SP0845 is accessible to antibodies.

<p>(A) Mid-logarithmic phase TIGR4 cells were incubated with mouse anti-SP0845^23–350 or mouse preimmune sera (negative control) followed by incubation with F(ab')₂ fragment phycoerythrin-conjugated goat anti-mouse IgG + IgM (H + L) antibody. The processed samples were observed under a fluorescence microscope. The fluorescent images obtained with anti-SP0845^23–350 and preimmune sera are in the upper left and right panels, respectively. The lower panels show the corresponding phase contrast images (magnification = 1000X). Surface expression of SP0845 was studied for pneumococcal strains TIGR4 (B), ATCC 6303 (C), ATCC 6314 (D), D39 (E) and R36A (F). Pneumococcal cells were incubated with either preimmune or anti-SP0845^23–350 sera for 1 hr followed by a FITC-conjugated F(ab')₂ fragment goat anti-mouse IgG + IgM (H + L) antibody as secondary antibody. The surface staining was detected by flow cytometry.