Virus-like particles (VLPs) mimic the whole construct of virus particles devoid of viral genome as used in subunit vaccine design. VLPs can elicit efficient protective immunity as direct immunogens compared to soluble antigens co-administered with adjuvants in several booster injections. Up to now, several prokaryotic and eukaryotic systems such as insect, yeast, plant, and E. coli were used to express recombinant proteins, especially for VLP production. Recent studies are also generating VLPs in plants using different transient expression vectors for edible vaccines. VLPs and viral particles have been applied for different functions such as gene therapy, vaccination, nanotechnology, and diagnostics. Herein, we describe VLP production in different systems as well as its applications in biology and medicine.

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Background:The association between human papillomavirus (HPV) infections and cervical cancer has suggested the design of prophylactic and therapeutic vaccines against genital warts. The HPV capsid has made of two L1 and L2 coat proteins that have produced late in viral infections. Regarding to the recent studies, two commercial prophylactic vaccines have based on L1 viral like particles (VLPs) could strongly induce antibody responses, and protect human body from HPV infections. However, the use of these HPV vaccines has hindered due to their high cost and some limitations. Currently, among various vaccination strategies, live vector-based vaccines have attracted a great attention.Objectives:Herein, a non-pathogenic strain of the protozoan organism known as Leishmania tarentolae has utilized to induce potent humoral immunity in mice model.Materials and Methods:At first, cloning of HPV16 L1 gene into Leishmania expression vector has performed and confirmed by PCR and digestion with restriction enzymes. The promastigotes of Leishmania tarentolae (L.tar) have transfected with linearized DNA construct by electroporation. Protein expression has analyzed by SDS-PAGE and western blotting. Then, the immunogenicity of leishmania expressing L1 protein (L.tar-L1) has assessed in mice model.Results:Our data has indicated that subcutaneous immunization of mice with the recombinant L.tar-L1 has led to enhance the levels of IgG1 and lgG2a in comparison with control groups. Furthermore, there was no significant increase in antibody levels between two and three times of immunizations.Conclusions:The recombinant live vector was able to induce humoral immunity in mice without need of any adjuvant. However, further studies have required to increase its efficiency.