The Vitamin D Analogue Calcipotriol Reduces the Frequency of CD8+ IL-17+ T Cells in Psoriasis Lesions.

The vitamin D analogue calcipotriol is an immunomodulatory drug widely used to treat psoriasis; however, how calcipotriol affects the immune cells in psoriasis lesions is not fully understood. The aim of this study was to investigate the effect of calcipotriol on the frequency of CD4(+) and CD8(+) T cells and innate lymphoid cells (ILC) and their production of IL-17A, IFN-γ and IL-22 in psoriasis lesions in patients with chronic plaque psoriasis. Eighteen patients with psoriasis were included, and two similar psoriasis lesions were chosen for each patient. One lesion was treated with calcipotriol (50 µg/g) and the other with vehicle twice a day for 14 days. The clinical effect was measured by degree of erythema, scaling and induration in each lesion (SUM score). Skin biopsies were collected for histological and immunohistochemical analyses. Skin-derived cells were isolated and analysed by flow cytometry. After 14 days of treatment with calcipotriol, a significant clinical and histological effect was seen; however, we found no differences in the frequency of CD4(+) and CD8(+) T cells or ILC between calcipotriol- and vehicle-treated skin. The main finding was a significant decrease in CD8(+) IL-17(+) T cells in skin-derived cells from calcipotriol-treated skin, which was further supported by the absence of CD8(+) IL-17(+) T cells in immunohistochemical staining of calcipotriol-treated skin. No changes in the frequency of IL-22(+) or IFN-γ(+) cells were observed. Our findings show that the vitamin D analogue calcipotriol reduces the frequency of CD8(+) IL-17(+) T cells in psoriasis lesions concomitant with clinical improvement.

Increased number and frequency of group 3 innate lymphoid cells in nonlesional psoriatic skin.

BACKGROUND: Psoriasis is a common immune-mediated inflammatory disease that affects the skin and joints. The interleukin (IL)-23/IL-17A axis and IL-22 play key roles in the pathogenesis of psoriasis. IL-23-responsive innate lymphoid cells (ILCs) with a high capacity to produce IL-17 and/or IL-22 have recently been identified and associated with inflammatory bowel diseases. The occurrence and role of ILCs in human skin are poorly understood. OBJECTIVES: To describe the prevalence of the different ILC subpopulations in skin from healthy controls and patients with psoriasis or allergy to nickel. METHODS: Skin biopsies were taken from healthy skin, nonlesional and lesional psoriatic skin, and nickel- and petrolatum-exposed skin from patients with contact allergy to nickel, and lymphocytes were isolated. The cells were stained and characterized by flow cytometry. Cytokine and ligand mRNA expression were measured by quantitative polymerase chain reaction. RESULTS: We found that members of the three groups of ILCs were present in human skin. Remarkably, the number and frequency of RORγt(+) CD56(+) ILC3s, which are known to produce IL-22, were elevated in both nonlesional and lesional skin from patients with psoriasis compared with healthy skin and skin from patients with contact allergy to nickel. Furthermore, skin ILCs expressed high levels of the natural killer receptor NKG2D. NKG2D binds to stress-induced ligands, including major histocompatibility complex class I-related chain A, which we found to be strongly upregulated in lesional skin from patients with psoriasis. CONCLUSION: These results show that ILCs are present in human skin and indicate that RORγt(+) CD56(+) ILC3 may be involved in the pathogenesis of psoriasis.

In vitro production and characterization of partly assembled human CD3 complexes.

Pairwise assembly of human CD3 chains takes place in the endoplasmic reticulum of T cells. Subsequently, the CD3 heterodimers form complexes with Ti alpha and Tiss chains forming hexameric Ti alpha beta CD3 gamma epsilon delta epsilon complexes. Finally, association with the zeta 2 homodimer occurs in Golgi apparatus before the fully assembled T-cell receptor is transported to the cell surface. To study the structural properties of the human CD3 chains, we have developed new methods to produce and fold the extracellular domains of CD3 gamma, CD3 delta and CD3 epsilon. Proteins were expressed in Escherichia coli as denatured chains and de novo folded in vitro. CD3 gamma and CD3 epsilon folded as soluble monomers, whereas CD3 delta did not yield any soluble proteins. When folding the chains pairwise, soluble CD3 gamma epsilon and CD3 delta epsilon heterodimers could be isolated, whereas CD3 gamma delta heterodimers were not produced. Using antibodies as structural probes, we identified two different types of antigenic epitopes that were dependent on heterodimerization. Our data indicate that CD3 epsilon undergoes a conformational change after dimerization with CD3 gamma or CD3 delta. Furthermore, we demonstrated that the CD3 gamma epsilon heterodimer could be purified using immunoaffinity chromatography.

Proteasomal targeting and minigene repetition improve cell-surface presentation of a transfected, modified melanoma tumour antigen.

Melanoma antigen recognized by T cell 1 (MART-1) is regarded as a candidate peptide for vaccination against malignant melanoma, and it is of importance to develop strategies to improve the vaccine-elicited T-cell activation towards MART-1. T-cell activation is, among other determinants, dependent on the density of specific major histocompatibility complex-peptide complexes on the surface of the antigen-presenting cell. In this study, we explored the cell-surface presentation of a substituted MART-1 peptide encoded by transfected minigenes. We investigated the potential of proteasomal targeting compared to non-proteasomal targeting of the epitope to increase its cell-surface presentation. Furthermore, we explored the potential of incorporating multiple minigenes instead of one to increase cell-surface presentation. We show that both proteasomal targeting and repetition of the minigene increase cell-surface presentation of the epitope and propose both these approaches as potential strategies in DNA vaccines to increase MART-1-specific T-cell activation.