| Abstract: | Three animal test systems, two in guinea-pigs and one in mice, have been examined to differentiate the ability of three BCG vaccines with respect to their ability to protect the animals against infection when challenged with virulent bacilli. One test system showed great promise and was examined in greater detail in order to explain the mechanism of protection. These studies are continuing in order to test a series of BCG vaccines that will be given to groups of children and their protective effect observed. |
