Suppression of human lymphocyte proliferation and cytotoxic T lymphocyte generation by a soluble factor derived from K562 cells.
The human myeloid leukemia cell line, K562, secrets a lymphocyte growth-suppressive factor (LGSF). We report our investigation of the immunological and chemical features of this factor. LGSF showed no cytolytic effect on human peripheral blood mononuclear cells (PBMC). Nevertheless, LGSF adequately suppressed in vitro alloantigen- or mitogen (PHA, ConA, PWM)-stimulated human PBMC proliferation and alloantigen-induced cytotoxic T lymphocyte generation, in antigen-nonspecific and LGSF concentration-related manners. LGSF retained activity after filtration through a 0.22 microm filter membrane and storage at -80 degrees C for 6 months. Ultrafiltration experiments indicated that suppressive activity was retained in the higher molecular weight fraction (MW > 100,000) and that the activity was heat-labile at 56 degrees C for 30 min. These results strongly suggested that LGSF is a noncytotoxically immunosuppressive substance with a high molecular weight.
Hayamizu
K
K
The Second Department of Surgery, Hiroshima University School of Medicine, Hiroshima, Japan.
Yahata
H
H
Fukuda
Y
Y
Dohi
K
K
D006801:Humans; D020014:K562 Cells; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D008934:Mitogens; D012016:Reference Values; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D025521:Tumor Suppressor Proteins / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology
D008934:Mitogens; D025521:Tumor Suppressor Proteins