Skip to main content
. 2018 Apr 16;9:747. doi: 10.3389/fimmu.2018.00747

Figure 6.

Figure 6

Identification of pneumococcal proteins that cross-react with rabbit Streptococcus mitis antisera. (A) Immunogenic screening of on-chip purified Streptococcus pneumoniae TIGR4 protein microarray. Lysates of 30 recombinant proteins overexpressed in E. coli were printed on the chelated Cu++/PEG surface slides in triplicates. The slides were probed with S. mitis and S. pneumoniae antiserum to identify immunoreactive pneumococcal antigens. Pre- and post-immune serum from rabbits challenged with S. mitis type strain, and post-immune serum from rabbits challenged with S. pneumoniae were used on the slides. Values were obtained by ratio of fluorescence intensity of spot to fluorescence intensity of E. coli cell lysate. E. coli, His-tag MBP; ~50% similarity to SP2108. Abbreviations: PRE-SM, pre-inoculation S. mitis serum; POST-SM, post-inoculation S. mitis serum; POST-SP, post-inoculation S. pneumoniae serum; CbpD, choline-binding protein D; FtsH, cell division protein; PsaA, manganese ABC transporter adhesion lipoprotein; MBP, maltose-binding protein. (B) Reactivity of rabbit anti-S. mitis IgG antisera with S. pneumoniae TIGR4 and S. mitis PsaA by SDS-PAGE in gradient gels and immunoblotting. Each lane was loaded with 50 µg of protein from the indicated bacterial species. The pre- and post-inoculation sera were diluted 1:1,000. Abbreviations: M, S. mitis CCUG31611; P, S. pneumoniae TIGR4.