Killing of measles virus-infected cells by human cytotoxic T cells.

Lymphocytes from normal individuals were tested for the capacity to generate measles virus-specific cytotoxic T-cell responses after in vitro stimulation with measles virus. Approximately 12% (5 of 40) of the normal adults tested produced significant cytotoxic responses. The cytotoxic response was measles virus specific both at the level of stimulation and at the effector level. Studies of the specificity of cytotoxic effectors from five normal donors by direct lysis or cold target inhibition or both indicated that most, if not all, of the virus-specific activity was self-specific. A detailed analysis of one donor (W6) indicated that measles-specific cytotoxicity was largely HLA-A and -B restricted; unexplained cross-reactive lysis was observed with some targets, but this lysis appeared to be HLA related, since all of the targets expressed HLA-B12. An analysis of the cellular requirements for the production of measles-immune cytotoxic T lymphocytes demonstrated that T cells and macrophages (depleted of natural killer and K cells) were sufficient for the generation of killer cells. Most of the cytotoxic effector activity was mediated by OKT3+ OKT4- OKT8+ cells.