Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 1991 Aug;182(5):449-64.
doi: 10.1016/S0171-2985(11)80209-3.

IL-4 Decreases the Expression of the Monocyte Differentiation Marker CD14, Paralleled by an Increasing Accessory Potency

Comparative Study

IL-4 Decreases the Expression of the Monocyte Differentiation Marker CD14, Paralleled by an Increasing Accessory Potency

J Ruppert et al. Immunobiology. .


IL-4 has been found to affect the phenotype and a variety of functions of human monocytes and macrophages and has been discussed as a monocyte activating protein along with other cytokines, such as IL-1 and IL-6. In this study we compared the effects of the cytokines IL-1, IL-6, IL-4, and a combination of IL-1 and IL-6 on the expression of the CD14 antigen, the FcIIIg receptor molecule CD16 and the MHC-class II molecules HLA-DR and HLA-DP. These molecules represent characteristic monocyte surface markers. Furthermore, the CD14 molecule has been described as a surface antigen of high in vivo relevance representing an indirect receptor for LPS. We further analyzed the effect of IL-4 on monocytes and macrophages with respect to their accessory function to initiate T-lymphocyte proliferation. Human peripheral blood monocytes strongly express the antigen CD14 and maintain it as a stable surface molecule during their differentiation to macrophages. Flow cytometry analysis of cultured monocytes demonstrated that cells incubated in the presence of IL-4, but not IL-1 and/or IL-6 revealed a reduced expression of the CD14 antigen in a dose- and time-dependent manner. After 3 days IL-4 treated cells were virtually CD14-negative. At the same time the expression of the CD16 antigen (FcRIIIg) was also strongly reduced, whereas the treatment with IL-4 led to an increased expression of MHC class II antigens such as HLA-DR and HLA-DP. The spontaneous low expression of HLA-DQ antigen on monocytes was not affected by any of the cytokines. Functionally, IL-4 treated CD14-negative monocytes exhibited a more than 2-fold higher activity to stimulate an accessory cell-dependent T cell proliferation. This was found in a mitogenic assay and in MLC when compared to monocytes cultured in the absence of IL-4. These observations provide further evidence that IL-4 is a major modulator of monocyte surface antigen expression. Moreover, IL-4 has an enhancer-effect on monocytes as accessory cells and therefore may be of considerable importance as a regulatory factor during monocyte development to accessory cells. Inasmuch as the CD14 molecule functions as a receptor for LPS-binding protein, our results suggest that IL-4 might also play an important regulatory role in processes initiated by bacterial lipopolysaccharides during inflammation and sepsis.

Similar articles

See all similar articles

Cited by 15 articles

See all "Cited by" articles

Publication types

MeSH terms

LinkOut - more resources