I know that endotoxin (at levels 10-100 Eu/mL) in protein samples would not affect /stimulate purified T cells, but will stimulate PBMC. However, if people activate antigen-specific T cells with irradiated PBMC which generally act as antigen presenting cells, would a medium level of endotoxin (10-100 Eu/mL) also activate the irradiated PBMC to bring in unwanted background ?
Try this article
Immunosuppressive effects of radiation on human dendritic cells: reduced IL-12 production on activation and impairment of naïve T-cell priming
Thanks ! It reads like irradiation would impair the activation of DC by LPS
Please see below
CELLULAR IMMUNOLOGY AND IMMUNE REGULATION: Triggering of Dendritic Cell Responses after Exposure to Activated, but Not Resting, Apoptotic PBMCs Ulrika Johansson, Lilian Walther-Jallow, Anna Smed-Sörensen, and Anna-Lena Spetz
J Immunol 2007 179:1711-1720; doi:10.4049/jimmunol.179.3.1711
Abstract
Dendritic cells (DCs) can be activated by signaling via pathogen receptors, by interaction with activated T cells or by exposure to inflammatory mediators. Clearance of apoptotic cells by DCs is generally considered a silent event that is not associated with an inflammatory response. Necrotic cell death, in contrast, leads to induction of inflammation. However, emerging data challenge the view of apoptotic cells as inherently nonimmunogenic. In this study, we report that the activation state of the apoptotic cell may determine whether the exposed DC becomes activated and rendered proficient in Ag presentation. We show that coculture with activated, but not resting, apoptotic PBMCs leads to up-regulation of surface expression of the costimulatory molecules CD80, CD83, and CD86 in human DCs as well as release of proinflammatory cytokines. Furthermore, we show that DCs exposed to allogeneic, activated apoptotic PBMCs induce proliferation and IFN-γ production in autologous T cells. Together, these findings show that activated apoptotic PBMCs per se provide an activation/maturation signal to DCs, suggesting that activated apoptotic PBMCs possess endogenous adjuvant properties
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