Protective immunity against murine hepatitis virus (MHV) induced by intranasal or subcutaneous administration of hybrids of tobacco mosaic virus that carries an MHV epitope

Abstract

Hybrids of tobacco mosaic virus (TMV) were constructed with the use of fusion to the coat protein peptides of 10 or 15 amino acids, containing the 5B19 epitope from the spike protein of murine hepatitis virus (MHV) and giving rise to TMV-5B19 and TMV-5B19L, respectively. The TMV hybrids were propagated in tobacco plants, and the virus particles were purified. Immunogold labeling, with the use of the monoclonal MAb5B19 antibody, showed specific decoration of hybrid TMV particles, confirming the expression and display of the MHV epitope on the surface of the TMV. Mice were immunized with purified hybrid viruses after several regimens of immunization. Mice that received TMV-5B19L intranasally developed serum IgG and IgA specific for the 5B19 epitope and for the TMV coat protein. Hybrid TMV-5B19, administered by subcutaneous injections, elicited high titers of serum IgG that was specific for the 5B19 epitope and for coat protein, but IgA that was specific against 5B19 was not observed. Mice that were immunized with hybrid virus by subcutaneous or intranasal routes of administration survived challenge with a lethal dose (10 ؋ LD 50 ) of MHV strain JHM, whereas mice administered wild-type TMV died 10 d post challenge. Furthermore, there was a positive correlation between the dose of administered immunogen and protection against MHV infection. These studies show that TMV can be an effective vaccine delivery vehicle for parenteral and mucosal immunization and for protection from challenge with viral infection.Several plant viruses have been developed for use as vectors for the expression and delivery of foreign peptides (1-7). These examples include immunogenic epitopes that can be used in vaccines to confer protective immunity against human and animal diseases. We have demonstrated that a hybrid tobacco mosaic virus (TMV), containing the 13 amino acid sequence of the murine zona pellucida ZP3 epitope fused to a region near the C terminus of the coat protein (CP) successfully elicited the production of anti-ZP3 antibody in parenterally immunized animals. Anti-ZP3 antibody accumulated around the ova of immunized animals; however, it did not prevent fertilization (5).Murine hepatitis virus (MHV), a member of the Coronaviridae family, is responsible for a variety of acute and chronic diseases in its natural host. The strain JHM of MHV induces demyelinating encephalomyelitis with high mortality, and surviving mice exhibit chronic demyelination. MHV contains at least three dominant structural proteins: the membrane glycoprotein (M protein), the nucleocapsid protein (N protein), and the spike glycoprotein (S protein) (8). The S protein is posttranslationally processed to yield the S1 and the S2 proteins (9). The S protein has been the focus of many studies because of its important role in viral attachment to target cellular receptors (10), its membrane penetration, and its ability to induce cell fusion (11). The S protein is a critical determinant of viral pathogenicity and has been shown to contain major immunodomina...

Chimeric Plant Virus Particles as Immunogens for Inducing Murine and Human Immune Responses against Human Immunodeficiency Virus Type 1

“…A number of studies have recently documented the ability of CVPs displaying foreign peptides from several pathogens and delivered by different routes to induce protective immunity in animal models (6,7,15,20,21,36). Notably, in the present study we have shown that intranasal delivery of CVPs, inducing higher antigen-specific antibody titers, evokes a more efficient immune response than delivery through the systemic route.…”

“…When properly fused at different positions on the capsid proteins, exogenous sequences are expressed in plants, originating recombinant viral CP able to self-assemble and generate chimeric virus particles (CVPs) displaying the foreign sequence on their outer surfaces. The "epitope-displaying" strategy using plant virus CP as carriers for both viral and bacterial antigens (14) has been successfully tested for experimental vaccines in animal models (7,15,20,21,36). The two systems most frequently used are tobacco mosaic virus and cowpea mosaic virus, whose structures have been determined to atomic resolution, allowing the design of fusion proteins carrying modifications expected to be located at the surface of the assembled virion.…”

Replication of tobamovirus RNA

“…Tobamoviruses are suitable for this purpose, since large quantities of pure virus particles can easily be purified from infected plants. Turpen et al 90) and Koo et al 91) have inserted the malarial epitope and the murine hepatitis virus spike glycoprotein epitope at an internal site and in a C-terminal region of the CP, respectively; both sites are predicted to be exposed to the surface of the virion. These viruses replicate, spread systemically in plants, and successfully display immunogenic epitopes on the surfaces of assembled tobamovirus particles.…”

Potent neutralization of severe acute respiratory syndrome (SARS) coronavirus by a human mAb to S1 protein that blocks receptor association

“…The S1 and S2 domain of SARS-CoV S protein can be identified by sequence alignment with other coronavirus S proteins, especially with the more conserved S2 domain (8-10). The S protein is also the major antigenic determinant for coronaviruses (9,(11)(12)(13)(14). It has recently been demonstrated that the binding of the S1 domain to its receptor angiotensinconverting enzyme 2 (ACE2) on host cells is responsible for SARS-CoV entry into cells (15).…”