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Human serum was shown to contain a cytolytic factor coupled to an inhibitor. The lytic factor could be released by antibody specific to structures on the surface of human tumor cells. This factor could also be dissociated from its inhibitor by dialysis and obtained in a relatively pure state following electrophoresis. It then displayed a lytic effect on 4 established cell strains of human origin.
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Bertil Björklund (1960) studied this question.
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