Skip Ribbon Commands
Skip to main content

McElrath Progress Report Abstracts continued

Submitted October 18, 2011

To accelerate HIV vaccine development, our goal is to understand how innate immunity can enhance and improve vaccine-induced immunity. We have established and integrated four systems - an in vitro human system, in vivo mouse models, non-human primate models, and human clinical trials - to build a comprehensive matrix of the innate signatures of candidate adjuvant and vaccine formulations to determine which will provide optimal T- and B-cell memory responses. This platform is ideally suited to examine promising regimens emerging from the CAVD and from outside partners and to advance new HIV vaccine candidates and regimens into phase I clinical trials.

We have procured and constructed clinically relevant vaccine adjuvants and vectors (Objective 1), and have conducted extensive cross-platform preclinical evaluation of these materials using our four systems. In our in vitro human system (Objective 2) using CD8+ and CD4+ T-cell priming systems, we have identified distinct differences in the efficiency of poly I:C as an adjuvant to mature DC when used for priming as compared to boosting. Poly I:C also induces the most substantial and distinct transcriptional remodeling in dendritic cells compared to all of the other tested adjuvants.

Using in vivo murine models (Objective 3), we showed that the order of prime/boost using CN54gp140 protein vaccine with adjuvants and with a NYVAC vector impacts the immunogenicity of the vaccines. We are also analyzing and comparing the innate and adaptive responses to a variety of poxviral and adenoviral vectors.

We are using the rhesus macaque model to further test our vaccine concepts (Objective 4). Based on the findings and results from the RV144 study, we are performing a pivotal NHP study to model RV144 using a potentially more immunogenic MVA vector with SIV Env protein adjuvanted with Poly- IC/LC to detect protection against SIV acquisition and post-infection virologic control. We are also testing rapamycin, nanoparticle formulations and other clinically relevant adjuvants in separate NHP studies. Microarray transcriptional analysis has detected distinct signatures of innate immune responses from these adjuvants.

Findings from our in vitro and in vivo systems have led us to design and develop novel HIV vaccine regimens with the potential to induce effective protective immunity. We are exploring the options to test promising TLR3 and TLR9 adjuvants with HIV Env proteins in clinical trials. Meanwhile, we are continuing innate immune analyses of vaccines from current HVTN trials and will integrate those findings with our in vitro and in vivo study results, including transcriptional analysis by microarrays.

Submitted March 1, 2011 (Interim Report)

To accelerate HIV vaccine development, our goal is to understand how innate immunity can enhance and improve vaccine-induced immunity. We have established and integrated four systems - an in vitro human system, in vivo mouse models, non-human primate models, and human clinical trials - to build a comprehensive matrix of the innate signatures of candidate adjuvant and vaccine formulations to determine which will provide optimal T- and B-cell memory responses.  This platform is ideally suited to examine promising regimens emerging from the CAVD and from outside partners and to advance new HIV vaccine candidates and regimens into phase I clinical trials.

We have procured and constructed clinically relevant vaccine adjuvants and vectors (Objective 1), and have conducted extensive cross-platform preclinical evaluation of these materials using our four systems.  In our in vitro human system (Objective 2) using CD8+ and CD4+ T-cell priming systems, we have identified distinct differences in the efficiency of poly I:C as an adjuvant to mature DC when used for priming as compared to boosting.  Poly I:C also induces the most substantial and distinct transcriptional remodeling in dendritic cells compared to all of the other tested adjuvants. 

Using in vivo murine models (Objective 3), we showed that the order of prime/boost using CN54gp140 protein vaccine with adjuvants with a NYVAC vector impacts the immunogenicity of the vaccines.  We are also analyzing and comparing the innate and adaptive responses to a variety of poxviral and adenoviral vectors.
We are using the rhesus macaque model to further test our vaccine concepts (Objective 4).  Based on the findings and results from the RV144 study, we are performing a pivotal NHP study to model RV144 using a potentially more immunogenic MVA vector with SIV Env protein adjuvanted with Poly-ICLC to detect protection against SIV acquisition and post-infection virologic control.  We are also testing rapamycin, nanoparticle formulations and other clinically relevant adjuvants in separate NHP studies.  Microarray transcriptional analysis has detected distinct signatures of innate immune responses from these adjuvants.

Findings from our in vitro and in vivo systems have led us to design and develop novel HIV vaccine regimens with the potential to induce effective protective immunity.  We are preparing to test vaccine adjuvants with HIV Env protein CN54gp140 in prime/boost combinations with a NYVAC vector in clinical trials (Objective 5).  We will first compare Poly-ICLC with aluminum hydroxide adjuvant in a study in collaboration with HVTN, DAIDS, and Pantaleo CAVD/IPPOX.  The vaccine components are in the final stages of manufacturing and testing.  Meanwhile, we are continuing innate immune analyses of vaccines from current HVTN trials and will integrate those findings with our in vitro and in vivo study results, including transcriptional analysis by microarrays.

Submitted November 1, 2010

To accelerate HIV vaccine development, our goal is to understand how innate immunity can
enhance and improve vaccine-induced immunity. We have established and integrated four systems - an
in vitro human system, in vivo mouse models, non-human primates models, and human clinical trials - to
build a comprehensive matrix of the innate signatures of candidate adjuvant and vaccine formulations that
can provide optimal T- and B-cell memory responses. This platform is ideally suited to examine
promising regimens emerging from the CAVD and from outside partners and to advance new HIV vaccine
candidates and regimens into phase I clinical trials.

We have procured and constructed clinically relevant vaccine adjuvants and vectors (Objective
1), and have conducted extensive cross-platform preclinical evaluation of these materials using our four
systems. In our in vitro human system (Objective 2) using CD8+ and CD4+ T-cell priming systems, we
have identified TLR agonists that result in quantitative/qualitative differences in activated DCs and
responding T-cells and have found that poly IC is most effective in priming antigen-specific T-cells but
have different adjuvant properties as a boost.

Using in vivo models, we confirmed in mice (Objective 3) that poly IC is a strong adjuvant for
activating both antibody and T-cell responses. We have also shown that rapamycin is a potent adjuvant
for improving the quantity and quality of CD8+ T-cell responses, and that the nanoparticle formulation of
MPL and R837 adjuvants with HIV Env protein can significantly enhance the quantity and quality of B-cell
responses.

We are using the rhesus macaque model to further test our vaccine concepts (Objective 4). Our
heterologous prime-boost vaccine approach tested the protein/adjuvant/vector combinations in our first
large NHP study. The study compared TLR3, 4, 7/8 and 9 ligands and their combinations, and identified
poly IC as the best adjuvant to enhance CD4+ T-cell, cross-presented CD8+ T-cell and antibody
responses. Based on the findings and results from the RV144 study, we have started a pivotal NHP
study to model RV144 using a potentially more immunogenic MVA vector with SIV Env protein
adjuvanted with Poly IC/LC to detect protection against SIV acquisition and post infection virologic
control. We are also testing rapamycin, nanoparticle formulations and other clinically relevant adjuvants
in separate NHP studies.

Findings from our in vitro and in vivo systems have led us to design and develop novel HIV
vaccine regimens with the potential to induce effective protective immunity. We are preparing to test
vaccine adjuvants with HIV Env protein CN54gp140 in prime/boost combinations with a NYVAC vector in
clinical trials (Objective 5). We will first compare Poly IC/LC with aluminum hydroxide adjuvant in a study
in collaboration with HVTN, DAIDS, and Pantaleo CAVD/IPPOX. The vaccine components are in the final
stages of manufacturing and testing. Meanwhile, we are continuing innate immune analyses of vaccines
from current HVTN trials and will integrate those findings with our in vitro and in vivo study results,
including transcriptional analysis by microarrays.

 
Submitted March 1, 2010 (Interim Report)

To accelerate HIV vaccine development, we must understand how innate immunity can enhance vaccine-induced adaptive immunity. We have implemented a systematic in vitro and in vivo approach to unravel the precise molecular pathways of innate immunity that vaccine adjuvants and vectors stimulate. Coordinated studies assess the consequence of these activities on the quality and long-term persistence of the HIV-specific adaptive immune response. We are extending our findings into the design and development of novel HIV vaccine regimens that can induce potentially effective protective immunity.  The investigations are organized within the following five major objectives:

Objective 1: Construct or procure a diverse array of adjuvants and vectors that can lend insight into improved HIV vaccine design.  We now have access to all Toll-like receptor (TLR) agonists as adjuvants for enhancing antibody and T-cell responses for preclinical testing.  A variety of recombinant vectors that express HIV-1 or SIV genes have been produced.

Objective 2: Determine in an in vitro human system how innate immune activation by adjuvants alters dendritic cell phenotype/function and improves priming of antigen-specific T cells.  We have identified combinations of TLR agonists that result in quantitative/qualitative differences in activated DCs and responding T cells.  Poly I:C appears to be one of the strongest adjuvants in activating dendritic cells and priming CD4+ and CD8+ T cells.

Objective 3: Elucidate how adjuvants/innate responses shape the quality and persistence of T cell and antibody responses in mice.  Co-administration of rapamycin as an adjuvant enhances both the quantity and quality of CD8+ T cell effector and memory responses using Ad5 vector as immunogen.   A novel vaccine adjuvant formulation using PLGA nanoparticles with TLR4 ligand MPL and TLR7 ligand R837 was shown to synergistically enhance the magnitude and quality of antibody responses with a variety of vaccines.

Objective 4: Assess innate and adaptive T-cell immune responses upon vaccination of rhesus macaques with SIV immunogens.  We completed the first protein/adjuvant experiment that assessed the effectiveness of an SIV Gag protein prime with TLR agonists in potentiating the immunogenicity with an Ad5/gag boost and in protection against pathogenic SIV challenge in 64 animals.  We are finalizing a NHP vaccine efficacy study that follows up on both the adjuvant results of our first experiment and the RV144 clinical trial of ALVAC prime/env protein boost vaccination.  The animals will receive a prime boost combination of pox vector and poly I:C adjuvanted Env protein vaccines and be challenged with repeated low dose SIV.  The study is powered for assessment of infection acquisition.

Objective 5: Evaluate innate immune responses that drive improved antigen-specific T-cell responses in human trials.  Based on the preclinical immunogenicity data, we are planning a Phase I clinical trial to test the concept of priming with HIV Env protein and Poly I:C adjuvant and boosting with a viral vector.  Meanwhile, we are continuing the innate immune analysis of vaccines that are being tested in HVTN trials, including DNA/MVA, DNA/Ad5 and protein/adjuvant vaccines.

 
Submitted October 1, 2009 

To accelerate HIV vaccine development, we must understand how innate immunity can enhance vaccine-induced immunity. We have implemented a systematic in vitro and in vivo approach to unravel the precise molecular pathways of innate immunity that adjuvants and vectors stimulate. Coordinated studies assess the consequence of these activities on the quality and long-term persistence of the HIV-specific adaptive immune response. Our findings will rationally guide improved HIV vaccine designs that can induce effective protective immunity. These investigations are organized within the following five major objectives:
Objective 1: Construct or procure a diverse array of adjuvants and vectors that can lend insight into improved HIV vaccine design. We now have access to all Toll-like receptor (TLR) agonists for in vitro and in vivo preclinical testing alone or in combinations as adjuvants for enhancing antibody and T-cell responses. A variety of recombinant vectors have been procured, including adenovirus serotype 5, modified vaccinia Ankara, Listeria monocytogenes, Newcastle disease virus, and yellow fever virus. Each produced vector expresses HIV-1, SIV, or LCMV genes.
Objective 2: Determine in an in vitro human system how innate immune activation by adjuvants alters dendritic cell phenotype/function and improves priming of antigen-specific T cells. We have identified combinations of TLR agonists that result in quantitative/qualitative differences in activated DCs and responding T cells. Poly I:C appears to be one of the strongest adjuvants in activating dendritic cells and priming T cells.
Objective 3: Elucidate how adjuvants/innate responses shape the quality and persistence of memory T cells in mice. For protein vaccines, generation of CD4+ T-cell responses alone following primary immunization may not be sufficient to enhance CD8+ T-cell responses after an Ad5 SIV Gag boost. A novel vaccine using PLGA nanoparticles encapsulating TLR4 ligand (monophosphoryl lipid A; MPL) and TLR7 ligand R837 has been successfully designed, characterized, and tested as adjuvants for co-delivery with various recombinant protein-encapsulated PLGA nanoparticles, and has been shown to synergistically enhance the magnitude and quality of antibody responses. For vectors, various approaches were used to improve the quality of the Ad5-induced CD8+ T-cell memory, and co-administration of rapamycin appears to be beneficial for the differentiation and immune function of these memory T cells.
Objective 4: Assess innate and adaptive T-cell immune responses upon vaccination of rhesus macaques with SIV immunogens. The protein/adjuvant experiment has 54 animals immunized with SIV Gag that is formulated with either TLR3, TLR4, TLR7/8, and TLR9 ligand alone, or in various combinations, followed by an Ad5-Gag boost. Measurements of innate immune activation, Gag-specific T-cell and antibody responses are mostly complete. Alterations of gene expression in lymph nodes and PBMCs are being analyzed. The analysis of the SIV challenge phase is in progress. The Listeria prime/boost immunogenicity experiment is also in progress.

 
Submitted March 1, 2009 (Interim Report) 

To accelerate HIV vaccine development, our goal is to understand how innate immunity can enhance and improve vaccine-induced immunity. We have established and integrated four systems - in vitro human PBMC culture, in vivo mouse models, rhesus macaque models, and human clinical trials - to build a comprehensive matrix of the innate signatures of candidate adjuvant and vaccine formulations that can provide optimal T- and B-cell memory responses.  This platform is ideally suited to examine promising regimens emerging from the CAVD and from outside partners, to advance new HIV vaccine candidates and regimens.  We have identified two priming regimens, HIV protein with poly I:C and recombinant Listeria/HIV, that induce strong multifunctional T-cell and antibody responses.  We are conducting extensive preclinical testing of these vaccine candidates, and if deemed safe, our current plans are to advance these vaccines into phase I clinical trials.  Our investigations are organized within five major objectives:
Objective 1: Construct or procure a diverse array of adjuvants and vectors for improved HIV vaccine design. 
We now have access to agonists to Toll-like receptors (TLR) 2, 3, 4, 5, 7/8 and 9 for preclinical testing as adjuvants for enhancing antibody and T-cell responses.  A variety of recombinant vectors have been procured, including adenovirus serotype 5, modified vaccinia Ankara, Listeria monocytogenes, and yellow fever virus. Each recombinant vector has been engineered to express HIV or SIV genes.
Objective 2: Determine the effects of adjuvants in an in vitro human system. 
Using CD8+ and CD4+ T-cell priming systems, we have identified TLR agonists that result in quantitative/qualitative differences in activated DCs and responding T cells.  We are studying the effects of adjuvant combinations and have found that poly I:C is most effective in priming antigen-specific T cells.
Objective 3: Elucidate how adjuvants/vectors shape the quality of T cell responses in mice.
We utilized mouse immunogenicity and protection models to define novel prime – boost vaccine regimens that can generate potent, durable, and highly polyfunctional and protective T-cell responses. An SIV Gag + poly I:C prime followed by an Ad5/SIV Gag boost resulted in a higher frequency of CD8+ T cell responses than when Ad5/SIV Gag was given alone. Prime-boost immunization with live attenuated Listeria/SIV Gag (ANZA) and Ad5/SIV Gag induced potent and durable CD8+ T cell responses that were ~2 to 3-fold higher than when Ad5/SIV was given alone.
Objective 4: Assess innate and adaptive T-cell immune responses to SIV immunogens in rhesus macaques.
We have completed the immunogenicity phase in 40 rhesus macaques with the remaining 16 ongoing.  Using SIV Gag formulated with TLR3, TLR4, TLR7/8, and TLR9 ligand alone, or in combination, we found that poly I:C modulated the strongest SIV Gag-specific immune responses.  Plasma viral load and target cell depletion in peripheral blood and alveolar cells of challenged animals are being analyzed. We have planned a study to investigate the immunogenicity and innate immune characteristics of Listeria vectors in primates.
Objective 5: Evaluate innate immune responses that drive improved antigen-specific T-cell responses in human trials. 
We are planning a trial that will test the vaccine regime of HIV Gag (Env) protein with poly I:C as a prime and VRC Ad5/HIV Gag (Env) as a boost.  We are currently finalizing our decisions on the sequences of HIV proteins, the appropriate form of poly I:C, and the vaccine formulation.  Close to completion are the analyses of the innate and adaptive immune responses induced with the Merck Ad5 trivalent gag/pol/nef vaccine in HVTN Protocol 071.  We are also planning innate immune analyses for two additional upcoming HVTN trials.

 
Submitted October 1, 2008

To accelerate HIV vaccine development, we must understand how innate immunity can enhance vaccine-induced immunity. We have implemented a systematic in vitro and in vivo approach to unravel the precise molecular pathways of innate immunity that adjuvants and vectors stimulate. Coordinated studies assess the consequence of these activities on the quality and long-term persistence of the HIV specific adaptive immune response. Our findings will rationally guide improved HIV vaccine designs that can induce effective protective immunity. These investigations are organized within the following five major objectives:
Objective 1: Construct or procure a diverse array of adjuvants and vectors that can lend insight into improved HIV vaccine design. We now have access to all Toll-like receptor (TLR) agonists for in vitro and in vivo preclinical testing alone or in combinations as adjuvants for enhancing antibody and T cell responses. A variety of recombinant vectors have been procured, including adenovirus serotype 5,
modified vaccinia Ankara, Listeria monocytogenes, Newcastle disease virus, and yellow fever virus. Each produced vector expresses either HIV-1, SIV or LCMV genes.
Objective 2: Determine in an in vitro human system how innate immune activation by adjuvants alters dendritic cell phenotype/function and improves priming of antigen-specific CD8+ T cells. We have identified combinations of TLR agonists that result in quantitative/ qualitative differences in activated DCs and responding T cells. We also show that plasmacytoid DCs are activated and undergo maturation following genomic HIV-1 RNA exposure.
Objective 3: Elucidate how adjuvants/innate responses shape the quality and persistence of memory T cells in mice. Antigen-specific T cell responses elicited by Ad5 and Listeria vectors expressing LCMV glycoprotein epitopes have been compared to those induced by natural LCMV infection, which results in long-lived protective memory T cells in the murine model. Progress is being made in comparative analyses of the generation of effector cells that express granzyme B, up-regulate
survival molecules, produce cytokines upon restimulation, and expand upon antigenic recall.
Objective 4: Assess innate and adaptive T cell immune responses upon vaccination of rhesus macaques with SIV immunogens. The first experiment is in progress, with 54 animals being immunized with SIV Gag formulated with TLR3, TLR4, TLR7/8, and TLR9 ligand alone, or in
combination. Measurements of innate immune activation, Gag-specific T cell and antibody responses are mostly complete. Alterations of gene expression in lymph nodes and PBMCs are being analyzed.
The challenge study is in progress.
Objective 5: Evaluate innate immune responses that drive improved antigen-specific T cell responses in human trials. We implemented HVTN 071, a phase I clinical trial testing the Merck Ad5 vaccine and determined detailed kinetics of the innate immune responses in 11 Seattle participants. In peripheral blood we identified marked changes in cell trafficking, serum cytokine concentrations, and immune cell gene expression. Innate responses to Ad5 were strongest on Day 1 after vaccination, and immunoglobulin gene alterations were observed one week later.

 
Submitted March 1, 2008 (Interim Report)

To accelerate HIV vaccine development, we must understand how innate immunity can enhance vaccine-induced immunity. We have implemented a systematic in vitro and in vivo approach to unravel the precise molecular pathways of innate immunity that adjuvants and vectors stimulate. Coordinated studies assess the consequence of these activities on the quality and long-term persistence of the HIV-specific adaptive immune response. Our findings will rationally guide improved HIV vaccine designs that can induce effective protective immunity. These investigations are organized within the following five major objectives:

Objective 1: Construct or procure a diverse array of adjuvants and vectors that can lend insight into improved HIV vaccine design. We now have access to Toll-like receptor (TLR) 2, 3, 4, 5, 7, 8, and 9 agonists for in vitro and in vivo preclinical testing alone or in combinations as adjuvants for enhancing Ab and T cell responses. A variety of recombinant vectors have been procured, including adenovirus serotype 5, modified vaccinia Ankara, Listeria monocytogenes, Newcastle disease virus, and yellow fever virus. Insertions of HIV-1, SIV and LCMV genes into these vectors have been completed or are underway.

Objective 2: Determine in an in vitro human system how innate immune activation by adjuvants alters dendritic cell phenotype/function and improves priming of antigen-specific CD8+ T cells. We have identified combinations of TLR agonists that result in quantitative/qualitative differences in activated DCs and responding T cells. We also show that plasmacytoid DCs are activated and undergo maturation following genomic HIV-1 RNA exposure.

Objective 3: Elucidate how innate responses shape the quality and persistence of memory T cells in mice. Antigen-specific T cell responses elicited by Ad5 and Listeria vectors expressing LCMV glycoprotein epitopes have been compared to those induced by natural LCMV infection, which results in long-lived protective memory T cells in the murine model. In progress are comparative analyses of the generation of effector cells that express granzyme B, upregulate survival molecules, produce cytokines upon restimulation, and expand upon antigenic recall.

Objective 4: Assess innate and adaptive T cell immune responses upon vaccination of rhesus macaques with SIV immunogens. The first experiment with forty animals is in progress, immunizing with SIV Gag formulated with TLR3, TLR4, TLR7/8, and TLR9 ligand alone, or in combination. Measurements of innate immune activation, Gag-specific T cell and antibody responses are mostly complete. Alterations of gene expression in lymph nodes and PBMCs are being analyzed. A separate experiment will begin shortly to determine the efficacy of Flt3-Ligand with CpG in a DNA prime-MVA boost vaccine.

Objective 5: Evaluate innate immune responses that drive improved antigen-specific T cell responses in human trials. We implemented HVTN 071, a phase I clinical trial testing the Merck Ad5 vaccine, and determined detailed kinetics of the innate immune responses in 11 Seattle participants. In peripheral blood, marked changes in cell trafficking, serum cytokine concentrations, and immune cell gene expression were identified. Innate responses to Ad5 were strongest one day after vaccination, and immunoglobulin gene alterations were observed one week later.

 
Submitted October 1, 2007

To accelerate HIV vaccine development, our goal is to understand how innate immunity can enhance vaccine-induced immunity. We will use a systematic in vitro and in vivo approach to unravel the precise molecular pathways of innate immunity that adjuvants and vectors stimulate. Coordinated studies will assess the consequence of these activities on the quality and long-term persistence of the HIV-specific adaptive immune response. These findings will rationally guide improved formulations of adjuvants with candidate HIV immunogens. Our studies will be performed through 5 major objectives:

Objective 1: Construct or procure a diverse array of adjuvants and vectors, and combine with HIV antigens and genes for evaluation in partnerships with industry and academia.

Objective 2: Standardize and implement an in vitro platform using human PBMC to screen and fully evaluate the innate immune responses induced by vectors and adjuvants, alone and in combination; then assess the impact of these innate responses on the phenotype, function and magnitude of HIV-specific T cell responses induced.

Objective 3: Elucidate how adjuvants/innate responses shape the quality and persistence of memory T cells in mice.

Objective 4:  Ascertain, using an in vivo macaque model, the adjuvant effects with vaccines on innate and adaptive immunity in mucosal transmission sites and on protection from challenges.

Objective 5: Perform, for select adjuvants/vectors or combinations, clinical phase I trials administering adjuvants/immunogen combinations to evaluate the predictive value of findings in Objectives 2-4 and to identify innate markers that correlate with reactogenicity and enhanced HIV-specific immunity.

 
For general questions about the CAVD or the content of the these pages, please contact alliance.management@cavd.org.
For technical issues with the website, please contact portalsupport@cavd.org.