(A) Titers of PPS14-specific IgG isotypes in sera of BALB/c and BALB/c athymic nude mice (n=7), 14 days after a primary immunization (Primary) and 20 days after a secondary immunization (Secondary) with ≈ 2×108 latex beads, coated with the Ag combinations indicated, in alum + CpG-ODN. For IgG1 determinations a scale in weight units is included as a reference. (B) PspA-specific IgG isotype titers in selected BALB/c mice sera from several independent experiments chosen for having a similar content of PspA-specific IgG. Sera were collected 14 days after a primary immunization (Primary) and 7 days after the secondary immunization (Secondary). Values are expressed as geometric mean ± SEM. *p < 0.05 (titer−1 in primary relative to secondary response), #p < 0.05 (between the responses elicited in BALB/c versus athymic nude mice for each bleeding and group). ^p<0.05 (Only in panel B, relative to mice immunized with [PspA] beads)