DELAYED-TYPE HYPERSENSITIVITY IN MICE EXPERIMENTALLY INFECTED WITH FUSOBACTERIUM-NECROPHORUM

The foot-pad test was performed to reveal the induction of delayed-typ e hypersensitivity (DTH) to Fusobacterium necrophorum in mice experime ntally infected with F. necrophorum. For the foot-pad test, heat-kille d cells of F. necrophorum were found to be better than viable bacteria as eliciting antigens. The thickness of foot-pad could be measured pr operly at 48 hr after administration to the foot-pad of heat-killed ba cteria. An intraperitoneal dose of the order of 10(5) or 10(6) of viab le bacteria evoked a similar foot-pad response. Peak responses were fo und on days 4 and 14 after the sensitization. The response was found t o be specific. This response could be transferred by spleen cells to g enetically homogeneous mice, but not to genetically heterogeneous mice . Serum could not transfer the response to either heterogeneous or hom ogeneous mice. Thus, these results indicate that DTH could be induced by F. necrophorum.