Feather pulp organ cultures for assessing host resistance to infection with avian leukosis‐sarcoma viruses

Abstract

The purpose of this study was to improve in vitro procedures for detecting cellular resistance to the avian leukosis-sarcoma group of viruses. Four feather pulp organ cultures (FPOC) were prepared from each chicken by placing pulp squeezed from feathers in wells of microtitre plates that contained culture medium. Two of the four FPOC were inoculated with Rous sarcoma virus (RSV) of subgroup A and 5 to 6 days later the fluids from all four cultures were assayed for virus by inoculating chicken embryo fibroblasts (CEF) and examining for development of foci of transformed cells. Prior to the second assay of culture fluids, quail cells transformed by envelope-defective RSV [R(-)Q cells] were added to some RSV-inoculated and uninoculated FPOC. The R(-)Q cells produce infectious RSV when infected with avian leukosis virus (ALV), and hence made it possible to detect ALV in FPOC. Status of host infection was also assessed by tests for virus neutralising antibody and the enzyme-linked immunosorbent assay for group specific viral antigen. In one experiment FPOC from chickens not exposed to ALV were susceptible to RSV throughout the 140-day test period. In contrast, FPOC from ALV-inoculated chickens were usually infected with ALV and were resistant to RSV. FPOC from chickens reared in contact with the inoculated group for 121 days were free of ALV and were unexpectedly resistant to RSV. Two other experiments supported the observation that genetically susceptible chickens acquire cellular resistance to RSV as a result of persistent or transient ALV-infection. In Cornell K strain chickens there was close agreement between cellular susceptibility based on tests on FPOC prepared prior to inoculation of chickens with ALV and for antibody following inoculation with ALV. A New Hampshire strain showed a high degree of genetic cellular resistance by these test procedures.

Novel applications of feather tip extracts from MDV-infected chickens; diagnosis of commercial broilers, whole genome separation by PFGE and synchronic mucosal infection

“…While MDV is relatively stable in dry feather dust, retroviruses are unstable outside the bird and require a direct contact with biological material from an infected bird. For that reason the indirect transmission of ALV by air was considered relatively unimportant, although ALV‐A was detected in and even cultivated from the feather pulp and FFE [18,19]. Recent observations of commercial flocks revealed that ALV‐J spread horizontally and vertically to a greater extent than ALV‐A.…”

Diverse uses of feathers with emphasis on diagnosis of avian viral infections and vaccine virus monitoring

“…While MDV is relatively stable in dry feather dust, retroviruses are unstable outside the bird and require mostly a direct contact with biological material of an infected bird. For that reason the transmission of retroviruses by air is not trivial and was considered relatively unimportant, although avian leucosis virus, subgroup A (ALV-A) was detected, and even cultivated from the feather pulp and FFE (Spencer et al, 1983;1987). The feather pulp was also suitable for the development of an ELISA test to detect the group-specific antigens (Korec et al, 1984).…”

The feather tips of commercial chickens are a favorable source of DNA for the amplification of Marek's disease virus and avian leukosis virus, subgroup J

“…While MDV is relatively stable in dry feather dust, retroviruses are unstable outside the bird and require mostly a direct contact with biological material from an infected bird. For that reason, the indirect transmission of ALV by air was considered relatively unimportant, although ALV-A was detected in, and even cultivated from, the feather pulp and FFE (Spencer et al, 1983(Spencer et al, , 1987. Recent observations of commercial flocks revealed that ALV-J spread horizontally and vertically to a greater extent than ALV-A.…”