Innate lymphocyte and dendritic cell cross-talk: a key factor in the regulation of the immune response.

in Clinical & Experimental Immunology (2008), 152(2), 219-26

Dendritic cells (DC) are specialized in the presentation of antigens and the initiation of specific immune responses. They have been involved recently in supporting innate immunity by interacting with ... [more ▼]

Dendritic cells (DC) are specialized in the presentation of antigens and the initiation of specific immune responses. They have been involved recently in supporting innate immunity by interacting with various innate lymphocytes, such as natural killer (NK), NK T or T cell receptor (TCR)-gammadelta cells. The functional links between innate lymphocytes and DC have been investigated widely and different studies demonstrated that reciprocal activations follow on from NK/DC interactions. The cross-talk between innate cells and DC which leads to innate lymphocyte activation and DC maturation was found to be multi-directional, involving not only cell-cell contacts but also soluble factors. The final outcome of these cellular interactions may have a dramatic impact on the quality and strength of the down-stream immune responses, mainly in the context of early responses to tumour cells and infectious agents. Interestingly, DC, NK and TCR-gammadelta cells also share similar functions, such as antigen uptake and presentation, as well as cytotoxic and tumoricidal activity. In addition, NK and NK T cells have the ability to kill DC. This review will focus upon the different aspects of the cross-talk between DC and innate lymphocytes and its key role in all the steps of the immune response. These cellular interactions may be particularly critical in situations where immune surveillance requires efficient early innate responses. [less ▲]

The cross-talk between dendritic and regulatory T cells: good or evil?

in Journal of Leukocyte Biology (2007), 82(4), 781-94

Immune responses against pathogens require fine regulation in order to avoid excessive inflammation, which could be harmful to the host. Moreover, the immune system must be tolerant to non-pathogenic ... [more ▼]

Immune responses against pathogens require fine regulation in order to avoid excessive inflammation, which could be harmful to the host. Moreover, the immune system must be tolerant to non-pathogenic antigens in order to prevent allergy, autoimmunity and transplant rejection. There is accumulating evidence that interactions between dendritic cells (DC) and regulatory T (Treg) cells play a crucial role in the balance between immune response and tolerance. Communications between these cells are complex, bi-directional and mediated by soluble or cell surface molecules. The maturation status of DC, which may be influenced by different microenvironmental factors, is considered as an important checkpoint for the induction of peripheral tolerance through modifications of the activation status of T cells. Moreover, several lines of experimental evidence suggest that different subsets or the functional status of DC are also involved in the promotion of Treg cell differentiation. A better knowledge of the regulatory mechanisms of the immune response induced or inhibited by DC via their interactions with Treg cells could be relevant for the development of new immunotherapeutic approaches. [less ▲]

Le cancer du col de l'utérus: du virus au traitement

in Revue Médicale de Liège (2007), 62(S1)

Squamous cell cancer of the uterine cervix is associated with a high morbidity and mortality worldwide and in Belgium. New therapeutic approaches have been recently proposed. The development of this ... [more ▼]

Squamous cell cancer of the uterine cervix is associated with a high morbidity and mortality worldwide and in Belgium. New therapeutic approaches have been recently proposed. The development of this cancer is related to the infection by oncogenic human papillomavirus (HPV) types. The link between cervical cancer and HPV has, in recent years, generated, a great interest for studies aiming to better understand the role of the immune system in the control of these infections and for the development of prophylactic anti-HPV vaccines. [less ▲]

Defensis induce the recruitment of dendritic cells in cervical human papillomavirus-associated (pre)neoplastic lesions formed in vitro and transplanted in vivo

in FASEB Journal (2007), 21(11), 2765-75

In addition to their direct antimicrobial activity, defensins might also influence adaptive immunity by attracting immature dendritic cells (DC). As these cells have been shown to be deficient in uterine ... [more ▼]

In addition to their direct antimicrobial activity, defensins might also influence adaptive immunity by attracting immature dendritic cells (DC). As these cells have been shown to be deficient in uterine cervix carcinogenesis, we evaluated the ability of -defensin (HNP-2, human neutrophil defensin 2) and ß-defensin (HßD2, human beta defensin 2) to stimulate their migration in human papillomavirus (HPV)-associated (pre)cancers. We first observed, using RT-PCR and immunohistology, that HßD2 is absent in HPV-transformed keratinocytes and that it is weakly expressed in cervical (pre)neoplastic lesions in comparison with normal keratinocytes. We next demonstrated that defensins exert a chemotactic activity for DC in a Boyden Chamber assay and stimulate their infiltration in an in vitro-formed (pre)neoplastic epithelium (organotypic culture of HPV-transformed keratinocytes). To evaluate the ability of defensins also to recruit DC in vivo, we developed a model of immunodeficient mice grafted with organotypic cultures of HPV+ keratinocytes, which form an epithelium similar to a high-grade neoplastic lesion, with tumoral invasion and neovascularization. Intravenously injected human DC were able to infiltrate grafts of HPV+ keratinocytes after administration of HNP-2 in the transplantation chamber. Taken together, these results suggest that defensins could reverse a frequent immune alteration observed in cancer development. [less ▲]

Phase I/IIclinical trial of local GM-CSF application in patients with cervical HPV-associated low grade squamous intraepithelial lesions

Conference (2007)

Background: Quantitative and functional alterations of professional antigen-presenting cells (APC) in SIL suggest that these lesions may have a diminished capacity to capture viral antigens. Moreover, GM ... [more ▼]

Background: Quantitative and functional alterations of professional antigen-presenting cells (APC) in SIL suggest that these lesions may have a diminished capacity to capture viral antigens. Moreover, GM-CSF (whose production is decreased in HPV-transformed keratinocytes) is an essential factor for the migration of APC in cervical (pre)neoplastic lesions formed in vitro and transplanted in vivo on mouse. In this study we performed a phase I/II clinical trial in order to determine whether a local application of GM-CSF on cervical low-grade squamous intraepithelial lesions (LSIL) might increase the recruitment of APC into the epithelium and indirectly the viral antigen presentation to the immune system. Methods: Fifteen patients with LSIL (10 GM-CSF and 5 placebo) were enrolled in this study. Patients received 4 GM-CSF applications (or placebo gel) and were followed during 6-7 months. APC infiltration was quantified by immunostaining with anti-CD1a mAb. Cellular immune response was evaluated by using an IFN-gamma intracellular staining on PBMC stimulated in vitro with the E7 HPV16 protein and L1 HPV16 Virus-like particles (VLP). Hybrid capture was performed to semi-quantify the viral DNA in cervical brush specimens. Results: GM-CSF applications were well tolerated in all patients. No difference in the cytological/histological and viral parameters assessed at 2 and 6 months after the last application was observed between the GM-CSF and the placebo group. An increased number of CD1a+ APC was observed in 6/10 patients treated by GM-CSF compared to 1/5 patient in the placebo group. There was an increased immune response against HPV in the GM-CSF group showed by NK and T cells producing IFN-gamma. [less ▲]

MUCOADHESIVE PHARMACEUTICAL COMPOSITIONS COMPRISING CHEMOATTRACTANTS.

Patent (2006)

Production of large numbers of Langerhans' cells with intraepithelial migration ability in vitro

in Experimental Dermatology (2005), 14(6), 469-477

Phase I/II trial of immunogenicity of a human papillomavirus (HPV) type 16 E7 protein-based vaccine in women with oncogenic HPV-positive cervical intraepithelial neoplasia

in Cancer Immunology, Immunotherapy (2004), 53(7), 642-650

Purpose: Infection with oncogenic human papillomavirus (HPV) and HPV-16 in particular is a leading cause of anogenital neoplasia. High-grade intraepithelial lesions require treatment because of their ... [more ▼]

Purpose: Infection with oncogenic human papillomavirus (HPV) and HPV-16 in particular is a leading cause of anogenital neoplasia. High-grade intraepithelial lesions require treatment because of their potential to progress to invasive cancer. Numerous preclinical studies have demonstrated the therapeutic potential of E7-directed vaccination strategies in mice tumour models. In the present study, we tested the immunogenicity of a fusion protein (PD-E7) comprising a mutated HPV-16 E7 linked to the first 108 amino acids of Haemophilus influenzae protein D, formulated in the GlaxoSmithKline Biologicals adjuvant AS02B, in patients bearing oncogenic HPV-positive cervical intraepithelial neoplasia (CIN). Methods: Seven patients, five with a CIN3 and two with a CIN1, received three intramuscular injections of adjuvanted PD-E7 at 2-week intervals. Three additional CIN1 patients received a placebo. CIN3 patients underwent conization 8 weeks postvaccination. Cytokine flow cytometry and ELISA were used to monitor antigen-specific cellular and antibody responses from blood taken before and after vaccine or placebo injection. Results: Some patients had preexisting systemic IFN-gamma CD4(+) (1/10) and CD8(+) (5/10) responses to PD-E7. Vaccination, not placebo injection, elicited systemic specific immune responses in the majority of the patients. Five vaccinated patients (71%) showed significantly increased IFN-gamma CD8(+) cell responses upon PD-E7 stimulation. Two responding patients generated long-term T-cell immunity toward the vaccine antigen and E7 as well as a weak H. influenzae protein D (PD)-directed CD4(+) response. All the vaccinated patients, but not the placebo, made significant E7- and PD-specific IgG. Conclusions: The encouraging results obtained from this study performed on a limited number of subjects justify further analysis of the efficacy of the PD-E7/AS02B vaccine in CIN patients. [less ▲]

Epithelial metaplasia: an inadequate environment for antitumour immunity?

in Trends in Immunology (2004), 25(4), 169-73

Modèles expérimentaux in vitro des HPV

in Aubin, F.; Pretet, J. F.; Mougin, C. (Eds.) Papillomavirus Humains (2003)