FIG. 5.

Western immunoblot analysis of whole-cell lysates of S. pneumoniae D39 (A) and purified preparations of PdB (53 kDa), PspA fragment (43 kDa), and ClpP (21 kDa) (B) showing specificities of antibody responses to protein antigens. The proteins were separated by SDS-PAGE and then electroblotted onto nitrocellulose. They were then reacted with sera from groups of mice immunized with the proteins. Nitrocellulose membrane strips were reacted with sera from mice immunized with AlPO₄ adjuvant (lane 1), PdB plus AlPO₄ (lane 2), PspA plus AlPO₄ (lane 3), and ClpP plus AlPO₄ (lane 4).