Dengue hemorrhagic fever virus vaccine

FIELD OF THE INVENTION

The present invention relates to a dengue hemorrhagic fever virus vaccine and compositions thereof and methods of developing the vaccine, to generate an immunity against infection by dengue hemorrhagic fever viruses.

The following discussion of the background of the invention is merely provided to aid the reader in understanding the invention and is not admitted to describe or constitute prior art to the present invention.

Dengue Hemorrhagic Fever Virus (DHFV) is known as "break-bone fever" and is a positive strand RNA virus transmitted by mosquitoes in human subjects (1). It was recently observed to have increased in incidence in many parts of the world in which there are sub-tropical or tropical climates which support the prevalence of the arthropod vector (1). It is estimated that 50 to 100 million dengue infections occur each year (2-4). Thus, Dengue has emerged as a significant global health threat.

There are four major DHFV strains, and survival following the occurrence of the first DHFV infection is associated against life-long immunity against that infecting DHFV strain, but not to the other three heterologous strains (5). The neutralizing antibody immune response to the antigens of the DHFV strain that is the first to infect, is strong. In contrast, the neutralizing antibody response to the other three heterologous strains which cause an infection subsequent to the first strain is weak. These heterologous antibodies disappear within a matter of weeks after the infection. The weakness of this heterologous immune response means that it is not fully protective to three of the four strains (5). Importantly, the disappearance of the neutralizing antibodies to heterologous antigens has been associated with increased susceptibility to infection by the heterologous strains and to the development of DSS (6-8).

The initial event in an infection is inoculation of the virus into the skin by mosquitoes, followed by replication of the virus in dendritic cells (DCs), lymphocytes and monocytes, and then the entry of the virus into the bloodstream at high titers of one million infectious units/ml of blood which leads to seeding of visceral organs (5). This initial period of infection is often characterized by the sudden onset of high fever and rash with severe pain behind the eyes, joints, muscles and bone (which have led to the common name for DHFV infections: "break-bone fever") for 3-7 days, accompanied by flushing of the face and chest, petechia, clinically significant bleeding, myalgias, headache, vomiting and diarrhea, elevated serum levels of transaminases, thrombocytopenia, and lymphopenia.

Most often, after 3-7 days, the fever abates and the patient is left with long lasting immunity (due to high neutralizing antibody titers) against the infecting strain of DHFV. There is also short lived protection against the other three strains of DHFV due to a transient production of cross-strain neutralizing antibodies, but these cross-reactive neutralizing antibodies are low level and disappear after 3-4 months (5).

In some patients, at the time of resolution of the fever, this initial period is followed by a sudden and rapidly evolving syndrome of bleeding, edema, hypotension, systemic vascular collapse and death within 24 hours due to a capillary leak syndrome, and occasionally fulminant hepatic failure (9-10). This is called the Dengue Shock Syndrome (DSS). Halstead et al. (11) speculates, that DSS occurs in the setting of a secondary infection with a DHFV strain that is different from a previous infection with DHFV that was associated with a different serotype. Because this is a disease transmitted by mosquitoes, this disease worldwide affects populations of children in tropical and subtropical countries (3-4). DHFV infections have been reported in Florida in 2009 (12). There is no treatment for DHFV infections except for supportive care, and up to now, there is no effective vaccine that protects against all four viral strains.

The clinical features described above have been attributed to an immunological mechanism, which occurs in individuals who have experienced a previous infection with a different strain of DHFV. This phenomenon has been referred to as "antibody-dependent enhancement" (6-8). This may lead to the development of DSS in individuals with incomplete and transient immune protection against heterologous DHFV strains following a previous mild infection of the first DHFV strain to infect, or to the administration of an unsuccessful vaccination. This condition, in which the infection of an individual with a single strain of DHFV, can lead to blocking of the immune response to an infection with a second strain (6-8). Some experts speculate that this antibody enhancement leads to the more serious form of DHFV infection that results in vascular collapse, shock and death (6-8). This phenomenon, that of increased susceptibility to infection with a second strain of DHF virus, once a weak response to the first DHF virus strain specific vaccination has occurred, has been reported for DHFV (6-8).

Vaccine development for DHFV has been hampered by the poor replication of human isolates of DHFV in immunocompetent mice (13). Mouse models to study DHFV in which immunodeficient mice with defective interferon response are reconstituted with an immune response system, have been only modestly successful (13-16). Study of vaccine strategies in non-human primates (15) and swine have been tried as well (14), also with only limited success. Thus, the public health measures have focused on the control of the mosquito populations which carry the disease.

Recently, Sanofi reported (17) the partial failure of its new attenuated viral vaccine strategy for DHFV to protect vaccinated individuals against all four strains of DHFV (18). This has been reported as a major setback for the field. In this trial, which was reported in the article published in the Lancet (17), the efficacy was said to be 30%. This vaccine was based on an attenuated strain of yellow fever virus which contains DHFV antigens characteristic of the four major DHFR strains. Patients received vaccination at 0, 6 and 12 months with each of four strains, each one specific for a different strain of DHFV. Patients (>4000) were randomized 2:1 to receive the DHFV/yellow fever chimeric attenuated vaccine or a control vaccine. The incidence of the mild infection against DHFV strain 2 was not different in the two arms (no protective effect of the vaccine), and a moderate decrease in the treatment arm versus the control of cases of DHFV strain 1 (poor response). In contrast, there was 80-90% protection against DHFV strains 3 and 4 with the DHFV/yellow fever chimeric attenuated vaccine. The explanation for the incomplete protection against DHFV strain 2 and the partial protection against strain 1 was that the various strains of DHFV/yellow fever virus vaccines generated different titers in the vaccinated individuals and the strains with the low titers generated only low levels of neutralizing antibody response against the proteins from DHFV strains 1 and 2 (18).

Many factors can reduce the response of an individual to a viral infection or to the induction of an immune response to vaccination: chronic disease, chronic infection, cancer and advanced chronological age. Additional problems include: weak immunogenicity of the target antigen, qualitative or quantitative defects of CD4 helper T cells, defective response in the older aged population due to diminished expression of CD40L in activated CD4 helper T cells, or low levels of presentation of target antigens on Class I or II MHC in dendritic cells (DCs). Among individuals above the age of 55, less than 20% of individuals vaccinated with the yearly multi-valent particle inactivated influenza vaccine develop a fully positive immune response (19-22).

One explanation for this reduced response is the decrease in function of the immune system with age. For example, there is a decrease in the number of naive, antigen unexposed CD4 and CD8 T cells. Additionally, the ratio of the naive to memory CD8/CD4 cells decreases as the chronological age increases. Further, CD4 cells become impaired, acquiring both quantitative and functional defects, such as diminished levels of the CD40 ligand (CD40L) on the surface of CD4 cells as well as a temporal retardation of the rate at which CD40 ligand (CD40L) is expressed on the surface of the CD4 cells following activation. (23-24). Accordingly, the amount of antibody that an elderly individual is able to generate will be lower following infection or conventional vaccination. The CD40L is important for the expansion of antigen specific CD8 effector T cells and antigen specific B cells in response to vaccination.

SUMMARY OF THE INVENTION

Vaccines have been described that include an expression vector encoding a fusion protein that includes an antigen fused to CD40 ligand (25-35). See, e.g., U.S. Patent Application Publication US 2005-0226888 (U.S. patent application Ser. No. 11/009,533) titled "Methods for Generating Immunity to Antigen," filed Dec. 10, 2004. Also see, for example, publication WO/2007/056266, publication date May 18, 2007, International filing date Nov. 6, 2006, entitled "CD40 Ligand Fusion Protein Vaccine".

The present invention provides new vaccines for protecting against infection by dengue hemorrhagic fever virus ("DHFV"). An immune response to fragments of the dengue protein E is achieved by attaching inframe a series of epitopes from the E protein from each of the four DHFV strains to the ecdCD40L, to create a vaccine for all the major strains of the DHFV. Because the infection by an initial DHFV strain generates only short lived neutralizing antibodies that protect against heterologous strains, and the infection with an initial strain may sensitize an individual to more severe infectious with heterologous strains (5-8), it would be of advantage to immunize against all four strains simultaneously. In order to accomplish this, Applicant chose to use 3 fragments of domains III of the E antigen from all 4 strains of the DHFV to attach to the ecdCD40L, for an E/ecdCD40L DHFV vaccine.

The E protein of DHFV was selected for the target of our vaccine since in the flavivirus group, to which DHFV belongs, the E protein is one of the major targets for neutralizing antibodies (5, 36-37). The E protein is therefore thought to be necessary for attachment of the virus to host cells, and for the low pH fusion of the host cell membranes with the virus which is necessary for viral entry (36). The E protein has three domains:

Domain I: This region is thought to be the hinge between Domains II and III. Domain I contains primarily epitopes that elicit non-neutralizing antibodies (37).

Domain II: This domain is involved in virus mediated membrane fusion and contains epitopes which elicit both neutralizing as well as non-neutralizing antibodies (37).

Domain III: This domain which is approximately 100 amino acids long in each of the four strains, is thought to contain the host binding antireceptor which is necessary for initial attachment of the virus to the cell membrane (37). The epitopes in Domain III elicit only neutralizing antibodies and therefore has been chosen as the target domain for vaccine development (37).

Domain III is the preferred target in the E protein as compared to Domains I and II because: a. Domains I and II have epitopes which elicit non-neutralizing antibodies whereas all of the epitopes within Domain III induce neutralizing antibodies (37); b. Domain III mediates the first step of infection of host cells by the virus: that of attachment of the virus by cellular receptors (37). Thus, if that step is blocked by induction of neutralizing antibodies to Domain III, total protection will be produced. c. The above stated properties in (a) and (b), of the E protein are shared by each of the four strains.

In order to circumvent functional defects in the immune response (19-24), as well as increase the immunogenicity of the target associated antigens, Applicant's laboratory (25-35) designed the TAA/ecdCD40L vaccine strategy. There are four versions of this vaccine: 1. One in which the TAA/ecdCD40L transcription unit is embedded in a replication incompetent adenoviral vector (Ad-sig-TAA/ecdCD40L) which is then injected SC three times at seven day intervals; 2. One in which the TAA/ecdCd40L transcription unit is embedded in a replication incompetent adenoviral vector (Ad-sig-TAA/ecdCD40L) which is used as an initial priming injection, followed by two sc injections of the TAA/ecdCD40L protein; 3. One in which the vaccine consists solely of the TAA/ecdCD40L protein; and, 4. One in which the TAA/ecdCD40L is inserted into a plasmid DNA expression vector. The TAA is connected through a linker to the extracellular domain (ecd) of the potent immunostimulatory signal CD40 ligand (CD40L).

The attachment of such DHFV TAA to the CD40L accomplishes two things: the binding of the TAA/ecdCD40L protein to the CD40 receptor on the DCs as well as on the B cells and T cells, activate these cells thereby promoting a potent immune response (25, 27, 29); 2. once the TAA/ecdCD40L protein is engaged on the CD40 receptor of the DC, the entire TAA/ecdCD40L protein is internalized into the DC in a way that allows Class I as well as Class II MHC presentation (25).

The activated TAA loaded DCs then migrate to the regional lymph nodes (27, 29) where they can activate and induce expansion of the TAA specific CD8.sup.+ effector T cells. These antigen specific CD8.sup.+ effector cells become increased in number in the lymph nodes (27, 29), and egress from the lymph nodes into the peripheral blood. The antigen specific CD8 effector T cells exit the intravascular compartment and enter into the extra-vascular the sites of inflammation or infection (29). In addition to showing that this vaccine increases the antigen specific CD8.sup.+ effector T cells in the sites of inflammation (29), Applicant's laboratory has shown that the activation and expansion of the B cells by the TAA/ecdCD40L protein increases the levels of the TAA specific antibodies in the serum (29, 32, 33).

DETAILED DESCRIPTION OF THE INVENTION

As used herein an "antigen" is any foreign material that is specifically bound by the combining site of an antibody or by the combining site of a T cell antigen receptor. Antigens may also be immunogens if they are able to trigger an immune response, or haptens if not.

As used herein, "antigenic determinant" refers to a single antigenic site or epitope on a complex antigenic molecule or particle. a minimal portion of a molecule that interacts with an antibody or T cell receptor. Antigenic determinants may be linear or discontinuous.

In one approach, the sequence encoding the DHFV antigen in the fusion protein transcription unit is 5' to sequence encoding the CD40 ligand. In another approach, the sequence encoding the CD40 ligand in the fusion protein transcription unit is 5' to sequence encoding the DHFV antigen. In a preferred embodiment, the CD40 ligand lacks all or a portion of its transmembrane domain.

In another aspect, the invention provides methods of immunizing an individual against infection by DHFV. The method includes administering an expression vector which includes a transcription unit encoding a secretable fusion protein that contains a DHFV antigen associated and CD40 ligand. A fusion protein that encodes a DHFV antigen associated with the virus and CD40 ligand may also be administered before, concurrently or after administration of the vector. Preferably, the fusion protein is administered after the vector. In this approach, the DHFV antigen which is encoded by the vector is chosen to cross-react with the DHFV virus for which protection is being sought.

In preferred embodiments, the expression vector may be a viral expression vector or a non-viral expression vector; the expression vector may be an adenoviral vector; the vector may be advantageously administered subcutaneously; the vector may be administered on a subsequent occasion(s) to increase the immune response; a signal sequence may be placed upstream of the fusion protein for secretion of the fusion protein; immunity against the antigen may be long lasting and involve generation of cytotoxic CD8.sup.+ T cells against antigen expressing cells and the production of antibody to the antigen; the transcription unit may include sequence that encodes a linker between the DHFV antigen and the CD40 ligand; suitable linkers may vary in length and composition; the expression vector may include a human cytomegalovirus promoter/enhancer for controlling transcription of the transcription unit; and the CD40 ligand may be a human CD40 ligand.

Methods to chemically couple one protein to another (carrier) protein are well known in the art and include, for example, conjugation by a water soluble carbodiimide such as 1-ethyl-3-(3dimethylaminopropyl) carbodiimide hydrochloride, conjugation by a homobifunctional cross-linker having, for example, NHS ester groups or sulfo-NHS ester analogs, conjugation by a heterobifunctional cross-linker having, for example, and NHS ester and a maleimide group such as sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate and, conjugation with gluteraldehyde (see, for example, reference 40; see, also, U.S. Pat. Nos. 4,608,251 and 4,161,519).

The term "vector" which contains a transcription unit (aka. "expression vector") as used herein refers to viral and non-viral expression vectors that when administered in vivo can enter target cells and express an encoded protein. Viral vectors suitable for delivery in vivo and expression of an exogenous protein are well known and include adenoviral vectors, adeno-associated viral vectors, retroviral vectors, herpes simplex viral vectors, and the like. Viral vectors are preferably made replication defective in normal cells. See U.S. Pat. Nos. 6,669,942; 6,566,128; 6,794,188; 6,110, 744; 6,133,029.

As used herein, the term "cells" is used expansively to encompass any living cells such as mammalian cells, plant cells, eukaryotic cells, prokaryotic cells, and the like.

The term "adenoviral expression vector" as used herein, refers to any vector from an adenovirus that includes exogenous DNA inserted into its genome which encodes a polypeptide. The vector must be capable of replicating and being packaged when any deficient essential genes are provided in trans. An adenoviral vector desirably contains at least a portion of each terminal repeat required to support the replication of the viral DNA, preferably at least about 90% of the full ITR sequence, and the DNA required to encapsidate the genome into a viral capsid. Many suitable adenoviral vectors have been described in the art. See U.S. Pat. Nos. 6,440,944 and 6,040,174 (replication defective E1 deleted vectors and specialized packaging cell lines). A preferred adenoviral expression vector is one that is replication defective in normal cells.

"Adenoviral expression vectors" may include vectors that have been modified to better target and infect specific cell types (e.g., fibroblasts and dendritic cells), or that have been modified to avoid neutralization by pre-existing, high-titer antibodies, such as the antibodies circulating in humans against Ad5 and Ad2.

Adeno-associated viruses represent a class of small, single-stranded DNA viruses that can insert their genetic material at a specific site on chromosome 19. The preparation and use of adeno-associated viral vectors for gene delivery is described in U.S. Pat. No. 5,658,785.

Non-viral vectors for gene delivery comprise various types of expression vectors (e.g., plasmids) which are combined with lipids, proteins and other molecules (or combinations of thereof) in order to protect the DNA of the vector during delivery. Fusigenic non-viral particles can be constructed by combining viral fusion proteins with expression vectors as described.

The term "transcription unit" as it is used herein in connection with an expression vector means a stretch of DNA that is transcribed as a single, continuous mRNA strand by RNA polymerase, and includes the signals for initiation and termination of transcription. For example, in one embodiment, a transcription unit of the invention includes nucleic acid that encodes from 5' to 3,' a secretory signal sequence, a DHFV antigen and CD40 ligand. The transcription unit is in operable linkage with transcriptional and/or translational expression control elements such as a promoter and optionally any upstream or downstream enhancer element(s). A useful promoter/enhancer is the cytomegalovirus (CMV) immediate-early promoter/enhancer. See U.S. Pat. Nos. 5,849,522 and 6,218,140.

The term "secretory signal sequence" (aka. "signal sequence," "signal peptide," leader sequence," or leader peptide") as used herein refers to a short peptide sequence, generally hydrophobic in charter, including about 20 to 30 amino acids which is synthesized at the N-terminus of a polypeptide and directs the polypeptide to the endoplasmic reticulum. The secretory signal sequence is generally cleaved upon translocation of the polypeptide into the endoplasmic reticulum. Eukaryotic secretory signal sequences are preferred for directing secretion of the exogenous gene product of the expression vector. A variety of suitable such sequences are well known in the art and include the secretory signal sequence of human growth hormone, immunoglobulin kappa chain, and the like. In some embodiments the endogenous tumor antigen signal sequence also may be used to direct secretion.

As is well known in the art, an antigen may be protein in nature, carbohydrate in nature, lipid in nature, or nucleic acid in nature, or combinations of these biomolecules. As is well known in the art, an antigen may be native, recombinant or synthetic. For example, an antigen may include non-natural molecules such as polymers and the like. Antigens include self antigens and foreign antigens such as antigens produced by another animal or antigens from an infectious agent. Infectious agent antigens may be bacterial, viral, fungal, protozoan, and the like.

Applicant selected the E protein of DHFV for the target of our vaccine since in the flavivirus group, to which DHFV belongs, the E protein is one of the major targets for neutralizing antibodies (5, 36-37). The E protein is therefore thought to be necessary for attachment of the virus to host cells, and for the low pH fusion of the host cell membranes with the virus which is necessary for viral entry into cells (36-37).

The general criteria utilized for selecting fragments of the E protein, which when attached to the aminoterminal end of the ecdCD40L, can generate a neutralizing antibody immune response are as follows: 1. To prevent a DHFV infection by generating high levels of E protein specific neutralizing antibodies to DHFV, the fragment must have the ability to be recognized and bound by Class II MHC and occupy a region in the DHVF antigen needed for infection of cells by DHFV. 2. To prevent or reduce the probability of escape from the negative selective pressure of the immunological response due to sequence evolution of regions of the E protein selected for the vaccine by attaching 3 fragments of Domain III of each strain of the E protein (amino acids 294-320, amino acids 321-354. and amino acids 355-395), where each fragment is separately attached to the aminoterminal end of the ecdCD40L. 3. To prevent the destabilization of the homotrimeric structure of the ecdCD40L from the attachment of the TAA to the aminoterminal end of the ecdCD40L, the fragments of the E protein will be chosen such that the molecular weight of the combined TAA is not too big. 4. While three fragments of Domain III have been selected for each of the four strains as a preferred embodiment, one could select, for example, four or more fragments of Domain III of each strain of the E protein.

The vaccine is a fusion protein comprised of a fragment taken from the E protein of DHFV, which is essential for the binding and uptake of the DHFV by monocytes and other cells of the human host (36-37), which is attached to the extracellular domain (ecd) of the CD40 ligand (CD40L). Three separate fragments of Domain III of E (ED) which are numbered E.sub.294-320, E.sub.321-355 and E.sub.356-395 are chosen from Domain III of the E protein of the four different strains (SI, SII, SIII and SIV) of the DHFV (38). This generates 12 vaccines as shown below in Table I

The invention consists of generating 12 different TAA/ecdCD40L vaccines as shown in Table I as a preferred embodiment. In Table 1, E.sub.294-320, E.sub.321-355 and E.sub.356-395 refer to the fragment of Domain III of the E protein which is attached to the ecdCD40L. In addition, the Roman numeral that follows the "S" (I, II, III and IV) under the "Vaccine" column, refers to the strain of DHFV from which the E protein fragment comes.

TABLE-US-00001 TABLE 1 Vaccines for DHFV E Protein Fragment Strain of DHFV Vaccine I II III IV 1. E.sub.294-320SI/ecdCD40L X 2. E.sub.294-320SII/ecdCD40L X 3. E.sub.294-320SIII/ecdCD40L X 4. E.sub.294-320SIV/ecdCD40L X 5. E.sub.321-355SI/ecdCD40L X 6. E.sub.321-355SII/ecdCD40L X 7. E.sub.321-355SIII/ecdCD40L X 8. E.sub.321-355SIV/ecdCD40L X 9. E.sub.356-395SI/ecdCD40L X 10. E.sub.356-395SII/ecdCD40L X 11. E.sub.356-395SIII/ecdCD40L X 12. E.sub.356-395SIV/ecdCD40L X

The amino acid sequences of the fragments of the E protein from each Dengue strain are given below. These are derived from FIG. 3 of Sukupolvi-Petty et al, (38). 1. E.sub.294-320 Fragment from Strain I: LKGMSYVMCTGSFKLEKEVAETQHGTV (SEQ ID #1) 2. E.sub.294-320 Fragment from Strain II: LKGMSYSMCTGKFKVVKEIAETQHGTI (SEQ ID#2) 3. E.sub.294-320 Fragment from Strain III: LKGMSYAMCLSSFVLKKEVSETQHGTI (SEQ ID#3) 4. E.sub.294-320 Fragment from Strain IV: IKGMSYTMCSGKFSIDKEMAETQHGTT (SEQ ID #4) 5. E.sub.321-355 Fragment from Strain I: LVQVKYEGTDAPCKIPFSTQDEKGATQMGRLITA (SEQ ID #5) 6. E.sub.321-355 Fragment from Strain II: VIRVQYEGTGSPCKIPFEIMDLEKRHVLGRLITV (SEQ ID #6) 7. E.sub.321-355 Fragment from Strain III: LIKVEYKGEDAPCKIPFSTEDGQGKAHNGRLITA (SEQ ID #7) 8. E.sub.321-355 Fragment from Strain IV: VVKVKYEGAGAPCKVPIEIRDVNKEKVVGRIISS (SEQ ID #8) 9. E.sub.356-395 Fragment from Strain I: NPIVTDKEKPVNIEAEPPFGESYIVVGAGEKALKLSWFKK (SEQ ID #9) 10. E.sub.356-395 Fragment from Strain II: NPIVTEKDSPVNIEAEPPFGDSYIIIGVEPGQLKNWFKK (SEQ ID #10) 11. E.sub.356-395 Fragment from Strain III: NPVVTKKEEPVNIEAEPPFGESNIVIGIGDKALKINWYKK (SEQ ID #11) 12. E.sub.356-395 Fragment from Strain IV: TPLAENTNSATNIELEPPFGDSYIVIGVGNSALTLHWFRK (SEQ ID #12)

For example, the first vaccine listing under the "Vaccine" column, is E.sub.294-320SI/ecdCD40L, when read across the column on a horizontal basis, connotes that it applies to the E.sub.294-320 fragment of Domain III of the E Protein and to Strain I of the DHFV.

This mixture of these 12 vaccines (listed under the "Vaccine" column), can make the weak DHFV antigens potent immunogens, overcome the defective response in immunodeficient individuals, and induce an immune response to all VHF strains simultaneously. The vaccines in Table 1 could refer to transcription units in DNA plasmid, adenoviral vectors, or to the E/ecdCD40L fusion protein itself. In addition, the vaccine could be a combination of vector prime and protein boosts. Both the vector prime and protein boost are comprised of mixtures of 12 different vaccines (adenoviral vector or protein boost). If a plasmid vaccine is used, then mixtures of the 12 types of vaccine shown in Table 1 would be used.

The attachment of fragments of Domain III of the DHFV E protein to the ecdCD40L (E/ecdCD40L) would increase the potency of the E antigens from all 4 strains of DHFV as immunogens, thereby overcoming the more important factors which limit current vaccines for DHFV. The attachment of the E antigens to the ecdCD40L would make weak antigens more potent immunogens. The E/ecdCD40L vaccine would promote presentation of the E antigenic peptides on Class II MHC on DCs. Moreover, the administration of E/ecdCD40L vaccines, which contain fragments of domains of each of the three domains of the E protein for all 4 DHFV viral strains would induce high titer, fully protective neutralizing antibodies simultaneously to all four strains of the DHFV. This would prevent what is a major problem: immunological escape for heterologous strains and increased susceptibility to heterologous strains of the DHFV following the weak immune response to an initial vaccination or infection with a single strain.

These 12 vaccines are delivered as a mixture and administered subcutaneously. The vaccine can be delivered as a mixture of the fusion proteins. Alternatively, the vaccine can be delivered as a mixture of 12 adenoviral expression vectors. Alternatively, the vaccine can be delivered as a mixture of 12 plasmid DNA expression vectors.

Published Papers Relevant to the DHFV TAA/ecdCD40L Vaccine

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SEQUENCE LISTINGS

1

12127PRTArtificial SequenceSynthetic Construct 1Leu Lys Gly Met Ser Tyr Val Met Cys Thr Gly Ser Phe Lys Leu Glu1 5 10 15Lys Glu Val Ala Glu Thr Gln His Gly Thr Val 20 25227PRTArtificial SequenceSynthetic Construct 2Leu Lys Gly Met Ser Tyr Ser Met Cys Thr Gly Lys Phe Lys Val Val1 5 10 15Lys Glu Ile Ala Glu Thr Gln His Gly Thr Ile 20 25327PRTArtificial SequenceSynthetic Construct 3Leu Lys Gly Met Ser Tyr Ala Met Cys Leu Ser Ser Phe Val Leu Lys1 5 10 15Lys Glu Val Ser Glu Thr Gln His Gly Thr Ile 20 25427PRTArtificial SequenceSythetic Construct 4Ile Lys Gly Met Ser Tyr Thr Met Cys Ser Gly Lys Phe Ser Ile Asp1 5 10 15Lys Glu Met Ala Glu Thr Gln His Gly Thr Thr 20 25534PRTArtificial SequenceSynthetic Construct 5Leu Val Gln Val Lys Tyr Glu Gly Thr Asp Ala Pro Cys Lys Ile Pro1 5 10 15Phe Ser Thr Gln Asp Glu Lys Gly Ala Thr Gln Met Gly Arg Leu Ile 20 25 30Thr Ala634PRTArtificial SequenceSynthetic Construct 6Val Ile Arg Val Gln Tyr Glu Gly Thr Gly Ser Pro Cys Lys Ile Pro1 5 10 15Phe Glu Ile Met Asp Leu Glu Lys Arg His Val Leu Gly Arg Leu Ile 20 25 30Thr Val734PRTArtificial SequenceSynthetic Construct 7Leu Ile Lys Val Glu Tyr Lys Gly Glu Asp Ala Pro Cys Lys Ile Pro1 5 10 15Phe Ser Thr Glu Asp Gly Gln Gly Lys Ala His Asn Gly Arg Leu Ile 20 25 30Thr Ala834PRTArtificial SequenceSynthetic Construct 8Val Val Lys Val Lys Tyr Glu Gly Ala Gly Ala Pro Cys Lys Val Pro1 5 10 15Ile Glu Ile Arg Asp Val Asn Lys Glu Lys Val Val Gly Arg Ile Ile 20 25 30Ser Ser940PRTArtificial SequenceSynthetic Construct 9Asn Pro Ile Val Thr Asp Lys Glu Lys Pro Val Asn Ile Glu Ala Glu1 5 10 15Pro Pro Phe Gly Glu Ser Tyr Ile Val Val Gly Ala Gly Glu Lys Ala 20 25 30Leu Lys Leu Ser Trp Phe Lys Lys 35 401039PRTArtificial SequenceSynthetic Construct 10Asn Pro Ile Val Thr Glu Lys Asp Ser Pro Val Asn Ile Glu Ala Glu1 5 10 15Pro Pro Phe Gly Asp Ser Tyr Ile Ile Ile Gly Val Glu Pro Gly Gln 20 25 30Leu Lys Asn Trp Phe Lys Lys 351140PRTArtificial SequenceSynthetic Construct 11Asn Pro Val Val Thr Lys Lys Glu Glu Pro Val Asn Ile Glu Ala Glu1 5 10 15Pro Pro Phe Gly Glu Ser Asn Ile Val Ile Gly Ile Gly Asp Lys Ala 20 25 30Leu Lys Ile Asn Trp Tyr Lys Lys 35 401240PRTArtificial SequenceSynthetic Construct 12Thr Pro Leu Ala Glu Asn Thr Asn Ser Ala Thr Asn Ile Glu Leu Glu1 5 10 15Pro Pro Phe Gly Asp Ser Tyr Ile Val Ile Gly Val Gly Asn Ser Ala 20 25 30Leu Thr Leu His Trp Phe Arg Lys 35 40