Description: Segment 1 Allison begins the lecture by outlining different kinds of immunity - innate and acquired. He refers specifically to immunity to polio, which is not innate in humans, but is in some monkey species, for example. Allison shows a table listing different immune responses of the body when fighting infection. He refers to immunodeficiency and shows a table listing the results of an experiment to artifically creat immunodeficiency in animals. Time start: 00:00:00:00 Time end: 00:06:18:08 Length: 00:06:18:08 Segment 2 Allison continues to discuss immunodeficiency. He refers to the research of professor Soothill which looks in detail at natural immunodeficiencies. He uses tables and charts to lay out the complex differences in different types of immunodeficiency, comparing in particular the differences between defective immunoglobulin levels and cell-mediated immunity. Time start: 00:06:18:08 Time end: 00:11:53:20 Length: 00:05:35:12 Segment 3 Allison moves on to discuss in detail what happens when antibodies and cells rise up against virus infections. He refers to a series of diagrams to illustrate his points. He discusses, in particular, the role of phagocytosis (foreign cell digestion). Time start: 00:11:53:20 Time end: 00:15:16:00 Length: 00:03:22:05 Segment 4 Allison turns to discuss the role of phagocytosis in the body's fight against bacterial, rather than viral, infections. He admits that the process by which both viral and bacterial infections are inactivated in cells is largely unknown he discusses several possible hypotheses which attempt to explain this. Time start: 00:15:16:00 Time end: 00:21:37:00 Length: 00:06:21:00 Segment 6 Allison discusses other virus types, each of which are attacked by the body's immune system in a different way. He shows a series of photomicrographs which compare infections in the cells of a normal and an immunosuppressed mouse. He concludes the lecture with a brief discussion of the specific role of T-lymphocytes. Time start: 00:27:12:00 Time end: 00:32:18:07 Length: 00:05:06:07