Kristina Larsson

Functional and transcriptional profiling of MUTZ-3, a myeloid cell line acting as a model for dendritic cells

The incidence of allergy is steadily increasing, but the molecular mechanisms involved in the allergic immune response are still not fully understood. In particular, further investigations focusing on dendritic cells, which are central in orchestrating the immune response, are needed. The objective of this study was to investigate the ability of myeloid leukaemia‐derived cell lines, such as KG‐1, THP‐1 and MUTZ‐3, to serve as in vitro models for dendritic cells. The ability of these cell lines to mature into functional dendritic cells, expressing costimulatory molecules, was assessed by functional and transcriptional profiling and compared with that of monocyte‐derived dendritic cells, which are now used as a standard source of dendritic cells. High‐density microarray analysis was utilized to study the transcriptional activity and kinetics of activation of the differentiated MUTZ‐3 cell line, in response to a cocktail of inflammatory cytokines. The data obtained clearly demonstrate that MUTZ‐3 cells have the ability to induce antigen‐independent proliferation in CD4+ CD45RA+ T cells, whereas KG‐1 and THP‐1 only induced a marginal response. Furthermore, MUTZ‐3 displayed the phenotypic and transcriptional profiles of immature dendritic cells, after differentiation with granulocyte–macrophage colony‐stimulating factor and interleukin‐4. Upon activation with inflammatory cytokines, MUTZ‐3 matured phenotypically and exhibited a gene induction similar to that of monocyte‐derived dendritic cells. This delineation of the cellular and transcriptional activity of MUTZ‐3, in response to maturational stimuli, demonstrates the significance of this cell line as a model for functional studies of inflammatory responses.

Augmented Phl p 5-specific Th2 response after exposure of Dendritic Cells to allergen in complex with specific IgE compared to IgG1 and IgG4

In this study we have elucidated the effects of allergen-specific antibodies on human DCs and T-cells. Monocyte-derived DCs from allergic patients were exposed to Phl p 5 alone or in complex with Phl p 5-specific human IgG1, IgG4 or IgE and further co-cultured with autologous memory CD4(+) T-cells. We demonstrate that DCs treated with Phl p 5/IgE-complexes secrete higher levels of IL-1alpha, IL-6, VEGF and MCP-3 compared to Phl p 5 alone. Furthermore, we show that the ability of DCs to present allergen to memory CD4(+) T-cells and induce a Th2 cytokine profile is significantly augmented when the uptake is mediated by specific IgE antibodies, whereas IgG1 and IgG4 have no such effect. The differences in cytokine profiles depending on the antibody subtype could partly explain the ability of allergic individuals to amplify allergen-specific immune response and could thus be involved in the etiology of allergic responses.

CD4+ T-cells have a key instructive role in educating dendritic cells in allergy

Background: Dendritic cells (DCs) are central in allergy as regulators of the Th1/Th2 balance. We have recently demonstrated a unique transcriptional profile of DCs in patients with ongoing allergy compared with healthy subjects and shown that crosstalk between DCs and memory T cells affects the transcriptional profile of T cells. However, the transcriptional profile of DCs educated by T cells in allergy is unknown. Methods: In the present study, we have examined the transcriptional profiles of DCs after stimulation with grass pollen allergens, Phleum pratense and coculture with autologous CD4+ memory T cells using high-density microarray. Protein analysis was performed using flow cytometry and recombinant antibody protein microarrays. Patients with allergic rhinitis and healthy subjects were compared. Results: The results reveal a distinct T-cell-induced DC profile in atopic individuals. Accordingly, about 170 genes were upregulated and 40 genes downregulated. For example, the chemokine receptor CXCR4 and the tumor necrosis factor receptor CD30 were upregulated in DCs derived from atopic donors, and this could also be verified at the protein level. Conclusion: We conclude that crosstalk between CD4+ memory T cells and autologous DCs induces transcriptional reprogramming in DCs. This finding suggests that T cells have a key instructive role in educating DCs in Th2-type responses.