Immune-competent Animals Research Articles

Macrophage response to herpes simplex encephalitis in immune competent and T cell-deficient mice

Corneal inoculation of Nude (athymic) mice and Balb/c mice with herpes simplex virus Type I produces a brainstem encephalitis with demyelination of the trigeminal root entry zone. The extent of CNS demyelination is less in the immune-deficient athymic mice 7 days after infection compared to the immune-competent Balb/c mice. Both groups demonstrate a macrophage response and beginning myelin disruption approximately 3 days after corneal infection when herpes viral particles are first observed within central nervous system cells. Five to seven days after infection when differences in the extent of demyelination between the immune-competent and immune-deficient animals become evident, the Balb/c mice demonstrate T cells and increasing numbers of macrophages at the trigeminal root entry zones. These findings suggest an interaction between macrophages and T cells which leads to an extension of the demyelination in the immune competent Balb/c mice and that lack of T cells is important in limiting demyelination in Nude (athymic) mice.

Experimental pythiosis in rabbits.

Rabbits were injected by subcutaneous, intraperitoneal and intravenous routes with suspensions of motile zoospores of a Pythium sp. isolated from a subcutaneous lesion of a horse in north Queensland. Some animals injected by the subcutaneous route were also treated by cortisone injections. Animals in each group were found to be highly susceptible to infection. Injection by the subcutaneous route resulted in progressive granulomatous eosinophilic abscesses in all normal and cortisone-treated animals. Preferential hepatic invasion developing into severe necrotizing hepatitis was the most common lesion in the intraperitoneally injected group. In intravenously injected animals severe embolic mycotic nephritis was the principal lesion. A significant progressive leukocytosis with moderate neutrophilia and mild monocytosis was observed in the subcutaneously and intraperitoneally injected immune competent animals. Cortisone-treated subcutaneously injected animals did not develop a leukocytosis. Many of the cortisone-treated control animals showed increased susceptibility to bacterial infections while the cortisone-treated fungal-injected animals did not.