Humoral immune response to r<i>Sm</i>Synt vaccination.

<p>(A) Sera from r<i>Sm</i>Synt-vaccinated (black squares) and control (black circles) mice (mean +/− SD, n = 10) were tested by ELISA to evaluate the levels of specific IgG antibodies to r<i>Sm</i>Synt at the indicated time points during the vaccination trial. The vaccination scheme is depicted below the x-axis. Significantly greater levels of anti-r<i>Sm</i>Synt IgG antibodies were detected in the r<i>Sm</i>Synt-immunized group compared to controls, from the second immunization onwards. (B) IgG isotypes IgG1 and IgG2a levels (mean +/− SD, n = 10) detected in r<i>Sm</i>Synt-immunized versus control mice at the indicated time points during the vaccination trial. The vaccination scheme is depicted below the x-axis. The IgG1/IgG2a ratio is given (black diamonds). (C) Ten micrograms of protein extracts from adult parasites (Ad.) and schistosomula (Sch.) were resolved by SDS-PAGE, blotted to nitrocellulose membrane and probed with purified, polyclonal anti-r<i>Sm</i>Synt antibodies. The antisera detect a dominant band with the predicted size of syntenin, ∼32 kDa in both extracts (arrow); two minor protein bands (likely non-specific) are also seen in the adult lane. As a control, serum from naïve mice does not appreciably stain the membrane (not shown).