Rodriguez-Nuñez Mariajosé, Cepeda Mariana Del Valle, Bello Carlos, Lopez Miguel Angel, Sulbaran Yoneira, Loureiro Carmen Luisa, Liprandi Ferdinando, Jaspe Rossana Celeste, Pujol Flor Helene, Rangel Héctor Rafael
Laboratorio de Virología Molecular, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas 1020, Venezuela.
Biotecfar S.A., Facultad de Farmacia, Universidad Central de Venezuela, Caracas 1050, Venezuela.
Antibodies (Basel). 2023 Dec 7;12(4):80. doi: 10.3390/antib12040080.
The Receptor Binding Domain (RBD) of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is the functional region of the viral Spike protein (S), which is involved in cell attachment to target cells. The virus has accumulated progressively mutations in its genome, particularly in the RBD region, many of them associated with immune evasion of the host neutralizing antibodies. Some of the viral lineages derived from this evolution have been classified as Variant of Interest (VOI) or Concern (VOC). The neutralizing capacity of a F(ab')2 preparation from sera of horses immunized with viral RBD was evaluated by lytic plaque reduction assay against different SARS-CoV-2 variants. A F(ab')2 preparation of a hyperimmune serum after nine immunizations with RBD exhibited a high titer of neutralizing antibodies against the ancestral-like strain (1/18,528). A reduction in the titer of the F(ab')2 preparation was observed against the different variants tested compared to the neutralizing activity against the ancestral-like strain. The highest reduction in the neutralization titer was observed for the Omicron VOC (4.7-fold), followed by the Mu VOI (2.6), Delta VOC (1.8-fold), and Gamma VOC (1.5). Even if a progressive reduction in the neutralizing antibodies titer against the different variants evaluated was observed, the serum still exhibited a neutralizing titer against the Mu VOI and the Omicron VOC (1/7113 and 1/3918, respectively), the evaluated strains most resistant to neutralization. Therefore, the preparation retained neutralizing activity against all the strains tested.
引发新冠疫情的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的受体结合域（RBD）是病毒刺突蛋白（S）的功能区域，参与病毒与靶细胞的附着。该病毒在其基因组中逐渐积累了突变，特别是在RBD区域，其中许多突变与宿主中和抗体的免疫逃逸有关。源于这种进化的一些病毒谱系已被分类为关注变异株（VOI）或受关注变异株（VOC）。通过针对不同SARS-CoV-2变异株的噬斑减少试验，评估了用病毒RBD免疫的马血清中F(ab')2制剂的中和能力。用RBD进行九次免疫后获得的超免疫血清的F(ab')2制剂对原始样毒株表现出高滴度的中和抗体（1/18,528）。与针对原始样毒株的中和活性相比，观察到F(ab')2制剂针对所测试的不同变异株的滴度降低。中和滴度降低最多的是奥密克戎VOC（4.7倍），其次是缪毒株VOI（2.6倍）、德尔塔VOC（1.8倍）和伽马VOC（1.5倍）。即使观察到针对所评估的不同变异株的中和抗体滴度逐渐降低，该血清对缪毒株VOI和奥密克戎VOC仍表现出中和滴度（分别为1/7113和1/3918），这两种评估毒株对中和最具抗性。因此，该制剂对所有测试毒株均保留了中和活性。
