RESISTANCE TO CRYPTOCOCCUS-NEOFORMANS IS ASSOCIATED WITH AN INFLAMMATORY RESPONSE TO TOXOPLASMA-GONDII IN THE CENTRAL-NERVOUS-SYSTEM OF MICE

We have studied the resistance of Toxoplasma gondii-infected mice to s ubsequent infection with Cryptococcus neoformans. Mice infected with t he moderately virulent ME49 strain of T. gondii are resistant to proli feration of yeast cells in their brains after intravenous inoculation of the serotype A C. neoformans strain 184. The resistance serves to l imit proliferation of yeast cells that colonize the brain, Maximal lev els of resistance correlate not with maximal systemic specific anti-To xoplasma resistance but rather with high levels of inflammatory respon se, presumably to parasites released from cysts in the brain, Resistan ce is localized, as mice infected with ME49 show only limited resistan ce in their lungs after intratracheal instillation of yeast cells, but there is substantial protection against development of cerebral crypt ococcosis.