Isolation and Characterization of 2019-nCoV-like Coronavirus from Malayan Pangolins

The outbreak of 2019-nCoV in the central Chinese city of Wuhan at the end of 2019 poses unprecedent public health challenges to both China and the rest world1. The new coronavirus shares high sequence identity to SARS-CoV and a newly identified bat coronavirus2. While bats may be the reservoir host for various coronaviruses, whether 2019-nCoV has other hosts is still ambiguous. In this study, one coronavirus isolated from Malayan pangolins showed 100%, 98.2%, 96.7% and 90.4% amino acid identity with 2019-nCoV in the E, M, N and S genes, respectively. In particular, the receptor-binding domain of the S protein of the Pangolin-CoV is virtually identical to that of 2019-nCoV, with one amino acid difference. Comparison of available genomes suggests 2019-nCoV might have originated from the recombination of a Pangolin-CoV-like virus with a Bat-CoV-RaTG13-like virus. Infected pangolins showed clinical signs and histopathological changes, and the circulating antibodies reacted with the S protein of 2019-nCoV. The isolation of a coronavirus that is highly related to 2019-nCoV in the pangolins suggests that these animals have the potential to act as the intermediate host of 2019-nCoV. The newly identified coronavirus in the most-trafficked mammal could represent a continuous threat to public health if wildlife trade is not effectively controlled.

Immune effects of a precocious line of Eimeria necatrix with different doses and at different immunization times.

This study was designed to assess the immune protective effects of the vaccine strain of a precocious line of Eimeria necatrix with different doses and at different immunization times. The immunizations had a negative effect on weight gains of chickens to a certain degree but could be compensated during the "compensatory growth period" after immunity was established in the chickens. The number of oocysts excreted was positively correlated with the immunization dose. All the immunized chickens, whether they were immunized once or twice or immunized with different doses of sporulated oocysts, were able to resist attack from 1x105 virulent sporulated oocysts of E. necatrix. The lesion scoring showed that no significant difference existed in the chicken groups immunized with different doses (300 and 600) of sporulated oocysts. However, a difference existed in the immune homogeneity established in the different immunized groups, and two artificial immunizations were superior to one artificial immunization, indicating that two could extend the duration of oocyst excretion and allow more chances for the immunized chickens to become repeatedly infected.

Immune effects of a precocious line of Eimeria necatrix with different doses and at different immunization times

This study was designed to assess the immune protective effects of the vaccine strain of a precocious line of Eimeria necatrix with different doses and at different immunization times. The immunizations had a negative effect on weight gains of chickens to a certain degree but could be compensated during the “compensatory growth period” after immunity was established in the chickens. The number of oocysts excreted was positively correlated with the immunization dose. All the immunized chickens, whether they were immunized once or twice or immunized with different doses of sporulated oocysts, were able to resist attack from 1x105 virulent sporulated oocysts of E. necatrix. The lesion scoring showed that no significant difference existed in the chicken groups immunized with different doses (300 and 600) of sporulated oocysts. However, a difference existed in the immune homogeneity established in the different immunized groups, and two artificial immunizations were superior to one artificial immunization, indicating that two could extend the duration of oocyst excretion and allow more chances for the immunized chickens to become repeatedly infected.

Evolution of porcine reproductive and respiratory syndrome virus GP5 and GP3 genes under swIFN-ß immune pressure and interferon regulatory factor-3 activation suppressed by GP5.

In this study, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) strain, PRRSV GD07 was continuously propagated in MARC-145 cell cultures primed with swIFN-ß for 50 passages to develop the PRRSV GDßfn strains. And a control strain PRRSV GDfn was passaged without swIFN-ß. The sequencing analysis indicated that under swIFN-ß immune pressure, molecular variation of PRRSV GP5 was accelerated in gene (NS/S>2.50), and the acceleration of GP3 was not significant (NS/S<2.50). swIFN-ß mRNA level induced by Poly(I:C) is lower in cells primed with PRRSV GDßfn than in cells without PRRSV GDfn, although both of them are much less than the control group. Effect of GP5 on IRF3 was analyzed by SDS-PAGE and western-blot. Our results indicated that GP5 protein prevents IRF3 phosphorylation. Therefore, we conclude that swIFN can promote viral mutation in GP5, and, in turn GP5 inhibits IRF3 activation to escape from swIFN-ß.