GSC and cyst: The analysis of life-form-specific qPCR markers, including those for the trophic form (Sp), a serine protease expressed approximately 8-fold more in this life form, and Gsc1, which encodes a β−1,3-glucan synthase highly expressed in the cyst form (31), revealed a significantly higher abundance of these Pneumocystis forms in the Clec7a−/−Fcer1g−/− infected lungs compared with the other two mouse strains tested (Fig. 1B and D).