Immunotherapy for pythiosis: Effect on NTPDase activity in lymphocytes of an experimental model.
NTPDase (EC 3.6.1.5) occurs in lymphocytes and plays an important role in immune function, in that hydrolyzes extracellular nucleoside tri- and/or diphosphates to form AMP. Pythium insidiosum causes the disease pythiosis, a pyogranulomatous disease of horses, dogs, cattle, cats and humans. Most antifungal drugs are ineffective against this pathogen, and immunotherapy, a treatment approach that relies on the injection of P. insidiosum antigen, has been successfully used in humans and horses to manage this disease. In this study, we investigated NTPDase activity in lymphocytes from rabbits inoculated with zoospores of P. insidiosum. After immunotherapy, we investigated the relationship between enzymatic activity and the pattern of the immune response. One milliliter of zoospores was inoculated subcutaneously into the coastal region of each rabbit. An average of 17,500 viable mobile zoospores/mL of induction medium was administered. Inoculated rabbits were checked weekly, and the subcutaneous nodular area (cm²) was measured 28 days after inoculation. Rabbits that developed lesions received four doses of immunotherapy at intervals of 14 days. Blood samples were collected by heart puncture twice a month for the determination of NTPDase activity. The results demonstrated that NTPDase activity in lymphocytes was increased in relation to ATP hydrolysis (by about 100%) in pythiosis and returned to normal values after immunotherapy. The data demonstrating NTPDase activity before and after immunotherapy reinforce the previously elaborated hypothesis that the change from a Th2 to a Th1 immune response is responsible for the curative properties of immunotherapy.
Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Prédio 20, 97105-900 Santa Maria, RS, Brazil.
Barbara Charlotte
BC
Bach
Daniela Bitencourt Rosa
DB
Leal
Jader Betsch
JB
Ruchel
Viviane do Carmo Gonçalves
Vdo C
Souza
Grazieli
G
Maboni
Marcelo
M
Dal Pozzo
Karine Bizzi
KB
Schlemmer
Sydney Hartz
SH
Alves
Janio Morais
JM
Santurio
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D006868:Hydrolysis; D007167:Immunotherapy; D008214:Lymphocytes / Q000201:enzymology*; D008297:Male; D008962:Models, Theoretical; D043583:Nucleoside-Triphosphatase / Q000378:metabolism*; D058968:Pythiosis / Q000201:enzymology / Q000276:immunology* / Q000628:therapy*; D011775:Pythium; D011817:Rabbits
D000255:Adenosine Triphosphate; D043583:Nucleoside-Triphosphatase