Reactogenicity to vaccine in sensitized vs unsensitized guinea pigs.

<p>Images are representative of guinea pigs inoculated i.n. with <i>C</i>. <i>burnetii</i> (C and D) or unsensitized (saline) (A and B), then challenged with a 2 μg intradermal dose of vaccine (Coxevac) at day 42 p.i.. A) Inflammation at day 7 p.c. in unsensitized guinea pig is multifocal (arrows) and limited to the deep dermis. B) Inflammation at day 21 p.c. in unsensitized guinea pig is similar to day 7 (arrow). C) More severe inflammation with extension through the dermis (arrows) at day 7 p.c. in <i>Cb</i>9M-sensitized guinea pig. D) Progression of inflammation in <i>Cb</i>9M-sensitized guinea pig at day 21 p.c. (arrows) with increased frequency of neutrophils and presence of microabscesses (arrowheads).</p>