Publications by authors named "Helga Sennefelder"

Background: Reconstructed human epidermis (RhE) is widely used to replace animal models in order to assess the proinflammatory and allergenic effects of chemicals. Unfortunately, RhE lacks proinflammatory responsiveness for metal haptens, which are the most prevalent human contact allergens, raising concerns about its reliability for predicting skin allergens.

Objectives: To investigate whether this limitation of RhE might be attributable to a lack of functional expression of Toll-like receptor 4 (TLR4), which governs proinflammatory sensitivity to nickel and cobalt.

View Article and Find Full Text PDF

There is experimental and clinical evidence that some exanthematous allergic drug hypersensitivity reactions are mediated by drug-specific T cells. We hypothesized that the capacity of certain drugs to directly stimulate the innate immune system may contribute to generate drug-specific T cells. Here we analyzed whether abacavir, an HIV-1 reverse transcriptase inhibitor often inducing severe delayed-type drug hypersensitivity, can trigger innate immune activation that may contribute to its allergic potential.

View Article and Find Full Text PDF

Chromium allergy is a common occupational skin disease mediated by chromium (VI)-specific T cells that induce delayed-type hypersensitivity in sensitized individuals. Additionally, chromium (VI) can act as an irritant. Both responses critically require innate immune activation, but if and how chromium (VI) elicits this signal is currently unclear.

View Article and Find Full Text PDF

Dendritic cells (DC) are the most important antigen presenting cells and play a pivotal role in host immunity to infectious agents by acting as a bridge between the innate and adaptive immune systems. Monocyte-derived immature DCs (iDC) were infected with viable resting conidia of Aspergillus fumigatus (Af293) for 12 hours at an MOI of 5; cells were sampled every three hours. RNA was extracted from both organisms at each time point and hybridised to microarrays.

View Article and Find Full Text PDF

Dysregulation of the Th1/Th2 cytokine balance and a switch to a Th2 immune response contribute to the development of and the unfavorable outcome from invasive aspergillosis (IA). We explore in this paper the role of glycogen synthase kinase 3 (GSK-3) in human immature dendritic cells (iDCs) relative to infection caused by A. fumigatus by the use of GSK-3 inhibitors (LiCl, SB415286) and RNA interference technology.

View Article and Find Full Text PDF

Invasive aspergillosis is a significant cause of morbidity and mortality in patients after stem cell transplantation, in solid organ transplant recipients, and in patients with hematological malignancies. The interactions between human immature dendritic cells (iDCs) and Aspergillus fumigatus antigens are widely uncharacterized. We analyzed the immune response of iDCs to different recombinant A.

View Article and Find Full Text PDF

Background: Increasing the efficacy of chemotherapeutics by reducing chemoresistance may be a useful strategy in cancer therapy. Constitutive activation of nuclear factor-kappa B (NF-kappaB) is a hallmark of various cancers, including melanoma, which is almost universally resistant to chemotherapy. NF-kappaB is regulated by inhibitory kappaB (IkappaB) proteins, which are in turn phosphorylated by the IkappaB kinase (IKK) complex.

View Article and Find Full Text PDF

While the extravasation cascade of lymphocytes is well characterized, data on their intraepithelial positioning and morphology are scant. However, the latter process is presumably crucial for many immune functions. Integrin alpha(E)(CD103)beta(7) has previously been implicated in epithelial retention of some T cells through binding to E-cadherin.

View Article and Find Full Text PDF