Abstract：
Camelid single-domain antibodies (VHH) represent a promising class of immunobiologicals for therapeutic applications due to their remarkable stability, specificity, and therapeutic potential. To enhance the effectiveness of antivenoms for snakebites, various methods have been explored to address limitations associated with serum therapy, particularly focusing on mitigating local damage and ensuring sustainable production. Our study aimed to characterize the pharmacological profile and neutralization capacity of anti-Phospholipase A2 (PLA2) monomeric VHH (Genbank accessions: KC329718). Using a post-envenoming mouse model, we used intravital microscopy to assess leukocyte influx, measured CK and LDH levels, and conducted a histopathology analysis to evaluate VHH KC329718\'s ability to neutralize myotoxic activity. Our findings demonstrated that VHH KC329718 exhibited heterogeneous distribution in muscle tissue. Treatment with VHH KC329718 reduced leukocyte influx caused by BthTX-I (a Lys-49 PLA2) by 28 %, as observed through intravital microscopy. When administered at a 1:10 ratio [venom or toxin:VHH (w/w)], VHH KC329718 significantly decreased myotoxicity, resulting in a 35-40 % reduction in CK levels from BthTX-I and BthTX-II (an Asp-49 PLA2) and a 60 % decrease in CK levels from B. jararacussu venom. LDH levels also showed reductions of 60%, 80%, and 60% induced by BthTX-I, BthTX-II, and B. jararacussu venom, respectively. Histological analysis confirmed the neutralization potential, displaying a significant reduction in tissue damage and inflammatory cell count in mice treated with VHH KC329718 post B. jararacussu venom inoculation. This study underscores the potential of monomeric anti-PLA2 VHH in mitigating myotoxic effects, suggesting a promising avenue for the development of new generation antivenoms to address current therapeutic limitations.
摘要：
骆驼类单结构域抗体（VHH）由于其卓越的稳定性，代表了一类有前途的用于治疗应用的免疫生物制剂。特异性，和治疗潜力。为了增强抗蛇毒血清对蛇咬伤的有效性，已经探索了各种方法来解决与血清治疗相关的局限性，特别注重减轻当地损害和确保可持续生产。我们的研究旨在表征抗磷脂酶A2（PLA2）单体VHH（Genbank材料：KC329718）的药理学特征和中和能力。使用envenoming后的小鼠模型，我们使用活体显微镜来评估白细胞流入，测量CK和LDH水平，并进行了组织病理学分析，以评估VHHKC329718中和肌毒性活性的能力。我们的发现表明，VHHKC329718在肌肉组织中表现出异质性分布。用VHHKC329718治疗可使BthTX-I（Lys-49PLA2）引起的白细胞流入减少28％，通过活体显微镜观察。当以1:10的比例[毒液或毒素：VHH（w/w）]给药时，VHHKC329718显著降低了肌毒性，导致BthTX-I和BthTX-II（Asp-49PLA2）的CK水平降低35-40％，而B.jaracussu毒液的CK水平降低60％。LDH水平也显示降低了60%，80%,60%由BthTX-I诱导，BthTX-II,B.jararacussu毒液，分别。组织学分析证实了中和电位，在B.jaracussu毒液接种后，用VHHKC329718处理的小鼠中，组织损伤和炎症细胞计数显着减少。这项研究强调了单体抗PLA2VHH在减轻肌毒性作用方面的潜力，提出了开发新一代抗血清的有希望的途径，以解决当前的治疗局限性。
