Journal: mBio

Article Title: A protective and broadly binding antibody class engages the influenza virus hemagglutinin head at its stem interface

doi: 10.1128/mbio.00892-25

Figure Lengend Snippet: HA head–stem epitope antibodies bind cell surface-anchored HA. Flow cytometry histograms depict the fluorescence intensities of recombinant IgG binding to K530 cell lines expressing recombinant, native HA on the cell surface. K530 cells were labeled with 400 ng/mL of the four head–stem epitope antibodies or control antibodies targeting the HA receptor binding site (HC19 , K03.12 , and H5.3 ), the head interface (S5V2-29 ), a lateral head epitope (HC45) , stem (FI6v3 ), or SARS-CoV spike protein (CR3022 ). HA abbreviations correspond to H1/SI06: A/Solomon Islands/3/2006(H1N1), H1/CA09: A/California/04/2009(H1N1), H2/JP57: A/Japan/305/1957(H2N2), H5/VN04: A/Vietnam/1203/2004(H5N1), H6/TW13: A/Taiwan/2/2013(H6N1), H8/CA07: A/northern shoveler/California/HKWF1204/2007(H8N4), H3/HK68: A/Aichi/02/1968(H3N2)(X31), H3/TX12: A/Texas/50/2012(H3N2), H4/NB10:A/American black duck/New Brunswick/00464/2010, H7/TW13: A/Taiwan/1/2017(H7N9), H10/JX13: A/Jiangxi/IPB13/2013(H10N8), and H14/WI10: A/mallard/Wisconsin/10OS3941/2010(H14N6).

Article Snippet: After washing, bound S8V1-157 was detected by incubating the microspheres with 2 μg/mL phycoerythrin (PE)-conjugated rat anti-mouse IgG1 (SB77e, Southern Biotech) for 1 h at room temperature, followed by washing and data collection.

Techniques: Flow Cytometry, Fluorescence, Recombinant, Binding Assay, Expressing, Labeling, Control, Northern Blot

Journal: mBio

Article Title: A protective and broadly binding antibody class engages the influenza virus hemagglutinin head at its stem interface

doi: 10.1128/mbio.00892-25

Figure Lengend Snippet: HA head–stem epitope antibodies protect against lethal influenza virus infection and severe disease. C57BL/6 mice ( n = 7 per group) were intraperitoneally injected with 150 µg of recombinant antibody via intraperitoneal injection 3 h prior to intranasal challenge with 5×LD 50 of A/Aichi/02/1968(H3N2)(X31). Mice were weighed daily and euthanized at a humane endpoint of 25% loss of body weight. Antibodies passively transferred included musinized IgG1 and IgG2c versions of HA head–stem epitope antibodies S8V1-157 and S1V2-65, neutralizing antibody HC19 , head-interface antibody S5V2-29 , and SARS-CoV antibody CR3022 . Mice injected with PBS were included as an additional control. (A) Post-infection survival rate. (B–D) Body weight curves for infected mice administered S8V1-157 (B), S1V2-65 (C), or S5V2-29 (D) antibodies, compared with controls. * P < 0.05 and *** P < 0.001 compared with the isotype control CR3022. n.s., not significant, P > 0.05; †, P < 0.05; ††, P < 0.01; and ††††, P < 0.0001 IgG2c compared with IgG1.

Article Snippet: After washing, bound S8V1-157 was detected by incubating the microspheres with 2 μg/mL phycoerythrin (PE)-conjugated rat anti-mouse IgG1 (SB77e, Southern Biotech) for 1 h at room temperature, followed by washing and data collection.

Techniques: Virus, Infection, Injection, Recombinant, Control

Journal: mBio

Article Title: A protective and broadly binding antibody class engages the influenza virus hemagglutinin head at its stem interface

doi: 10.1128/mbio.00892-25

Figure Lengend Snippet: The HA head–stem epitope is immunogenic in humans. ( A ) Additional 528 Nojima culture supernatants from donors K01, K03, S1, S5, S8, S9, and S12 were screened for competition with a recombinant musinized S8V1-157 IgG1 for HA binding. Culture supernatants that inhibited S8V1-157 binding by >90% are colored and specified. ( B ) HA reactivity of S8V1-157-competing Nojima culture supernatants, as determined by multiplex Luminex assay. N.D., not determined.

Article Snippet: After washing, bound S8V1-157 was detected by incubating the microspheres with 2 μg/mL phycoerythrin (PE)-conjugated rat anti-mouse IgG1 (SB77e, Southern Biotech) for 1 h at room temperature, followed by washing and data collection.

Techniques: Recombinant, Binding Assay, Multiplex Assay, Luminex