Detection of avian leukosis virus subgroups in albumen of commercial and native fowl eggs using RT-PCR in Iran

Abstract

Avian leukosis viruses (ALVs) belong to Alpharetrovirus genus of the family Retroviridae that are widespread in nature. Different subgroups of ALV commonly infect egg-laying hens. They are responsible for economic losses due to both mortality and depressed performance in chickens. To investigate the presence of these viruses in chickens in Iran, 560 egg albumens were selected from different farms of Fars province, Iran. These eggs were obtained from flocks of two research centers of native fowl production (60 eggs), a broiler grandparent farm (100 eggs), three broiler breeder farms (300 eggs), and a commercial layer flock (100 eggs). Firstly, for primary screening a degenerative primer set (PU1 and PU2) were used in reverse transcriptase-polymerase chain reaction (RT-PCR). Positive cases were detected in 47 of 300 (15.7%) samples from three broiler breeders, 40 of 100 (40%) samples from commercial layer, 53 of 60 (88.3%) samples from flocks of two research centers of native fowl production, and none from the samples of broiler grandparent. Then RT-PCR was undertaken with primers PA1 and PA2 on the positive samples. RT-PCR analysis detected ALVs in two of 47 (4.3%) samples from three broiler breeders, 13 of 40 (32.5%) samples from commercial layer, and 19 of 53 (35.8%) samples from flocks of two research centers of native fowl production. The sequencing results showed that subgroup E of ALV was the most detected virus among chicken eggs and subgroup B was more prevalent in the eggs of native fowls. This is the first report of the ALV subgroup B and E in egg albumen in Iran.

Identification of a novel B-cell epitope specific for avian leukosis virus subgroup J gp85 protein

“…Currently, there are many methods used to diagnose ALV infection, such as IFA, detection of the group-specific antigen p27 using antigen-capture ELISA, reverse transcription PCR and viral isolation [39][40][41][42][43]. To the best of our knowledge, there is no ELISA method to detect an ALV-J antigen.…”

Preparation of a novel monoclonal antibody against Avian leukosis virus subgroup J Gp85 protein and identification of its epitope

“…The gp85 gene of ALV determines the properties of the antibody neutralization and becomes one of the main references to classify the ALV subgroups ( Payne and Nair, 2012 ). Currently, there are some specific diagnosis methods for the ALV subgroups, such as RT-PCR, ELISA, and IFA, which were set up according to the ALV-J gp85 gene or protein sequence in clinical detection ( Rajabzadeh et al., 2010 ; Liu et al., 2018 ; Zhang et al., 2019b ). In this study, two prokaryotic expression plasmids pET28a-ALV-J- gp85 (His-tag) and pGEX-6P-1-ALV-J- gp85 (GST-tag) were constructed containing the ALV-J gp85 gene.…”

Development and characterization of monoclonal antibodies to subgroup A avian leukosis virus

“…Many methods have been developed for the diagnosis of ALV infections, including detection of viral group specific antigen (gsa) p27 by the antigen‐capture ELISA (AC‐ELISA), IFA, virus isolation and reverse transcription polymerase chain reaction (RT‐PCR) . In China, a few large poultry breeders are trying to establish exogenous ALV free poultry flocks, which were evaluated by ELISA detection.…”