Langerhans cells from human cutaneous squamous cell carcinoma induce strong type 1 immunity

Langerhans cells (LCs) are dendritic cells (DCs) localized to the epidermis. They should be the first antigen-presenting cells to encounter squamous cell carcinoma (SCC). The aim of this study was to investigate the ability of LCs isolated from human SCC to induce T-cell proliferation and polarization. We investigated the ability of LCs from SCC and peritumoral skin to induce T-cell proliferation and polarization. We also studied the effect of SCC supernatant on the ability of LCs from normal skin, in vitro-generated LCs, and DCs to activate and polarize T cells. LCs from SCC were stronger inducers of allogeneic CD4(+) and CD8(+) T-cell proliferation and IFN-γ production than LCs from peritumoral skin. We found that tumor supernatants (TSNs) were rich in immunosuppressive cytokines; despite this, allogeneic CD4(+) and CD8(+) T-cell proliferation and IFN-γ induction by LCs were augmented by TSN. Moreover, TSN facilitated IFN-γ induction by in vitro-generated LCs, but suppressed the ability of in vitro-generated DCs to expand allogeneic CD4(+) and CD8(+) T cells. We have demonstrated that LCs from SCC can induce type 1 immunity. TSN induces IFN-γ induction by in vitro-generated LCs. This contrasts greatly with prior studies showing that DCs from SCC cannot stimulate T cells. These data indicate that LCs may be superior to DCs for SCC immunotherapy and may provide a new rationale for harnessing LCs for the treatment of cancer patients.     

Epidermal cells bearing both I-A and I-E subregion antigens can induce hen egg white lysozyme-specific T lymphocyte proliferation

Antigen-primed T lymphocytes require accessory cells to initiate a proliferative response. These cells have been designated antigen presenting cells. In the present investigation, we found that immune associated antigen (Ia) bearing, mouse epidermal cells possess antigen presenting activity. These epidermal cells also display substantial levels of mixed lymphocyte reaction (MLR) activity. However, this MLR of itself did not suppress nor enhance antigen presenting activity. Genetic mapping studies demonstrated that compatibility at the I-A and I-E subregions of the MHC is important for effective presentation of either lysozyme or ovalbumin. In vitro inhibition and blocking studies using alloantisera confirmed that I-A and I-E gene products of these epidermal cells may play an important role in the interaction of primed T lymphocytes and antigen-pulsed epidermal cells. In addition, epidermal cells bearing Fc and C3 receptors on the cell surfaces were more efficient at inducing the lymphocyte proliferation than were epidermal cells depleted of these cells. These results suggest that Ia positive epidermal cells may be involved in the initiation of delayed type hypersensitivity reactions through antigen recognition followed by antigen presentation and T lymphocyte proliferation.     

Induction of tumor peptide-specific cytotoxic T cells under serum-free conditions by mature human dendritic cells

Abstract Tumor vaccination strategies using antigen-pulsed dendritic cells (DC) are currently under development. We established an in vitro system using cultured DC from HLA-typed volunteers for the induction of tumor peptide-specific CD8⁺ T cells. The strength and specificity of the resulting CTL responses were investigated. For stimulation of syngeneic CD8⁺ T cells two well-defined DC populations were generated: CD1a⁺ immature DC cultured in the presence of GM-CSF and IL-4 and mature CD83⁺ DC generated by additional stimulation with a cytokine cocktail. Stimulations were performed under serum-free conditions and in the absence of exogenous cytokines. Analysis of T cell responses showed that mature DC, but not immature DC, were able to induce the expansion of syngeneic tumor peptide-specific CD8⁺ T cells. Priming of CD8⁺ T cells with peptide-pulsed mature DC rapidly increased the frequency of antigen-specific T cells (ELISPOT technique). T cells induced by mature DC showed strong antigen-specific cytotoxicity in ⁵¹Cr-release assays whereas no antigen-specific cytotoxicity was detectable in CTL generated by immature DC. These data show that terminally differentiated mature DC are necessary for the induction of tumor antigen-specific CTL responses. Received: 13 January 2000 / Revised: 23 March 2000 / Accepted: 23 March 2000     

Polyarginine-mediated protein delivery to dendritic cells presents antigen more efficiently onto MHC class I and class II and elicits superior antitumor immunity

Protein transduction domains (PTDs) have been used increasingly to deliver reagents to a variety of cell types in vitro and in vivo. We have previously shown that HIV TAT-PTD-containing whole protein antigens (Ags)-transduced dendritic cells (DCs) stimulated Ag-specific CD8+ and CD4+ T cells. Although the cytotoxic T lymphocytes (CTL) activity generated was sufficient to prevent engraftment of mice with Ag-expressing tumors, treatment of tumor-bearing mice with TAT-PTD Ag-transduced DCs resulted in tumor regression in some animals. Recently, several other PTDs were reported to promote higher transduction efficiencies than TAT-PTD. To evaluate the role of individual PTDs in induction of immune responses in tumor vaccination studies, we engineered recombinant fusion Ovalbumin (OVA) that contained three differrent PTDs, including the most efficacious known PTD (polyarginine (R9)-PTD). Our results demonstrated that R9-PTD-containing OVA transduced DCs most efficiently, and that transduction efficacy was closely correlated with the extent of Ag-specific CD4+ and CD8+ T-cell activation in vitro and in vivo. Repeated vaccination with R9-PTD-OVA-transduced DC in (OVA-expressing) tumor-bearing mice induced enhanced antitumor immunity, and elicited complete rejection of tumors when DC was co-injected with adjuvants. This vaccination strategy may be clinically applicable, and offers theoretical and practical advantages to those that are in current use.     

Suprathreshold doses of hapten are required to induce both contact hypersensitivity and tolerance

Whereas both high (conventional) and low (optimal) doses of epicutaneously applied hapten induce contact hypersensitivity in normal mice, only conventional doses retain their capacity to induce contact hypersensitivity after acute, low dose ultraviolet B radiation in UVB-resistant mice. Recent evidence indicates that conventional doses of hapten as well as acute, low dose ultraviolet B radiation destroy virtually all epidermal Langerhans cells, which leads to the conclusions that (a) dermal antigen presenting cells have a prominent role to play in contact hypersensitivity induction, and that (b) Langerhans cell provide this function only in normal skin, and only if non-toxic amounts of hapten are present. We have now explored the ability of suprathreshold, threshold, and sub-threshold doses of hapten to induce tolerance when painted on or injected into normal skin or skin exposed to ultraviolet B radiation. Our results indicate that a single exposure of low dose, ultraviolet B radiation generated tolerance-promoting signals within the epidermis when a threshold dose of hapten was painted on the exposed site. By contrast, suprathreshold doses of hapten painted on skin after four consecutive daily doses of ultraviolet B radiation led to tolerance that arose exclusively from cells within the dermis. In absence of ultraviolet B radiation, epicutaneously applied hapten failed uniformly to induce tolerance, whether applied at suprathreshold, threshold or sub-threshold doses. We conclude that normal skin lacks cells with inherent tolerance-promoting capacity, but that cells of this type can emerge within either epidermis or dermis after exposure to acute, low dose ultraviolet B radiation.     

Vaccination of Japanese patients with advanced melanoma with peptide, tumor lysate or both peptide and tumor lysate-pulsed mature, monocyte-derived dendritic cells

We performed a clinical trial to assess the feasibility and efficacy of immunotherapy with peptides, tumor lysate or both peptides and tumor lysate-pulsed mature, monocyte-derived dendritic cells (DC) for advanced malignant melanoma patients that are resistant to conventional therapies. Sixteen patients were enrolled in this trial. All patients received DC vaccines i.d. in the proximal thigh, close to the inguinal lymph nodes, one treatment per week or 2 weeks. Several factors such as clinical findings, computed tomography (CT) images, delayed type hypersensitivity (DTH) response, enzyme-linked immunosorbent spot (ELISPOT) assay, and immunohistochemistry in primary, metastatic lesions and the DTH site were evaluated. Clinical results through DC vaccination were as follows: in 11 evaluable cases, three stable disease, six progression of disease and two disease-free from the time of study entry to the completion of one vaccination course. One patient showed reduction of the tumors in the metastases on chest CT during the first and second course of DC vaccination. Ten out of 14 evaluable cases showed positive DTH responses to more than one treatment with melanoma peptides or tumor lysate. Eight out of 13 evaluable cases showed positive immunological responses to more than one treatment with melanoma peptides or tumor lysate in an ELISPOT assay. As for the experiences with toxicity and adverse reactions, autosensitization dermatitis-like eruptions appeared in five cases during DC vaccination. No severe adverse effects were seen in any of the patients. In our study, the clinical efficacy in prolongation of the patients' survival was confirmed. At the same time, cancer immunoediting of the tumor was also found. It will be necessary to improve the tumor-specificity of this therapeutic approach and to analyze the mechanism(s) of tumor escape from immunosurveillance in melanoma.     

FGF expression allows nevus cells to survive in three-dimensional collagen gel under conditions that induce apoptosis in normal human melanocytes.

Melanocytes, the pigment forming cells of the skin, form an almost nonproliferating cell population located to the lowermost part of the epidermis. Normally melanocytes are not found higher in the epidermis or in the dermis. Nevi consist of melanocytes with altered growth characteristics and localization. The common pigmented nevus, a benign skin lesion, develops when melanocytes proliferate in the dermo-epidermal junction or in the dermis. Here we report growth characteristics of in vitro cultured normal human melanocytes and dermal nevus-derived melanocytes. As previously reported, nevus cells have a moderate to high FGF-2 expression level. Here we demonstrate that dermal nevus cells are able to survive in three-dimensional type 1 collagen culture, while normal human melanocytes rapidly undergo apoptosis. Melanocytes also, however, survive in collagen cultures in the presence of exogenous FGF-2. The survival of nevus cells in collagen is suppressed by protamine, an inhibitor of FGF-mediated cell stimulation. The in vivo growth environment of dermal nevus cells consists largely of type I and type III collagens. The results suggest that FGF-2 expression by nevus cells allows them to adapt to grow in the dermis. FGF-2 obviously has importance as a melanocyte survival factor and probably also in the development of malignant melanoma.     

Leiomyosarcoma of the skin--a diagnostic and therapeutic problem tumor

It is reported about an uncommon problematic tumour of the skin by means of 3 patients with a leiomyosarcoma. The own experiences in this field are compared with the not very extensive literature, and the clinical and histological criteria of diagnostic are discussed also therapeutical recommendation in consideration of the prognostic aspects are derived.     

The role of dendritic cells in cutaneous immunity

This article reviews the role of dendritic cells in cutaneous immunity. Langerhans cells (LC) found in the epidermis are the best-characterized dendritic cell population. They have the ability to process antigen in the periphery, transport it to the draining lymph nodes (DLN) where they are able to cluster with, and activate, antigen-specific naive T cells. During migration LC undergo phenotypic and functional changes which enable them to perform this function. There are other less well-characterized dendritic cells including dendritic epidermal T cells, dermal dendrocytes and dermal ‘LC-like’ cells. Although there is no evidence that dendritic epidermal T cells (DETC) can present antigen or migrate to lymph nodes, they do influence the intensity of cutaneous immune responses to chemical haptens. Antigen-presenting cells (APC) in the dermis may provide alternative routes of antigen presentation which could be important in the regulation of skin immune responses. Therefore, dendritic cells are vital for the induction of immune responses to antigens encountered via the skin. LC are particularly important in primary immune responses due to their ability to activate naive T cells. The faster kinetics of secondary responses, and the ability of nonprofessional APC to induce effector function in previously activated cells, suggest that antigen presentation in the DLN may be less important in responses to previously encountered antigens. In these seondary responses, dendritic and nondendritic APC in the skin may directly induce effector functions from antigen-specific recirculating cells. Received: 24 April 1995     

T cells, immunosurveillance, and cutaneous immunity

This presentation deals with the key role of the skin in immune function, briefly reviewing what is known about the cell trafficking patterns and molecular events involved in the generation of a specific immune response in the skin. Such information provides a basis for understanding the pathogenesis of autoimmunity-related diseases, and may provide clues to eventual therapeutic approaches.     

Mast cells as initiators of immunity and host defense

Until recently, mast cells have been viewed primarily as harmful because of their key role as effector cells of allergic and potentially lethal anaphylactic reactions. Their contribution to human health appeared instead to be limited to the elimination of parasites. There is, however, growing evidence for additional beneficial functions of mast cells, particularly regarding the initiation of acquired immune reactions. Thus, mast cells can phagocytize diverse particles, take up antigens, and express a number of receptors, particularly MHC class I and II antigens, ICAM-1 and -3, CD43, CD80, CD86 and CD40L which allow them to interact with T and B lymphocytes. They can also secrete numerous cytokines that induce and enhance recruitment and functions of lymphocytes. Finally, there is good evidence that mast cells present e.g. pollen and bacterial antigens, respond to bacterial superantigens, but fail to react to endogenously produced antigens or superantigens. Mast cells can also activate B cells directly to produce IgE, but this activity and the ability to produce IL-4 or IL-13 is restricted primarily to basophil leukocytes and mucosal mast cells. Finally, recent evidence attributes a pivotal role to the cells in natural immunity to bacteria. There is also emerging evidence that mast cells can downmodulate the immune response. While these data require further clarification, the basic ability of mast cells to initiate innate and acquired immune reactions can no longer be questioned.     

Mast cells as regulators of skin inflammation and immunity

Mast cells are known to be the effector cells of immediate-type allergy, but experimental evidence obtained during the last decade has revealed their role in innate and acquired immunity. Upon activation mast cells can undergo an anaphylactic or piecemeal degranulation or degranulation-independent mediator secretion, resulting in rapid or slow release of soluble mediators, such as serine proteinases, histamine, lipid-derived mediators, cytokines, chemokines and growth factors. Mast cells can express different receptors and ligands on the cell surface, molecules that can activate the cells of the immune system, such as different subsets of T cells. All these mediators and cell surface molecules can promote inflammation in the skin. During the last years, a new role for mast cells has emerged; induction of tolerance or immunosuppression and interaction with regulatory T cells. However, the mechanisms that switch the proinflammatory function of mast cells to an immunosuppressive one are unknown. In this review, the immunoregulatory function of mast cells and its relation to skin inflammation are discussed.     

Purified flagella from Treponema phagedenis biotype Reiter does not induce protective immunity against experimental syphilis in rabbits

Thirteen rabbits were immunized three times at weekly intervals with 50 micrograms of flagella purified from Treponema phagedenis biotype Reiter. Fourteen rabbits were inoculated in the same way with a placebo preparation. Rabbits immunized with the flagella developed an immune response to the flagella but showed no statistically significant prolongation of incubation time or diminution of lesion severity when challenged intradermally with 4 X 10(3) Treponema pallidum organisms.     

Tromantadine hydrochloride in the treatment of herpes simplex. Results of a double-blind therapeutic trial and an open prophylactic investigation

In a randomised, double-blind trial on 20 patients with herpes simplex, tromantadine hydrochloride (TH) ointment had a significant therapeutic effect. No side effects were observed. 12 lesions were treated with the active drug and 13 with placebo. In an open study on 19 patients with recurrent herpes simplex, the prophylactic effect of the drug was good in most patients. During long-term treatment, 2 patients developed eczematous lesions. It is concluded that TH is a valuable topical agent for the treatment of herpes simplex.     

The antistaphylococcal properties of plant extracts in relation to their prospective use as therapeutic and prophylactic formulations for the skin

Antistaphylococcal activities of plant extracts (12 water alcohol glycerol, WAG, 6 water alcohol, WA, 8 alcohol glycerol, AG, extracts) towards reference strains and those isolated from patients with pyoinflammatory diseases of the skin were examined by diluting the preparations in solid media. The strains under study were 69 S. aureus, 44 S. epidermidis, and 2 S. saprophyticus ones. Fifteen plant extracts have shown antistaphylococcal activities. The most active were oak bark, sage and St. John's wort grass WAG extracts, horse radish root and leaf AG extracts, celandine grass WA extract; bur marigold and yarrow grass WA extracts were active towards S. aureus. S. aureus strains isolated from patients were found less sensitive to oak bark, German camomile flower WAG and celandine, bur marigold, and brewing waste WA extracts that the reference strains. S. epidermidis strains isolated from patients with acne rash were less sensitive to sweet flag rhizome WAG, celandine and brewing waste WA extracts that the reference strains. These data may be useful when developing compositions including plant extracts for patients with skin diseases.