Cytotoxicity of isolated plasma membranes from lymph node cells.

Abstract

DESTRUCTION of certain other cells on contact is a specialised capability of some cells of the lymphoid system. Our recent study has indicated that the actual lysis results from osmotic effects1, but the biochemical process which precedes this step is unknown2. If the effector cells are killed before they come into contact with the target cells, cytotoxicity is abolished2. Once contact of effector cells and target cells is established, however, killing of the effector cells with specific antibody and complement does not interrupt the lysis of target cells, which continues to completion3,4. These observations suggest that viable lymphocytes are required to establish the correct type of contact with target cells (probably because lymphocyte motility is involved2,5,6), but that once effective contact has occurred lymphocyte viability is no longer necessary. Since contact of plasma membranes of lymphocytes with those of target cells is required for the lytic process2, we have examined the possibility that the plasma membranes of lymphoid cells themselves have cytolytic capacity. This interpretation would be consistent with our previous report7 that subcellular sedimentable fractions from livers of mice infected with Mycobacterium tuberculosis (BCG), and heavily infiltrated with mononuclear cells, are lytic for tumour cells.