Development of an Inhibition Enzyme-Linked Immunosorbent Assay (ELISA) Prototype for Detecting Cytotoxic Three-Finger Toxins (3FTxs) in African Spitting Cobra Venoms

An immunodetection assay developed using cobra cytotoxin-specific antibodies: Potential diagnostics for cobra envenoming

Cobra (Naja spp.) envenoming is a life-threatening medical emergency, and a correct diagnosis is crucial to initiating timely and appropriate antivenom treatment. However, snakebite diagnostics remain unavailable in Southeast Asia. This study, therefore, developed an immunodetection assay with a potential diagnostic application for cobra envenoming. The cytotoxin of Naja kaouthia (Thai Monocled Cobra) (Nk-CTX) was purified from its venom to produce CTX-specific antibodies in rabbits and chickens. A double-antibody sandwich enzyme-linked immunosorbent assay was developed using the purified anti-Nk-CTX antibodies (immunoglobulin G and immunoglobulin Y), and its selectivity, specificity, and sensitivity for the venoms of five major cobra species in Southeast Asia (N. kaouthia, Naja sumatrana, Naja sputatrix, and Naja siamensis, Naja philippinensis) were studied. The results showed the immunoassay discriminates cobra venoms from other species commonly implicated in snakebites in Southeast Asia, i.e., the Malayan Krait, Many-banded Krait, King Cobra, Eastern Russell's Viper, Malayan Pit Viper and White-lipped Pit Viper. The immunoassay has a high sensitivity for the five cobra venoms, with detection limits (LoD) ranging from 0.6 to 2.6 ng/ml. Together, the findings suggest the potential diagnostic application of the cytotoxin immunoassay for cobra envenoming. The immunoassay was found to exhibit high immunoreactivity toward ten Asiatic cobra venoms (absorbance>1.5), in contrast to African cobra venoms with low immunoreactivity (absorbance<0.9). Considering the varying CTX antigenicity between Asiatic and African cobras, the immunoassay for African cobras should utilize antibodies produced specifically from the cytotoxins of African cobra venoms.

Comparison of Short-Term Restorative Effects and Periodontal Health Status of Restorations Made of Different Materials in Full-Crown Restoration of Mandibular Premolar Tooth Defects

Purpose

To compare the short-term restorative effect and periodontal health status of restorations with different materials in full-crown restoration of mandibular premolar tooth defects.

Methods

A total of 105 cases (123 affected teeth) of mandibular premolar tooth defects who visited the Department of Stomatology between January 2019 and January 2020 were selected, of which 58 cases (68 affected teeth) restored with cobalt-chromium alloy porcelain crowns were included in the metal-ceramic crown (MCC) group and 47 cases (55 affected teeth) repaired by zirconium dioxide all-ceramic crowns were assigned to the zirconia crown (ZC) group. The restorative effect, inflammatory factors (high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor-α (TNF-α)) and periodontal health indicators (human cartilage glycoprotein-39 (YKL-40), resistin, aspartate aminotransferase (AST), and alkaline phosphatase (ALP)) after treatment, and the occurrence of adverse reactions were compared between the two groups.

Results

The ZC group outperformed the MCC group in terms of margin fitness, restoration fracture, gingival condition, and color matching. After restoration, hs-CRP and TNF-α were statistically decreased in both groups, while YKL-40, resistin, AST, and ALP were significantly increased; and compared with the MCC group, hs-CRP, TNF-α, YKL-40, resistin, AST, and ALP were lower in the ZC group. The ZC group also scored statistically higher in retention effect, aesthetic effect, masticatory function, voice function, and comfort. Moreover, the ZC group had a higher total effective rate and a lower incidence of adverse reactions than the MCC group, with statistical significance.

Conclusions

Zirconia dioxide all-ceramic crowns contribute to a better short-term restorative effect in the full-crown restoration of mandibular premolar tooth defects, with little impact on periodontal health and high patient satisfaction, which deserves popularization and application.

Development and Characterization of Anti-Naja ashei Three-Finger Toxins (3FTxs)-Specific Monoclonal Antibodies and Evaluation of Their In Vitro Inhibition Activity

Antivenom immunotherapy is the mainstay of treatment for snakebite envenoming. Most parts of the world affected by snakebite envenoming depend on broad-spectrum polyspecific antivenoms that are known to contain a low content of case-specific efficacious immunoglobulins. Thus, advances in toxin-specific antibodies production hold much promise in future therapeutic strategies of snakebite envenoming. We report anti-3FTxs monoclonal antibodies developed against N. ashei venom in mice. All the three test mAbs (P4G6a, P6D9a, and P6D9b) were found to be IgG antibodies, isotyped as IgG1. SDS-PAGE analysis of the test mAbs showed two major bands at approximately 55 and 29 kDa, suggestive of immunoglobulin heavy and light chain composition, respectively. The immunoaffinity-purified test mAbs demonstrated higher binding efficacy to the target antigen compared to negative control. Similarly, a cocktail of the test mAbs was found to induce a significantly higher inhibition (p-value < 0.0001) compared to two leading commercial brands of antivenoms on the Kenyan market, implying a higher specificity for the target antigen. Both the test mAbs and 3FTxs polyclonal antibodies induced comparable inhibition (p-value = 0.9029). The inhibition induced by the 3FTxs polyclonal antibodies was significantly different from the two antivenoms (p-value < 0.0001). Our results demonstrate the prospects of developing toxin-specific monoclonal-based antivenoms for snakebite immunotherapy.