Host Innate Immune Responses of Ducks Infected with Newcastle Disease Viruses of Different Pathogenicities

Abstract

Though previous studies have identified two strains of duck-origin Newcastle disease virus (NDV) with varying levels of pathogenicity, the relationship between the early-phase host innate immune response, and pathogenesis of ducks infected with these strains in the lungs and thymuses remains unclear. In this study, we compared the viral distribution and mRNA expression of immune-related genes in ducks following infection with two NDV strains, Duck/CH/GD/SS/10 (SS-10) and Duck/CH/GD/NH/10 (NH-10). Both NDV strains replicated systemically in tested tissues (i.e., small intestine, cecal tonsils, brain, lung, bursa of Fabricius, thymus, and spleen) and exhibited different biological properties in duck pathogenicity. Real-time quantitative polymerase chain reaction showed that the expression of TLR3, TLR7, RIG-I, MDA5, IL-1β, IL-2, IL-6, IL-8, IFN-alpha, IFN-beta, IFN-gamma in the lungs was significantly greater than in the respective thymus genes during the early post infection stage. However, in the lungs, the expression of TLR3, TLR7, IL-1β, IL-2, IL-8, IFN-alpha, IFN-gamma, and MHC II induced by SS-10 at 72 h post-inoculation (hpi) was less than with NH-10. Furthermore, the expression of IL-6 and IFN-beta in the lungs and thymuses following infection with SS-10 was greater than that with NH-10 at 24 and 48 hpi. These results highlight important differences in host innate immune responses, courses of infection, and pathogenesis following NDV infection. Further studies should work to expand understandings of the molecular mechanisms related to NDV infection.

Pathobiology of Avian avulavirus 1: special focus on waterfowl

“…Furthermore, the higher expression level of TLR3, TLR7, IL-1β, IL-2, IL-8, IFN-α, IFN-γ and MHC II were induced by NH-10 than SS-10 in the lungs. Whereas, the expression of the IL-6 and IFN-β in lung as well as thymus was higher for SS-10 group [7]. Similarly, a study of the Zhong et al [49] has demonstrated the upregulation of the viperin (an IFN stimulated gene) in the DEFs and also in the spleen, kidneys, liver, brain, and blood of Changbai ducks infected with G7 APMV-1 through intranasal or intramuscular route.…”

“…A key reason for less susceptibility of waterfowl to APMV-1 is the presence of retinoic acid-inducible gene I (RIG-I). RIG-I is absent in the chicken [33] whereas it is present in ducks and goose ( Figure 1) [7,34]. RIG-I and melanoma differentiationassociated gene 5 (MDA5) are the foremost part of retinoic acid inducible gene-like receptors (RLRs) (Figure 1), which senses the cytoplasmic RNA [35].…”

“…Our viewpoint supports the group of scientists, which claims that birds should be vaccinated. Because, it had already been established that APMV-1 cause the disease in waterfowl [7,46,49,52] and vaccination prevent the chances of the outbreak. Second most important reason is the prolonged virus shedding by non-vaccinated birds, which may transfer to other poultry species and cause heavy economic losses.…”

“…Structural proteins include nucleoprotein (NP), matrix (M), fusion (F), hemagglutinin-neuraminidase (HN), phosphoprotein (P) and large RNA-dependent RNA-polymerase (L). The RNA editing of the P gene can result in the expression of V and W only in the virus infected cells [7][8][9][10]. Virulence of APMV-1 varies and depends upon the host species, and chicken and turkey are more susceptible than ducks and geese.…”

Phylogenetic and Pathotypic Characterization of Newcastle Disease Viruses Circulating in South China and Transmission in Different Birds

“…A total of 214 swab samples were collected in 1.5 mL centrifuge tubes containing 1.0 mL transport medium (50% glycerol in phosphate-buffered saline [PBS]) with antibiotics (penicillin, 2000 U/mL; amphotericin B, 2000 U/mL; streptomycin, 2 mg/mL) and shipped to South China Agricultural University. The oropharyngeal and cloacal swab samples were inoculated in 10-days-old specific-pathogen-free (SPF) embryonated chicken eggs, as previously described (Kang et al, 2015 ). A hemagglutination (HA)-inhibition (HI) test was conducted using four HA units of the isolates and virus purification performed, as described by Office International Des Epizooties (OIE; OIE, 2012 ).…”