Anti-SLA IgG1 antibodies predominated over IgG2a in non-protected mice. (A) Sera were collected at 7 weeks pi from mice vaccinated with pCMV-HISA70m2A and control mice treated with PBS alone or with empty vector. Titers of anti-SLA IgG1 and IgG2a antibodies were determined by ELISA. (B) Leishmania-specific IgG2a : IgG1 ratio. Asterisks indicate P < 0.05 with respect to both groups of control mice (PBS only, empty vector only). Results are the mean and SD (bars) for groups of mice (n = 6) from two independent experiments.