H5N1 Avian Influenza Pre-pandemic Vaccine Strains in China

Objective To prepare the 4 candidate vaccine strains of H5N1 avian influenza virus isolated in China Methods Recombinant viruses were rescued using reverse genetics. Neuraminidase （NA） and hemagglutinin （HA） segments of the A/Xinjiang/1/2006, A/Guangxi/1/2009, A/Hubei/1/2010, and A/Guangdong/1/2011 viruses were amplified by RT-PCR. Multibasic amino acid cleavage site of HA was removed and ligated into the pCIpoll vector for virus rescue. The recombinant viruses were evaluated by trypsin dependent assays. Their embnjonate survival and antigenicity were compared with those of the respective wild-type viruses. Results The 4 recombinant viruses showed similar antigenicity compared with wild-type viruses, chicken embryo survival and trypsin-dependent characteristics. Conclusion The 4 recombinant viruses rescued using reverse genetics meet the criteria for classification of low pathogenic avian influenza strains, thus supporting the use of them for the development of seeds and production of pre-pandemic vaccines.

A Natural Vaccine Candidate Strain Against Cholera

E1 Tor Vibrio cholerae (EVC) strains may be classifled into two kinds-epidemigenic (EEVC) strains and non-epidemigenic (NEEVC) strains-based on a phage-biotyping system. A large number of EEVC strains have been screened for toxigenic and putative colonization attributes. One such naturally occurring strain (designated IEM 101) has been found which is devoid of genes encoding cholera toxin (CT), accessory cholera enterotoxin (ACE), zonula occludens toxin (ZOT), but possesses RS1 sequences and toxin-coregulated pilus A gene (tcpA) although tcpA is poorly expressed. It expresses type B pili but does not posses type C pili. It is an E1 Tor Ogawa strain and does not cause fluid accumulation in rabbit ileal loop tests. Active immunization of rabbits with strain IEM 101 elicited good protection against challenge with virulent strains of V cholerae O1. Oral administrationcaused no side effects in 15 human volunteers, colonized the gut for four to ten days and elicited good immune responses

Effect of Attenuated Highly Pathogenic Pig Reproductive and Respiratory Syndrome(HP-PRRS) TJM-F92 Strain Vaccine on Immune Antibody Levels against Classical Swine Fever(CSF) and Foot-and-Mouth Disease(FMD)

Effects of attenuated highly pathogenic pig reproductive and respiratory syndrome（HP-PRRS）TJM-F92 strain vaccine on immune antibody level against classical swine fever（CSF）and foot-and-mouth disease（FMD）were studied from October 8 to November 12 in 2014,in order to optimize vaccination program of CSF,HP-PRRS and FMD and to provide scientific guidance for animal disease control and prevention work.The results showed that attenuated HP-PRRS（TJMF92 strain）vaccine had no significant effect on immune antibody level of hog cholera lapinized virus（HCLV,ST passage cell vaccine）attenuated vaccine and FMD-O inactivated vaccines（OZK/93 strain）,and single or combined use of three vaccines received good immunization effects.

Antibody Dynamic Changes in SPF Chickens and SPF Ducks Immuned with Recombinant Avian Influenza Virus H5 Subtype Bivalent Inactivated Vaccine

To study the immune effect of recombinant avian influenza virus H5 subtype bivalent inactivated vaccine （ HSN1, Re-6 strain ＋ Re-4 strain） and to provide the basis for formulating reasonable immune procedure of avian influenza vaccine in clinical practice. A total of 12 batches of vaccines from three companies were used for the iannune of SPF chickens and SPF ducks. Each chicken or duck serum was separately collected every 3 weeks until the immunization up to the 24^th week. The serum antibody titers of Re-6 and Re-4 were detected. The results showed that the HI titers of the inoculated SPF chickens and SPF ducks roached the peak when the immune time were the 6^th and 3^rd week after the first immunization respectively; then the titer decreased gradually as time prolonged; the highest titer of SPF chickens was greater than that of SPF ducks; the high titer duration of SPF chickens were longer than that of SPF ducks ; and all the vaccines from the three companies showed a good immune effect.

Protection of SA14-14-2 live attenuated Japanese encephalitis vaccine against the wild-type JE viruses

Objective To explore on the immunity of live attenuated Japanese Encephalitis (JE) vaccine (SA14-14-2) to different wild JE virus (JEV) strains.Methods The neutralizing effect of the vaccine against different wild JE virus strains was detected by plaque reduction neutralization test ( PRNT), and the immunogenicity was studied on mice by vaccination - challenge protection test. In the PRNT , pooled sera from vaccinated human were tested against 10 strains of JEV , one isolated in Taiwan and 9 from other Asian countries. In the vaccination challenge test, mice received one dose of the live vaccine subcutaneously and were challenged intraperitoneally 14 days later against 22 JEV virus strains, 11 were isolated in China and the other 11 from Tailand, Vietnahailam, Indonesia, India, Philippines and Japan.Results The protection rates to all the 22 challenge virus were 90% -100% when 340 PFU/0.1 ml vaccinate virus was administered. The neutralizing effect showed that all the JEV isolates many have neutralized by the sera.Conclusion SA14-14-2 live attenuated prepared with strain SA14-14-2 is broadly immunogenic and mav have effective protection against in Asian JE affected countries.