The immune response against Francisella tularensis live vaccine strain in Lpsn and Lpsd mice

Abstract The impact of Lps gene on the course of immune response against subcutaneous infection of mice with Francisella tularensis live vaccine strain was studied. Production and specificity of antibodies, cytotoxic responses of macrophages and NK-cells, spontaneous production ex vivo of cytokines IL-1α, IL-2, IL-4, IL-6, IL-10, IFN-γ, and TNF-α in spleen cell cultures in C3H/HeJ ( Lps ^d) mice in comparison with C3H/HeN ( Lps ^r) mice were tested. The value of LD₅₀ was significantly different in the two strains of mice (8.0 × 10³ cfu for C3H/HeJ versus 4.61 × 10⁵ cfu for C3H/HeN mice after subcutaneous inoculation). The production of NO₂ is also impaired in C3H/HeJ mice in the early intervals after infection. Thus, the defective Lps gene of C3H/HeJ mice influences both the level of innate resistance of mice to F. tularensis live vaccine strain infection and the process of induction and regulation of immune response against this intracellular bacterial pathogen.