Activation of inflammatory cells and cytokines by peptide epitopes in vitro: a simple in-vitro screening assay for prioritizing them for in-vivo studies

Abstract

Antigen-specific immune modulation is an attractive approach to atherosclerosis treatment. The aim of this study was to develop an in-vitro assay to screen peptide molecules for their inflammatory propensity. Human dendritic cells derived from CD14(+) monocytes were activated using peptides derived from apolipoprotein B100 (ApoB), heat shock protein 60 (HSP60) and complement cascade (peptide A) in vitro, and used for priming autologous T cells. Proliferation of T cells, their differentiation to regulatory cells (Treg) and their cytokine profile were studied. The efficacy of the peptides in preventing atherosclerosis was studied in ApoB(tm2Sgy)/Ldlr(tm1Her/J) knockout mice. ApoB and HSP60 peptides induced T-cell proliferation and expansion of regulatory T cells with interleukin-10 and transforming growth factor-β secretion. In comparison, peptide A was a poor stimulator of T cells and was found to induce tumor necrosis factor-α secretion by activated T cells. ApoB and HSP60 peptides were found to reduce early atherosclerotic lesion formation in mice by 32.1 and 33.5%, respectively, while the reduction with peptide A was 5.7%. Thus the in-vitro assay shows an apparent correlation with in-vivo activity and can be developed as a screening assay to prioritize the candidate molecules for animal efficacy testing.