Study of two in vitro infection models of human macrophagic cell lines with clinical isolates of multidrug-resistant Mycobacterium tuberculosis

NOEMÍ YOKOBORI; CARMEN SABIO Y GARCÍA; LUCÍA BARRERA; SILVIA DE LA BARRERA; BEATRIZ LÓPEZ; VIVIANA RITACCO; MARÍA DEL CARMEN SASIAIN

Los Cocos

Congreso; LXI Reunión Anual de la Sociedad Argentina de Inmunología; 2013

Sociedad Argentina de Inmunología

The impact of intraspecies variability in Mycobacterium tuberculosis (Mtb) has become evident in the recent years, and we have recently reported that the epidemiological virulence correlate with particular responses induced in the macrophage (M). M is the preferred niche of Mtb for replication and several in vitro infection models are used to study their interaction, but divergent results can be observed depending on the cell type used. We have previously shown that differences in growth rate and cytokine (CK) induction in human monocyte derived M (MDM) among the outbreak strain M and its closely related low virulence strain 410 are abolished in PMA-differentiated U937 M-like cells, probably due to differences in critical cell surface receptor expression. In the current work we evaluated the interaction of strains H37Rv, M and 410 with the more widely used THP-1 cells compared to U937 cells. Briefly, THP-1 or U937 cells were seeded into 48-well culture plates, allowed to differentiate to M-like cells with 100nM PMA for 3 days, and infected with the different strains at MOI of 5. Supernatants were harvested at 6, 12 and 24 h post infection and assayed with ELISA and LDH activity kits for CK and cell death induction respectively. In both models the % of cell lysis achieved at 24 h was comparable (MeanSEM in THP-1 cells, H37Rv: 623, M: 301. In U937 cells H37Rv: 562; M: 292. p