After centrifugation

of the purified bacteria, 1 mL of the pellet [0.8 × 106 DNA copies of FAM cycle threshold (Ct) at 21.41] was used to infect fresh RG7204 nmr XTC-2, Vero or L929 cells (control) for 1 h at room temperature. Then, 4 mL of either fresh L-15M medium (5% FBS) or MEM (4% FBS) that was either supplemented with (2%) TPB or unsupplemented (growth control) was added to the culture flasks containing each cell line. All of the inoculated flasks were incubated at 28 °C. The medium was replaced every week with fresh medium (L-15M or MEM with or without TPB) for 3 weeks to ensure adequate nutrition. Finally, to verify that R. felis was successfully maintained in Vero and L929 cells, subpassages were performed every 3 weeks. Each experiment was performed at least twice. The viability and growth rate of R. felis in XTC-2, Vero and L929 cells were detected using quantitative PCR (qPCR), Gimenez staining and indirect fluorescent-antibody (IFA) staining of cytospin preparations. For qPCR, a specific probe (6FAM-AGGTGATGGAGAGGTTACCGGTGGAG-TAMRA) and a primer pair (Fwd: 5′-CCGTTGCCGGTAGCTTGTAT-3′; Rev: 5′-GCATTTGCAGCCCCCTCTAT-3′) were designed to target the cell surface antigen-like protein Sca7 gene of R. felis. Relative quantification of the qPCR results was performed as described by Mba et al. (2011). For IFA staining, a mouse monoclonal

Selleckchem ABT-263 antibody against R. felis was used to confirm the intracellular growth of R. felis, which was monitored by Gimenez staining. Comparative analysis of R. felis replication was investigated in amphibian Molecular motor and mammalian cells inoculated with R. felis species in two culture media, L-15M and MEM, which were unsupplemented or supplemented with TPB. Using L-15M:TPB medium, qPCR, Gimenez and IFA results showed that R. felis replicated better in XTC-2 cells than in either mammalian cell line on day 7 (50 × 106 DNA copies), but both XTC-2 and L929 cells enabled better R. felis growth

(40–50 × 106 DNA copies) than did Vero cells (9 × 106 DNA copies) (Table 1, Supporting Information, Fig. S1) on day 14. A cytopathic effect of infected cells was observed for Vero and L929 cells during the third and second weeks, respectively, using inverted phase contrast microscopy (Fig. S2). When using MEM:TPB medium, qPCR showed that R. felis growth was similar in Vero and L929 cells after 7 days whereas at day 14, R. felis growth was greater in L929 cells (50 × 106 DNA copies) than in Vero cells (10 × 106 DNA copies) (Table 1). Overall, R. felis growth was similar in Vero and L929 cells in both MEM:TPB medium and L-15M:TPB medium at day 7, but R. felis grew better in L929 cells than in Vero cells at day 14 in both media and grew to similar levels in L929 cells and XTC-2 cells in L-15M:TPB medium (Table 1). Using media with and without TPB, we found a positive effect of TPB on R.