Crotoxin B: Heterologous Expression, Protein Folding, Immunogenic Properties, and Irregular Presence in Crotalid Venoms.

Crotoxin complex CA/CB and crotamine are the main toxins associated with envenomation besides the enzymatic activities of phospholipases (PLA) and proteases. The neutralization at least of the crotoxin complex by neutralizing the subunit B could be a key in the production process of antivenoms against crotalids. Therefore, in this work, a Crotoxin B was recombinantly expressed to evaluate its capacity as an immunogen and its ability to produce neutralizing antibodies against crotalid venoms. A Crotoxin B transcript from was cloned into a pCR2.1-TOPO vector (Invitrogen, Waltham, MA, USA) and subsequently expressed heterologously in bacteria. HisrCrotoxin B was extracted from inclusion bodies and refolded in vitro. The secondary structure of HisrCrotoxin B was comparable to the secondary structure of the native Crotoxin B, and it has PLA activity as the native Crotoxin B. HisrCrotoxin B was used to immunize rabbits, and the obtained antibodies partially inhibited the activity of PLA from . The anti-HisrCrotoxin B antibodies neutralized the native Crotoxin B and the whole venoms from , and Additionally, anti-HisrCrotoxin B antibodies recognized native Crotoxin B from different species, and they could discriminate venom in species with high or low levels of or absence of Crotoxin B.