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MUTZ‐3, a monocytic model cell line for interleukin‐4 and lipopolysaccharide studies
Author(s) -
QUENTMEIER H.,
DUSCHL A.,
HU Z.B.,
SCHNARR B.,
ZABORSKI M.,
DREXLER H. G.
Publication year - 1996
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.1996.d01-780.x
Subject(s) - cd14 , cell culture , microbiology and biotechnology , monocyte , biology , lipopolysaccharide , receptor , interleukin 1 receptor , interleukin , cytokine , flow cytometry , endocrinology , immunology , biochemistry , genetics
The human monocytic cell lines MUTZ‐3 and MONO‐MAC‐6 express the lipopolysaccharide (LPS) receptor CD14. Paralleling the situation in peripheral blood monocytes (PBMo), recombinant human interleukin‐4 (IL‐4) down‐regulated the expression of CD14 on the cell surface of MUTZ‐3, but not that of MONO‐MAC‐6 cells. In addition, preincubation with IL‐4 prevented the LPS‐induced up‐regulation of IL‐1β mRNA levels in MUTZ‐3, but not in MONO‐MAC‐6 cells. We examined whether the differential responsiveness of the cell lines was due to the missing expression of the IL‐4 receptor (IL‐4R) α or γ c chain in MONO‐MAC‐6 cells. Flow cytometric and immunoprecipitation analysis revealed expression of both IL‐4R chains in both cell lines. In addition, short‐term stimulation with IL‐4 induced tyrosine‐phosphorylation of the γ c chain. As both cell lines also expressed signal transducer and activator of transcription 6 (STAT 6), our data suggested that the differential reaction patterns of MUTZ‐3 and MONO‐MAC‐6 cells were not due to a generally defective IL‐4R complex. Interestingly, long‐term (48 hr) treatment with LPS rendered MONO‐MAC‐6 cells sensitive to IL‐4. LPS up‐regulated expression of monocyte‐specific esterase (MSE) mRNA as well as CD14 protein in MONO‐MAC‐6 cells; both effects were inhibited by IL‐4. This stimulation was not paralleled by an increase of IL‐4R mRNA or protein expression supporting the above hypothesis of a constitutively present and active IL‐4R. We discuss possible causes for the differential reaction patterns of MUTZ‐3 and MONO‐MAC‐6 cells to IL‐4.