DEVELOPMENT OF AN ALLOANTISERUM (R2) THAT DETECTS SUSCEPTIBILITY OF CHICKENS TO SUBGROUP-E ENDOGENOUS AVIAN-LEUKOSIS VIRUS

An alloantiserum, termed R2, specifically agglutinates red blood cells (RBC) from line 100B chickens that are susceptible to avian leukosis viruses (ALV) belonging to subgroups B and E, but does not agglutinate RBC from congenic inbred line 7(2) chickens that are resistant to ALV B and E. The R2 antigen was also detected on lymphocytes and thromboc ytes. Using chickens from a special cross, it was found that R2 reacti vity requires that the chickens must: (1) be susceptible to infection by ALV-E; and (2) express a viral envelope gene with subgroup E specif icity. With R2 antiserum, a nearly perfect association was observed be tween agglutination and susceptibility to ALV-B in Fa chickens contain ing endogenous viral genes ev2 and/or ev3. These results support earli er evidence that ALV-B and ALV-E share receptors. Moreover, the R2 ant iserum was shown to neutralize ALV-E. The R2 antigen showed Mendelian segregation in chickens of a commercial White Leghorn strain-cross con taining ev3, ev6 and ev9. However; commercial chickens with or without the R2 antigen did not differ in susceptibility to lymphoid leukosis induction or immune response on infection with ALV of subgroup A for c omplex reasons we discuss.