In vitro effects of recombinant chicken interferon-gamma on immune cells.

We used the recombinant chicken interferon-gamma (ChIFN-gamma) to determine its in vitro effects on chicken immune cells. We found that ChIFN-gamma induced nitric oxide (NO) production, upregulated Ia expression on the cell surface, and inhibited the replication of Newcastle disease virus in NCSU and HD11 cells (chicken macrophage cell lines). In addition, ChIFN-gamma had an antiproliferative effect on RP9 cells, a chicken B cell line. Finally, ChIFN-gamma inhibited mitogenic proliferation of normal chicken spleen cells and induced the cells to generate NO. Inhibition of viral replication and mitogenic proliferation of normal cells were correlated with NO production. We conclude that recombinant chicken ChIFN-gamma modulates chicken immune cells.

Recombinant fowlpox viruses coexpressing chicken type I IFN and Newcastle disease virus HN and F genes: influence of IFN on protective efficacy and humoral responses of chickens following in ovo or post-hatch administration of recombinant viruses.

We have constructed recombinant (r) fowl pox viruses (FPVs) coexpressing chicken type I interferon (IFN) and/or hemagglutinin-neuraminidase (HN) and fusion (F) proteins of Newcastle disease virus (NDV). We administered rFPVs and FPV into embryonated chicken eggs at 17 days of embryonation or in chickens after hatch. Administration of FPV or rFPVs did not influence hatchability and survival of hatched chicks. In ovo or after hatch vaccination of chickens with the recombinant viruses resulted in protection against challenge with virulent FPV and NDV. Chickens vaccinated with FPV or FPV-NDV recombinant had significantly lower body weight 2 weeks following vaccination. This loss in body weight was not detected in chickens receiving FPV-IFN and FPV-NDV-IFN recombinants. Chickens vaccinated with FPV coexpressing IFN and NDV genes produced less antibodies against NDV in comparison with chickens vaccinated with FPV expressing NDV genes.

The safe and effective use of fowlpox virus as a vector for poultry vaccines.

The safety and efficacy of a fowlpox-Newcastle disease vaccine were evaluated by in vitro and in vivo methods. Genetic and phenotypic stability following cell culture and chick passage were demonstrated. The safety characteristics of the recombinant virus equalled or exceeded those of the parent fowlpox virus, as determined by lack of shed and spread to contacts, failure to revert to virulence following passage in chicks and innocuity in other avian species. The fowlpox-Newcastle Disease virus effectively immunized against virulent fowlpox challenge and virulent Newcastle disease challenge (intramuscular or intra-ocular administration). These results indicate that the recombinant FPV/NDV virus is a safe and effective vaccine for poultry.

Transcription termination within the Escherichia coli origin of DNA replication, oriC.

Initiation of DNA replication from the Escherichia coli origin, oriC, is dependent on an RNA polymerase-mediated transcription event. The function of this RNA synthetic event in initiation, however, remains obscure. Since control of the synthesis of this RNA could serve a key role in the overall initiation process, transcription regulatory sites within and near oriC were identified using the galK fusion vector system. Our results confirm the existence of a transcription termination signal within oriC, first identified by Hansen et al. (1981), for the 16 kd transcript that is transcribed counterclockwise towards oriC. Termination is shown to be 92% efficient. A similar approach led to the detection of transcription termination within the chromosomal replication origin of Klebsiella pneumoniae. Approximately 50% of the E. coli 16 kd transcripts appear to terminate before reaching oriC between the XhoI (+416 bp) and the HindIII (+243 bp) sites. The predominant 3' ends of RNA that enter oriC, as determined by SI nuclease mapping, were located at positions +20 +/- 2, +23 +/- 2, +37, +39, +52, +66, +92, and +107. These termination sites, which map cl to RNA . DNA junctions identified by Kohara et al. (1985), appear as triplets and quadruplets. The E. coli oriC Pori-L promoter described in in vitro transcription studies by Lother and Messer (1981) was not detected in this study in either wildtype cells or isogenic dnaA mutants at the nonpermissive temperature. A new promoter activity, Pori-R1, was identified within the E. coli origin in the clockwise direction.