Preparation and characterization of monoclonal antibody specific for Naja nivea cardiotoxin VII1

Horse immunization with short-chain consensus α-neurotoxin generates antibodies against broad spectrum of elapid venomous species

Antivenoms are fundamental in the therapy for snakebites. In elapid venoms, there are toxins, e.g. short-chain α-neurotoxins, which are quite abundant, highly toxic, and consequently play a major role in envenomation processes. The core problem is that such α-neurotoxins are weakly immunogenic, and many current elapid antivenoms show low reactivity towards them. We have previously developed a recombinant consensus short-chain α-neurotoxin (ScNtx) based on sequences from the most lethal elapid venoms from America, Africa, Asia, and Oceania. Here we report that an antivenom generated by immunizing horses with ScNtx can successfully neutralize the lethality of pure recombinant and native short-chain α-neurotoxins, as well as whole neurotoxic elapid venoms from diverse genera such as Micrurus, Dendroaspis, Naja, Walterinnesia, Ophiophagus and Hydrophis. These results provide a proof-of-principle for using recombinant proteins with rationally designed consensus sequences as universal immunogens for developing next-generation antivenoms with higher effectiveness and broader neutralizing capacity.

Far-u.v. CD-spectroscopy and immunological properties of synthetic sequential peptides derived from cardiotoxin VII1 of Naja nivea venom: an amphipathic alpha-helix formed by sequence 15-25 of a beta-protein

1. Immunological properties of cardiotoxin V(II)1 of Naja nivea were investigated. 2. Polyvalent antiserum raised against the cardiotoxin was tested for its interaction with synthetic peptides of overlapping sequence in order to locate possible sequential epitopes. 3. The conformation of each synthetic peptide in various solvents was determined by circular dichroism spectroscopy for relating immunological to structural properties. 4. It was found that sequential epitopes are absent in this cardiotoxin, but that region 15-25, although part of a beta-structured region, could be a possible T-cell epitope through the formation of an amphipathic helix.

Preparation and characterization of monoclonal antibody specific for alpha-bungarotoxin and localization of the epitope

We prepared a monoclonal antibody (mAb) specific for alpha-bungarotoxin (alpha-BuTX) which can neutralize the lethal toxicity of the toxin and inhibit the binding of [3H]-alpha-BuTX to the nicotinic acetylcholine receptor. The radiolabelled toxin has a high affinity for the mAb. alpha-BuTX was digested with acid protease A and the resulting peptide fragments were isolated by reverse-phase HPLC. The epitope recognized by the mAb has been localized on the basis of competition radioimmunoassay between [3H]-alpha-BuTX and the peptide fragments of alpha-BuTX towards the antibody. The epitope specific for the mAb may be located in the second loop of alpha-BuTX, probably involving residues 34-41.

Monoclonal antibody specific for cyanoginosin-LA: preparation and characterization

The toxin cyanoginosin-LA (MW 909), isolated from Microcystis aeruginosa, was successfully conjugated with polylysine and muramyl dipeptide to form a high molecular weight complex consisting of a hapten, a carrier and a built-in adjuvant. This complex was used for the immunization of mice. Monoclonal antibodies specific for cyanoginosin-LA were produced using the hybridoma technique. The ten most efficient producers of these antibodies were further characterized and the monoclonal antibody produced by them was found to be identical on the basis of additivity test, isoelectric focussing and sub-class immunoglobulin typing results. The anti-cyanoginosin-LA monoclonal antibody focussed at a pH of approximately 6.55 and was found to belong to the mouse immunoglobulin subclass IgM. Large scale production of the antibody (in vivo) was followed by purification with ammonium sulphate precipitation and high performance liquid chromatography. The anticyanoginosin-LA monoclonal antibody, when reacted with six variants of cyanoginosin (other than cyanoginosin-LA), bound all with equal efficiency.