Fig 1.
Characterization of C. diphtheriae clinical isolates. Representative clinical isolates from each subgroup were examined for the presence of spaA by PCR amplification (A) and for the expression of SpaA by Western blotting (B) and ELISA (C) with antibodies to SpaA (α-SpaA). ELISA analyses were performed in triplicate, and error bars represent standard deviations. Strain names, subgroups 1 to 7 without toxin (tox−) or with toxin (tox+) and having 0, 1, 2, or 3 types of pili (pili0, pili1, etc.), and markers are indicated.