Loxoscelism is a recognized public health problem in Brazil, but the
venom from Loxosceles similis, which is widespread in Brazil due to its adaptability to the urban environment, remains poorly characterized. Loxtox is a family of
phospholipase D enzymes (PLDs), which are the major components of
Loxosceles venom and are responsible for the clinical effects of
loxoscelism. Loxtox toxins correspond to 15% of L. similis
venom gland transcripts, but the Loxtox family of L. similis has yet to be fully described. In this study, we cloned and functionally characterized recLoxtox s1A and recLoxtox s11A. These recombinant toxins exhibited different in vitro activities depending on pH, and recLoxtox s1A had more intense effects on rabbit skin than did recLoxtox s11A in vivo. Both recombinant toxins were used in immunization protocols, and mapping of their
epitopes revealed different immunological reactions for the produced
immune serums. Additionally, polyclonal
antibodies raised against recLoxtox s1A had greater capacity to significantly reduce the in vitro and in vivo effects of L. similis
venom. In summary, we obtained and characterized two novel Loxtox
isoforms from L. similis
venom, which may be valuable biotechnological and immunological tools against
loxoscelism.