INVESTIGADORES
PEREZ Pablo Fernando
congresos y reuniones científicas
Título:
Interaction of bifidobacteria with THP1 monocytic cell line
Autor/es:
DÍAZ, M.; ROLNY, I. S.; MINNAARD, J. Y PÉREZ, P. F.
Reunión:
Simposio; Congreso. IV Simposio Internacional de Bacterias Lácticas; 2013
Resumen:
Interaction between
bifidobacteria and host´s cells is relevant for the health promoting effects
and studies with professional phagocytic cells could contribute to the
understanding of the mechanisms involved in the probiotic effect.
The present work aimed to
evaluated the interaction of bifidobacteria with monocytic cells from human
origin (THP1 cells).
Bifidobacterium bifidum 5310 and B. adolescentis 5317 were
cultured (48 hs; 37°C) in MRS broth in anaerobic conditions. Cultures were
centrifuged, washed and suspended in DMEM medium. Bacteria were labeled with
FITC.
THP1 cells (1 x 106 cell/ml) were differentiated with phorbol
myristate acetate (PMA) 200 nm in DMEM 10% fetal bovine serum for 3 days at
37°C in 5% CO2 atmosphere..
Coincubations (THP1 cells-bacteria) were performed for 1 h at 37°C at
different multiplicities of infection (MOI). The effect of the presence of Bacillus
cereus B10502 (MOI 25 or 50 for 30 min) was also studied.
Association and invasion were
evaluated by flow cytometry (FL1+ cells), epifluorescence microscopy and plate
counts in MRS agar. Necrosis was assessed by flow cytometry after propidium
iodide staining (FL2+ cells). Internalization was evaluated after quenching of
exocellular bacteria with trypan blue.
Bacteria were found as large
clusters around the monocytes. This was particularly evident for strain CIDCA
5310.
Flow cytometry analysis showed
92.3 ± 4.8 % of cells associated to strain CIDCA 5310 (FL1 + events)
irrespectively of the MOI assayed. These findings suggest that
monocyte-bacteria interaction is saturated at low MOI. In contrast, strain
CIDCA 5317 showed a dose-response behavior; i. e. 12.6 ± 3.8 %; 30.3 ± 6.0 %
and 61.2 ± 17.6 % for MOI 25, 50 and 100 respectively. After quenching with
trypan blue, percentage of FL1 + cells ranged from 1 to 5 % thus suggesting
that high number of bacteria remained exocellular. MOI of 50 and higher of
strain CIDCA 5310 lead to around 70 % necrosis (FL2+ cells) whereas values
remains similar to controls (20 %) for strain CIDCA 5317.
When monocytes were incubated
with bifidobacteria and strain B10502 of Bacillus cereus a 2 to 3 fold
increase in the percentage of cells associated to bifidobacteria was found.
Results demonstrated that
bifidobacteria interact with phagocytic cells in a strain-dependent manner.
These findings could be related to differences in surface properties already
reported for the strains under study and could be relevant for the
understanding of the immunomodulating effects of these potentially probiotic
strains.