Comparative recognition of STF2.HA1-1, STF2.HA1-2, STF2.HA1-3 and PR8 virus by neutralizing monoclonal antibodies.

<p>A) Ribbon diagram depicting of the known antigenic regions of the HA globular head. B–E) ELISA plates were coated with either PR8 virus or the STF2 fusion proteins and probed with a mAb specific for the Sb, Sa, Ca1, Ca2 and Cb region. All STF2 fusion proteins are produced from E coli. F–I) ELISA plates were coated with STF2.HA1-2 and competed against soluble form of HA1-1, HA1-2, STF2.HA1-2, STF2.HA1-3 in binding of the panel of monoclonal antibodies (H37-64, 18 ng/ml; H37-77, 8 ng/ml; H36-11, 188 ng/ml and H163, 500 ng/ml). Bound antibodies were detected by 450 nm absorption. HA1-1 and STF2.HA1-1 were produced in insect cell culture. Both proteins have C-terminal 6His tag. HA1-2, STF2.HA1-2 and STF2.HA1-3 were produced in E. coli. HA1-2 has 6His tag at C-terminus.