Neutralization of lethal potency and inhibition of enzymatic activity of a phospholipase A2 neurotoxin, crotoxin, by non-precipitating antibodies (Fab).
Rabbit antibodies were prepared against both purified catalytic (component-B) and purified non-catalytic (component-A) subunits of crotoxin, the major phospholipase A2 neurotoxin from the South American rattlesnake. They cross-react with crotoxin-like toxins from the venom of several Crotalus species as well as with single-chain phospholipase A2 neurotoxins from Crotalid and Viperid venoms (agkistrodontoxin and ammodytoxin A) but not from Elapid venoms (notexin). Immunological cross-reactions of anti-component-A and anti-component-B sera with crotoxin and with its isolated components A and B showed that component-A exposes determinants of low immunogenicity which are present on component-B, whereas the major antigenic determinants of component-B are not present on component-A. Anti-component-B antibodies, but not anti-component-A antibodies, neutralize the lethal potency of crotoxin and inhibit its enzymatic activity. Furthermore, non-precipitating anti-component-B Fab fragments were as potent as antibodies, indicating that crotoxin neutralization results from the binding of the antibodies to the catalytic subunit, rather than the formation of an immunoprecipitate.
Choumet
V
V
Laboratoire des Venins, Institut Pasteur, Paris, France.
Jiang
M S
MS
Radvanyi
F
F
Ownby
C
C
Bon
C
C
D000906:Antibodies / Q000276:immunology / Q000302:isolation & purification; D000918:Antibody Specificity; D000941:Antigens / Q000276:immunology; D001665:Binding Sites; D003435:Crotalid Venoms / Q000276:immunology*; D003439:Crotoxin / Q000276:immunology* / Q000378:metabolism; D004546:Elapid Venoms / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D007106:Immune Sera / Q000276:immunology; D007140:Immunoglobulin Fab Fragments / Q000276:immunology* / Q000302:isolation & purification; D010206:Papain; D010740:Phospholipases / Q000276:immunology*; D010741:Phospholipases A / Q000276:immunology*; D054467:Phospholipases A2; D014757:Viper Venoms / Q000276:immunology
C031442:Agkistrodon venoms; D000906:Antibodies; D000941:Antigens; D003435:Crotalid Venoms; D004546:Elapid Venoms; D000939:Epitopes; D007106:Immune Sera; D007140:Immunoglobulin Fab Fragments; D014757:Viper Venoms; C005082:notexin; D003439:Crotoxin; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D010206:Papain