Induction of cytotoxic CD8+CD56+ T cells from human thymocytes by interleukin-15.
CD8(+) CD56(+) cells isolated from human peripheral blood lymphocytes have been shown recently to represent a population of cytotoxic active T cells. However, it is not known if these cells are intrathymically or extrathymically developed or how these cells are influenced by growth factors. In the present study, we investigated the effects of interleukin-2 (IL-2) and IL-15 on human thymocytes with respect to development of CD8(+) CD56(+) T cells. Freshly isolated thymocytes contain few CD8(+) CD56(+) cells, but the number of these cells increases significantly when thymocytes are grown in the presence of IL-15 or IL-2. However, IL-15 induced a significantly higher fraction of CD8(+) CD56(+) cells compared with IL-2. Thus, although IL-2 and IL-15 are known to have a number of redundant functions, we here demonstrate that IL-15 is superior to IL-2 in inducing CD8(+) CD56(+) T cells from cultures of thymocytes. The majority of the IL-15-grown CD8(+) CD56(+) cells were CD45R0(+), representing a memory phenotype, and showed high expression of the IL-15R-complex and high numbers of CD69(+) cells. Moreover, cytotoxic activity was confined to this cell population.
Thulesen
S
S
Institute of Medical Anatomy, Department A, Institute of Medical Microbiology and Immunology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark. s.thulesen@mai.ku.dk
Nissen
M H
MH
Ødum
N
N
Röpke
C
C
D001769:Blood / Q000276:immunology; D019002:CD56 Antigen / Q000032:analysis*; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D006801:Humans; D007156:Immunologic Memory; D016130:Immunophenotyping; D018664:Interleukin-12 / Q000494:pharmacology; D019409:Interleukin-15 / Q000494:pharmacology*; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D016176:T-Lymphocyte Subsets / Q000145:classification; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*
D019002:CD56 Antigen; C508024:IL15RA protein, human; D019409:Interleukin-15; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2; D018664:Interleukin-12