Bioassays for the detection of a cytokine that enhances the development of cytolytic T lymphocytes.
Interleukin 2 (IL-2) is an important growth factor for cytolytic T lymphocytes (CTL). Other factors here termed cytolytic differentiation factor(s) (CDF) may be required for CTL responses, but it has been difficult to identify suitable bioassays. We report a polyclonal assay in which lytic activity develops after 2 days of culture with lectin and lymphokines. CDF is required for the development of Thy-1+, CD8+, CD4- CTL in this assay. The responsive T cells are thymocytes from certain strains of mice (A, Swiss NCS, B6.H-2k) or peripheral T cells cultured in the presence of high doses of hydrocortisone acetate. If these precautions are taken, little or no lytic activity develops in the presence of rIL-2 alone. CDF is present in the media of mitogen-stimulated mouse spleen or human blood mononuclear cells, but not in the conditioned media of a number of mouse and human cell lines. It is immunologically distinct from IL-2, but only acts in concert with IL-2 to induce CTL. A large panel of available mouse and human cytokines do not synergize with Il-2 in the bioassay. These include interferons, colony-stimulating factors, lymphotoxin/tumor necrosis factor, and IL-1, -3, and -4. Therefore a distinct CDF(s) seems essential for the induction of at least some CTL. The assays described here should be useful in purifying the molecule responsible for this biological activity.
Cernetti
C
C
Rockefeller University, New York, New York 10021.
Steinman
R M
RM
Granelli-Piperno
A
A
D000818:Animals; D001681:Biological Assay; D001688:Biological Products / Q000032:analysis* / Q000096:biosynthesis / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D016207:Cytokines; D004357:Drug Synergism; D005260:Female; D006854:Hydrocortisone / Q000494:pharmacology; D007376:Interleukin-2 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D008811:Mice, Inbred DBA / Q000276:immunology; D011994:Recombinant Proteins / Q000494:pharmacology; D013154:Spleen / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects*; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology*
D001688:Biological Products; D016207:Cytokines; D007376:Interleukin-2; D011994:Recombinant Proteins; D006854:Hydrocortisone