Document Type

Student Research Paper

Date

Spring 2022

Academic Department

Biology

Faculty Advisor(s)

Dr. Jodi Lancaster

Abstract

Activation of dendritic cells (DCs) through toll-like receptor (TLR) agonists causes release of cytokines. DC2.4 cells are immature murine DCs derived from the bone marrow that express TLRs, including TLR3. The response of DC2.4 cells to varying doses and times of the TLR3 agonist, poly(I:C), was evaluated. In contrast to previously studied MuTu DCs, DC2.4 cells produced little to no interleukin-12 (IL-12) after 12-hour exposure to doses from 0.1-100 µg/mL poly(I:C). This was surprising because literature suggests that the expression of TLR3 dramatically increases when DCs are maturing, which should occur upon poly(I:C) exposure. Once fully mature, DCs receive inflammatory signals to reduce TLR3 expression. Treatment of DCs with interferon-a (IFN-α) has been found to enhance IL-12 production by increasing TLR3 expression. DC2.4s exposed to IFN-α prior to poly(I:C) treatment also failed to produce IL-12. Experiments using lipopolysaccharide (LPS) confirmed that the cells can make IL-12 through activation of the TLR4 pathway. Ongoing studies are investigating the functionality of the TLR3 pathway in the cells. Luciferase assays with IFN-β plasmids are being conducted to confirm the presence of a functional TLR3. Western blotting and immunofluorescence are also being explored to qualitatively determine whether the DC2.4 cell line expresses TLR3, as reported in literature. Additionally, the maturation status of the lab’s DC2.4 cells is being considered. Analysis of TLR3 levels and production of IL-12 by DC2.4s allows for greater understanding of how different lab-derived lines of DCs exhibit responses to TLR agonists.

Notes

Honors Senior Thesis; Honors in the Discipline; BIO 492 Honors Research in Biology

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