title: Molecular cloning, expression, function and immunoreactivities of members of a gene family of sphingomyelinases from Loxosceles venom glands.
abstract: Loxoscelism is the clinical condition produced by the venom of spiders belonging to the genus Loxosceles, which can be observed as two well-defined clinical variants: cutaneous loxoscelism and systemic or viscerocutaneous loxoscelism. We have recently identified, purified and characterised the toxins (sphingomyelinases) from Loxosceles intermedia venom that are responsible for all the local (dermonecrosis) and systemic effects (complement dependent haemolysis) induced by whole venom. In the present study, we have cloned and expressed the two functional sphingomyelinases isoforms, P1 and P2, and shown that the recombinant proteins display all the functional characteristics of whole L. intermedia venom, e.g., dermonecrotic and complement-dependent hemolytic activities and ability of hydrolyzing sphingomyelin. We have also compared the cross-reactivities of antisera raised against the toxins from different Loxosceles species and show here that the cross-reactivity is high when toxins are from the same species (P1 and P2 from L. intermedia) but low when the toxins are from different species (L. intermedia versus L. laeta). These data suggest that in order to obtain a suitable comprehensive neutralizing antiserum using the recombinant toxin as an immunogen, a mixture of the recombinant toxins from the different species has to be used. The use of anti-recombinant toxin antisera may have clinical benefits to those individuals displaying acute loxoscelic lesions.
authors.affiliation: Laboratório de Imunoquímica, Instituto Butantan, Av. Prof. Vital Brazil, 1500, CEP 05503-900 São Paulo, SP, Brazil. dvtambourgi@butantan.gov.br
authors.forename: Denise V
authors.initials: DV
authors.lastname: Tambourgi
authors.forename: Matheus
authors.initials: M
authors.lastname: de F Fernandes Pedrosa
authors.forename: Carmen W
authors.initials: CW
authors.lastname: van den Berg
authors.forename: Rute M
authors.initials: RM
authors.lastname: Gonçalves-de-Andrade
authors.forename: Matheus
authors.initials: M
authors.lastname: Ferracini
authors.forename: Danielle
authors.initials: D
authors.lastname: Paixão-Cavalcante
authors.forename: B Paul
authors.initials: BP
authors.lastname: Morgan
authors.forename: Neil K
authors.initials: NK
authors.lastname: Rushmere
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D003429:Cross Reactions; D008969:Molecular Sequence Data; D005810:Multigene Family; D010727:Phosphoric Diester Hydrolases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D010802:Phylogeny; D013108:Sphingomyelin Phosphodiesterase / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D013111:Spider Venoms / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D013112:Spiders / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
chemical_list: D013111:Spider Venoms; C055161:loxosceles venom; D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase