Specific sIgA antibodies against swine influenza virus H3N2 infection / 中国人兽共患病学报

To study different breed pigs reply the swine flu virus infections,specific antibody of sIgA secretion regularity of respiratory tract and the differences of sIgA antibody according to different antigen proteins were detected.A/swine/Nanjing/ 51/2010(H3N2) was intranasally infected pigs (1 × 107 TCID50/mL and 2 mL/pig),and then the nasal swab samples were collected at different time points within 21 days after infection.M1,NS1 and PB1 recombinant protein,respectively,were used to establish indirect ELISA method for detecting specific antibody of sIgA,and to analyze its secretion regularity.Results displayed that there was no significant difference among three kinds of recombinant protein in the whole test,characterizing by specificity sIgA antibody levels rising rapidly after 5 infection days and reaching peak at day 14,then began to decline.Among different varieties of pigs,sIgA antibody production of PB1 protein in Obama group was significantly higher than that in binary pigs at 14th and 21st day (P＜0.05).It had no significant difference between M1 group and the NS1 group (P＞0.05).This experiment preliminary explores the secretion regularity of specificity sIgA antibody after infected swine flu virus,which laid a foundation for further study of SIV mucosal antibody diagnostic reagents.

A novel M2e-multiple antigenic peptide providing heterologous protection in mice

Swine influenza viruses (SwIVs) cause considerable morbidity and mortality in domestic pigs, resulting in a significant economic burden. Moreover, pigs have been considered to be a possible mixing vessel in which novel strains loom. Here, we developed and evaluated a novel M2e-multiple antigenic peptide (M2e-MAP) as a supplemental antigen for inactivated H3N2 vaccine to provide cross-protection against two main subtypes of SwIVs, H1N1 and H3N2. The novel tetra-branched MAP was constructed by fusing four copies of M2e to one copy of foreign T helper cell epitopes. A high-yield reassortant H3N2 virus was generated by plasmid based reverse genetics. The efficacy of the novel H3N2 inactivated vaccines with or without M2e-MAP supplementation was evaluated in a mouse model. M2e-MAP conjugated vaccine induced strong antibody responses in mice. Complete protection against the heterologous swine H1N1 virus was observed in mice vaccinated with M2e-MAP combined vaccine. Moreover, this novel peptide confers protection against lethal challenge of A/Puerto Rico/8/34 (H1N1). Taken together, our results suggest the combined immunization of reassortant inactivated H3N2 vaccine and the novel M2e-MAP provided cross-protection against swine and human viruses and may serve as a promising approach for influenza vaccine development.

Protective effect of N-acetylcysteine on mice with acute lung injury in-duced by H9N2 swine influenza virus / 中国病理生理杂志

AIM:To investigate the effects of N-acetylcysteine (NAC) on acute lung injury induced by H9N2 swine influenza virus ( SIV) in mice.METHODS: BALB/c mice were used to establish the animal model of acute lung injury by nasal inoculation of H9N2 SIV.The mice were divided into control group (without SIV infection), H9N2 SIV group (inoculation of H9N2 SIV) and NAC group (inoculation of H9N2 SIV plus pretreatment with NAC).The pulmonary edema was evaluated by determining the lung wet weight /dry weight ( W/D) ratio.The pathological changes of the lung tis-sues were observed .The concontrations of TNF-α, IL-1βand IL-6 in bronchoalveolar lavage fluid ( BALF) were meas-ured.The virus titer, T-SOD activity, MPO activity and MDA content in the homogenate of the lung tissues were detected . RESULTS:Treatment with NAC decreased the morality of infected mice , and significantly prolonged the survival time of infected mice .The pathological changes of the lung tissues , the lung W/D ratio and the lung index were relieved when SIV infected the mice treated with NAC .Treatment with NAC significantly decreased the infiltration of inflammatory cells inclu-ding macrophages, lymphocytes and neutrophils in the BALF .The levels of TNF-α, IL-6, IL-1βand MDA and the activity of MPO were also decreased.Treatment with NAC also significantly increased the T-SOD activity.CONCLUSION: The protective effect of NAC on the acute lung injury mouse model is related to suppression of the oxidative stress and inflamma -tory responses .

Protective efficacy of a high-growth reassortant swine H3N2 inactivated vaccine constructed by reverse genetic manipulation

Novel reassortant H3N2 swine influenza viruses (SwIV) with the matrix gene from the 2009 H1N1 pandemic virus have been isolated in many countries as well as during outbreaks in multiple states in the United States, indicating that H3N2 SwIV might be a potential threat to public health. Since southern China is the world's largest producer of pigs, efficient vaccines should be developed to prevent pigs from acquiring H3N2 subtype SwIV infections, and thus limit the possibility of SwIV infection at agricultural fairs. In this study, a high-growth reassortant virus (GD/PR8) was generated by plasmid-based reverse genetics and tested as a candidate inactivated vaccine. The protective efficacy of this vaccine was evaluated in mice by challenging them with another H3N2 SwIV isolate [A/Swine/Heilongjiang/1/05 (H3N2) (HLJ/05)]. Prime and booster inoculation with GD/PR8 vaccine yielded high-titer serum hemagglutination inhibiting antibodies and IgG antibodies. Complete protection of mice against H3N2 SwIV was observed, with significantly reduced lung lesion and viral loads in vaccine-inoculated mice relative to mock-vaccinated controls. These results suggest that the GD/PR8 vaccine may serve as a promising candidate for rapid intervention of H3N2 SwIV outbreaks in China.

Isolation and Genetic Characterization of H1N2 Subtype of Influenza A Virus from Pigs in Korea

In order to investigate swine influenza virus (SIV) infection in South Korea, 180 nasal swabs from pigs with respiratory symptoms of 18 different farms were collected between November 2001 and February 2002. Of the 180 swabs, 52 were positive for SIV by a multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay. Positive samples were then subtyped by two multiplex RT-PCR assays, and 43 and 9 samples were found to be H1N2 and H3N2, respectively. SIV was isolated from the positive samples using embryonated chicken eggs. Two H1N2 isolates designated as A/Sw/ Korea/CY01/02 and A/Sw/Korea/CY02/02 were genetically characterized. Comparison of the nucleotide sequences between the two isolates showed 99.6% to 99.9% nucleotide identity of each gene segment. Pairwise sequence analysis of the hemagglutinin (HA)1 gene segments indicated that HA genes of the Korean isolates were more closely related to those of the US H1N2 isolates (94.5% to 97.9% amino acid identity) than those of the Japanese H1N2 isolates (82.4% to 93.7% amino acid identity). Amino acid sequences of the Korean isolate (A/Sw/Korea/CY02/02) showed high homology with the US H1N2 isolates; neuraminidase (NA) (97.4~99.2%), matrix (98.8~99.9%), nucleoprotein (97.6~ 98.0%), non-structural (96.8~98.6%), PA (97.9~98.7%), PB1 (98.3~99.6%) and PB2 (97.8~98.9%) genes.