Protective effects of E. coli Nissle 1917 on chickens infected with Salmonella pullorum.

The probiotic E. coli Nissle 1917 (EcN) plays an important role in regulating the microbial components of the gut and preventing inflammation of the gastrointestinal tract. Currently, the long-term use of antibiotics for the treatment of lethal white diarrhea in chicks caused by Salmonella has led to increased morbidity and mutation rates.

Protection against genotype VII Newcastle disease virus challenge by a minicircle DNA vaccine coexpressing F protein and chicken IL-18 adjuvant.

Genotype VII Newcastle disease virus (NDV) is still one of the most important virus threats severely affecting poultry production worldwide. Although inactivated vaccines are commercially available, there is still an urgent need to develop novel vaccine candidates for convenient and affordable vaccine application. Oral immunization using live attenuated bacteria such as Salmonella has recently attracted increasing interest, and in a previous study, we used a regulated delayed lysis Salmonella vector to deliver a DNA vaccine encoding the F protein and chicken IL-18 adjuvant together, named pYL23.

In Vivo Production of HN Protein Increases the Protection Rates of a Minicircle DNA Vaccine against Genotype VII Newcastle Disease Virus.

The Cre-recombinase mediated in vivo minicircle DNA vaccine platform (CRIM) provided a novel option to replace a traditional DNA vaccine. To further improve the immune response of our CRIM vaccine, we designed a dual promoter expression plasmid named pYL87 which could synthesize short HN protein under a prokaryotic in vivo promoter P and full length HN protein of genotype VII Newcastle disease virus (NDV) under the previous eukaryotic CMV promoter at the same time. Making use of the self-lysed strain as a delivery vesicle, chickens immunized with the pYL87 construction showed an increased serum haemagglutination inhibition antibody response, as well as an increased cell proliferation level and cellular IL-4 and IL-18 cytokines, compared with the previous CRIM vector pYL47.