Characteristics of the Interaction in Vitro Between Cytotoxic Thymus‐Derived Lymphocytes and Target Monolayers Infected with Lymphocytic Choriomeningitis Virus

Abstract

Cell‐mediated lysis of target monolayers intccted with lymphocytic choriomeningitis virus has previously been shown to be a property of specifically sensitized thymus‐derived lymphocytes (T cells). The cytotoxic potential of individual effector lymphocytes is maximally expressed when infected monolayers are confluent and overlaying immune spleen cells cover less than the total target area. The data presented support the following interpretations [l] Cell‐mediated injury depends on close association between sensitized T cells and infected L cells. [2] Any attachment made is readily reversible. [3] Effector lymphocytes may damage more than one target cell, operating, perhaps, in a rather circumscribed area. [4] Cell death is a ‘one hit’ phenomenon. [5] Cytolysis is a property of individual T cells, there being no obvious requirement for co‐operation between different populations of spleen cells, [6] Substances secreted into the medium at large are neither directly cytotoxic nor capable of sensitizing normal spleen cells. [7] Specific lysis occurs at temperatures ranging from 27°C to 40°C, being maximal at the higher temperature