Antiviral protein linked to depressed mood in mice

The flu and other viral infections have long been known to cause mood changes, beyond the more familiar symptoms of fever and sore throat. A study in mice now reveals how the antiviral immune response alters brain activity. Upon infection, brain cells lining blood vessels produce a protein called CXCL10, which impairs neuronal firing in the hippocampus — a brain region important in learning, memory, and mood.