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Isolation of Human Monocytes by Double Gradient Centrifugation and Their Differentiation to Macrophages in Teflon-coated Cell Culture Bags
Published on: September 9, 2014
HTLV-1-infected cells drive the differentiation of monocytes into macrophages in vitro
Sabrina de Souza1, Guilherme Affonso Melo2, Carolina Calôba2
1Laboratório de Imunologia Básica e Aplicada, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, CEP 21941- 590, Brazil.
Background:
The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HAM/TSP is a chronic inflammatory neurodegenerative disease characterized by leukocyte infiltration in the spinal cord. T-lymphocytes are the most important targets of HTLV-1 infection, but monocytes are also infected. Monocytes from HTLV-1-infected individuals exhibit important functional differences compared to cells from uninfected donors. Here, we investigated the effects of cell-cell physical contact and/or secreted factors of HTLV-1-infected cells in monocyte activation and differentiation.
Methods:
The THP-1 human monocytic cell line was co-cultured with a human cell line transformed by HTLV-1 (MT-2) for 6 days. To determine the effects of co-culturing HTLV-1-infected cells in THP-1 monocytes cells were characterized by flow cytometry, immunofluorescence microscopy, and real-time PCR. Computational analysis of published transcriptomic datasets was realized to compare molecular profiles of macrophages and mononuclear cells from HTLV-1 carriers.
Results:
Co-culture of monocytes with HTLV-1-infected cells induced macrophage differentiation and upregulation of typical macrophages-associated molecules (HLA-DR, CD80, and CD86), increased cytokine (TNFα, IL-6, and IL-1β) levels and their coding genes expression. Consistently, published transcriptomic datasets showed changes in important genes associated with inflammation during HAM/TSP in patients. The presence of HTLV-1-infected cells in the culture also induced significant upregulation of Interferon Stimulated Genes (ISG), indicating viral infection. Monocyte activation and differentiation into pro-inflammatory macrophages occurred in a cell-to-cell contact-independent manner, suggesting the role of factors secreted by infected cells.
Conclusions:
Together, our results indicated that HTLV-1-infected cells induced monocyte differentiation into macrophages inflammatory, predominantly.
