Design of a predicted MHC restricted short peptide immunodiagnostic and vaccine candidate for Fowl adenovirus C in chicken infection.

Fowl adenoviruses (FAdVs) are the ethiologic agents of multiple pathologies in chicken. There are five different species of FAdVs grouped as FAdV-A, FAdV-B, FAdV-C, FAdV-D, and FAdV-E. It is of interest to develop immunodiagnostics and vaccine candidate for Peruvian FAdV-C in chicken infection using MHC restricted short peptide candidates. We sequenced the complete genome of one FAdV strain isolated from a chicken of a local farm. A total of 44 protein coding genes were identified in each genome. We sequenced twelve Cobb chicken MHC alleles from animals of different farms in the central coast of Peru, and subsequently determined three optimal human MHC-I and four optimal human MHC-II substitute alleles for MHC-peptide prediction. The potential MHC restricted short peptide epitope-like candidates were predicted using human specific (with determined suitable chicken substitutes) NetMHC MHC-peptide prediction model with web server features from all the FAdV genomes available. FAdV specific peptides with calculated binding values to known substituted chicken MHC-I and MHC-II were further filtered for diagnostics and potential vaccine epitopes. Promiscuity to the 3/4 optimal human MHC-I/II alleles and conservation among the available FAdV genomes was considered in this analysis. The localization on the surface of the protein was considered for class II predicted peptides. Thus, a set of class I and class II specific peptides from FAdV were reported in this study. Hence, a multiepitopic protein was built with these peptides, and subsequently tested to confirm the production of specific antibodies in chicken.

Naturally Occurring ß-Nicotinamide Adenine Dinucleotide-Independent Avibacterium paragallinarum Isolate in Peru.

The ß-nicotinamide adenine dinucleotide (NAD) requirement has been considered to be essential for the isolation of the causal agent of infectious coryza, Avibacterium paragallinarum. Nevertheless, NAD-independent reports from South Africa and Mexico dismissed this paradigm. It is now accepted that both NAD-dependent and NAD-independent agents are able to cause infectious coryza and thus belong to the species A. paragallinarum. Here, we report for the first time in Peru a NAD-independent isolate from broiler chickens with typical signs of infectious coryza that have received a trivalent inactivated vaccine against infectious coryza. The isolate was identified based on its morphology, biochemical and serologic tests, and PCR results. Partial 16S rRNA gene sequence analysis confirmed the isolate as A. paragallinarum. There have been no cases of NAD-independent A. paragallinarum isolates reported in South America. Increasing reports around the world highlight not only the need to reconsider the in vitro nutritional requirements of this species for its correct isolation but also the cross-protection conferred by commercial infectious coryza vaccines against NAD-independent isolates.

An evaluation of serotyping of Avibacterium paragallinarum by use of a multiplex polymerase chain reaction.

In the present study, the ability of a recently proposed multiplex polymerase chain reaction (mPCR) to determine the serogroups (A, B, and C) of Avibacterium paragallinarum was evaluated. A total of 12 reference strains and 69 field isolates of Av. paragallinarum from Ecuador, Mexico, Panama, and Peru were included in the study. With some exceptions (which were serotyped in the current study), all of the isolates and strains had been previously examined by 2 serotyping schemes (Page and Kume) or were the formal reference strains for the schemes. Three of 6 (50%) reference strains of serogroup A, 2 (100%) of serogroup B, and 1 of 4 (25%) reference strains of serogroup C were correctly serotyped by the mPCR. With the field isolates, the mPCR correctly recognized 16 of the 17 serogroup A isolates, 10 of the 12 serogroup B isolates, and 18 of the 37 serogroup C isolates. Overall, the specificity and sensitivity of the PCR test was as follows: 82.6% and 87.3% (serogroup A), 85.7% and 71.9% (serogroup B), and 46.3% and 100% (serogroup C). The poor performance of the mPCR in terms of recognition of serogroup C isolates (low sensitivity of 46.3%) and the relatively high level of uncertainty about the accuracy of the serogroup A and B results (specificity of 87.3% and 71.9%, respectively) means that the assay cannot be recommended as a replacement for conventional serotyping.