A2 and 10C4, which recognize the readily mutable 190-helix region near the receptor binding site in the hemagglutinin (HA) protein, react only with the Yamagata lineage of influenza B virus. By contrast, HuMAb 5A7 broadly neutralizes influenza B strains that were isolated from 1985 to 2006, belonging to both Yamagata and Victoria lineages. Epitope mapping revealed that 5A7 recognizes 316G, 318C and 321W near the C terminal of HA1, a highly conserved region in influenza B virus. Indeed, no mutations in the amino acid residues of the epitope region were induced, even after the virus was passaged ten times in the presence of HuMAb 5A7. Moreover, 5A7 showed significant therapeutic efficacy in mice, even when it was administered 72 hours post-infection. These results indicate that 5A7 is a promising candidate for developing therapeutics, and provide insight for the development of a universal vaccine against influenza B virus.

Dengue virus neutralization and antibody-dependent enhancement activities of human monoclonal antibodies derived from dengue patients at acute phase of secondary infection

“…Total RNA extracted from individual hybridoma clones using an RNeasy Mini kit (Qiagen, Tokyo, Japan) was subjected to RT-PCR using a PrimeScript RT reagent kit (Takara, Shiga, Japan) with an oligo (dT) primer, as described previously (Yasugi et al, 2013).…”

Human monoclonal antibodies targeting the haemagglutinin glycoprotein can neutralize H7N9 influenza virus

“…2c). Escape mutants were also selected by culturing H7N9 virus in MDCK cells in the presence of serial tenfold dilutions of HuMAb as described previously 19 . After five passages, stable variants were obtained for both HuMAbs, which grew at similar levels in the presence and absence of the antibody, and no inhibitory effect was seen in HI tests.…”

A human monoclonal antibody derived from a vaccinated volunteer recognizes heterosubtypically a novel epitope on the hemagglutinin globular head of H1 and H9 influenza A viruses

“…Hybridoma cells producing HuMAbs against influenza viruses were prepared using SPYMEG cells, as previously described [15,18]. Briefly, 10 ml of blood was collected from a healthy volunteer (23 years old, male, Thai) vaccinated in January 2011 with the trivalent HA split influenza vaccine (VAXIGRIP, Sanofi Pasteur), containing antigens from influenza A H1N1 virus, H3N2 virus and influenza B virus.…”

“…VN assays were performed as previously described [18]. Briefly, 2-fold serial dilutions of purified HuMAb (100 lg/ml) were preincubated with 100 FFU of each virus for 1 h at 37°C.…”

“…In contrast, we have reported a cell-to-cell fusion method using a new fusion partner cell line, SPYMEG, and donor-derived peripheral blood mononuclear cells (PBMCs) [9,[15][16][17][18]. In this study, we report the characterization of an anti-influenza HuMAb generated from the PBMCs of a volunteer vaccinated with seasonal influenza vaccine.…”