Gamma-irradiated peripheral blood mononuclear cells can express LAK activity.
Peripheral blood mononuclear cells (PBMC) irradiated with high dose gamma-radiation (1000-5000 rad) are commonly used as feeder cells during the cloning of T lymphocytes, natural killer (NK) and lymphokine activated killer (LAK) cells. We report here that such gamma-irradiated PBMC can be stimulated with interleukin 2 (IL-2) to express the ability to lyse a variety of tumor cell targets. The non-major histocompatibility complex (MHC) restricted cytotoxicity demonstrated by irradiated PBMC is, however, lower than that expressed by their non-irradiated counterparts. The numbers of viable, gamma-irradiated LAK cells are significantly increased by the addition of the mitogen, phytohemagglutinin (PHA). Purification of the gamma-irradiated cells expressing cytotoxic activity by flow cytometry determined that the effector cells were predominantly CD3- cells, although some CD3+ cells also expressed moderate LAK activity. The ability of gamma-irradiated cells to proliferate in the presence of PHA alone, or with IL-2 + PHA, was maximal at day 4-5; but proliferation, as detected by 3H-thymidine uptake, was not detectable beyond 12-15 days of in vitro culture. Because many of the LAK, T cell and NK cell cloning procedures require the presence of feeder layers, growth factors (usually IL-2) and mitogens, the presence of residual feeder cells expressing cytotoxic activity may affect the specificity of such clones. Thus, efforts should be made to ensure that such gamma-radiation-resistant cells capable of expressing cytotoxic activity are completely eliminated before the cloned cells are used for further experiments.
Chong
A S
AS
Department of General Surgery, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois.
Bier
D E
DE
Grimes
W J
WJ
Hersh
E M
EM
D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D005720:Gamma Rays; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D015979:Killer Cells, Lymphokine-Activated / Q000166:cytology / Q000502:physiology / Q000528:radiation effects*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D010641:Phenotype; D011836:Radiation Tolerance
D007376:Interleukin-2