Method for detecting flavivirus-specific antibodies utilizing flaviviral NS1 polypeptides comprising the wing domain

A method for detecting antibodies against a first flavivirus in an isolated sample presumed to contain antibodies against at least one second flavivirus which is different from said first flavivirus, said method comprising

• a) forming an immunoreaction admixture by admixing said isolated sample with a labeled flavivirus NS 1 polypeptide of said first flavivirus species, said flavivirus NS 1 polypeptide comprising a flavivirus NS1 wing domain of said first flavivirus species and a complete or partial sequence of the β-ladder domain as specific binding partner, wherein the cross-reactivity against said at least one second flavivirus is eliminated by adding an unlabeled polypeptide comprising an NS1 β-ladder domain of a flavivirus as the only NS1 domain;
• b) maintaining said immunoreaction admixture for a time period sufficient for allowing antibodies present in the body fluid sample against said flavivirus NS 1 wing domain to immunoreact with said flavivirus NS 1 wing domain to form an immunoreaction product;
• c) detecting the presence and/or the concentration of any of said immunoreaction product;
• and
• d) thereby, detecting antibodies specific for a first flavivirus species.