Primate Monocytes - CD14, CD16 - Ziegler-Heitbrock

A model system in haematology and immunology: the human monocytic cell line Mono-Mac-1

Abstract

MONO MAC 1 is a human cell line with properties of blood monocytes, which can be used as a model system to study monocytic functions in vitro. In the present study, we prepared a karyotype of MONO MAC 1, analysed the growth behaviour, determined the presence of differentiation associated antigens and studied the expression and secretion of several cytokines upon stimulation with 12 O tetradecanoyl phorbol 13 acetate (TPA) and lipopolysaccharide (LPS). The MONO MAC 1 cells have a near diploid karyotype and contain several recurrent chromosomal rearrangements, in particular the translocation (9;11) commonly found in AML M5. Stimulation with TPA or LPS induced changes in morphology and gene expression, especially an increase in the level of the differentiation marker CD14 and the production of monocyte related cytokines. Both biomodulators alone were sufficient to promote TNF alpha release; however, the combination of TPA and LPS resulted in a synergistic increase of TNF alpha secretion. Northern blot analysis indicated that upregulated production of TNF alpha was due to induced synthesis of mRNA. The mRNA accumulation peaked approximately 2 h after stimulation and maximum levels of TNF alpha were found in the supernatants after 4 8 h of culture. The MONO MAC 1 cells could not be restimulated with the same inducer to release TNF alpha when a 48 h pre treatment was carried out with LPS or TPA. LPS induced the release of granulocyte colony stimulating factor (G CSF), while TPA failed to do so. Vice versa, secretion of macrophage CSF (M CSF) could be induced by TPA, but not by LPS. However, LPS enhanced the TPA induced M CSF production. Similarly, incubation of MONO MAC 1, simultaneously with TPA and LPS, led to granulocyte macrophage CSF (GM CSF) and interleukin 1 beta (IL 1 beta)secretion, while both stimulators alone had almost no (TPA) or only a weak (LPS) effect on the secretion of GM CSF and IL 1 beta. Our results demonstrate that MONO MAC 1 is a unique cell line with distinct monocytic features; certain monocytic properties can be upregulated by activation of intracellular signalling pathway(s). We suggest that, besides the LPS receptor CD14, activation of PKC participates in these process, especially in the production and secretion of cytokines by MONO MAC 1 cells. (C) 1997 Elsevier Science Ltd.