ABSTRACT
Leptospirosis is a zoonotic disease caused by pathogenic spirochetes of theLeptospira genus. Vaccination with bacterins has severe limitations. Here, we evaluated the N-terminal region of the leptospiral immunoglobulin-like B protein (LigBrep) as a vaccine candidate against leptospirosis using immunisation strategies based on DNA prime-protein boost, DNA vaccine, and subunit vaccine. Upon challenge with a virulent strain ofLeptospira interrogans, the prime-boost and DNA vaccine approaches induced significant protection in hamsters, as well as a specific IgG antibody response and sterilising immunity. Although vaccination with recombinant fragment of LigBrep also produced a strong antibody response, it was not immunoprotective. These results highlight the potential of LigBrep as a candidate antigen for an effective vaccine against leptospirosis and emphasise the use of the DNA prime-protein boost as an important strategy for vaccine development.
Subject(s)
Animals , Cricetinae , Female , Antigens, Bacterial/immunology , Bacterial Proteins/immunology , Bacterial Vaccines/immunology , Leptospira/immunology , Leptospirosis/prevention & control , Vaccination/methods , Adjuvants, Immunologic , Biopsy , Chlorocebus aethiops , Conserved Sequence , Enzyme-Linked Immunosorbent Assay , Immunity, Humoral/immunology , Immunoglobulin A/genetics , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Immunoglobulins/genetics , Immunoglobulins/immunology , Kidney/pathology , Leptospirosis/immunology , Lung/pathology , Mesocricetus , Survival Analysis , Vero Cells , Vaccines, DNA/immunology , Vaccines, Synthetic/immunology , Vaccines, Synthetic/microbiologyABSTRACT
We studied the feasibility of using halloysite clay nanotubes (HNTs) and carboxyl-functionalised multi-walled carbon nanotubes (COOH-MWCNTs) as antigen carriers to improve immune responses against a recombinant LipL32 protein (rLipL32). Immunisation using the HNTs or COOH-MWCNTs significantly increased the rLipL32-specific IgG antibody titres (p < 0.05) of Golden Syrian hamsters. None of the vaccines tested conferred protection against a challenge using a virulent Leptospira interrogans strain. These results demonstrated that nanotubes can be used as antigen carriers for delivery in hosts and the induction of a humoral immune response against purified leptospiral antigens used in subunit vaccine preparations.