Submitted to: Avian Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 22, 1999
Publication Date: N/A
Interpretive Summary: Some chickens, as humans and other animals, have been shown to possess a form of viruses (endogenous viruses) that can be inherited in their hereditary material (DNA). If endogenous viruses are inherited and expressed they render chickens susceptible to infection by similar viruses that commonly exist in poultry houses that are known to decrease production of eggs or meat, and to cause development of tumors. We recently developed a blood-typing antiserum (R2) in chickens that will detect the expression of endogenous viruses on blood cells. This manuscript describes the utilization of the R2 antiserum in a way that allows the identification of a critical part of the expressed endogenous virus in blood plasma. This method permits relatively easy identification of expression of endogenous virus in experimental lines of chickens, and the assay was shown to be effective in commercial egg producing and broiler chickens. The assay may prove useful to commercial poultry breeders as a method to identify and reduce the presence or expression of unwanted endogenous viruses.
Technical Abstract: The resolution of genes determining resistance to disease is described regarding chicken lines developed and/or maintained at the Avian Disease and Oncology Laboratory (ADOL). This description includes a summary of: (1) existing selected and inbred lines differing for resistance to viral induced tumors, i.e. Marek's disease (MD) and lymphoid leukosis (LL), and of the use of inbred and line crosses to define relevant disease resistance genes; e.g. TV, ALVE, B, R, LY4, TH1, BU1 and IGG1; (2) the development of TVB*/ALVE congenic lines to establish the affects of endogenous virus expression on resistance to avian leukosis virus (ALV), and methods to detect ALVE expression; (3) the development of B congenic lines for defining the influence of the major histocompatibility complex (MHC) on MD resistance and vaccinal immunity, for producing B antisera, and for evaluating DNA sequences of class I and II genes; and (4) the current development of 6C.7 recombinant congenic strains (RCS) to define the role of non-MHC genes influencing susceptibility to MD and LL tumors, immune competence and epistatic effects of genes. The procedures of pedigree mating to avoid or maintain inbreeding, and of blood-typing to assure genetic purity of the lines are also described.