Mutacytin-1, a New C-Type Lectin-Like Protein from the Venezuelan Cuaima (Lachesis muta muta Linnaeus, 1766) (Serpentes: Viperidae) Snake Venom Inducing Cardiotoxicity in Developing Zebrafish (Danio rerio) Embryos.

Envenomation by the Venezuelan bushmaster snake (Lachesis muta muta) (Serpentes: Viperidae) is characterized by local and cardiac alterations. This study investigates the in vivo cardiac dysfunction, tissue destruction, and cellular processes triggered by Lachesis muta muta snake crude venom and a C-type lectin (CTL)-like toxin named Mutacytin-1 (MC-1). The 28 kDa MC-1 was obtained by molecular exclusion, ion exchange, and C-18 (checking pureness) reverse-phase chromatographies. N-terminal sequencing of the first eight amino acids (NNCPQ LLM) revealed 100% identity with Mutina (CTL-like) isolated from Lachesis stenophrys, which is a Ca2+-dependent-type galactoside-binding lectin from Bothrops jararaca and CTL BpLec from Bothrops pauloensis. The cardiotoxicity in zebrafish of MC-1 was evaluated by means of specific phenotypic expressions and larvae behavior at 5, 15, 30, 40 and 60 min post-treatment. The L. muta muta venom and MC-1 also produced heart rate/rhythm alterations, circulation modifications, and the presence of thrombus and apoptotic phenomenon with pericardial damages. Acridine orange (100 µg/mL) was used to visualize apoptosis cellular process in control and treated whole embryos. The cardiotoxic alterations happened in more than 90% of all larvae under the action of L. muta muta venom and MC-1. The findings have demonstrated the potential cardiotoxicity by L. muta muta venom, suggesting the possibility of cardiovascular damages to patients after bushmaster envenoming.

IgY pharmacokinetics in rabbits: implications for IgY use as antivenoms.

This paper presents the first study of chicken IgY pharmacokinetics (PK) in rabbits. We measured IgY blood serum concentrations using a specific high sensitivity ELISA method. The fast initial component observed when studying horse Fab, F(ab')2 or IgG was absent from IgY PK. During the first 80 min of observation there was only a single slow exponential decay, which sped up afterward to the point that IgY became undetectable after 216 h of observation; due to this time course, PK parameters were determined with trapezoidal integration. The most significant IgY pharmacokinetic parameters determined were (all presented as medians and their 95% confidence interval): Area Under the Curve = 183.8 (135.2, 221.5) mg·h·L(-1); Distribution volume of the central compartment·[Body Weight (BW)](-1) = 46.0 (21.7, 70.3) mL·kg(-1); Distribution volume in steady state·BW(-1) = 56.8 (44.4, 68.5) mLkg(-1); Mean Residence Time = 40.1 (33.6, 48.5) h; Total plasma clearance·BW(-1) = 1.44 (1.15, 1.66) mL·h(-1)·kg(-1). Anti IgY IgG titers determined by ELISA increased steadily after 72 h, and reached 2560 (1920, 5760) dilution(-1) at 264 h; anti-chicken IgG concentrations rose up to 3.19 (2.31, 6.17) µg/mL in 264 h. Our results show that IgY PK lacks the fast initial decay observed in other PK studies using horse IgG, F(ab')2 or Fab, remains in the body 39.0 (28.7, 47.2) % much as IgG and is ≈3 times more immunogenic that horse IgG in rabbits.

IgY antibodies anti-Tityus caripitensis venom: purification and neutralization efficacy.

Tityus caripitensis is responsible for most of scorpion stings related to human incidents in Northeastern Venezuela. The only treatment for scorpion envenomation is immunotherapy based on administration of scorpion anti-venom produced in horses. Avian antibodies (IgY) isolated from chicken egg yolks represent a new alternative to be applied as anti-venom therapy. For this reason, we produced IgY antibodies against T. caripitensis scorpion venom and evaluated its neutralizing capacity. The anti-scorpion venom antibodies were purified by precipitation techniques with polyethylene glycol and evaluated by Multiple Antigen Blot Assay (MABA), an indirect ELISA, and Western blot assays. The lethality neutralization was evaluated by preincubating the venom together with the anti-venom prior to testing. The IgY immunoreactivity was demonstrated by a dose-dependent inhibition in Western blot assays where antibodies pre-absorbed with the venom did not recognize the venom proteins from T. caripitensis. The anti-venom was effective in neutralizing 2LD50 doses of T. caripitensis venom (97.8 mg of IgY neutralized 1 mg of T. caripitensis venom). Our results support the future use of avian anti-scorpion venom as an alternative to conventional equine anti-venom therapy in our country.