Detection of extracellular leucocyte DNA in the abdominal cavity of mice vaccinated against brucellosis after injection of Brucella abortus

Shmelkova T.P., Kravtsov A.L., Malyukova T.A., Popov Yu.A.

FSSI "Russian Anti-Plague Institute "Microbe"" of the Rospotrebnadzor, Saratov, Russia

Aim – analysis of the reaction of nuclear chromatin of phagocytes in the abdominal cavity of intact mice and mice vaccinated against brucellosis in response to brucella.
Methods. Immune and intact BALB/c mice were intraperitoneally injected with B. abortus at doses of 103 CFU and 107 CFU. After 4 h, flow cytometric analysis of the mouse abdominal cavity swabs was performed to determine the presence of phagocyte DNA and extracellular DNA fragments (ecDNA) with visualization of neutrophil extracellular traps (NETs) using fluorescence microscopy.
Results. In mice immunized against brucellosis, the number of phagocytes with activated chromatin increased to 30%, and the content of ecDNA fragments – to 15% in response to both doses of B. abortus.
Conclusions. In the abdominal cavity of mice vaccinated against brucellosis, the process of leukocytolysis in response to brucella was observed with the formation of NETs, which can initiate IgG-mediated allergic reactions.