Exocytic responses of single leukaemic human cytotoxic T lymphocytes stimulated by agents that bypass the T cell receptor

摘要: Cytotoxic T lymphocytes kill targets via secretion of lytic agents including perforin and granzymes. Recently, new methods have been developed to monitor cytotoxic lymphocyte degranulation. These include detecting the appearance lysosome-associated membrane protein on cell's surface, monitoring decreases in cellular content. We combined these with microscopy flow cytometry provide first analysis how single cells degranulate. used TALL-104 human leukaemic as a model system, stimulated them thapsigargin PMA, soluble that mimic two major signalling pathways activated by cell receptor cross-linking. Our results indicate essentially every responds maximal stimulation releasing about half its granule complement. This reflects complete release contents granules, rather than partial all granules. Sub-maximal reduces both fraction respond magnitude responses. find individual variable latency, evidence that, once it starts, degranulation is slow process taking tens minutes.