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Precursor frequency analysis of human cytolytic T lymphocytes directed against autologous melanoma cells
Author(s) -
Coulie Pierre G.,
Somville Michel,
Lehmann Frédéric,
Hainaut Philippe,
Brasseur Francis,
Devos René,
Boon Thierry
Publication year - 1992
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910500220
Subject(s) - ctl* , peripheral blood mononuclear cell , cytotoxic t cell , k562 cells , immunology , melanoma , t lymphocyte , biology , cytolysis , microbiology and biotechnology , interleukin 2 , lytic cycle , antigen , cancer research , in vitro , cytokine , cd8 , leukemia , biochemistry , virus
Limiting numbers of peripheral‐blood mononuclear cells (PBMC) from melanoma patients were stimulated with irradiated autologous tumor cells in the presence of interleukins‐2 and −4 and in the absence of feeder cells. The responder cells were restimulated every week. After 2 to 4 weeks, the micro‐ cultures were tested for their lytic activity against the autologous tumor cells. Significant lysis of the tumor cells was observed with a fraction of these microcultures, whereas no lysis was observed with control microcultures seeded without stimulator melanoma cells. Because our aim was to measure the precursor frequency of CTL showing specificity for the tumor, and not that of NK‐like effectors that were also capable of lysing the melanoma cells, we used cold‐target inhibition with an excess of NK target K562 to inhibit the NK‐like activity. Microcultures whose lysis on the tumor cells was not abolished by K562 competition were observed. The specificity of these CTL clones was confirmed by the absence of lytic activity on autologous T‐cell blasts. The numbers of microcultures with anti‐tumor CTL activity fitted the zero‐order of the Poisson distribution equation, indicating that they resulted from the activity of single T‐cell clones. The frequency of anti‐tumor CTL precursor cells (CTL‐P) of 7 melanoma patients ranged from 1/900 to 1/33,000. Frequencies of anti‐tumoral CTL‐P were higher and NK‐like effectors were less frequent when sorted CDS + T lymphocytes were used as responder cells.