Characterization of the endogenous retroviral envelope glycoproteins found in the sera of ev3 and ev6 chickens.

Chicken sera may contain components that immunologically crossreact with avian retroviral glycoprotein. Sera from chickens carrying the endogenous viral loci ev3 and ev6 contain glycoproteins with molecular weights of approx. 85 000, which on the basis of tryptic peptide analysis are related to exogenous viral glycoprotein. Such endogenous viral glycoproteins are present in a free form, lacking disulphide-bonded gp35.