Seneca Valley virus induces immunodepressionin suckling piglets by selective apoptosis of B lymphocytes

• Published in: Microbial pathogenesis 2021-09, Vol.158, p.105022-105022, Article 105022
• Main Authors: Oliveira, Thalita Evani Silva de, Leme, Raquel Arruda, Agnol, Alais Maria Dall, Gerez, Juliana Rubira, Pelaquim, Isadora Fernanda, Miyabe, Flavia Megumi, Alfieri, Alice Fernandes, Alfieri, Amauri Alcindo, Headley, Selwyn Arlington
• Format: Article
• Language: English
• Subjects: Apoptosis; Immunohistochemistry; Immunosuppression; Picornavirus; Senecavirus A; Swine disease
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2021.105022

Seneca Valley virus (SVV) is the causative agent of an emerging infectious vesicular disease in swine that is clinically indistinguishable from other vesicular diseases of swine. This study utilized healthy suckling piglets (control) and SVV-naturally infected suckling piglets to determine the effects of SVV on lymphoid tissues and determined the SVV RNA load by quantitative RT-PCR (qRT-PCR). Furthermore, immunohistochemistry (IHC) analyses were performed to quantify the expression of T and B cell lymphocytes, natural killer cells, cleaved caspase 3, and ki-67. The main histopathologic finding in the infected group was severe lymphoid depletion. The highest average of SVV RNA load by qRT-PCR (Log10 genomic copies/g of tissue) occurred at the spleen (8.54 ± 0.8), followed by the tonsils (8.04 ± 1.42), and mesenteric lymph nodes (6.90 ± 1.42). The IHC analyses revealed that there was an increased in cellular apoptosis with concomitant reduction in the proliferation of B cells. The results from this study have demonstrated that SVV-infected piglets exhibited decreased lymphocyte density probably due to lymphoid apoptosis, affecting particularly B-cells lymphocytes. •Seneca Valley virus (SVV) induces lymphocytic density reduction and immunodepression in piglets•SVV replicates efficiently in piglet tonsils, mesenteric lymph nodes and spleen.•SVV induces selective apoptosis of B lymphocytes of suckling piglets