Adjuvant viral particle

#1. Field of the Invention

#The present invention relates to a viral particle bearing immunogens and having immunopotentiation or adjuvant activity. The invention particularly relates to recombinant viral particles and method for enhancing an immune response in a human or an animal by means of these particles.

#2. Description of Prior Art

#FIG. 1 illustrates an electron micrograph of purified PapMV;

#FIG. 2 illustrate tricine SDS-PAGE analysis of the PapMV CP(A) and immunogold laveling showing that the fusion is exposed at the surface of the PapMV VLP (B);

#FIGS. 3A to 3F illustrate electron micrographs of PapMV and PapMV VLP assembled in vitro;

#In accordance with the present invention, there is provided a virus-like particle carrying immunogen in fusion with endogenous viral proteins, therefore forming a new type of immunogen-carrier being also capable of immunopotentiation or having an adjuvant effect.

#In one embodiment of the present invention, there is provided a class of carriers which when linked genetically to an immunogen or hapten can enhance the host's immune response to the immunogen or hapten regardless of whether the complex is administered parenterally, enterally or orally. In addition their use does not result in the formation of large lesions at injection sites.

#Accessory cells such as macrophages, B lymphocytes, and dendritic cells are essential for the induction of T cell-dependent immune responses. Accessory cells present antigens to MHC-restricted T cells and produce membrane-associated and secreted costimulators that enhance the proliferation and differentiation of T lymphocytes. Therefore, the presence of competent accessory cells stimulates T cell-dependent immune responses, and their absence leads to deficient responses. Resting macrophages and naïve, unstimulated B lymphocytes sented by such antigen-presenting cells (APCs) may fail to stimulate naïve CD4+ T cells, and may even induce T cell tolerance. In contrast, dendritic cells and activated macrophages and B cells do express costimulators, as well as high levels of APCs. A mechanism of action of the immunogen-carrier of the present invention, is to enhance the expression of costimulators on macrophages and other APCs. Because of this, the administration of immunogens or protein antigens with the immunogen carriers of the invention, acting simultaneously as an adjuvant, promotes cell-mediated immunity and T cell-dependent antibody production. Immunogens are most effective for generating systemic immunity when administered coupled together with an immunogen-carrier of the present invention.