Synergistic Effect between Amoxicillin and TLR Ligands on Dendritic Cells from Amoxicillin-Delayed Allergic Patients

Maria J Sanchez-Quintero,Tahia D Fernandez,Miguel Blanca,Lidia Melendez,Inmaculada Doña,Cristobalina Mayorga,Enrique Gómez,Maria J Torres,Inmaculada Andreu,Adriana Ariza,Ana B Blazquez,Bruno Lourenco Diaz

doi:10.1371/journal.pone.0074198

Abstract

Amoxicillin, a low-molecular-weight compound, is able to interact with dendritic cells inducing semi-maturation in vitro. Specific antigens and TLR ligands can synergistically interact with dendritic cells (DC), leading to complete maturation and more efficient T-cell stimulation. The aim of the study was to evaluate the synergistic effect of amoxicillin and the TLR2, 4 and 7/8 agonists (PAM, LPS and R848, respectively) in TLR expression, DC maturation and specific T-cell response in patients with delayed-type hypersensitivity (DTH) reactions to amoxicillin. Monocyte-derived DC from 15 patients with DTH to amoxicillin and 15 controls were cultured with amoxicillin in the presence or absence of TLR2, 4 and 7/8 agonists (PAM, LPS and R848, respectively). We studied TLR1-9 gene expression by RT-qPCR, and DC maturation, lymphocyte proliferation and cytokine production by flow cytometry. DC from both patients and controls expressed all TLRs except TLR9. The amoxicillin plus TLR2/4 or TLR7/8 ligands showed significant differences, mainly in patients: AX+PAM+LPS induced a decrease in TLR2 and AX+R848 in TLR2, 4, 7 and 8 mRNA levels. AX+PAM+LPS significantly increased the percentage of maturation in patients (75%) vs. controls (40%) (p=0.036) and T-cell proliferation (80.7% vs. 27.3% of cases; p=0.001). Moreover, the combinations AX+PAM+LPS and AX+R848 produced a significant increase in IL-12p70 during both DC maturation and T-cell proliferation. These results indicate that in amoxicillin-induced maculopapular exanthema, the presence of different TLR agonists could be critical for the induction of the innate and adaptive immune responses and this should be taken into account when evaluating allergic reactions to these drugs.

Highlights

Delayed-type hypersensitivity (DTH) reactions induced by drugs appear hours or days after the drug administration and usually affect the skin
Maculopapular exanthema (MPE) reactions are T-cell mediated with a Th1 pattern [3,4], several studies have reported the involvement of dendritic cells (DCs) and natural killer cells in the early stages of the immune response [5,6]
Low-molecular-weight compounds such as drugs are able to induce DC maturation [11,12], a phenomenon that differs between drug-induced DTH and tolerant subjects [14]

Summary

Introduction

Delayed-type hypersensitivity (DTH) reactions induced by drugs appear hours or days after the drug administration and usually affect the skin. MPE reactions are T-cell mediated with a Th1 pattern [3,4], several studies have reported the involvement of dendritic cells (DCs) and natural killer cells in the early stages of the immune response [5,6]. DCs are professional antigen-presenting cells (APC) [7] that have a key role in the induction of specific immune responses, depending on the state of maturation at which they present the antigen to T lymphocytes [8,9]. Monocyte-derived DCs (moDCs) can be activated by allergens [10] and low-molecularweight compounds such as nickel and drugs [11,12,13], determining tolerance versus hypersensitivity responses. The low expression of costimulatory molecules on DCs, the mixed T-cell phenotype and the low cytokine production by both DCs and T cells

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