Protection afforded against aerosol challenge by systemic immunisation with inactivated Francisella tularensis live vaccine strain (LVS)

• Published in: Microbial pathogenesis Vol. 44; no. 2; pp. 164 - 168
• Main Authors: Eyles, J.E., Hartley, M.G., Laws, T.R., Oyston, P.C.F., Griffin, K.F., Titball, R.W.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier India Pvt Ltd 01-02-2008; Elsevier
• Subjects: Adjuvant; Adjuvants, Immunologic - administration & dosage; Aerosols; Aluminum Hydroxide - administration & dosage; Animals; Antibodies, Bacterial - blood; Applied microbiology; Bacterial Vaccines - immunology; Bacteriology; Biological and medical sciences; Female; Francisella tularensis - immunology; Fundamental and applied biological sciences. Psychology; Immunization; Immunoglobulin G - blood; Injections, Intramuscular; ISCOMs - administration & dosage; Mice; Mice, Inbred BALB C; Microbiology; Miscellaneous; Mucosal; Oligodeoxyribonucleotides - administration & dosage; Pathogen; Survival Analysis; Tularemia; Tularemia - immunology; Tularemia - prevention & control; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, Inactivated - immunology; Virulence factors; Immunization; Adjuvant; Mucosal; Pathogen; Virulence factors; Tularemia; Vaccine strain; Mucosa; Virulence; Vaccine; Inhalation; Infection; Immunological adjuvant; Bacteriosis; Bacteria; Francisella tularensis; Inactivated strain
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2007.08.009

BALB/c mice were immunised with inactivated
Francisella tularensis live vaccine strain (LVS) and the level of protection afforded against aerosol challenge with virulent strains of
F. tularensis ascertained. Intramuscular (IM) injection of inactivated LVS with an aluminium-hydroxide-based adjuvant-stimulated IgG1-biased LVS-specific antibody responses and afforded no protection against aerosol challenge with subspecies
holarctica (strain HN63). Conversely, IM injection of inactivated LVS adjuvanted with preformed immune-stimulating complexes (ISCOMS) admixed with immunostimulatory CpG oligonucleotides afforded robust protection against aerosol-initiated infection with HN63. However, despite a significantly extended time-to-death relative to naïve controls, the majority of mice immunised with the most potent vaccine formulation were not protected against a low-dose aerosol challenge with subspecies
tularensis (strain Schu S4). These data indicate that parenterally administered non-living vaccines can be used for effective immunisation against aerosol challenges with subspecies
holarctica, although not high virulence strains of
F. tularensis.