RESUMO
1. Preheparin plasma from mice, but not rats or man, contains high levels of phospholipase A and lysophospholipase activities which are distinct from lecithin:cholesterol acyltransferase (LCAT). 2. Neither the phospholipase A nor the lysophospholipase activities in preheparin plasma are inhibited by incubation in the presence of protamine sulphate or high salt concentrations. 3. When mouse plasma is incubated in the presence of an antiserum specific for rat hepatic triacylglycerol lipase (HTGL), the phospholipase activities are abolished. 4. These observations suggest that the phospholipase activities are attributable to the action of HTGL, which, in the mouse appears to be a freely circulating enzyme, whereas for other species this enzyme only appears in the blood following administration of heparin.
Assuntos
Heparina/farmacologia , Soros Imunes , Lipase/imunologia , Fígado/enzimologia , Lisofosfolipase/antagonistas & inibidores , Fosfolipases A/antagonistas & inibidores , Animais , Humanos , Lisofosfolipase/sangue , Camundongos , Fosfatidilcolina-Esterol O-Aciltransferase/sangue , Fosfolipases A/sangue , Protaminas/farmacologia , Ratos , Cloreto de Sódio/farmacologiaRESUMO
Interspecific interactions between Nippostrongylus brasiliensis and Eimeria nieschulzi were studied by measuring fecal lysophospholipase (LYPH) activity and relative numbers of peripheral eosinophils in rats singly or concurrently infected with one or both parasite species. Three groups of 10 rats each were inoculated with 2 X 10(3) N. brasiliensis L3 larvae and/or 5 X 10(5) E. nieschulzi sporulated oocysts. Groups 1 and 2 were infected with E. nieschulzi or N. brasiliensis, respectively. Group 3 rats were infected first with N. brasiliensis, followed on day 8 postinoculation (PI) with E. nieschulzi. Each rat served as its own control. Results revealed LYPH levels rose steadily in Group 2 rats, reaching significant peaks on days 10 and 12 PI before decreasing to control levels. Lysophospholipase activity in Groups 1 and 3, however, did not differ from control values. Group 2 rats also demonstrated peripheral eosinophilia, with peak values occurring on days 10, 12, 14, and 16 PI, while rats in Groups 1 and 3 exhibited no eosinophilia. These results demonstrate that E. nieschulzi suppressed intestinal LYPH activity and relative peripheral eosinophilia and demonstrate that a host's immune response to a single parasite may be significantly altered when a second parasite species is present.