Immunohistochemical localization of avian leukosis virus subgroup J in tissues from naturally infected chickens

The tissue tropism of avian leukosis virus (ALV) subgroup J (ALV-J) was investigated in congenitally infected broiler chickens by an immunohistochemistry technique detecting gp85 viral glycoprotein. All organs examined contained detectable antigen. The most intense staining was in the adrenal gland, heart, kidney, and proventriculus. Intense staining for viral antigen in the heart may explain the ability of ALVs to cause cardiomyopathy. Although recent investigations failed to demonstrate specific viral staining in bone marrow from infected chickens, we were able to show moderate staining in myelocytic precursor cells in bone marrow. This finding agrees with previous work showing cell cultures of bone marrow are susceptible to ALV-J infection and the tendency of subgroup J to predominantly induce myeloid rather than lymphoid neoplasms.