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Spontaneous human lymphocyte‐mediated cytotoxicity against tumor target cells. V. The role of serum‐derived heterologous membrane antigens
Author(s) -
Pross Hugh F.,
Luk Samuel S.,
Baines Malcolm G.
Publication year - 1978
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.2910210307
Subject(s) - cytotoxicity , antigen , lymphocyte , biology , k562 cells , immunology , heterologous , microbiology and biotechnology , leukemia , in vitro , biochemistry , gene
The effect of serum on the K562 assay for spontaneous human lymphocyte‐mediated cytotoxicity (SLMC) was examined systematically at the level of the assay system and with respect to the serum used for the long‐term maintenance of the K562 target cells. It was found that the assay did not require the presence of serum, but all sera tested increased the level of cytotoxicity observed. Lymphocyte and target cell preparation in serum‐free medium led to a high non‐specific cell loss which could be avoided by substituting 5% human serum albumin for fetal calf serum. With this serum‐free assay, the effect of long‐term culture of K562 in 5% human serum was examined. High SLMC by normal donors was obtained in spite of the fact that the target cells had been cultured in human serum. This occurred even when the serum used for long‐term culture was autologous to the lymphocyte donor, and as long as the experiment was continued (10 months). The relative cytotoxicity of each donor relative to the other two tested in this series of experiments was similar for each of the K562 sources tested, and every time that the experiment was performed. Persistence of susceptibility to cytotoxicity after 10 months of culture in 5% human serum, partial sensitivity to pronase and trypsin, and resistance to neuraminidase, all indicated that the antigen recognized by the effector cells in this assay is distinct from the heterologous membrane antigen described by Irie et al. (1974 a, b ). The ability of lymphocytes to lyse target cells cultured in serum autologous to the lymphocyte donor indicated that SLMC is not mediated by lymphocyte recognition of serum‐derived antigens or serum‐derived mitogenic factors. The “recovery” of the SLMC susceptibility of pronase or trypsin‐treated target cells in serum‐free medium also suggests that the K562‐SLMC “antigen” is intrinsic to the K562 target cell and is independent of the serum used to culture these cells.