Immunosuppression Induced by Avian Leukosis and Sarcoma Virus

Avian Leukosis/Sarcoma Viruses (ALSVs) belong to the genus Alpha retrovirus of family Retroviridae. ALSVs that occur in chickens have been divided into 6 envelope subgroups (A–E and J) based on the differences in their viral envelope glycoproteins. ALSV infections usually induce several kinds of neoplasm of infected hosts which lead to severe morbidity and mortality. Most importantly, hosts infected with ALSVs often develop immunosuppression, similar as Acquired Immunodeficiency Syndrome (AIDS) caused by Human Immunodeficiency Virus (HIV) in human. Immunosuppression can be induced by different subgroups of ALSVs in different mechanisms. Some possiblemechanisms were reviewed in this short paper.