IADR Abstract Archives
Neutrophils Modulate Natural Killer Cell’s Response to Aggregatibacter Actinomycetemcomitans (JP2 Clone) Infection
Objectives: To explore the role of NK cells during AgP infection and their relation to bone resorption, and to study the crosstalk between Neutrophils and NK cells on later NK functions.
Methods: Primary human neutrophils from periodontally healthy and MIPP patients were inoculated with JP2 and their supernatant were collected. NK-like (YTS) and primary human NK cells were inoculated with the supernatants, and their functions were analyzed and included cell cycle and NK priming using flow cytometry with propodeum iodide or specific antibodies respectfully. NK`s cytokine expression was measured by ELISA and RT-PCR. Primary monocytes pre-osteoclast differentiation was tested in the presence of supernatants of naïve NK or NK exposed to neutrophils supernatant. MIPP was induced in C57bl mice by sub-gingival injection of JP2 and bone loss was measured following neutrophils or NK depletion and compared with WT controls.
Results: Exposure of primary NK and YTS cells to supernatant of neutrophils that wer previously inoculated with JP2 led to NK cell arrest. NK exposure to the supernatant also promoted the expression of NK activation markers - CD16 and TNFα expression. The supernatant induced roust NK expression of osteoprotegerin and not RANKL, leading to a shift in OPG/RANKL ratio to osteoclastogenesis prevention. Incubation of monocytes with NK supernatant led to osteoclastgenesis, while NK that were pre-exposed to neutrophils supernatant showed reduced ability to induce osteoslastgensis. Micro-CT of mice showed a significant bone defect in the mice with neutrophil depletion compared with all other groups.
Conclusions: The present study portrays a cross-talk between neutrophils and NK cells during JP2 infection which plays a major role in the regulation of bone loss mechanism by modulating the RANKL-OPG axis via NK.
Methods: Primary human neutrophils from periodontally healthy and MIPP patients were inoculated with JP2 and their supernatant were collected. NK-like (YTS) and primary human NK cells were inoculated with the supernatants, and their functions were analyzed and included cell cycle and NK priming using flow cytometry with propodeum iodide or specific antibodies respectfully. NK`s cytokine expression was measured by ELISA and RT-PCR. Primary monocytes pre-osteoclast differentiation was tested in the presence of supernatants of naïve NK or NK exposed to neutrophils supernatant. MIPP was induced in C57bl mice by sub-gingival injection of JP2 and bone loss was measured following neutrophils or NK depletion and compared with WT controls.
Results: Exposure of primary NK and YTS cells to supernatant of neutrophils that wer previously inoculated with JP2 led to NK cell arrest. NK exposure to the supernatant also promoted the expression of NK activation markers - CD16 and TNFα expression. The supernatant induced roust NK expression of osteoprotegerin and not RANKL, leading to a shift in OPG/RANKL ratio to osteoclastogenesis prevention. Incubation of monocytes with NK supernatant led to osteoclastgenesis, while NK that were pre-exposed to neutrophils supernatant showed reduced ability to induce osteoslastgensis. Micro-CT of mice showed a significant bone defect in the mice with neutrophil depletion compared with all other groups.
Conclusions: The present study portrays a cross-talk between neutrophils and NK cells during JP2 infection which plays a major role in the regulation of bone loss mechanism by modulating the RANKL-OPG axis via NK.