Role of extracellular phospholipases and mononuclear phagocytes in dissemination of cryptococcosis in a murine model

R Santangelo, H Zoellner, T Sorrell, C Wilson… - Infection and …, 2004 - Am Soc Microbiol
R Santangelo, H Zoellner, T Sorrell, C Wilson, C Donald, J Djordjevic, Y Shounan, L Wright
Infection and immunity, 2004Am Soc Microbiol
Secreted phospholipase B (PLB) activity promotes the survival and replication of
Cryptococcus neoformans in macrophages in vitro. We therefore investigated the role of
mononuclear phagocytes and cryptococcal PLB in the dissemination of infection in a mouse
model, using C. neoformans var. grubii wild-type strain H99, a PLB1 deletion mutant (Δ
plb1), and a reconstituted strain (Δ plb1rec). PLB facilitated the entry of endotracheally
administered cryptococci into lung IM. PLB was also required for lymphatic spread from the …
Abstract
Secreted phospholipase B (PLB) activity promotes the survival and replication of Cryptococcus neoformans in macrophages in vitro. We therefore investigated the role of mononuclear phagocytes and cryptococcal PLB in the dissemination of infection in a mouse model, using C. neoformans var. grubii wild-type strain H99, a PLB1 deletion mutant (Δplb1), and a reconstituted strain (Δplb1rec). PLB facilitated the entry of endotracheally administered cryptococci into lung IM. PLB was also required for lymphatic spread from the lung to regional lymph nodes and for entry into the blood. Langhans-type giant cells containing budding cryptococci were seen free in the lymphatic sinuses of hilar nodes of H99- and Δplb1rec-infected mice, suggesting that they may have a role in the dissemination of cryptococcal infection. The transfer of infected lung macrophages to recipient mice by tail vein injections demonstrated that these cells can facilitate hematogenous dissemination of cryptococci to the brain, independent of cryptococcal PLB secretion. PLB activities of cryptococci isolated from lung macrophages or infected brains were not persistently increased. We conclude that mononuclear phagocytes are a vehicle for cryptococcal dissemination and that PLB activity is necessary for the initiation of interstitial pulmonary infections and for dissemination from the lung via the lymphatics and blood. PLB is not, however, essential for the establishment of neurological infections when cryptococci are presented within, or after passage through, mononuclear phagocytes.
American Society for Microbiology