MYD88 and infection: Here, we investigated whether Myd88-/- mice can acquire vaccine immunity against infection with the systemic dimorphic fungi B. dermatitidis and H. capsulatum. Myd88-/- mice were unable to control the live, attenuated #55 vaccine strain of B. dermatitidis and succumbed to dissemination and infiltration of the lungs by the yeast (Fig 1A).