Phenotypic non‐equivalence of murine (monocyte‐) macrophage cells in biomaterial and inflammatory models

Abstract

Cells of the mononuclear phagocytic system including monocytes and macrophages (e.g., pooled human monocytes, bone marrow-derived macrophages, etc.) are often employed for in vitro assessment of novel biomaterials and to assay anti-inflammatory drug activity. In this context, numerous macrophage cells are treated interchangeably in the literature despite a lack of demonstrated equivalence among immortalized cell lines and further, between cell lines and primary-derived macrophages of different species. Three murine (monocyte-) macrophage cell lines (IC-21, J774A.1, and RAW 264.7), commonly utilizedin biomaterial and pharmaceutical screening research, have been compared with primary-derived murine bone marrow macrophages. Significant differences were discovered in the expression of cell surface proteins requisite for cell adhesion and activation among cell lines and primary-derived cells as well as between the different cell lines. Results demonstrate activation but with reduced cytokine expression to chemical stimulus (lipopolysaccharide) by cell lines compared with that of primary-derived macrophages. Limited correlation between cultured primary and immortalized cells in cytokine production, phenotype and intrinsic activation states has relevance to fidelity for in vitro testing. These differences warrant justification for selection of various cell lines for specific assay purposes, and merit caution if comparisons to primary cell types (i.e., for biocompatibility) are required.

Reduced immune cell responses on nano and submicron rough titanium

“…The down-regulated pro-inflammation cytokine release by macrophages found in the present study was also consistent with a prior study [19] which showed that macrophage movement was restricted on nanostructured titanium compared to flat titanium surfaces and nanostructured titanium elicited the secretion of fewer pro-inflammatory enzyme molecules and cytokines. Despite the wide use of cell lines as a model for primary macrophages in the present study and many other prior studies, it also has to be noted that there are sufficient differences between the two [10,20,21] and results from cell lines need careful interpretation to address the phenotypic biology of primary macrophages. Thus, validating the findings from this study with primary macrophages, and most importantly, with in vivo studies, is necessary in the future.…”

“…Despite differences between this cell line and the primary peripheral bold monocyte (PBM), a prior study supports the use of THP-1 for biocompatibility tests and found that the secretory activity of PBMs was generally well represented by THP-1s [10]. Thus, the human THP-1 monocyte cell line (TIB-202; ATCC; passage numbers between 2 and 5) was used in this study.…”

A macrophage/fibroblast co-culture system using a cell migration chamber to study inflammatory effects of biomaterials

“…Furthermore, these THP-1-derived macrophages can be further differentiated in a proinflammatory M1 phenotype by lipopolysaccharide (LPS) stimulation [7]. Since experimental models applying only one cell type can only identify a limited set of pro-inflammatory signals [16,17], cell co-culture systems involving two or more types of cells have been employed to mimic more accurately the complexity of the in vivo inflammatory situation [11,18,19]. So far, different in vitro macrophage/fibroblast co-culture models have been used to study inflammatory reactions [18,20,21].…”

Human and Animal Isolates of Yersinia enterocolitica Show Significant Serotype-Specific Colonization and Host-Specific Immune Defense Properties

“…To examine whether the amount and profile of released cytokines vary between macrophages of different host species, we used Luminex cytokine analysis technology to determine the cytokine levels in supernatants of infected porcine and murine bone marrow-derived macrophages (BMDMs). BMDMs were used because a significantly reduced intrinsic activation state and low cytokine expression levels for lipopolysaccharides were observed with macrophage cell lines (IC-21, J774A.1, and Raw264.7) compared with primary macrophages (42). Secretion of several murine and porcine cytokines (TNF-␣, macrophage inflammatory protein 2 [MIP-2]/IL-8, IL-1␤, IL-4, IL-6, IL-12, alpha interferon [IFN-␣], IFN-␥, and IL-10) were tested.…”