Nippostrongylus brasiliensis: ability of plasma to prime free radical generation by leukocytes in response to adult worms not due to gamma-interferon or tumour necrosis factor.
Plasma-borne factors prime leukocytes from both infected and uninfected rats for radical generation in response to N. brasiliensis. The concentration of these factors is increased following infection and reaches maximal levels on day 8 post-infection (p.i.) as demonstrated by the striking ability of plasma from infected rats to prime leukocytes from uninfected rats to produce free radicals in response to adult worms. The cytokines, gamma-interferon and tumour necrosis factor (TNF) can be detected in plasma during infection with a variety of organisms and several lines of immunological and pathophysiological evidence, including radical generation, weight loss, anaemia and diarrhoea, implicate generation of these proteins in response to infection with N. brasiliensis. We therefore investigated whether gamma-interferon and TNF were detectable in the plasma of rats infected with N. brasiliensis and whether the presence of these cytokines correlated with the ability of plasma to enhance radical generation in response to N. brasiliensis. However, gamma-interferon was not detected in the plasma of rats at any time after infection with N. brasiliensis and neutralizing monoclonal antibody to rat gamma-interferon had no effect on the ability of plasma to prime free radical generation. TNF was detected in the plasma of heavily-infected rats but only at very low levels (< 1 ng/ml), though copius in vivo synthesis of TNF could be induced by treatment of the infected rats with lipopolysaccharide (LPS). However, neither parasite-induced nor parasite plus LPS-induced plasma TNF correlated with the ability of plasma to enhance radical generation in response to N. brasiliensis.(ABSTRACT TRUNCATED AT 250 WORDS)
Smith
N C
NC
Division of Biochemistry and Molecular Biology, School of Life Sciences, Australian National University, Canberra.
Ovington
K S
KS
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001769:Blood / Q000276:immunology*; D001835:Body Weight; D005260:Female; D005609:Free Radicals / Q000378:metabolism; D007371:Interferon-gamma / Q000097:blood / Q000276:immunology; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism*; D008163:Luminescent Measurements; D009559:Nippostrongylus / Q000276:immunology*; D010537:Peritoneum / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D017206:Strongylida Infections / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000276:immunology
D000911:Antibodies, Monoclonal; D005609:Free Radicals; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma