Genetic characterization of bovine viral diarrhea virus strains in Beijing, China and innate immune responses of peripheral blood mononuclear cells in persistently infected dairy cattle

Abstract

To acquire epidemiological data on the bovine viral diarrhea virus (BVDV) and identify cattle persistently infected (PI) with this virus, 4,327 samples from Holstein dairy cows were screened over a four-year period in Beijing, China. Eighteen BVD viruses were isolated, 12 from PI cattle. Based on genetic analysis of their 5'-untranslated region (5'-UTR), the 18 isolates were assigned to subgenotype BVDV-1m, 1a, 1d, 1q, and 1b. To investigate the innate immune responses in the peripheral-blood mononuclear cells of PI cattle, the expression of Toll-like receptors (TLRs), RIG-I-like receptors, interferon-α (IFN-α), IFN-β, myxovirus (influenza virus) resistance 1 (MX1), and interferon stimulatory gene 15 (ISG15) was assessed by qPCR. When compared with healthy cattle, the expression of TLR-7, IFN-α, and IFN-β mRNA was downregulated, but the expression of MX1 and ISG-15 mRNA was upregulated in PI cattle. Immunoblotting analysis revealed that the expression of interferon regulatory factor 3 (IRF-3) and IRF-7 was lower in PI cattle than in healthy cattle. Thus, BVDV-1m and 1a are the predominant subgenotypes in the Beijing region, and the strains are highly divergent. Our findings also suggest that the TLR-7/IRF-7 signaling pathway plays a role in evasion of host restriction by BVDV.

Genetic Diversity of Bovine Pestiviruses Detected in Backyard Cattle Farms Between 2014 and 2019 in Henan Province, China

“…Subsequent reports revealed that Pestivirus A−1m is emerging in most of provinces and is considered to be a predominant Pestivirus A genotype in herds (27,30,50,54,57), and also detected in Henan province and neighbor province (29). In addition, sequences of Pestivirus A−1m strains in different regions showed highnucleotide homology, indicating that these strains share the same origin (27,49). Recently, other surveys on goats uncovered that the Pestivirus A−1m could infect goats naturally and cause diarrhea (58).…”

Heterogeneity of <i>Pestivirus</i> Species in Asia

“…Among BVDV-1b genotype, only two BVDV-b1 have been reported in cattle (Zhang et al, unpublished) [2], while the large majority (n = 41) were BVDV-1b2, 13 in cattle, 27 in yaks [2] and one in a Bactrian camel (Camelus bactrianus) [31]. Four bovine strains (Gao et al, unpublished) [6] belonged to genotype BVDV-1.3. Two other bovine strains (S133 and TY05), reported as M [7] [8] resulted BVDV-1.6.…”

“…The geographic distribution of genotypes varied considerably, and in certain countries as China, over the half of the 23 genotypes described in the species, 12 could be identified: BVDV-1a, 1b1 and 1b2, 1.3, 1.6, 1.7, 1.8, 1.10, 1.11, 1.15, 1.18, 1.21 and 1.23. BVDV-1a (n = 4) was reported in two bovines [6], two Bactrian camels [31] and one pig [32]. Despite belonging to the same BVDV-1a genotype, strains NH01 (bovine) and SH1060 (pig) were low related, showing 89.2% homology and a divergence of 11 bp in the IRES.…”

Immune Responses in Mice Immunized with Mastitis Multiple Vaccines Using Different Adjuvants

“…Immune system is the major contributor to host defense against infection and maintaining heath, which consists of immune organs, immunocytes and immune molecules [19,32]. The thymus, one of the most important immune organ, is the location of T-cell development where bone marrow-derived progenitors differentiate to become mature thymocytes before emigration into the periphery as new T cells [14].…”