[Show abstract][Hide abstract] ABSTRACT: Vaccination has been a major advance for health care, allowing eradication or reduction of incidence and mortality of various infectious diseases. However, there are major pathogens, such as Human Immunodeficiency Virus (HIV) or the causative agent of malaria, for which classical vaccination approaches have failed, therefore requiring new vaccination strategies. The development of new vaccine strategies relies on the ability to identify the challenges posed by these pathogens. Understanding the pathogenesis and correlates of protection for these diseases, our ability to accurately direct immune responses and to vaccinate specific populations are such examples of these roadblocks. In this respect, the use of a robust, cost-effective and predictive animal model that recapitulates features of both human infection and vaccination is currently a much-needed tool. We discuss here the major limitations faced by modern vaccinology and notably, the development of humanized mice for assessing the immune system, along with their potential as vaccine models.
[Show abstract][Hide abstract] ABSTRACT: Transcutaneous immunization (TCI) requires targeting of a maximum number of skin antigen-presenting cells as non-invasive as possible on small skin areas. In two clinical trials, we introduced cyanoacrylate skin surface stripping (CSSS) as a safe method for TCI. Here, using ex vivo human skin, we demonstrate that one CSSS procedure removed only 30% of stratum corneum, but significantly increased the penetration of 200nm polystyrene particles deep into vellus and intermediate hair follicles from where they could not been retrieved by conventional tape stripping. Two subsequent CSSS had no striking additional effect. CSSS increased particle penetration in superficial stratum corneum and induced Langerhans cell activation. Formulation in amphiphilic ointment or massage did not substantially influence the interfollicular penetration profiles. Hair follicle targeting by CSSS could become a highly effective tool for TCI when combined with carrier-based delivery and is gaining new attention as our understanding on the hair follicle immune system increases.This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Skin vaccination aims at targeting epidermal and dermal antigen-presenting cells (APCs), indeed many subsets of different origin endowed with various functions populate the skin. The idea that the skin could represent a particularly potent site to induce adaptive and protective immune response emerged after the success of vaccinia virus vaccination by skin scarification. Recent advances have shown that multiple subsets of APCs coexist in the skin and participate in immunity to infectious diseases. Induction of an adaptive immune response depends on the initial recognition and capture of antigens by skin APCs and their transport to lymphoid organs. Innovative strategies of vaccination have thus been developed to target skin APCs for tailored immunity, hence this review will discuss recent insights into skin APC subsets characterization and how they can shape adaptive immune responses.
Human Vaccines and Immunotherapeutics 08/2014; 11(1). DOI:10.4161/hv.34299 · 2.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: As the primary protective barrier of the body, the skin plays a crucial role of immune-surveillance through a highly diverse skin immune system. Epidermal and dermal skin layers are particularly rich in antigen presenting cells (APCs): Langerhans cells (LCs) and several subsets of dermal dendritic cells (DCs) endowed with specific roles in capturing antigens, initiating and driving the appropriate adaptive immune response against antigen intrusion (1).This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: The magnitude, quality, and maintenance of immunological memory after infection or vaccination must be considered for future design of effective influenza vaccines. In 2009, the influenza pandemic produced disease that ranged from mild to severe, even fatal, illness in infected healthy adults and led to vaccination of a portion of the population with the adjuvanted, inactivated influenza A(H1N1)pdm09 vaccine. Here, we have proposed a multiparameter quantitative and qualitative approach to comparing adaptive immune memory to influenza 1 year after mild or severe infection or vaccination. One year after antigen encounter, severely ill subjects maintained high levels of humoral and polyfunctional effector/memory CD4+ T cells responses, while mildly ill and vaccinated subjects retained strong cellular immunity, as indicated by high levels of mucosal homing and degranulation markers on IFN-γ+ antigen-specific T cells. A principal component analysis distinguished 3 distinct clusters of individuals. The first group comprised vaccinated and mildly ill subjects, while clusters 2 and 3 included mainly infected individuals. Each cluster had immune memory profiles that differed in magnitude and quality. These data provide evidence that there are substantial similarities between the antiinfluenza response that mildly ill and vaccinated individuals develop and that this immune memory signature is different from that seen in severely ill individuals.
[Show abstract][Hide abstract] ABSTRACT: It is accepted that an effective prophylactic HIV-1 vaccine is likely to have the greatest impact on viral transmission rates. As previous reports have implicated DNA-priming, protein boost regimens to be efficient activators of humoral responses, we sought to optimize this regimen to further augment vaccine immunogenicity. Here we evaluated single versus concurrent intradermal (i.d.) and intramuscular (i.m.) vaccinations as a DNA-priming strategy for their abilities to elicit humoral and cellular responses against a model HIV-1 vaccine antigen, CN54-gp140. To further augment vaccine-elicited T and B cell responses, we enhanced cellular transfection with electroporation and then boosted the DNA-primed responses with homologous protein delivered subcutaneously (s.c.), intranasally (i.n.), i.m., or transcutaneously (t.c.). In mice, the concurrent priming regimen resulted in significantly elevated gamma interferon T cell responses and high-avidity antigen-specific IgG B cell responses, a hallmark of B cell maturation. Protein boosting of the concurrent DNA strategy further enhanced IgG concentrations but had little impact on T cell reactivity. Interestingly protein boosting by the subcutaneous route increased antibody avidity to a greater extent than protein boosting by either the i.m., i.n., or t.c. route, suggesting that this route may be preferential for driving B cell maturation. Using an alternative and larger animal model, the rabbit, we found the concurrent DNA-priming strategy followed by s.c. protein boosting to again be capable of eliciting high-avidity humoral responses and to also be able to neutralize HIV-1 pseudoviruses from diverse clades (clades A, B, and C). Taken together, we show that concurrent multiple-route DNA vaccinations induce strong cellular immunity, in addition to potent and high-avidity humoral immune responses.
Journal of Virology 04/2014; 88(12). DOI:10.1128/JVI.00183-14 · 4.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Activating different adaptive immune component is required to confer long-time protection against influenza viruses. By investigating the co-mobilization of immune compartments following A/H1N1 2009 pandemic vaccine (A(H1N1)pdm09 influenza vaccine–Panenza®, Sanofi Pasteur), we show that multiple vaccination with 2000-2003 seasonal influenza vaccines leads to a broader immune repertoire than the one theoretically expected by vaccine strains. Moreover, in case of contact with strains previously encountered, the A(H1N1)pdm09-specific immune response is extended to non-humoral immune components (i.e. CD8+ and/or CD4+ T-cells response).
European geriatric medicine 04/2014; 5(2). DOI:10.1016/j.eurger.2014.01.010 · 0.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Rationale: The biology of fatal pandemic influenza infection remains undefined. Methods: This multicenter study included 34 unvaccinated patients with very severe or fatal confirmed influenza A(H1N1) infections. It analyzed plasma A(H1N1) 2009 RT-PCR, hemagglutinin 222G viral mutation, and humoral and cellular immune responses to the virus, assessed in hemagglutination inhibition (HI), microneutralization, ELISA, lymphoproliferative, ELISpot IFN-, and cytokine/chemokine assays. Measurements and Main Results: The patients' median age was 34 years. Influenza A(H1N1) 2009 viremia was detected in 4/34 cases, and a 222G hemagglutinin mutation in 7/17 cases, all of them with SOFA≥8. HI antibodies were detectable in 19/26 survivors and undetectable in all 6 fatal fulminant cases. ELISA and microneutralization titers were concordant. B-cell immunophenotyping and plasma levels of immunoglobulin classes did not differ between patients who survived and died. After immune complex dissociation, influenza ELISA serology became strongly positive in the bronchoalveolar lavage of the 2 fatal cases tested. H1N1-specific T-cell responses in lymphoproliferative and IFN- assays were weak in survivors' peripheral blood, and lymphoproliferative assays were negative in the 3 fatal cases tested. Plasma levels of IL-6 and IL-10 were high in fatal cases and correlated with severity. Finally, a negative HI serology 4 days after the onset of influenza symptoms predicted death from fulminant influenza (p=0.04). Conclusions: Early negative A(H1N1) 2009 HI serology can predict death from influenza. This negative serology in fatal cases in young adults reflects the trapping of anti-H1N1 antibodies in immune complexes in the lungs, associated with poor specific helper T-cell response.
American Journal of Respiratory and Critical Care Medicine 03/2014; 189(10). DOI:10.1164/rccm.201311-2071OC · 13.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Transcutaneous immunization is a promising vaccination strategy for the treatment of infectious diseases and cancer. In this study, we investigate the combination of cyanoacrylate skin surface stripping (CSSS) and particle-based antigen delivery to target the HIV-1 p24 protein to skin antigen presenting cells (APC). The CSSS treatment pre-activates skin APC and opens hair follicles, where protein-loaded particles accumulate and allow for sustained delivery of the loaded antigen to perifollicular APC. We found that poly-lactic acid and (PLA) polystyrene (PS) particles targeted the adsorbed HIV-1 p24 protein to the hair follicles. Small amounts of PS and PLA particles were found to translocate to the epidermis and be internalized by skin cells, whereas most of the particles aggregated in the hair follicle canal, where they released the loaded antigen. The p24 protein diffused to the epidermis and dermis and was detected in skin cells, especially in Langerhans cells and dermal dendritic cells. Furthermore, the combination of CSSS and particle-based delivery resulted in activation and maturation of Langerhans cells (HLA-DR, CD80, CD83). We conclude that particle-based antigen delivery across partially disrupted skin barrier is a feasible and effective approach to needle-free transcutaneous vaccination.
[Show abstract][Hide abstract] ABSTRACT: Most vaccines, including those against influenza, were developed by focusing solely on humoral response for protection. However, vaccination activates different adaptive compartments that might play a role in protection. We took advantage of the pandemic 2009 A(H1N1) influenza vaccination to conduct a longitudinal integrative multiparametric analysis of seven immune parameters in vaccinated subjects. A global analysis underlined the predominance of induction of humoral and CD4 T cell responses, whereas pandemic 2009 A(H1N1)-specific CD8 responses did not improve after vaccination. A principal component analysis and hierarchical clustering of individuals showed a differential upregulation of influenza vaccine-specific immunity including hemagglutination inhibition titers, IgA(+) and IgG(+) Ab-secreting cells, effector CD4 or CD8 T cell frequencies at day 21 among individuals, suggesting a fine-tuning of the immune parameters after vaccination. This is related to individual factors including the magnitude and quality of influenza-specific immune responses before vaccination. We propose a graphical delineation of immune determinants that would be essential for a better understanding of vaccine-induced immunity in vaccination strategies.
The Journal of Immunology 06/2013; 191(2). DOI:10.4049/jimmunol.1203483 · 4.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Expression of the CC chemokine receptor 1 (CCR1) by tumor cells has been associated with protumoral activity; however, its role in nontumoral cells during tumor development remains elusive. Here, we investigated the role of CCR1 deletion on stromal and hematopoietic cells in a liver metastasis tumor model. Metastasis development was strongly impaired in CCR1-deficient mice compared to control mice and was associated with reduced liver monocyte infiltration. To decipher the role of myeloid cells, sublethally irradiated mice were reconstituted with CCR1-deficient bone marrow (BM) and showed better survival rates than the control reconstituted mice. These results point toward the involvement of CCR1 myeloid cell infiltration in the promotion of tumor burden. In addition, survival rates were extended in CCR1-deficient mice receiving either control or CCR1-deficient BM, indicating that host CCR1 expression on nonhematopoietic cells also supports tumor growth. Finally, we found defective tumor-induced neoangiogenesis (in vitro and in vivo) in CCR1-deficient mice. Overall, our results indicate that CCR1 expression by both hematopoietic and nonhematopoietic cells favors tumor aggressiveness. We propose CCR1 as a potential therapeutical target for liver metastasis therapy.
Neoplasia (New York, N.Y.) 06/2013; 15(6):641-8. DOI:10.1593/neo.121866 · 4.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Every year, the National Foundation for Infectious Diseases brings together more than 300 participants to review progress in vaccine research and development and identify the most promising avenues of research. These conferences are among the most important scientific meetings entirely dedicated to vaccine research for both humans and animals, and provide a mix of plenary sessions with invited presentations by acknowledged international experts, parallel sessions, poster sessions, and informal exchanges between experts and young researchers. During the Fifteenth Conference that took place in Baltimore in May 2012, various topics were addressed, including the scientific basis for vaccinology; exploration of the immune response; novel vaccine design; new adjuvants; evaluation of the impact of newly introduced vaccines (such as rotavirus, HPV vaccines); vaccine safety; and immunization strategies. The new techniques of systems biology allow for a more comprehensive approach to the study of immune responses in order to identify correlates of protection and to design novel vaccines against chronic diseases such as AIDS or malaria, against which natural immunity is incomplete.
Archives de Pédiatrie 04/2013; 20(4):449–458. DOI:10.1016/j.arcped.2013.01.003 · 0.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: For years, most vaccines have been administered via the intramuscular or subcutaneous routes. New attractive alternatives to vaccine delivery via hair follicle or intradermal (ID) routes have therefore been developed. Vaccines based on solid or biodegradable nanoparticles (NPs), virus-like particle, virosomes, liposomes have shown promise as good approaches to recombinant proteins for immunization. The potential for ID or transcutaneous NPs-based vaccines with patch or tape-stripping has been validated with several vaccine models in animals studies and human clinical trials. Skin-immunization with conventional vaccine are comparable and are sometimes superior when compared to conventional vaccination. More human clinical trials are necessary to evaluate the efficacy of particle-based vaccines, including specific patient populations such as immunocompromised patients.
Nanotechnology in Dermatology, 01/2013: pages 165-178; , ISBN: 978-1-4614-5033-7
[Show abstract][Hide abstract] ABSTRACT: Over the past years, hair follicles have gained a lot of interest in the field of skin penetration research as they represent an important penetration pathway for topically applied substances. They function as reservoirs [1, 2] and also as portals of entry to the viable skin layers . Under physiological conditions the intact stratum corneum significantly impairs skin penetration, especially of large hydrophilic molecules and particulate structures. Hair follicles, in contrast, represent interruptions in this barrier and the importance of the transfollicular route of penetration has been demonstrated by several independent studies on various animal skin models, where hairy skin was compared with hair follicle-free skin areas [4, 5]. The role of the follicular penetration pathway compared to transepidermal route was also demonstrated by selective blockage of the follicular orifices in porcine ear skin  as well as human skin explants . In vivo experiments with caffeine applied as shampoo formulations on skin with open or sealed hair follicles further underlined the importance of hair follicles for the transdermal permeation and systemic delivery of hydrophilic drugs . The follicular route seems to be of special importance for particle penetration in skin. Particulate structures ranging from liposomes to solid inorganic particles and microspheres up to a diameter of 10 μm were shown to aggregate and remain in hair follicle openings. Such observations provided the basis for the idea of hair follicle targeting with particulate drug carriers . Modifications of nanoparticle physicochemical properties, use of permeabilizing agents, as well as partial removal of the stratum corneum are some of the methods which were shown to increase the hair follicle penetration of drug-loaded nanoparticles as well as their targeting ability [10, 11]. In the following chapter, we outline how hair follicles act as entry pathway and reservoir structure for topically applied particles. We review the penetration properties of specific particle types and the influence of hair follicle parameters, e.g., hair follicle types, growth activity, and sebum production as modifying factors of particle–skin interactions. In fact, studies by our group and others strongly suggest that the hair follicle provides an important interface for such interactions. Nanoparticle-based hair follicle targeting aims at utilizing these interactions for therapeutic purposes, e.g., to deliver functionalized particles loaded with active compounds selectively to the hair follicles or even to specific skin compartments and cell populations. Particle-based targeting of hair follicles may include deposition of active compounds in the follicular reservoir, targeting of active compounds to specific compartments within the follicular duct, e.g., sebaceous gland, stem cell region, or even targeting of specific cell populations such as perifollicular antigen-presenting cells (Fig. 9.1).
Nanotechnology in Dermatology, 01/2013: pages 95-107; , ISBN: 978-1-4614-5033-7
[Show abstract][Hide abstract] ABSTRACT: The bone marrow (BM) has been identified as a possible organ for T cell priming, yet the fundamental mechanisms of a polyclonal immune response in the BM remain unknown. We found that after intradermal injection of modified vaccinia Ankara virus, unexpected sources of newly primed polyclonal virus-specific CD8(+), but not CD4(+), T cells were localized in the BM and the draining lymph nodes (dLNs) prior to blood circulation. We identified neutrophils as the virus-carrier cells from the dermis to the BM. In both neutrophil-depleted and Ccr1(-/-) mice, virus-specific BM CD8(+) responses were lost. Myeloid antigen-presenting cells were required for BM CD8(+) T cell priming. A systems biology analysis of dLN and BM virus-specific CD8(+) T cells revealed distinct transcriptional and multifunctional profiles for cells primed in each organ. We provide direct evidence for how antigen is transported to the BM, providing a source of virus-specific memory CD8(+) T cells.
[Show abstract][Hide abstract] ABSTRACT: While the immunological correlates of hepatitis C virus (HCV)-specific immunity are not well understood, it is now admitted that an effective vaccine against HCV will need to induce both cellular and humoral immune responses and address viral heterogeneity to prevent immune escape. We developed a vaccine platform specifically aimed at inducing such responses against HCV antigens displayed by recombinant retrovirus-based virus-like particles (VLPs) made of Gag of murine leukemia virus. Both ex vivo produced VLPs and plasmid DNA encoding VLPs can be used as vaccines. Here, we report that immunizations with plasmid DNA forming VLPs pseudotyped with HCV E1 and E2 envelope glycoproteins (HCV-specific plasmo-retroVLPs) induce strong T-cell-mediated immune responses that can be optimized by using proper DNA delivery methods and/or genetic adjuvants. Additionally, multigenotype or multi-specific T-cell responses were observed after immunization with plasmids that encode VLPs pseudotyped with E1E2 derived from numerous viral genotypes and/or displaying NS3 antigen in capsid proteins. While homologous prime-boost immunizations with HCV-specific plasmo-retroVLPs or ex vivo produced VLPs induce a low level of specific antibody responses, optimal combination of plasmo-retroVLPs and VLPs was identified for inducing HCV-specific T-cell and B-cell responses as well as neutralizing antibodies. Altogether, these results have important meanings for the development of anti-HCV preventive vaccines and exemplify the flexibility and potential of our retrovirus-based platform in inducing broad cellular and humoral immune responses.
[Show abstract][Hide abstract] ABSTRACT: The protective host immune response to viral infections requires both effective innate and adaptive immune responses. Cross-talk between the two responses is coordinated by the chemokine network and professional APCs such as dendritic cells (DCs). In mice, subpopulations of myeloid DCs in peripheral tissues such as lungs and in blood express CX3CR1 depending on the inflammation state. We thus examined the host response of mice deficient in the chemokine receptor CX3CR1 to an intranasal vaccinia virus infection. CX3CR1-deficient mice displayed significantly more severe morbidity and mortality compared with control wild-type mice within 10 d following vaccinia virus infection. CX3CR1(-/-) mice had increased viral loads and a reduced T cell response compared with wild-type mice. Finally, an adoptive transfer of CX3CR1(+/+) DCs completely protected CX3CR1(-/-) mice to a previously lethal infection. This study therefore opens up the possibility of novel antiviral therapeutics targeting lung DC recruitment.
The Journal of Immunology 01/2012; 188(3):952-6. DOI:10.4049/jimmunol.1004164 · 4.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The potential of the skin immune system for the generation of both powerful humoral and cellular immune responses is now well established. However, the mechanisms responsible for the efficacy of skin antigen-presenting cells (APCs) during intradermal (ID) vaccination still remain to be elucidated. We have previously demonstrated in clinical trials that preferential targeting of Langerhans cells (LCs) by transcutaneous immunization shapes the immune response toward vaccine-specific CD8 T cells. Others have shown that ID inoculation of a vaccine, which targets dermal APCs, mobilizes both the cellular and humoral arms of immunity. Here, we investigated the participation of epidermal LCs in response to ID immunization. When human or mouse skin was injected ID with a particle-based vaccine, we observed significant modifications in the morphology of epidermal LCs and their mobilization to the dermis. We further established that this LC recruitment after ID administration was essential for the induction of antigen-specific CD8 T cells, but was, however, dispensable for the generation of specific CD4 T cells and neutralizing antibodies. Thus, epidermal and dermal APCs shape the outcome of the immune responses to ID vaccination. Their combined potential provides new avenues for the development of vaccination strategies against infectious diseases.