P2RX7 and pneumocystosis: Grin2a and Grin2b levels were also significantly lower in PCP treated P2rx7−/− mice, when compared to PCP treated P2rx7+/+ mice (Fig. 5b,c), whereas in saline treated P2rx7−/− mice Grin2b was upregulated when compared to saline treated P2rx7+/+ mice (Fig. 5c).