Description: Segment 1 Dr Ian Gilliland introduces Dr Ian MacLennan. MacLennan talks to camera, introducing the subject of how the immune system brings about the destruction of foreign cells. He describes some of the clinical situations in which this kind of destruction might occur. He refers to previous studies in depth which aimed to isolate different instances of foreign cell destruction. Time start: 00:00:00:00 Time end: 00:05:29:00 Length: 00:05:29:00 Segment 2 MacLennan continues to discuss previous research studies in the area of foreign cell destruction by the immune system. He refers to diagrams which attempt to illustrate what happens when this kind of destruction occurs. He speaks in detail about a 1965 study by Werner Muller in Stockholm in which Muller attempted to provoke cell killing through the use of artificially inseminated antibodies. Time start: 00:05:29:00 Time end: 00:11:37:00 Length: 00:06:08:00 Segment 3 The role of antibodies in cell killing is discussed further. MacLennan then introduces different ways of quantitating cytotoxic cells. He shows a graph which displays normal levels of cytotoxic cells in the blood then shows what happens when chromium is released from a target cell, thus inducing cell killing. Levels of cytotoxic cells in the blood on certain long-term medications are then shown in a graph. Time start: 00:11:37:00 Time end: 00:17:21:00 Length: 00:05:44:00 Segment 4 MacLennan shows a graph which details levels of cytotoxic cells in different lymphoid populations. He refers to an experiment on rats' spleens following thoracic duct drainage to alter the levels of cytotoxic cells in their blood. He describes the results of this experiment in depth. Time start: 00:17:21:00 Time end: 00:22:08:00 Length: 00:04:47:00 Segment 6 MacLennan discusses further the earlier experiment on rats' spleens. He also talks about IgG in detail and analyses the role of this immune hormone on the body. Time start: 00:33:39:00 Time end: 00:39:54:00 Length: 00:06:15:00. Segment 7 MacLennan talks in further detail about IgG and shows a table listing different sub-classes of IgG. He ends the lecture by saying what a difficult subject it is to analyse and offering hints to further researchers. Time start: 00:39:54:00 Time end: 00:45:06:03 Length: 00:05:12:03