Some S2 epitopes inducing nAbs were reported. A peptide containing aa 1055–1192 can elicit neutralizing activity [48]. Two other proteins Trx-F3 and Trx-F9 containing linear antigenic determinants (Leu 803 to Ala 828 and Pro 1061 to Ser 1093, respectively) on the S2 domain were identified by using sera from convalescent SARS-CoV patients. Trx-F3 was capable of inducing nAbs in some animals [49].