Immunogen sequence: GCWILTAAHC LRASKTHRYQ IWTTVVDWIH PDLKRIVIEY VDRIIFHENY NAGTYQNDIA LIEMKKDGNK KDCELPRSIP ACVPWSPYLF QPNDTCIVSG WGREKDNERV FSLQWGEVKL ISNCSKFYGN RFYEKEMECA GTYDG. Factor I, a serine protease, is a regulatory component of both the altern