A humanised murine monoclonal antibody protects mice from Venezuelan equine encephalitis virus, Everglades virus and Mucambo virus when administered up to 48 h after airborne challenge.

Currently there are no licensed antiviral treatments for the Alphaviruses Venezuelan equine encephalitis virus (VEEV), Everglades virus and Mucambo virus. We previously developed a humanised version of the mouse monoclonal antibody 1A3B-7 (Hu1A3B-7) which exhibited a wide range of reactivity in vitro and was able to protect mice from infection with VEEV. Continued work with the humanised antibody has now demonstrated that it has the potential to be a new human therapeutic.

Lethality and pathogenesis of airborne infection with filoviruses in A129 α/β -/- interferon receptor-deficient mice.

Normal immunocompetent mice are not susceptible to non-adapted filoviruses. There are therefore two strategies available to establish a murine model of filovirus infection: adaptation of the virus to the host or the use of genetically modified mice that are susceptible to the virus. A number of knockout (KO) strains of mice with defects in either their adaptive or innate immunity are susceptible to non-adapted filoviruses.

A humanised murine monoclonal antibody with broad serogroup specificity protects mice from challenge with Venezuelan equine encephalitis virus.

In murine models of Venezuelan equine encephalitis virus (VEEV) infection, the neutralising monoclonal antibody 1A3B-7 has been shown to be effective in passive protection from challenge by the aerosol route with serogroups I, II and Mucambo virus (formally VEE complex subtype IIIA). This antibody is able to bind to all serogroups of the VEEV complex when used in ELISA and therefore is an excellent candidate for protein engineering in order to derive a humanised molecule suitable for therapeutic use in humans. A Complementarity Determining Region (CDR) grafting approach using human germline IgG frameworks was used to produce a panel of humanised variants of 1A3B-7, from which a single candidate molecule with retained binding specificity was identified.

A recombinant humanized monoclonal antibody completely protects mice against lethal challenge with Venezuelan equine encephalitis virus.

A recombinant humanized antibody to Venezuelan equine encephalitis virus (VEEV) was constructed in a monocistronic adenoviral expression vector with a foot-and-mouth-disease virus-derived 2A self-cleavage oligopeptide inserted between the antibody heavy and light chains. After expression in mammalian cells, the heavy and light chains of the humanized antibody (hu1A4A1IgG1-2A) were completely cleaved and properly dimerized. The purified hu1A4A1IgG1-2A retained VEEV binding affinity and neutralizing activity similar to its parental murine antibody.

Development of a novel monoclonal antibody with reactivity to a wide range of Venezuelan equine encephalitis virus strains.

Background: There is currently a requirement for antiviral therapies capable of protecting against infection with Venezuelan equine encephalitis virus (VEEV), as a licensed vaccine is not available for general human use. Monoclonal antibodies are increasingly being developed as therapeutics and are potential treatments for VEEV as they have been shown to be protective in the mouse model of disease. However, to be truly effective, the antibody should recognise multiple strains of VEEV and broadly reactive monoclonal antibodies are rarely and only coincidentally isolated using classical hybridoma technology.

Improved efficacy of a gene optimised adenovirus-based vaccine for venezuelan equine encephalitis virus.

Background: Optimisation of genes has been shown to be beneficial for expression of proteins in a range of applications. Optimisation has increased protein expression levels through improved codon usage of the genes and an increase in levels of messenger RNA. We have applied this to an adenovirus (ad)-based vaccine encoding structural proteins (E3-E2-6K) of Venezuelan equine encephalitis virus (VEEV).

Alpha interferon as an adenovirus-vectored vaccine adjuvant and antiviral in Venezuelan equine encephalitis virus infection.

There are no widely available vaccines or antiviral drugs capable of protecting against infection with Venezuelan equine encephalitis virus (VEEV), although an adenovirus vector expressing VEEV structural proteins protects mice from challenge with VEEV and is potentially a vaccine suitable for human use. This work examines whether alpha interferon (IFN-alpha) could act as an adjuvant for the adenovirus-based vaccine. IFN-alpha was either expressed by a plasmid linked to the adenovirus vaccine or encoded by a separate adenovirus vector administered as a mixture with the vaccine.

CpG used as an adjuvant for an adenovirus-based Venezuelan equine encephalitis virus vaccine increases the immune response to the vector, but not to the transgene product.

An adenovirus-based (ad-based) vaccine delivering antigens from the Alphavirus Venezuelan equine encephalitis virus (VEEV) is a strategy that offers clinical potential. A vaccine against VEEV is desirable because of the re-emerging nature of this virus, and also the potential that it may be used as a biological weapon. This study was designed to investigate whether the co-administration of CpG oligodeoxynucleotides (ODNs) with an ad-based VEEV vaccine could enhance the protective efficacy of the vaccine.

Airborne transmission of lyssaviruses.

In 2002, a Scottish bat conservationist developed a rabies-like disease and subsequently died. This was caused by infection with European bat lyssavirus 2 (EBLV-2), a virus closely related to Rabies virus (RABV). The source of this infection and the means of transmission have not yet been confirmed.

Venezuelan equine encephalitis virus complex-specific monoclonal antibody provides broad protection, in murine models, against airborne challenge with viruses from serogroups I, II and III.

The alphavirus Venezuelan equine encephalitis virus (VEEV) is highly infectious by the airborne route. It is a hazard to laboratory workers, has been developed as a biological weapon and is a potential bioterrorist agent. A suitable vaccine appears in an advanced stage of development but there remains a need for antiviral drugs, effective in prophylaxis of disease prior to or a short time after exposure to airborne virus.

Boosting with an adenovirus-based vaccine improves protective efficacy against Venezuelan equine encephalitis virus following DNA vaccination.

There is a requirement for a vaccine that protects against the alphavirus, Venezuelan equine encephalitis virus (VEEV). Previous work has shown that DNA vaccines encoding structural proteins of VEEV can elicit immune responses and protection against VEEV though this protection is incomplete against airborne VEEV. In this study, we demonstrate that particle-mediated epidermal delivery of a DNA vaccine encoding the E2 glycoprotein of VEEV can be boosted with a mucosally-delivered Ad-based vaccine encoding the same E2 glycoprotein.

DNA vaccines for biodefence.

The advantages associated with DNA vaccines include the speed with which they may be constructed and produced at large-scale, the ability to produce a broad spectrum of immune responses, and the ability for delivery using non-invasive means. In addition, DNA vaccines may be manipulated to express multiple antigens and may be tailored for the induction of appropriate immune responses. These advantages make DNA vaccination a promising approach for the development of vaccines for biodefence.

VP22 enhances antibody responses from DNA vaccines but not by intercellular spread.

In some species DNA vaccines elicit potent humoral and cellular immune responses. However, their performance in humans and non-human primates is less impressive. There are suggestions in the literature that an increase in the intercellular distribution of protein expressed from a DNA vaccine may enhance immunogenicity.

Protective efficacy of a recombinant plague vaccine when co-administered with another sub-unit or live attenuated vaccine.

Vaccines against bioterrorism agents offer the prospect of providing high levels of protection against airborne pathogens. However, the diversity of the bioterrorism threat means that it may be necessary to use several vaccines simultaneously. In this study we have investigated whether there are changes to the protective immune response to a recombinant sub-unit plague vaccine when it is co-administered with other sub-unit or live attenuated vaccines.

Intranasal immunisation with defective adenovirus serotype 5 expressing the Venezuelan equine encephalitis virus E2 glycoprotein protects against airborne challenge with virulent virus.

There is no vaccine licensed for human use to protect laboratory or field workers against infection with Venezuelan equine encephalitis virus (VEEV). Infection of these groups is most likely to occur via the airborne route and there is evidence to suggest that protection against airborne infection may require high antibody levels and the presence of antibody on the mucosal surface of the respiratory tract. Recombinant defective type 5 adenoviruses, expressing the E3E26K structural genes of VEEV were examined for their ability to protect mice against airborne challenge with virulent virus.

Characterization and manipulation of the human adenovirus 4 genome.

Human adenovirus 4 (HAdV-4), the only serotype of the species HAdV-E to be isolated from man, was first identified by its association with outbreaks of acute respiratory disease in military recruits. To combat such outbreaks, a live, oral HAdV-4 vaccine that is delivered via an enteric-coated capsule was developed. This vaccine has been used for nearly 40 years and has been shown to be safe and efficacious.

Antibody and interleukin-12 treatment in murine models of encephalitogenic flavivirus (St. Louis encephalitis, tick-borne encephalitis) and alphavirus (Venezuelan equine encephalitis) infection.

Early and sustained treatment with interleukin-12 (IL-12) ameliorated disease in a mouse model of infection with the encephalitogenic flavivirus, St. Louis encephalitis virus (SLEV, Japanese encephalitis serogroup). However, this effect was not reproduced in murine infections with either the flavivirus tick-bore encephalitis virus (TBEV) or the alphavirus Venezuelan equine encephalitis virus (VEEV).

Cytotoxic T-cell activity is not detectable in Venezuelan equine encephalitis virus-infected mice.

Previously published research has established that the immune response to the Venezuelan equine encephalitis virus (VEEV) vaccine strain TC-83 is Th 1-mediated, with local activation of both CD4+ and CD8+ T cells. This suggests that cytotoxic lymphocytes CTL may play a role in protection against virulent VEEV. Studies involving a variety of immunisation schedules with either TC-83 or strain CAAR 508 (serogroup 5) of VEEV, and six different haplotypes of mice, failed to reveal functional CTL activity against VEEV-infected targets in secondary antigen-stimulated lymphocyte cultures from either the draining lymph nodes (LN) or spleen.

Role for mucosal immune responses and cell-mediated immune functions in protection from airborne challenge with Venezuelan equine encephalitis virus.

Venezuelan equine encephalitis virus (VEEV) replicates in lymphoid tissues following peripheral inoculation and a high titre viraemia develops. Encephalitis develops after the virus enters the central nervous system from the blood, with the earliest neuronal involvement being via the olfactory nerve. Following aerosol challenge with virulent VEEV, the virus is thought to replicate in the nasal mucosa and there could be direct entry into the olfactory nerve via infected neuroepithelial cells.

Monoclonal antibody protects mice against infection and disease when given either before or up to 24 h after airborne challenge with virulent Venezuelan equine encephalitis virus.

Airborne infection with Venezuelan equine encephalitis virus (VEEV) is a significant hazard for laboratory workers, who may not be immunised against VEEV infection as there is no vaccine currently available suitable for human use. We describe a potential alternative strategy that could protect workers exposed to VEEV or similar viruses. VEEV-specific murine monoclonal antibodies (MAB), given by intraperitoneal (i.

Vaccinia virus recombinants encoding the truncated structural gene region of Venezuelan equine encephalitis virus (VEEV) give solid protection against peripheral challenge but only partial protection against airborne challenge with virulent VEEV.

Vaccinia virus (VV) recombinants that contain the genes encoding the Venezuelan equine encephalitis virus (VEEV) structural gene region (C-E3-E2-6 K-E1) solidly protect mice against peripheral challenge with virulent VEEV, but provide only partial protection against airborne challenge. To improve upon these results we focussed on the principal antigens involved in protection. VV recombinants encoding the structural genes E3-E2-6 K-E1, E3-E2-6 K or 6 K-E1 were prepared and evaluated for their ability to protect Balb/c mice after a single dorsal scarification with 10(8) PFU against peripheral or airborne challenge with virulent VEEV.

The immune response to vaccinia virus is significantly reduced after scarification with TK- recombinants as compared to wild-type virus.

Although it is unlikely that large-scale vaccination against smallpox will ever be required again, it is conceivable that the need may arise to vaccinate against a human orthopoxvirus infection. A possible example could be the emergence of monkey poxvirus (MPV) as a significant human disease in Africa. Vaccinia virus (VV) recombinants, genetically modified to carry the immunogenic proteins of other pathogenic organisms, have potential use as vaccines against other diseases present in this region.

An immunological profile of Balb/c mice protected from airborne challenge following vaccination with a live attenuated Venezuelan equine encephalitis virus vaccine.

The live attenuated vaccine strain of Venezuelan equine encephalitis virus (VEEV), TC-83, protects mice against challenge (subcutaneous and aerosol) with virulent VEEV but is not suitable for widescale human use. Elucidation of the immune response profile of protected mice should assist in the development of an improved vaccine. We determined the optimum dose of TC-83 required to consistently protect Balb/c mice from airborne challenge with the virulent Trinidad Donkey strain of VEEV and studied the development of humoral and cellular immune responses in protected mice between 6 h and 21 days post-vaccination.