Vincent, Dickson, Rich, and Alan review the 100 year old finding by Peyton Rous of a transmissible sarcoma of chickens, a discovery that ushered in the era of tumor virology.

Vincent, Rich, Alan and Gabriel review the production of antibodies by B cells, and how high affinity antibodies are selected in the germinal centers of lymph nodes.

Vincent and Rich visit the Microbiology and Immunology Department at the University of Michigan Medical School, and speak with Alice and Kathy about their work on HIV genome dimerization, and packaging and pathogenesis of mouse adenovirus.