The Overall aim Of this study was to analyze the phenotypic changes of the host cells that can occur during the primary interaction of Francisella tularensis microbes with professional phagocytes. The cell line J774.2, derived from female BALB/c mouse (ECACC, No. 85011428), Was used as a model of host cell, which can represent first line of defense in host tissues infected with intracellular bacterial pathogens. Francisella tularensis live vaccine strain (Francisella tularensis LVS, ATCC 29684, American type culture collection, ManasSas, .Va, USA) Was used for infection in vitro. Detection and identification of the changes induced by infection was done by flow cytometry. For all selected markers the commercially available specific monoclonal antibodies (Immunotech, BD Pharmingen or Serotech) including negative isotypic controls were used. All of them were directly conjugated with fluorescein isothiocyanate (FITC) or phycoerythrine (PE) fluorochromes. After standard staining procedure the flow cytometric analysis using flow cytometer Coulter^R Epics^R XL (Coulter, Fullerton, USA) equipped with software version Epics XL Flow Cytometry Work Station — System II^TM ver. 3.0 was performed under standard operating procedure. Only identification of intracellular marker MOMA-2 required two additional steps during staining procedure — fixation and permeabilization. The flow cytometric phenotyping of J774.2 cells was monitored before and during 24 hours of infection in vitro With Francisella tularensis LVS, each 6 hrs and than after 48 hrs....

Keywords: Francisella tularensis; MHC