A single subcutaneous or intranasal immunization with adenovirus-based SARS-CoV-2 vaccine induces robust humoral and cellular immune responses in mice

Optimal vaccines are needed for sustained suppression of SARS-CoV-2 and other novel coronaviruses. Here, we developed a recombinant type 5 adenovirus vector encoding the gene for the SARS-CoV-2 S1 subunit antigen (Ad5.SARS-CoV-2-S1) for COVID-19 immunization and evaluated its immunogenicity in mice. A single immunization with Ad5.SARS-CoV-2-S1 via S.C. injection or I.N delivery induced robust antibody and cellular immune responses. Vaccination elicited significant S1-specific IgG, IgG1, and IgG2a endpoint titers as early as 2 weeks, and the induced antibodies were long lasting. I.N. and S.C. administration of Ad5.SARS-CoV-2-S1 produced S1-specific GC B cells in cervical and axillary LNs, respectively. Moreover, I.N. and S.C. immunization evoked significantly greater antigen-specific T-cell responses compared to unimmunized control groups with indications that S.C. injection was more effective than I.N. delivery in eliciting cellular immune responses. Mice vaccinated by either route demonstrated significantly increased virus-specific neutralization antibodies on weeks 8 and 12 compared to control groups, as well as BM antibody forming cells (AFC), indicative of long-term immunity. Thus, this Ad5-vectored SARS-CoV-2 vaccine candidate showed promising immunogenicity following delivery to mice by S.C. and I.N. routes of administration, supporting the further development of Ad-based vaccines against COVID-19 and other infectious diseases for sustainable global immunization programs.

Skin delivery of hapten and neurokinin-1 receptor antagonists by microneedle arrays targets neurogenic inflammation and prevents contact dermatitis

Contact dermatitis (CD) is a chronic inflammatory disease caused by type-1 immunity. Skin exposure to haptens stimulates the secretion of Substance-P (SP) and initiates the neurogenic inflammation that intensifies CD. Neurokinin-1 receptor (NK1R)-signaling by SP or hemokinin-1 (HK1) amplifies immune responses. Nonetheless, the role and therapeutic implications of the NK1R-SP-HK1 axis in CD remain unclear. We show that SP, HK-1 and the NK1R are required for CD. Specific deletion of the NK1R in keratinocytes decreased the rapid release of IL-1β and IL-6 at the site of contact sensitization which impaired the innate and adaptive immunity of CD whereas deletion of the receptor in dendritic cells (DC) prevented only the adaptive immune response of the disease. Therefore, we hypothesized that blockade of NK1R during sensitization would be a feasible immunosuppressive intervention to treat CD. We developed a system of microneedle arrays (MNA) that co-deliver hapten and NK1R antagonists into mouse skin. This immunosuppressive approach resulted in decreased skin migration and lymph node homing of stimulatory dermal DC transporting the hapten from the sensitization site. Conversely, the immunosuppressive MNA did not affect the migration and lymph node homing of epidermal Langerhans cells (LC), and depletion of LC resulted in loss of the NK1R antagonist beneficial effects. In addition, immunosuppressive MNA caused deletion of hapten-specific T cells and increased T-regulatory cells, which prevented CD-onset and -relapses in a hapten-specific manner. Our findings indicate that immune-regulation by engineering localized skin neuroimmune-networks can be used to treat cutaneous diseases that, like CD are caused by type-1 immunity.

Graft-derived extracellular vesicles transported across subcapsular sinus macrophages elicit B cell alloimmunity after transplantation

Despite the role of donor-specific antibodies (DSAs) in recognizing major histocompatibility complex (MHC) antigens and mediating transplant rejection, how and where recipient B cells in lymphoid tissues encounter donor MHC antigens remains unclear. Contrary to the dogma, we demonstrated here that migration of donor leukocytes out of skin or heart allografts is not necessary for B or T cell allosensitization in mice. We found that mouse skin and cardiac allografts and human skin grafts release cell-free donor MHC antigens via extracellular vesicles (EVs) that are captured by subcapsular sinus (SCS) macrophages in lymph nodes or analog macrophages in the spleen. Donor EVs were transported across the SCS macrophages, and donor MHC molecules on the EVs were recognized by alloreactive B cells. This triggered B cell activation and DSA production, which were both prevented by SCS macrophage depletion. These results reveal an unexpected role for graft-derived EVs and open venues to interfere with EV biogenesis, trafficking, or function to restrain priming or reactivation of alloreactive B cells.

Emerging skin-targeted drug delivery strategies to engineer immunity: A focus on infectious diseases

INTRODUCTION

Infectious pathogens are global disrupters. Progress in biomedical science and technology has expanded the public health arsenal against infectious diseases. Specifically, vaccination has reduced the burden of infectious pathogens. Engineering systemic immunity by harnessing the cutaneous immune network has been particularly attractive since the skin is an easily accessible immune-responsive organ. Recent advances in skin-targeted drug delivery strategies have enabled safe, patient-friendly, and controlled deployment of vaccines to cutaneous microenvironments for inducing long-lived pathogen-specific immunity to mitigate infectious diseases, including COVID-19.

AREAS COVERED

This review briefly discusses the basics of cutaneous immunomodulation and provides a concise overview of emerging skin-targeted drug delivery systems that enable safe, minimally invasive, and effective intracutaneous administration of vaccines for engineering systemic immune responses to combat infectious diseases.

EXPERT OPINION

In-situ engineering of the cutaneous microenvironment using emerging skin-targeted vaccine delivery systems offers remarkable potential to develop diverse immunization strategies against pathogens. Mechanistic studies with standard correlates of vaccine efficacy will be important to compare innovative intracutaneous drug delivery strategies to each other and to existing clinical approaches. Cost-benefit analyses will be necessary for developing effective commercialization strategies. Significant involvement of industry and/or government will be imperative for successfully bringing novel skin-targeted vaccine delivery methods to market for their widespread use.

Blockade of the neurokinin-1 receptor in keratinocytes prevents neuroinflammation and decreases innate and adaptive immune responses in the skin

Substance P (SP) is a proinflammatory neuropeptide that following Ag entrance in peripheral tissues signals via the neurokinin 1 receptor (NK1R) to initiate innate and support adaptive cellular immune responses. These mechanisms underlie chronic skin inflammatory disorders like contact dermatitis (CD). Here we propose to develop an immunosuppressive method to prevent and treat CD by blocking the effects of SP during skin sensitization with haptens. We utilized microneedle arrays to efficiently deliver the hapten 2,4-dinitrocholorobencene (DNCB) and NK1R antagonists simultaneously to the skin of C57/BL6 mice. This approach, restrained neuroinflammation, increased T regulatory cells and decreased the viability of Th1 and Tc1 biased cells in the draining lymph nodes. Together these effects inhibited local and systemic CD and prevented its relapses. Using the Cre-Lox P system, we demonstrate that specific deletion of the NK1R in keratinocytes but not in leukocytes inhibited the sensitization phase of CD by blocking the release of IL-1β and IL-6. Whereas deletion of the receptor in keratinocytes or in dendritic cells was necessary to abrogate the adaptive cellular immunity. Our data demonstrate the possibility of preventing the development of cellular immunity by engineering the skin microenvironment to restrain the effects of neuroinflammatory peptides accounting for the onset of chronic skin inflammatory diseases.

Microneedle array delivered recombinant coronavirus vaccines: Immunogenicity and rapid translational development

BACKGROUND

Coronaviruses pose a serious threat to global health as evidenced by Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and COVID-19. SARS Coronavirus (SARS-CoV), MERS Coronavirus (MERS-CoV), and the novel coronavirus, previously dubbed 2019-nCoV, and now officially named SARS-CoV-2, are the causative agents of the SARS, MERS, and COVID-19 disease outbreaks, respectively. Safe vaccines that rapidly induce potent and long-lasting virus-specific immune responses against these infectious agents are urgently needed. The coronavirus spike (S) protein, a characteristic structural component of the viral envelope, is considered a key target for vaccines for the prevention of coronavirus infection.

METHODS

We first generated codon optimized MERS-S1 subunit vaccines fused with a foldon trimerization domain to mimic the native viral structure. In variant constructs, we engineered immune stimulants (RS09 or flagellin, as TLR4 or TLR5 agonists, respectively) into this trimeric design. We comprehensively tested the pre-clinical immunogenicity of MERS-CoV vaccines in mice when delivered subcutaneously by traditional needle injection, or intracutaneously by dissolving microneedle arrays (MNAs) by evaluating virus specific IgG antibodies in the serum of vaccinated mice by ELISA and using virus neutralization assays. Driven by the urgent need for COVID-19 vaccines, we utilized this strategy to rapidly develop MNA SARS-CoV-2 subunit vaccines and tested their pre-clinical immunogenicity in vivo by exploiting our substantial experience with MNA MERS-CoV vaccines.

FINDINGS

Here we describe the development of MNA delivered MERS-CoV vaccines and their pre-clinical immunogenicity. Specifically, MNA delivered MERS-S1 subunit vaccines elicited strong and long-lasting antigen-specific antibody responses. Building on our ongoing efforts to develop MERS-CoV vaccines, promising immunogenicity of MNA-delivered MERS-CoV vaccines, and our experience with MNA fabrication and delivery, including clinical trials, we rapidly designed and produced clinically-translatable MNA SARS-CoV-2 subunit vaccines within 4 weeks of the identification of the SARS-CoV-2 S1 sequence. Most importantly, these MNA delivered SARS-CoV-2 S1 subunit vaccines elicited potent antigen-specific antibody responses that were evident beginning 2 weeks after immunization.

INTERPRETATION

MNA delivery of coronaviruses-S1 subunit vaccines is a promising immunization strategy against coronavirus infection. Progressive scientific and technological efforts enable quicker responses to emerging pandemics. Our ongoing efforts to develop MNA-MERS-S1 subunit vaccines enabled us to rapidly design and produce MNA SARS-CoV-2 subunit vaccines capable of inducing potent virus-specific antibody responses. Collectively, our results support the clinical development of MNA delivered recombinant protein subunit vaccines against SARS, MERS, COVID-19, and other emerging infectious diseases.

Reciprocal immune enhancement of dengue and Zika virus infection in human skin

Dengue virus (DENV) and Zika virus (ZIKV) are closely related mosquito-borne flaviviruses that co-circulate in tropical regions and constitute major threats to global human health. Whether preexisting immunity to one virus affects disease caused by the other during primary or secondary infections is unknown but is critical in preparing for future outbreaks and predicting vaccine safety. Using a human skin explant model, we show that DENV-3 immune sera increased recruitment and infection of Langerhans cells, macrophages, and dermal dendritic cells following inoculation with DENV-2 or ZIKV. Similarly, ZIKV immune sera enhanced infection with DENV-2. Immune sera increased migration of infected Langerhans cells to the dermis and emigration of infected cells out of skin. Heterotypic immune sera increased viral RNA in the dermis almost 10-fold and reduced the amount of virus required to infect a majority of myeloid cells by 100- to 1000-fold. Enhancement was associated with cross-reactive IgG and induction of IL-10 expression and was mediated by both CD32 and CD64 Fcγ receptors. These findings reveal that preexisting heterotypic immunity greatly enhances DENV and ZIKV infection, replication, and spread in human skin. This relevant tissue model will be valuable in assessing the efficacy and risk of dengue and Zika vaccines in humans.

Dissolving undercut microneedle arrays for multicomponent cutaneous vaccination

The skin is an attractive tissue target for vaccination, as it is readily accessible and contains a dense population of antigen-presenting and immune-accessory cells. Microneedle arrays (MNAs) are emerging as an effective tool for in situ engineering of the cutaneous microenvironment to enable diverse immunization strategies. Here, we present novel dissolving undercut MNAs and demonstrate their application for effective multicomponent cutaneous vaccination. The MNAs are composed of micron-scale needles featuring pyramidal heads supported by undercut stem regions with filleted bases to ensure successful skin penetration and retention during application. Prior efforts to fabricate dissolving undercut microstructures were limited and required complex and lengthy processing and assembly steps. In the current study, we strategically combine three-dimensional (3D) laser lithography, an emerging micro-additive manufacturing method with unique geometric capabilities and nanoscale resolution, and micromolding with favorable materials. This approach enables reproducible production of dissolving MNAs with undercut microneedles that can be tip-loaded with multiple biocargos, such as antigen (ovalbumin) and adjuvant (Poly(I:C)). The resulting MNAs fulfill the geometric (sharp tips and smooth edges) and mechanical-strength requirements for failure-free penetration of human and murine skin to simultaneously deliver multicomponent (antigen plus adjuvant) vaccines to the same cutaneous microenvironment. Cutaneous vaccination of mice using these MNAs induces more potent antigen-specific cellular and humoral immune responses than those elicited by traditional intramuscular injection. Together, the unique geometric features of these undercut MNAs and the associated manufacturing strategy, which is compatible with diverse drugs and biologics, could enable a broad range of non-cutaneous and cutaneous drug delivery applications, including multicomponent vaccination.

Restraining neuroinflammation during antigen delivery as an immunosuppressive approach to prevent and treat contact dermatitis

Neuroinflammation promotes the initiation and sustains chronic inflammatory disorders. Substance-P, released by sensory neurons, is the prototype neuropeptide that signals via the neurokinin 1 receptor (NK1R) to enhance cellular immunity. We observed that NK1RKO or SPKO mice do not develop contact dermatitis (CD). Hence, we hypothesized that limiting neuroinflammation during Ag entrance induces an immune-suppressive environment to prevent T cell priming and eliminate memory T cells that cause CD. We co-delivered OVA or 2,4-dinitrocholorobencene (DNCB) and two different NK1R antagonists during sensitization of a DTH reaction induced to C57/BL6 mice reconstituted or not with OTI and OTII cells. For efficient skin delivery, we generated microneedle arrays loaded with OVA or DNCB and NK1R antagonists. We demonstrate that our approach prevents the innate and adaptive immunity accounting for the initiation of CD and mitigates pre-existing pathogenic memory T cells that cause local or systemic CD relapses. Mechanistic studies demonstrate that NK1R antagonists suppress the release of pro-inflammatory cytokines in the skin, promote the death of activated CD4 Th1 and CD8 T-cells, and generate Tregs in the skin draining lymph nodes. Our data demonstrates that controlling neuroinflammation during Ag entrance prevents the generation of pathogenic effector and memory T cells accounting for the initiation and relapses of chronic inflammatory skin disorders like CD. NIH R01 AR068249 and AR071277 to ATL and LDF.

Evaluation of Different Formulations and Routes for the Delivery of the Ionizing Radiation Mitigator GS-Nitroxide (JP4-039)

BACKGROUND/AIM

The mitochondrial targeted GS-nitroxide, JP4-039, is an effective total body irradiation (TBI) mitigator when delivered intravenously (IV) up to 72 h after exposure. Effective systemic and localized administration to oral cavity/oropharynx and esophagus has been demonstrated. The objective of the study was to establish alternatives to IV administration suitable for JP4-039 delivery to mass casualties.

MATERIALS AND METHODS

JP4-039 was administered to C57BL/6 mice by topically applied carboxy-methyl-cellulose microneedle arrays (MNAs) or by intramuscular (IM) injection. Three different formulations that have passed Food and Drug Administration review, namely Captisol, 2-hydroxypropyl-β-cyclodextrin (cyclodextrin), and Miglyol-812-N, were used for drug delivery. Intraoral (IO) administration with each formulation was also evaluated.

RESULTS

All tested formulations and MNAs successfully delivered JP4-039. However, IM delivery of the Miglyol-812-N displayed very efficient and highly reproducible radiation mitigation.

CONCLUSION

Effective IM delivery of JP4-039 in animal models after TBI or partial-body irradiation suggested the use of the Miglyol-812-N formulation in both medical indications and radiation countermeasures.

Interplay between Keratinocytes and Myeloid Cells Drives Dengue Virus Spread in Human Skin

The skin is the site of dengue virus (DENV) transmission following the bite of an infected mosquito, but the contribution of individual cell types within skin to infection is unknown. We studied the dynamics of DENV infection in human skin explants using quantitative in situ imaging. DENV replicated primarily in the epidermis and induced a transient IFN-α response. DENV infected a wide range of cells, including Langerhans cells, macrophages, dermal dendritic cells, mast cells, fibroblasts, and lymphatic endothelium, but keratinocytes were the earliest targets of infection and made up 60% of infected cells over time. Virus inoculation led to recruitment and infection of Langerhans cells, macrophages, and dermal dendritic cells, and these cells emigrated from skin in increased numbers as a result of infection. DENV induced expression of proinflammatory cytokines and chemokines by infected keratinocytes. Blocking keratinocyte-derived IL-1β alone reduced infection of Langerhans cells, macrophages, and dermal dendritic cells by 75-90% and reduced the overall number of infected cells in dermis by 65%. These data show that the innate response of infected keratinocytes attracts virus-permissive myeloid cells that inadvertently spread DENV infection. Our findings highlight a role for keratinocytes and their interplay with myeloid cells in dengue.

Topical chemo-immunotherapy converts a pro-tumorigenic tumor microenvironment to a pro-inflammatory phenotype in human cutaneous squamous cell carcinoma

We have previously demonstrated that microneedle array (MNA) delivery of anti-tumor agents improves survival in mouse models of melanoma and non-melanoma skin cancers and induces cell death in freshly excised human cutaneous squamous cell carcinomas (cSCCs). As tumors employ strong immunosuppressive and tumor-promoting mechanisms that prevent their elimination by immune surveillance mechanisms and support their proliferation, we sought to determine if application of MNAs containing anti-tumor agents could abrogate their protumorigenic phenotype and promote an anti-tumor phenotype in a human model of cSCC, the second most common human malignancy worldwide. To accomplish this, we compared Nanostring gene expression data from human cSCCs treated with MNAs containing doxorubicin (MNA-Dox) to matched, untreated cSCC controls and unmatched normal skin. As compared to matched, untreated cSCC controls, MNA-Dox-treated cSCCs demonstrated significantly decreased expression of genes associated with a pro-tumorigenic environment, including IDO, ARG2, S100A7 and VEGF-A. Further, MNA-Dox-treated cSCCs demonstrated significantly increased expression of genes associated with an anti-tumor phenotype, including CXCL14, HMGB1, P53, and Caspase-8. Comparison of MNA-Dox-treated cSCCs and unmatched, untreated normal skin suggested a reversion of a pro-tumorigenic phenotype to a normal skin phenotype, with similarly low expression of pro-tumorigenic genes seen in both groups. Together, these results suggest the potential of MNA-administered doxorubicin to effectively transform a pro-tumor microenvironment to one favoring the induction of tumor immunity in a human cSCC.

Preventative Vaccines for Zika Virus Outbreak: Preliminary Evaluation

Since it emerged in Brazil in May 2015, the mosquito-borne Zika virus (ZIKV) has raised global concern due to its association with a significant rise in the number of infants born with microcephaly and neurological disorders such as Guillain-Barré syndrome. We developed prototype subunit and adenoviral-based Zika vaccines encoding the extracellular portion of the ZIKV envelope gene (E) fused to the T4 fibritin foldon trimerization domain (Efl). The subunit vaccine was delivered intradermally through carboxymethyl cellulose microneedle array (MNA). The immunogenicity of these two vaccines, named Ad5.ZIKV-Efl and ZIKV-rEfl, was tested in C57BL/6 mice. Prime/boost immunization regimen was associated with induction of a ZIKV-specific antibody response, which provided neutralizing immunity. Moreover, protection was evaluated in seven-day-old pups after virulent ZIKV intraperitoneal challenge. Pups born to mice immunized with Ad5.ZIKV-Efl were all protected against lethal challenge infection without weight loss or neurological signs, while pups born to dams immunized with MNA-ZIKV-rEfl were partially protected (50%). No protection was seen in pups born to phosphate buffered saline-immunized mice. This study illustrates the preliminary efficacy of the E ZIKV antigen vaccination in controlling ZIKV infectivity, providing a promising candidate vaccine and antigen format for the prevention of Zika virus disease.

Precise vs General Feedback in Reducing Field-Dependence

To investigate the effect of feedback on performance of the Rod-and-frame Test the standard test procedure was altered. The result of the alteration was a procedure which was called the Rod-and-frame Test as a Learning Task. On this task the subject has to adjust the rod to the vertical twice in succession from each tilting position, whereby he is permitted a maximum of 10 trials in each tilting position and a range of tolerance of ±1°. After each trial the subject is given feedback about his performance. An experiment was conducted with 30 male and 30 female students to investigate whether a precise feedback giving both the direction and the degree of the rod's deviation from the vertical is more effective in reducing frame-dependence than a general feedback which states only the direction of deviation. The data were analyzed via analysis of variance with repeated measures on one factor. The results indicated a gradual improvement under precise feedback conditions for both men and women but under global feedback conditions only women improved their performance.

Tip-Loaded Dissolvable Microneedle Arrays Effectively Deliver Polymer-Conjugated Antibody Inhibitors of Tumor-Necrosis-Factor-Alpha Into Human Skin

Autoinflammatory skin diseases are characterized by a disequilibrium of cytokines in the local skin microenvironment, suggesting that local delivery of therapeutics, including anticytokine antibodies, may provide benefit without the unwanted off-target effects of systemically delivered therapies. Rapid diffusion of therapeutics away from the target site has been a challenge to the development of local therapies. Conjugation of high molecular weight hydrophilic polymers to cytokine neutralizing mAbs has been shown to be an effective strategy for local control of inflammation in healing burn wounds. However, the burn application is unique because the skin barrier is already breached. For the treatment of autoinflammatory skin diseases, the major challenge for local delivery lies in penetrating the stratum corneum. Here, we investigate a new therapeutic approach combining the use of tip-loaded dissolvable microneedle arrays (TL-dMNAs) for local application of polymer-conjugated antibody inhibitors of tumor-necrosis-factor-alpha (TNF-α). Specifically, intradermal delivery and pharmacokinetics of (anti-TNF-α-Ab)-(high molecular weight hyaluronic acid [HA]) conjugates from tip-loaded, obelisk-shaped dissolvable microneedle arrays were investigated in living human skin. The results indicate (1) TL-dMNAs can be successfully fabricated to integrate (anti-TNF-α-Ab)-HA at the tip portion of the microneedles while preserving the biological activity necessary for antibody ligand binding; (2) (anti-TNF-α-Ab)-HA can be effectively delivered into human skin using obelisk-shaped TL-dMNAs; and (3) polymer conjugation effectively inhibits antibody diffusion from the delivery site. Taken together, these results support the evaluation of microneedle array-based delivery of varying polymer-antibody conjugates for the treatment of inflammatory skin diseases.

Donor dendritic cell-derived exosomes promote allograft-targeting immune response

The immune response against transplanted allografts is one of the most potent reactions mounted by the immune system. The acute rejection response has been attributed to donor dendritic cells (DCs), which migrate to recipient lymphoid tissues and directly activate alloreactive T cells against donor MHC molecules. Here, using a murine heart transplant model, we determined that only a small number of donor DCs reach lymphoid tissues and investigated how this limited population of donor DCs efficiently initiates the alloreactive T cell response that causes acute rejection. In our mouse model, efficient passage of donor MHC molecules to recipient conventional DCs (cDCs) was dependent on the transfer of extracellular vesicles (EVs) from donor DCs that migrated from the graft to lymphoid tissues. These EVs shared characteristics with exosomes and were internalized or remained attached to the recipient cDCs. Recipient cDCs that acquired exosomes became activated and triggered full activation of alloreactive T cells. Depletion of recipient cDCs after cardiac transplantation drastically decreased presentation of donor MHC molecules to directly alloreactive T cells and delayed graft rejection in mice. These findings support a key role for transfer of donor EVs in the generation of allograft-targeting immune responses and suggest that interrupting this process has potential to dampen the immune response to allografts.

A topical chemo-immunotherapy for squamous cell carcinoma

We have previously demonstrated that dissolvable microneedle arrays can co-deliver cargos directly to the skin while avoiding systemic distribution. As squamous cell carcinoma (SCC) has a lifetime incidence of 7–11% in the United States and is the second most common non-melanoma skin cancer in persons of white European descent, we sought to determine if MNA delivery of anti-tumor agents induce cell death and improve survival in a mouse model of SCC and in freshly excised human SCCs. To accomplish this, we evaluated the effectiveness of doxorubicin, a chemotherapeutic demonstrated to induce immunogenic cell death, as an MNA delivered therapeutic. Effectiveness was evaluated in mice inoculated with SCC cells and later treated with Blank MNAs (MNA-Blank) or MNAs integrating doxorubicin (MNA-Dox), and in human SCCs treated with MNA-Dox. In mice, MNA-Dox treatment resulted in increased levels of pro-inflammatory cytokine gene expression, increased levels of cell death as determined by TUNEL assays, attenuated tumor growth, and substantially improved survival over MNA-Blank treatment at 20 days post-inoculation (100% survival in MNA-Dox group versus 0% survival in MNA-Blank group). Survival advantage persisted with 40% of MNA-Dox-treated mice alive at 40 days post-inoculation. Similarly, freshly excised human SCCs treated with MNA-Dox demonstrated increased levels of cell death as determined by TUNEL assays. Taken together, these results demonstrate the potential of MNA administration of doxorubicin to effectively induce tumor cell death in a murine model of squamous cell carcinoma and in human SCCs supporting further clinical development.

Polyguanine-conjugated antigens target scavenger receptors in dendritic cells and induce antitumor immunity against melanoma

We have developed a vaccine design involving the conjugation of polyguanine (Poly(dG)) to protein or peptide antigens for the specific targeting of scavenger receptors in dendritic cells with intrinsic adjuvant capabilities. We have shown that Poly(dG) conjugation to ovalbumin generates stable particle conjugates (Poly(dG)-OVA) that induce greater T cell (helper, cytotoxic, and memory) and antibody responses. In this study, we show that Poly(dG)-OVA treatment of DCs in vitro induces greater antigen internalization and expression of activation markers CD86, MHC II, and CCR7. In vivo, intradermal injection of Poly(dG)-OVA resulted in the formation of an antigen depot in the skin lasting for several days and an increase in recruited immune infiltrates. Increased association of Poly(dG)-OVA is observed with MHC II- and CD11c-expressing cells in the skin compared to OVA. This is accompanied by the expression of pro-inflammatory CCL2 and IL-6 in the skin. Poly(dG)-OVA was also able to internalize more in skin migrating DCs and was transported more efficiently to draining lymph nodes. Poly(dG)-OVA immunization of B16-OVA-bearing mice contributed to delayed tumor progression and improved survival. We also developed Poly(dG)-Mgp10025–33 and Poly(dG)-TRP2180–188 to study melanoma-specific responses. Immunization with the these conjugates led to significant peptide-specific in vivo cytotoxic T cell responses compared to unconjugated peptides. Mice with B16 tumors immunized with combined Poly(dG)-Mgp100 Poly(dG)-TRP2 had delayed tumor progression and improved survival. Our results show that Poly(dG) conjugation of antigens is an effective strategy for the development of antitumor vaccines with improved immune responses.

Therapeutic intradermal delivery of tumor necrosis factor-alpha antibodies using tip-loaded dissolvable microneedle arrays

Tumor necrosis factor-alpha (TNF-α) specific antibodies (anti-TNF-α Ab) have been shown to be potent TNF inhibitors and effective therapeutics for a range of inflammatory diseases. Typically, these drugs are administered systemically, but systemic dosing sufficient to achieve locally effective concentrations in peripheral tissues has been associated with systemic immunosuppression and related adverse events. Here, we evaluated the use of tip-loaded dissolvable microneedle arrays (MNAs) for localized intradermal delivery of anti-TNF-α Ab. MNAs with obelisk shape microneedles that incorporate the antibody cargo in the needle tips were created from carboxymethylcellulose (CMC) using a micromilling/spin-casting fabrication method. We found that anti-TNF-α Ab integrated into MNAs using this room temperature fabrication process maintained conformationally dependent TNF-α binding activity. Further, these MNAs efficiently delivered anti-TNF-α antibodies to the dermis of human skin with clinically applicable release profiles. To evaluate MNA delivered anti-TNF-α Ab function, we applied anti-TNF-α Ab containing MNAs to established psoriasiform lesions on the skin of mice. MNA anti-TNF-α Ab treatment reduced key biomarkers of psoriasiform inflammation including epidermal thickness and IL-1β expression. Taken together, these results demonstrate efficient and biologically effective MNA delivery of anti-TNF-α Ab to the intradermal microenvironment of the skin in mice and humans, and support the development of MNA mediated antibody delivery for clinical applications.

STATEMENT OF SIGNIFICANCE

Tumor necrosis factor-alpha (TNF-α) specific antibodies (anti-TNF-α Ab) have been shown to be potent TNF inhibitors and effective therapeutics for a range of inflammatory diseases. Typically, these drugs are administered systemically, but systemic dosing sufficient to achieve locally effective concentrations in peripheral tissues has been associated with systemic immunosuppression and related adverse events. Here we demonstrate efficient and biologically effective MNA delivery of anti-TNF-α Ab to the intradermal microenvironment of the skin in mice and humans. These results support the development of MNA mediated antibody delivery of therapeutic antibodies for clinical applications.

Polyguanine-conjugated antigens for scavenger receptor targeting and self-adjuvanting vaccines (VAC13P.1125)

We have recently developed a novel vaccine strategy that involves conjugating antigens to polyguanine sequences to fabricate aggregated particulates with exposed scavenger receptor ligands for in vivo targeting to antigen presenting cells. We have previously demonstrated that polyguanine-conjugated ovalbumin (Poly(dG)-OVA) leads to enhanced antigen-specific T cell and antibody responses. In this study, we show that exposing dendritic cells (DCs) to Poly(dG)-OVA results in increased antigen internalization that is inhibited by scavenger receptor ligands. Further, DCs internalizing Poly(dG)-OVA complexes exhibit increased cytokine secretion and inflammatory marker expression. In vivo, intradermal injection of Poly(dG)-OVA results in complex persistence in the skin for up to 7 days. Intradermally immunized mice demonstrated increased immune infiltrates in the skin and a persistent inflammatory cytokine profile. In these immunized animals, Poly(dG)-OVA particles reach the draining lymph nodes directly and in association with migratory DCs. We further demonstrate that Poly(dG)-OVA immunization of mice with established OVA-expressing melanoma tumors exhibited delayed tumor growth and improved survival. Taken together, these results suggest that immunization with polyguanine-conjugated antigens can induce more effective antitumor immunity by targeting DCs through scavenger receptors and inducing proinflammatory DC activation.

Poly(dG) oligo deoxynucleotide conjugated protein vaccine specifically targets skin APCs and induces robust T cell immunity in vivo. (APP3P.110)

The efficacy of current vaccines results from the induction of protective antibodies. However we still lack efficacious vaccines against many infectious agents that require durable and protective T cell immunity. Efficient and selective delivery of antigen and adjuvant to APCs in vivo remains a critical challenge to vaccine design. To accomplish both of these goals with a single delivery strategy we have designed an antigen and adjuvant delivery platform based on simple and direct coupling of Poly(dG) oligo deoxynucleotides to protein antigens. Initially we found that immunization of naïve animals by direct injection of conjugates of Poly(dG) and Ovalbumin, Poly(dG)-OVA induces priming of specific CTL responses, differentiation of naïve CD4 T cells into Th1 cells, induction of specific memory T cell responses and generation of specific antibody responses, in a scavenger receptor-dependent manner. Applying this strategy to HIV, we immunized mice with conjugated Poly(dG)-Gag and demonstrated potent induction of Gag-specific CTL and Th1-biased CD4 T cells immune responses in vivo. Further, in human models we show that intradermal injection of Poly(dG)-antigen conjugates result in efficient uptake by human dermal DCs that acquire potent T cell stimulatory functions. Our data suggests that the Poly(dG)-protein conjugate vaccine platform can both selectively target antigens to skin APCs and function as an APC-directed adjuvant to induce broad based cellular and humoral immunity.

Intradermal immunization with polyguanine conjugated antigens enables targeted and sustained delivery of protein antigens to dendritic cells in vivo. (APP3P.111)

Effective vaccine design depends on the ability to target specific antigens to antigen presenting cells (APCs), including dendritic cells (DCs). Conjugation of proteins antigens to polyguanine (Poly(dG)) molecules is a novel immunization approach capable of transforming soluble antigens into aggregated particulates with exposed scavenger receptor (SR) ligands. We have previously shown that Poly(dG) conjugation to protein antigen results in increased antigen-specific helper and cytotoxic T cell responses, memory T cell induction, and antibody titers. Here, we specifically investigate mechanisms of Poly(dG)-conjugated antigen delivery and internalization. Compared to soluble OVA, Poly(dG)-OVA is rapidly and more efficiently internalized by bone marrow derived DCs in vitro, and this internalization is inhibited by scavenger receptor blockade. Importantly, in a mouse model intradermally injected Poly(dG)-OVA results in antigen persistence in the skin for up to 7 days. This is accompanied by increased antigen uptake by skin resident DCs and persistent migration of antigen loaded DCs to the draining lymph nodes. DCs exposed to Poly(dG)-OVA had increased expression of CCR7 and secretion of MCP-1, TNF-α, and IL-6. These results suggest that coupling Poly(dG) to protein antigens enables efficient DC targeting through SRs, prolonged delivery of antigens in vivo, and activation of innate immunity. This approach may be used to design more efficient antiviral and antitumor vaccines.

Dissolvable microneedle arrays for intradermal delivery of biologics: fabrication and application

PURPOSE

Design and evaluate a new micro-machining based approach for fabricating dissolvable microneedle arrays (MNAs) with diverse geometries and from different materials for dry delivery to skin microenvironments. The aims are to describe the new fabrication method, to evaluate geometric and material capability as well as reproducibility of the method, and to demonstrate the effectiveness of fabricated MNAs in delivering bioactive molecules.

METHODS

Precise master molds were created using micromilling. Micromolding was used to create elastomer production molds from master molds. The dissolvable MNAs were then fabricated using the spin-casting method. Fabricated MNAs with different geometries were evaluated for reproducibility. MNAs from different materials were fabricated to show material capability. MNAs with embedded bioactive components were tested for functionality on human and mice skin.

RESULTS

MNAs with different geometries and from carboxymethyl cellulose, polyvinyl pyrrolidone and maltodextrin were created reproducibly using our method. MNAs successfully pierce the skin, precisely deliver their bioactive cargo to skin and induce specific immunity in mice.

CONCLUSIONS

We demonstrated that the new fabrication approach enables creating dissolvable MNAs with diverse geometries and from different materials reproducibly. We also demonstrated the application of MNAs for precise and specific delivery of biomolecules to skin microenvironments in vitro and in vivo.

Poly(dG) conjugated protein immunization targets dendritic cells and induces T cell immunity in vivo. (P4528)

The efficacy of current vaccines results primarily from the induction of protective antibodies. However, we still lack efficacious vaccines against many infectious agents that, like cancer, require durable and protective T cell immunity. Efficient and selective delivery of antigen and adjuvant to antigen presenting cells in vivo remains a critical challenge to vaccine design. Therefore, we have designed an antigen and adjuvant delivery platform based on simple and direct coupling of Poly(dG) oligo deoxynucleotides to protein antigens. In initial studies we found that immunization of naïve animals by direct injection of conjugates of Poly(dG) and Ovalbumin, Poly(dG)-OVA induces efficient priming of potent antigen specific CTL responses, differentiation of naïve CD4 T cells into Th1 cells, induction of specific memory T cell responses and generation of antigen-specific antibody responses. Applying this strategy to HIV, we immunized mice with conjugated Poly(dG)-SIV-Gag and demonstrated potent induction of Gag-specific CTL responses in vivo. Further, in human models we show that intradermal injection of Poly(dG)-antigen conjugates result in efficient uptake by human skin migratory DCs, preferentially dermal DCs, that also acquire potent T cell stimulatory functions. Our data suggests that the Poly(dG)-protein conjugate immunization platform can both selectively target antigens to skin APC and function as an APC-directed adjuvant to induce broad based humoral and T cell immunity.

Scavenger receptor-mediated dendritic cell internalization and activation by Polyguanine-conjugated antigen (P4234)

Targeting specific antigens to antigen presenting cells for efficient antigen processing and immune activation is an essential design consideration for vaccine development. Our group has developed polyguanine (Poly(dG))-conjugated antigens with intrinsic antigen targeting and adjuvant properties. These antigen conjugates can potentially increase vaccine efficiency by transforming soluble antigens into aggregated particulates that are targeted to the scavenger receptor in dendritic cells (DCs), resulting in efficient internalization, activation, and cross-presentation. We have successfully conjugated Poly(dG) residues to the model Ag ovalbumin (OVA) and found that Poly(dG)-OVA can induce robust antigen-specific helper, cytotoxic, memory T cell, and antibody responses. In this study, we measure DC internalization and demonstrate that Poly(dG)-OVA is internalized several times more efficiently than OVA alone. This internalization is specifically inhibited by scavenger receptor ligands. Treatment with Poly(dG)-OVA also resulted in upregulation of CCR7 expression and secretion of MCP-1, TNF-α, and IL-6 by DCs in vitro. These results suggest that coupling Poly(dG) to antigens enables efficient DC targeting and activation through the scavenger receptor. This vaccine design can be applied to viral or tumor protein or peptide antigens for the production of more efficient antiviral and antitumor vaccines without the need for additional adjuvants.

Differential expression and subcellular-localization of protein-kinase-C, alpha, gamma, delta, xi and zeta isoforms in agf T-cells - modification during pma-induced differentiation

The steady-state level and translocation of the protein kinase C (PKC) isozymes during the early stages of phorbol 12-myristate 13-acetate (PMA)-induced differentiation, was followed in AGF cells by Western blot analysis of various cell fractions, immunofluorescence staining and by confocal microscopy. By Western blot analysis, uninduced AGF cells express four PKC isoforms, PKC-alpha, PKC-gamma, PKC-epsilon and PKC-zeta with no expression of PKC-beta or PKC-delta. PKC-alpha was exclusively localized to the cytosol, whereas PKC-epsilon was localized predominantly in the cytosol. PKC-gamma and PKC-zeta were found in the cytosolic, as well as in the nuclear and the membrane fractions. Following stimulation with PMA from 15 min to 24 h, cytosolic PKC-alpha did not translocate to the membrane or nuclear fractions. PKC-gamma expression in the membrane and nuclear fractions was decreased following 1 h of PMA stimulation. The expression of PKC-zeta in the membrane and nuclear fractions was transiently increased (2-3 fold) between 3-6 h after PMA stimulation. The expression of PKC epsilon and delta was also affected by PMA treatment. While PKC epsilon, in the membrane fraction, was down-regulated by PMA treatment (3 h), the expression of PKC delta was induced by PMA. Confocal microscopy of the translocation of PKC isoforms during PMA-induced differentiation, confirmed the results obtained by Western blot analysis. Our results indicate that both Ca2+-dependent (PKC-alpha and PKC-gamma) and Ca2+-independent (PKC-epsilon, delta and PKC-zeta) isozymes are expressed in AGF cells and their pattern of expression differ in response to short and prolonged stimulation with phorbol ester. The demonstrated heterogeneity of PKC isozymes in AGF cells, suggests that each PKC isoform may provide a unique contribution to signal transduction pathways and growth control.

Cutaneous delivery of Poly(dG) conjugated protein antigens targets and activates dendritic cells in vivo. (106.13)

Efficient and specific targeting of antigen (Ag) to Ag presenting cells (APCs) in vivo is a critical challenge for vaccine design. Ag delivery and formulation strategies have been directly linked to type and the quality of induced immune responses. APCs acquire Ags in a variety of forms from a variety of sources and endocytic mechanisms can predetermine intracellular Ag routing, processing and presentation to CD4 or CD8 T cells. We have designed an APCs targeting strategy based on simple and direct coupling of Poly(dG) oligo deoxynucleotides to protein Ags. In comparison to soluble OVA, we find that conjugates of Poly(dG) and OVA (Poly(dG)-OVA) are rapidly internalized by DCs and follow distinct intracellular processing pathways. Importantly, immunization of naïve animals by direct injection of Poly(dG)-OVA induces protective multifunctional T cell immunity. This includes efficient priming of potent antigen specific CTL responses, differentiation of naïve CD4 T cells into Th1 CD4 T cells, induction of specific memory T cell responses, and generation of Ag-specific antibody responses. Extending our findings to human skin, we show that intradermal injection of Poly(dG)-Ag results in efficient uptake by human skin migratory DCs, preferentially dermal CD14+ DCs, that also acquire potent T cells stimulatory functions. Our data suggest that Poly(dG) can both target Ags to human skin immune APCs and function as an adjuvant to induce potent CD4 and CD8 mediated T cell immunity.

Internalization of Poly(dG)-antigens by dendritic cells (106.14)

Effective vaccine design depends in part on the ability to target specific antigens (Ag) to Ag presenting cells (APCs), including dendritic cells (DCs). Further, to generate effective antitumor and antiviral immunity, vaccine platforms should enable efficient MHC class I and class II restricted antigen processing leading to synergistic CD4 and CD8 T-cell responses. To facilitate targeted vaccine delivery, we have developed Poly(dG)-protein Ags. These Ag conjugates have the potential to greatly increase vaccine efficiency by inducing spontaneous aggregation of Ag into particulate complexes with intrinsic adjuvant function. The resulting particulate structure includes exposed phosphate groups with affinity for scavenger receptors expressed by APCs. We have successfully conjugated Poly(dG) residues to the model Ag ovalbumin (OVA) and found that Poly(dG)-OVA can be rapidly endocytosed, and efficiently presented to class II-restricted T cells, and cross-presented to class I-restricted T cells in vitro and in vivo. We compared DCs internalization of Poly(dG) conjugated and unconjugated Ag using confocal microscopy and found that Poly(dG)-OVA bound to the cell surface of DCs with higher affinity and was internalized several times more efficiently than Ag alone. These results suggest that coupling Poly(dG) to Ags enables efficient APCs targeting. Understanding the mechanisms of internalization, processing, and presentation of Poly(dG)-Ags will contribute to future vaccine design.

Dissolvable microneedle arrays deliver live adenovirus to the skin for genetic immunization. (58.16)

Recombinant DNA vaccines show incredible promise for the prevention of human disease by their capacity to effectively inducing both humoral and cellular immune responses. Among the available technologies adenovirus (Ad) vectored vaccines are among the most appealing. To date the clinical deployment of Ad-based vaccines has been limited by several considerations including the lack of delivery technology to enable safe, reproducible and effective vector delivery to patients. The skin is readily accessible and rich in antigen presenting cells, making it a preferred target site for immunization. To enable Ad-based clinical immunization, we developed microneedle arrays (MNAs) to deliver live Ad-vectors to the skin. The MNA design and fabrication process we developed results in MNAs that effectively preserve Ad viability, and enable efficient delivery of infectious vector to the skin. Specifically, MNA embedded live Ad5 virus retained infectivity for up to a year. Topical application of MNAs resulted in transduction of skin cells. Further, immunization of mice with an Ad5 expression vector encoding the SIVmac239 gag antigen resulted in the generation of potent CTL activity against the dominant gag 76-84 eptiope. Taken together, our results demonstrate the capacity of MNAs to preserve and deliver Ad5 virus to the skin for genetic immunization. This novel technology platform may enable a wide range of topical skin-targeted Ad vaccines.

(100.32)

Efficient and specific targeting of exogenous antigen to antigen presenting cells (APCs) in vivo is a critical challenge for vaccine design. APCs acquire antigens from a variety of sources and endocytic mechanisms can predetermine intracellular antigen routing, processing and presentation to CD4+ or CD8+ T cells. We have designed an APC targeting strategy based on simple and direct coupling of Poly(dG) oligodeoxynucleotides to protein antigens. In comparison to soluble OVA, we find that conjugates of Poly(dG) and OVA (OVA-Poly(dG)) are rapidly internalized by dendritic cells (DCs) and follow distinct intracellular processing pathways. Functionally, OVA-Poly(dG) is both presented to OVA-specific CD4+ T cells (OT-II cells) and efficiently cross-presented to OVA-specific CD8+ T cells (OT-I cells) by DCs in vitro. Importantly, immunization of naïve animals by direct injection of OVA-Poly(dG) results in efficient priming of potent antigen specific CTL responses. Further, OVA-Poly(dG) generate a specific memory CD8+ T cells response and promote OVA-specific antibody responses. Extending our findings to human skin, we show that I.D. injection of antigen-Poly(dG) conjugates results in efficient uptake by human skin migratory DCs, preferentially dermal CD14+DCs that also acquire potent T cell allostimulatory function. Our data suggests that Poly(dG) can both target antigens to human skin immune APCs and function as an adjuvant to induce potent CD4 and CD8 mediated T cell immunity.

Novel approach to gene expression profiling in Sézary syndrome

BACKGROUND

Microarray hybridization studies in Sézary syndrome (SS) have compared T lymphocytes from patients with cutaneous T-cell lymphoma with those of normal controls; a major limitation of this design is that significant inherent genetic variability of lymphocyte populations between individuals may produce differences in gene expression unrelated to disease state.

OBJECTIVE

The objective of this study was to minimize the heterogeneity of information derived from whole-genome expression analysis and to identify specific genetic differences between highly purified malignant and nonmalignant (control) T cells from the same patient with SS.

METHODS

Peripheral blood mononuclear cells were obtained from a patient with SS, stained with anti-T-cell receptor Vb (TCR-Vb) antibodies, and sorted by multiparameter flow cytometry. Malignant cells expressed the dominant TCR-Vb; control T cells lacked the dominant TCR-Vb but were otherwise phenotypically identical (CD3+CD4+CD45RO+). These cell populations were compared using the Illumina Inc. Sentrix Human-6 expression BeadChip system.

RESULTS

Transcriptome analysis using the J5 test, which was selected for data analysis based on an efficiency analysis of competing statistical methods, showed differential expression of 44 genes between the malignant and nonmalignant cell subsets. Promyelocytic leukaemia zinc finger protein (ZBTB16) was the most profoundly upregulated gene in the malignant cell population, while interferon regulatory factor 3 (IRF3) and interferon-induced protein 35 (IFI35), which are important elements of the cellular response to viral infection, were significantly downregulated.

CONCLUSIONS

The results of this study suggest the feasibility of this novel comparative approach to genomic profiling in SS. Using this method, we identified several differentially expressed genes and pathways not previously described in SS. While these findings require validation in larger studies, they may be important in SS pathogenesis.

Partial characterization of normal and Haemophilus influenzae-infected mucosal complementary DNA libraries in chinchilla middle ear mucosa

OBJECTIVES

We sought to construct and partially characterize complementary DNA (cDNA) libraries prepared from the middle ear mucosa (MEM) of chinchillas to better understand pathogenic aspects of infection and inflammation, particularly with respect to leukotriene biogenesis and response.

METHODS

Chinchilla MEM was harvested from controls and after middle ear inoculation with nontypeable Haemophilus influenzae. RNA was extracted to generate cDNA libraries. Randomly selected clones were subjected to sequence analysis to characterize the libraries and to provide DNA sequence for phylogenetic analyses. Reverse transcription-polymerase chain reaction of the RNA pools was used to generate cDNA sequences corresponding to genes associated with leukotriene biosynthesis and metabolism.

RESULTS

Sequence analysis of 921 randomly selected clones from the uninfected MEM cDNA library produced approximately 250,000 nucleotides of almost entirely novel sequence data. Searches of the GenBank database with the Basic Local Alignment Search Tool provided for identification of 515 unique genes expressed in the MEM and not previously described in chinchillas. In almost all cases, the chinchilla cDNA sequences displayed much greater homology to human or other primate genes than with rodent species. Genes associated with leukotriene metabolism were present in both normal and infected MEM.

CONCLUSIONS

Based on both phylogenetic comparisons and gene expression similarities with humans, chinchilla MEM appears to be an excellent model for the study of middle ear inflammation and infection. The higher degree of sequence similarity between chinchillas and humans compared to chinchillas and rodents was unexpected. The cDNA libraries from normal and infected chinchilla MEM will serve as useful molecular tools in the study of otitis media and should yield important information with respect to middle ear pathogenesis.

Cutaneous delivery of Poly(dG) conjugated protein antigens targets and activates DCs in vivo. (130.38)

Efficient and specific targeting of exogenous antigen to antigen presenting cells (APCs) in vivo is a critical challenge for vaccine design. APCs acquire antigens from a variety of sources and endocytic mechanisms can predetermine intracellular antigen routing, processing and presentation to CD4+ or CD8+ T cells. We have designed an APC targeting strategy based on simple and direct coupling of Poly(dG) oligo deoxynucleotides to protein antigens. In comparison to soluble OVA, we find that conjugates of Poly(dG) and OVA (OVA-Poly(dG)) are rapidly internalized by dendritic cells (DCs) and follow distinct intracellular processing pathways. Functionally, OVA-Poly(dG) is both presented to OVA-specific CD4+ T cells (OT-II cells) and efficiently cross-presented to OVA-specific CD8+ T cells (OT-I cells) by DCs in vitro. Importantly, immunization of naïve animals by direct injection of OVA-Poly(dG) results in efficient priming of potent antigen specific CTL responses. Extending our findings to human skin, we show that I.D. injection of antigen-Poly(dG) conjugates results in efficient uptake by human skin migratory DCs including Langerin+ DCs that also acquire potent T cell allostimulatory function. Our data suggest that Poly(dG) can both target antigens to human skin immune APCs and function as an adjuvant to induce potent CD4 and CD8 mediated T cell immunity.

Biodegradable dissolving microneedle arrays effectively deliver antigens and adjuvants to skin DCs for the induction of antigen specific immune responses. (48.12)

The skin contains a high density of antigen presenting cells making it an attractive target for vaccine delivery. However, the remarkable barrier function of the skin continues to present a formidable obstacle to topical vaccine delivery. To overcome this barrier we designed carboxy-methyl cellulose microneedle arrays (MNAs) to topically deliver antigens and adjuvants into the skin. MNAs were designed and fabricated to enable advantages in penetration, delivery, and diversity of biocompatibility over existing skin delivery technologies. Initially we fabricated MNAs with integrated tracer antigens. Following MNA immunization labeled antigens were identified in dendritic cells in human and murine skin, and in the draining lymph nodes of immunized animals. To evaluate immunogenicity, we incorporated the model antigen OVA in combination with various adjuvants into MNAs. MNA-mediated delivery of low dose antigen/adjuvant induced potent and durable CTL responses compared to those generated by traditional intradermal immunization. Further, MNA immunization utilizing B16 tumor cell lysates as a source of antigen induced B16 specific DTH reactions and inhibited tumor growth in a B16 tumor model. Taken together, these results demonstrate the feasibility of the use of CMC microneedle arrays for cutaneous immunization and suggest potentially broad applicability for the co-delivery of structurally diverse antigens and adjuvants.

Administration of dendritic cells signaled via the neurokinin 1 receptor favors type-1 cellular immunity by mechanisms involving exogenous and endogenous dendritic cell populations (98.12)

Induction of type-1 immunity is the focus of current dendritic cell (DC)-vaccination approaches for tumors and intracellular infections. The pro-inflammatory neuropeptides, substance P and hemokinin-1, favor cell-mediated immunity by binding the neurokinin 1 receptor (NK1R). DCs express functional NK1R; however, the ability of NK1R agonists to modulate the T cell stimulatory and biasing functions of DCs remains unknown. In the present work, we analyzed the effects of ex vivo-generated DCs signaled via the NK1R to exert T cell stimulatory and type-1 biasing functions. We demonstrate that agonistic signaling via the NK1R promotes the maturation of murine bone marrow-derived DCs (BMDCs) and inhibits their secretion of IL-10. Adoptive transfer of NK1R-signaled BMDCs favors enhanced Ag specific type-1 CD4+ (Th1) and CD8+ (CTL/Tc1) responses in vivo. The individual roles of adoptively transferred BMDCs and endogenous DCs, under our experimental conditions, were further addressed by comparing the development of type-1 immunity in C57BL/6 wild type, IL-12p35-/- and CD11c+DTR mice (the latter depleted of endogenous DCs). Our results demonstrate that generation of type-1 immunity required inhibition of IL-10 by transferred BMDCs and secretion of IL-12p70 by endogenous DCs. Together, our data strongly suggest that adoptive transfer of NK1R-signaled BMDCs promotes type-1 immunity by mechanisms involving both the adoptively transferred and endogenous DC populations.

Topical patch vaccines target antigen to cutaneous dendritic cells efficiently inducing potent cell mediated immune responses (132.19)

The skin contains a high density of accessible dendritic cells making it an attractive target for vaccine delivery. However, the remarkable barrier function of the skin continues to present a formidable physical obstacle to cutaneous vaccine design. To selectively overcome this obstacle, we evaluated the capacity of dissolving microneedle arrays (MNAs) to deliver protein vaccines to the skin and skin DCs. In initial experiments, biocompatible solid MNAs were fabricated with integrated particulate tracers. Image analysis demonstrated that these MNAs effectively penetrated both mouse and human skin. Further, following patch immunization labeled particulates were identified in dendritic cells in human and murine skin, and in the draining lymph nodes of immunized animals. To evaluate immunogenicity, we incorporated OVA as a soluble (sOVA) or particulate (pOVA) model protein antigen into fabricated patches, and evaluated CTL responses in immunized animals. Patch delivery of low doses of either sOVA or pOVA efficiently induced potent CTL responses comparable to those generated by optimized gene gun based immunization. Taken together, these results demonstrate the feasibility of antigen delivery for cutaneous immunization, and support the development of topical patch vaccines as an efficient and potent strategy for protein antigen based immunization. Funded by NIH.

Targeted delivery of Poly(dG) conjugated protein antigens to antigen presenting cells results in efficient cross-priming in vivo (78.32)

The development of strategies to efficiently and specifically deliver antigen to antigen presenting cells (APCs) in vivo is a major goal of vaccine design. Internalization of antigen by APCs is a crucial step in immune activation and the mechanism of antigen internalization and trafficking can influence localization in antigen processing compartments and the presentation of antigen to CD4+ or CD8+ T cells. We have designed an APC targeting strategy based on simple and direct coupling of Poly(dG) oligo deoxynucleotides to protein antigens. In comparison to soluble OVA, we find that conjugates of Poly(dG) and OVA (OVA-Poly(dG)) are rapidly internalized by DCs and transverse distinct intracellular processing pathways. OVA-Poly(dG) is both presented to OVA-specific CD4+ T cells (OT-II cells) and efficiently cross-presented to OVA-specific CD8+ T cells (OT-I cells) by DCs in vitro. Importantly, immunization of naïve animals by direct injection of OVA-Poly(dG) results in efficient priming of potent antigen specific CTL responses. Our results suggest that Poly(dG) can target antigen to APCs and serve as a potent adjuvant to induce strong CD8+ T cell-mediated immunity against tumors or viruses. Funding provided by NIH.

Agonistic signaling via the neurokinin 1 receptor and CD40 have a synergistic effect to promote dendritic cell survival and potent CTL responses (135.56)

Immune competent organs are richly innervated and pro-inflammatory neuropeptides released by nerve endings favor the initiation of innate and adaptive immune responses. By binding the neurokinin 1 receptor (NK1R), the pro-inflammatory neuropeptide substance P promotes immune cell survival and potent cellular immunity. Dendritic cells (DCs) express surface NK1R and the priming of T cell responses requires Ag presentation by DCs able to withstand apoptotic signaling. We hypothesized that signaling DCs via the NK1R prevents apoptosis of DCs favoring sustained DC-T cell contact and robust CTL responses. Using murine bone marrow-derived DCs (BMDCs) cultured with the NK1R agonist [Sar9Met(02)11]-SP (SarSP-DCs), we demonstrate that signaling via the NK1R utilizes the PI3K-Akt pathway to prolong the expression of anti-apoptotic molecules. Additionally, SarSP-DCs showed increased expression of surface CD40. Adoptive transfer of Ag-loaded SarSP-DCs showed enhanced longevity in local draining lymph nodes vs. control DCs, which was a result of a combination of signaling via the NK1R and CD40 molecules. Importantly, SarSP-DCs elicited potent CTL responses compared to control DCs. We conclude that agonistic signaling via the NK1R and CD40 have a synergistic effect that enhances DC survival and favors the generation of potent CTL responses.

Supported by NIH grant: R01 CA100893 (ATL)