Trypanosoma lewisi-induced immunosuppression: the effects on alveolar macrophage activities against Cryptococcus neoformans.
The immunosuppressive effect of Trypanosoma lewisi infection on alveolar macrophage (AM) activities against Cryptococcus neoformans was studied in an animal model. Two groups of rats were treated with T. lewisi and killed after 4 (4d-rats) and 7 days (7d-rats), respectively. A third group not given T. lewisi, served as control. AM were challenged in vitro with C. neoformans. Phagocytosis was assessed with a fluorescence method. Superoxide anion production was evaluated with the nitroblue tetrazolium (NBT) test. The survival of cryptococci was estimated by counting colony-forming units. The numbers of detached AM from culture plates were determined using a Bürker chamber. The NBT response, adhesion to plate surface and killing activity, but not the phagocytosis of AM from 4d-rats were significantly impaired compared to control or 7d-rats. Thus, T. lewisi causes transitory immunosuppressive effects on AM activities. This rapid T. lewisi immunosuppression model may be useful to study new approaches to anticryptococcal therapy.
Centro de Investigaciones en Enfermedades Tropicales (CIET), Facultad de Microbiologia, Universidad de Costa Rica, San Pedro Mts de Oca, Costa Rica.
Norma Teresa
NT
Gross
Olga Marta
OM
Guerrero
Misael
M
Chinchilla
Connie
C
Jarstrand-Hall
D000818:Animals; D002470:Cell Survival; D003453:Cryptococcosis / Q000276:immunology*; D003455:Cryptococcus neoformans / Q000276:immunology*; D004195:Disease Models, Animal; D007108:Immune Tolerance; D016867:Immunocompromised Host; D007202:Indicators and Reagents; D016676:Macrophages, Alveolar / Q000276:immunology*; D008297:Male; D009580:Nitroblue Tetrazolium; D010587:Phagocytosis / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014350:Trypanosoma lewisi / Q000276:immunology*; D014352:Trypanosomiasis / Q000276:immunology*
D007202:Indicators and Reagents; D009580:Nitroblue Tetrazolium