The molecular basis of cross-reactivity in the Australian Snake Venom Detection Kit (SVDK)

Steuten, Jessica Anne; Winkel, Kenneth D.; Carroll, T.; Williamson, Nicholas A.; Ignjatović, Vera; Fung, Kim Y. C.; Purcell, Anthony W.; Fry, Bryan G.

doi:10.1016/j.toxicon.2007.07.023

Cited by 35 publications

(19 citation statements)

References 22 publications

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“…[82]), gauge their relative toxicity in different animal models, and more accurately assess the potential danger of these snakes to human bite victims. Alongside proteomic characterisation, it is important that the extent and basis of any cross-reactivity of these venoms with currently available antivenoms and the snake venom detection kit (SVDK) [110] be ascertained.…”

Section: Discussionmentioning

confidence: 99%

Venom Down Under: Dynamic Evolution of Australian Elapid Snake Toxins

Jackson

Sunagar

Undheim

et al. 2013

Toxins

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Despite the unparalleled diversity of venomous snakes in Australia, research has concentrated on a handful of medically significant species and even of these very few toxins have been fully sequenced. In this study, venom gland transcriptomes were sequenced from eleven species of small Australian elapid snakes, from eleven genera, spanning a broad phylogenetic range. The particularly large number of sequences obtained for three-finger toxin (3FTx) peptides allowed for robust reconstructions of their dynamic molecular evolutionary histories. We demonstrated that each species preferentially favoured different types of α-neurotoxic 3FTx, probably as a result of differing feeding ecologies. The three forms of α-neurotoxin [Type I (also known as (aka): short-chain), Type II (aka: long-chain) and Type III] not only adopted differential rates of evolution, but have also conserved a diversity of residues, presumably to potentiate prey-specific toxicity. Despite these differences, the different α-neurotoxin types were shown to accumulate mutations in similar regions of the protein, largely in the loops and structurally unimportant regions, highlighting the significant role of focal mutagenesis. We theorize that this phenomenon not only affects toxin potency or specificity, but also generates necessary variation for preventing/delaying prey animals from acquiring venom-resistance. This study also recovered the first full-length sequences for multimeric phospholipase A2 (PLA2) ‘taipoxin/paradoxin’ subunits from non-Oxyuranus species, confirming the early recruitment of this extremely potent neurotoxin complex to the venom arsenal of Australian elapid snakes. We also recovered the first natriuretic peptides from an elapid that lack the derived C-terminal tail and resemble the plesiotypic form (ancestral character state) found in viper venoms. This provides supporting evidence for a single early recruitment of natriuretic peptides into snake venoms. Novel forms of kunitz and waprin peptides were recovered, including dual domain kunitz-kunitz precursors and the first kunitz-waprin hybrid precursors from elapid snakes. The novel sequences recovered in this study reveal that the huge diversity of unstudied venomous Australian snakes are of considerable interest not only for the investigation of venom and whole organism evolution but also represent an untapped bioresource in the search for novel compounds for use in drug design and development.

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Section: Discussionmentioning

confidence: 99%

Venom Down Under: Dynamic Evolution of Australian Elapid Snake Toxins

Jackson

Sunagar

Undheim

et al. 2013

Toxins

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“…False negatives may still arise because of a hook effect that occurs when a high venom concentration results in saturation of the binding antibodies in the kit, preventing formation of a sandwich. The labelled conjugate is removed in the washing step, resulting in a negative result 1,8 …”

Section: Discussionmentioning

confidence: 99%

“…The labelled conjugate is removed in the washing step, resulting in a negative result. 1,8 Venom levels below the detection limit of the test may also result in a false negative, because of subclinical envenomation that may or may not subsequently require antivenom therapy.…”

Section: Discussionmentioning

confidence: 99%

Prospective determination of the specificity of a commercial snake venom detection kit in urine samples from dogs and cats

Ong

Swindells²,

Mansfield³

2010

Aust Veterinary J

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Objective To determine the specificity of a snake venom detection kit in urine samples from dogs and cats presenting to a referral centre for diseases unrelated to snake envenomation.Design Urine was collected from 50 dog and 25 cats presented for investigation and treatment of diseases unrelated to snake envenomation. Urine was collected as a voided sample, by cystocentesis or by catheterisation, and routine urinanalysis was performed. Snake venom testing was performed within 2 h of collection using a commercially available snake venom detection kit, which was observed continuously during the 10-min colour reaction phase for evidence of a visible colour indicating a positive test. ResultsNo false-positive reactions occurred in any sample analysed. ConclusionThe snake venom detection kit appears to have 100% specificity for using urine as a test sample. T he CSL Snake Venom Detection Kit® is a rapid, freeze-dried, sandwich enzyme immunoassay. Each well of the test kit contains pairs of antibodies against a particular snake immunotype. Tiger, brown, black, death adder and taipan snake immunotypes are represented in the kit, together with a negative control, positive control and a blank well. One of the antibodies is attached to the plastic surface of the well and the other is modified by attachment of peroxidase and left free within the well. Any venom present in the test sample binds to the antibodies in the well and a washing phase subsequently removes any unbound material. Tetramethylbenzidine chromogen and peroxide are added to the wells, with oxidation of tetramethylbenzidine resulting in the development of a blue colour considered positive for a specific venom immunotype. This allows administration of the appropriate monovalent antivenom to the affected patient if indicated.1 Clinical sensitivity and specificity based on the presence of symptoms have been reported in the human literature at 53% and 83%, respectively.2 Cross-reactivity to other snake venoms and anecdotal incidences of false positives in urine containing haemoglobin have also been described.3-5 A case of brown snake bite without definitive evidence of envenomation, but displaying a positive result for black snake envenomation on snake venom detection kit testing of urine, has also been reported. 6 The incidence of false positives for urine samples is currently unknown in the veterinary population. Materials and methodsCats and dogs presenting to Murdoch University Veterinary Hospital for conditions other than suspected snake envenomation were assessed routinely and any urine samples obtained during the study period (March 2008 to August 2009) with sufficient residual volume were used for this study. On completion of the study, the medical records of the patients were reviewed to confirm that the patient's disease process had been unrelated to snake envenomation. This project had full Murdoch University Animal Ethics Committee approval.All urine samples had the method of collection recorded and were stored at room temperature after collection....

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“…In Australia it is a useful test but its relative insensitivity, high levels of false positive results [5] and problems relating to cross reactivity [40,41] compared with the standard EIA also leave a lot to be desired although, as stated above, the new assay is more sensitive. It was concluded [42] that the SVDK may assist in regions where the range of medically-important snakes is too broad to permit the use of monospecific antivenoms.…”

Section: Major Roles Of Enzyme-linked Immunosorbent Assay (Elisa) mentioning

confidence: 99%

Diagnosis of Snakebite and the Importance of Immunological Tests in Venom Research

Theakston

Laing

2014

Toxins

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In many cases of envenoming following snake bite, the snake responsible for the accident remains unidentified; this frequently results in difficulty deciding which antivenom to administer to the systemically-envenomed victim, especially when only monospecific antivenoms are available. Normally the specific diagnosis of snake bite can be conveniently made using clinical and laboratory methods. Where clinical diagnosis depends upon the recognition of specific signs of envenoming in the patient, laboratory diagnosis is based on the changes which occur in envenomed victims including the detection of abnormalities in blood parameters, presence/absence of myoglobinuria, changes in certain enzyme levels, presence/absence of neurotoxic signs and the detection in the blood of specific venom antigens using immunologically-based techniques, such as enzyme immunoassay. It is the latter which is the main subject of this review, together with the application of techniques currently used to objectively assess the effectiveness of new and existing antivenoms, to assess first aid measures, to investigate the possible use of such methods in epidemiological studies, and to detect individual venom components. With this in mind, we have discussed in some detail how such techniques were developed and how they have helped in the treatment of envenoming particularly and in venom research in general.

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The molecular basis of cross-reactivity in the Australian Snake Venom Detection Kit (SVDK)

Cited by 35 publications

References 22 publications

Venom Down Under: Dynamic Evolution of Australian Elapid Snake Toxins

Venom Down Under: Dynamic Evolution of Australian Elapid Snake Toxins

Prospective determination of the specificity of a commercial snake venom detection kit in urine samples from dogs and cats

Diagnosis of Snakebite and the Importance of Immunological Tests in Venom Research

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