title: Cryptococcus neoformans Thermotolerance to Avian Body Temperature Is Sufficient For Extracellular Growth But Not Intracellular Survival In Macrophages.
abstract: Cryptococcus neoformans is a fatal fungal pathogen of humans that efficiently parasitises macrophages. Birds can be colonised by cryptococci and can transmit cryptococcosis to humans via inhalation of inoculated bird excreta. However, colonisation of birds appears to occur in the absence of symptomatic infection. Here, using a pure population of primary bird macrophages, we demonstrate a mechanism for this relationship. We find that bird macrophages are able to suppress the growth of cryptococci seen in mammalian cells despite C. neoformans being able to grow at bird body temperature, and are able to escape from bird macrophages by vomocytosis. A small subset of cryptococci are able to adapt to the inhibitory intracellular environment of bird macrophages, exhibiting a large cell phenotype that rescues growth suppression. Thus, restriction of intracellular growth combined with survival at bird body temperature explains the ability of birds to efficiently spread C. neoformans in the environment whilst avoiding systemic disease.
authors.affiliation: Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, UK.|Bateson Centre, University of Sheffield, Sheffield, UK.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Johnston
authors.affiliation: Institute of Microbiology and Infection and School of Biosciences, University of Birmingham, Birmingham, UK.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Voelz
authors.affiliation: Institute of Microbiology and Infection and School of Biosciences, University of Birmingham, Birmingham, UK.|NIHR Surgical Reconstruction and Microbiology Research Centre, University Hospitals of Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Birmingham, UK.
authors.forename: Robin C
authors.initials: RC
authors.lastname: May
mesh_terms: D000818:Animals; D001717:Birds / Q000382:microbiology; D001831:Body Temperature; D002645:Chickens; D003455:Cryptococcus neoformans / Q000502:physiology*; D008264:Macrophages / Q000276:immunology / Q000382:microbiology*; D050296:Microbial Viability; D000071436:Thermotolerance