Development and characterization of a monoclonal antibody specific for fucosyltransferase VII (Fuc-TVII): discordant expression of CLA and Fuc-TVII in peripheral CD4+ and CD8+ T cells

Selective Expression of CCR10 and CXCR3 by Circulating Human Herpes Simplex Virus-Specific CD8 T Cells

Herpes simplex virus (HSV) infection is restricted to epithelial cells and neurons and is controlled by CD8 T cells. These cells both traffic to epithelial sites of recurrent lytic infection and to ganglia and persist at the dermal-epidermal junction for up to 12 weeks after lesion resolution. We previously showed that cutaneous lymphocyte-associated antigen (CLA), a functional E-selectin ligand (ESL), is selectively expressed on circulating HSV-2-specific CD8 T cells. CLA/ESL mediates adhesion of T cells to inflamed vascular endothelium. Later stages in T-cell homing involve chemokines (Ch) and lymphocyte chemokine receptors (ChR) for vascular wall arrest and diapedesis. Several candidate ChR have been implicated in skin homing. We measured cell surface ChR on HSV-specific human peripheral blood CD8 T cells and extended our studies to HSV-1. We observed preferential cell surface expression of CCR10 and CXCR3 by HSV-specific CD8 T cells compared to CD8 T cells specific for control viruses, Epstein-Barr virus (EBV) and cytomegalovirus (CMV), and compared to bulk memory CD8 T cells. CXCR3 ligand mRNA levels were selectively increased in skin biopsy specimens from persons with recurrent HSV-2, while the mRNA levels of the CCR10 ligand CCL27 were equivalent in lesion and control skin. Our data are consistent with a model in which CCL27 drives baseline recruitment of HSV-specific CD8 T cells expressing CCR10, while interferon-responsive CXCR3 ligands recruit additional cells in response to virus-driven inflammation.IMPORTANCE HSV-2 causes very localized recurrent infections in the skin and genital mucosa. Virus-specific CD8 T cells home to the site of recurrent infection and participate in viral clearance. The exit of T cells from the blood involves the use of chemokine receptors on the T-cell surface and chemokines that are present in infected tissue. In this study, circulating HSV-2-specific CD8 T cells were identified using specific fluorescent tetramer reagents, and their expression of several candidate skin-homing-associated chemokine receptors was measured using flow cytometry. We found that two chemokine receptors, CXCR3 and CCR10, are upregulated on HSV-specific CD8 T cells in blood. The chemokines corresponding to these receptors are also expressed in infected tissues. Vaccine strategies to prime CD8 T cells to home to HSV lesions should elicit these chemokine receptors if possible to increase the homing of vaccine-primed cells to sites of infection.

A single sub-erythematous exposure of solar-simulated radiation on the elicitation phase of contact hypersensitivity induces IL-10-producing T-regulatory cells in human skin

Solar ultraviolet (UV) radiation has hazardous effects on human health that are, in part, associated with its immunosuppressive effects via the induction of interleukin (IL)-10 production. Although IL-10 is produced by both T helper type 2 (Th2) cells and T-regulatory type 1 (Tr1) cells, the relative contribution of either subset in UV radiation-induced immunosuppression has not been established. Here, we show that T cells isolated from non-treated allergic contact dermatitis (ACD) reactions, 48 h following nickel challenge and propagated for 7-10 days in the presence of IL-2, were mainly CD4(+) and produced IL-10, but little interferon-gamma. A single sub-erythematous solar-simulated radiation (SSR) prior to antigen challenge exposure resulted in a clinical attenuation of the intensity of ACD reactions which was associated with a significant increase in both the magnitude of IL-10 production by skin-infiltrating T cells and the frequency of IL-10-producing Tr1 cells. Skin-infiltrating T cells in SSR-exposed, as well as non-exposed, ACD reactions showed a perturbed T-cell receptor (TCR)-Vbeta repertoire, without overexpression of a particular TCR-Vbeta gene product, indicating the presence of high frequencies of nickel non-specific T cells in ACD reactions. These results show that a single sub-erythematous SSR induces immunosuppression via the cutaneous infiltration of IL-10-producing Tr1, and to a lesser extent, Th2 cells.

T-cell dynamics of inflammatory skin diseases

The migration of memory T-cells to sites of inflammation is a multistep process controlled by an array of specific receptor-ligand pairs. Chemokines and their receptors represent a central paradigm of the molecular basis of the skin-homing of T-cells. Although CCR4 and CCR10 are both associated with conventionally defined skin-homing T-cells, the association is not necessarily perfect. Interaction between E-selectin and its ligand may represent more specific targets for therapeutic intervention. Although fucosyl transferase?VII is essential for generating E-selectin ligands necessary for T-cell homing to skin, fucosyltransferase-IV, another fucosyltransferase expressed to a significant degree in T-cells, can also generate E-selectin ligands. The induction and upregulation of both enzymes can be co-ordinately regulated depending on their state of activation and differentiation and the cytokine milieu. The dynamic balance between the two enzymes is a major check point for the regulation of skin-homing T-cell differentiation. Polarized T-cells regulate their adhesions on a minute-to-minute basis depending on the cytokine environment. Soluble adhesion molecules found to be increased in chronic inflammatory skin diseases may serve to limit the duration or magnitude of T-cell recruitment. In addition to T-cells migrating from the circulation, T-cells indigenously residing in the tissue itself, such as skin-resident T-cells, would also be responsible for tissue damage. It should also be appreciated that T-cell recruitment to the skin is critical for host defense and that no definitive means exist to distinguish protective regulatory T-cells from pathogenic T-cells.

In Vitro Differentiation from Naive to Mature E-Selectin Binding CD4 T Cells: Acquisition of Skin-Homing Properties Occurs Independently of Cutaneous Lymphocyte Antigen Expression

We previously showed that skin-homing CD4 T cells in peripheral blood can be subdivided into three populations on the basis of the expression pattern of the cutaneous lymphocyte Ag (CLA) and fucosyltransferase VII (FucT-VII): FucT-VII(+)CLA(-), FucT-VII(+)CLA(+), and FucT-VII(-)CLA(+). In view of the known late appearance of CLA during T cell differentiation, T cells programmed to attain skin-homing properties may start to generate E-selectin-binding epitopes at early stages of differentiation before induction of CLA expression. To this end, the in vitro differentiation from naive to CLA(+) memory T cells was followed after activation with anti-CD3 mAb. Here we demonstrate that naive skin-homing CD4 T cell precursors undergo a linear differentiation process from the FucT-VII(+)CLA(-) phenotype to the FucT-VII(+)CLA(+) phenotype and eventually to the FucT-VII(-)CLA(+) phenotype. The appearance of the FucT-VII(+)CLA(-) subset coincided with or could be immediately followed by the generation of E-selectin binding epitopes, and even after E-selectin-binding epitopes were no longer detectable, CLA remained expressed for prolonged periods of time, suggesting that induction of functional E-selectin ligands depends primarily on the expression of FucT-VII, but not CLA. Immunofluorescence and confocal microscopy studies of these T cells confirm that most E-selectin ligands were found independently of CLA expression.

Preferential expression of alphaEbeta7 integrin (CD103) on CD8+ T cells in the psoriatic epidermis: regulation by interleukins 4 and 12 and transforming growth factor-beta

BACKGROUND

Intraepidermal T lymphocytes are a critical element for sustaining the lesional pathology of psoriasis. Integrin alphaEbeta7 (CD103), a ligand for E-cadherin, may play a role in the localization of pathogenic T cells within the epidermis of psoriatic lesions. However, little information is available regarding alphaEbeta7 expression on intraepidermal T cells in psoriasis.

OBJECTIVES

To examine alphaEbeta7 expression on intraepidermal T cells in psoriatic lesions and the regulation of alphaEbeta7 expression on T cells in response to cytokines.

METHODS

T-cell expression of alphaEbeta7 was examined by immunohistochemistry and flow cytometry. In vitro regulation of alphaEbeta7 expression on CD4+ or CD8+ T cells purified from peripheral blood of healthy donors was also examined.

RESULTS

Immunohistochemical staining revealed expression of alphaEbeta7 on a greater proportion of epidermal T cells than dermal T cells. Nearly 30% of intraepidermal CD4+ T cells were found to express alphaEbeta7 on flow cytometry, whereas more than 80% of intraepidermal CD8+ T cells expressed this integrin. In contrast, few T cells expressed alphaEbeta7 in the peripheral blood of psoriatic patients. The in vitro culture experiment confirmed that alphaEbeta7 was preferentially expressed on CD8+ T cells after stimulation with anti-CD3 monoclonal antibodies. Addition of transforming growth factor-beta and interleukin-4 upregulated alphaEbeta7 expression on T cells, whereas interleukin 12 downregulated this. Furthermore, alphaEbeta7 expression on established memory CD8+ T cells was not so reversible as that on CD4+ T cells.

CONCLUSIONS

Preferential and stable expression of alphaEbeta7 on CD8+ T cells may be involved in the lesional pathology of psoriasis.