Immunogen sequence: SQSTRAASIF GGAKPVDTAA REREVEERLQ KEQEKLQRQL DEPKLERRPR ERHPSWRSEE TQERERSRTG SESSQTGTST TSSRNARRRE SEKSLENETL NKEEDCHSPT SKPPKPDQPL KVMPAPPPKE NAWVKRSSNP PARSQSSDTE QQSPTSGGGK VAPAQPSEEG PGRKDENKVD GMNAPKGQTG NSSRGPGDGG NRDHWKESDR KDG