TLR2 and leptospirosis: Although the stimulating activity of leptospiral LPS in peripheral monocytes is at least 1000-fold less than that of the LPS of E. coli[10], the TLR2 signal induced by leptospiral LPS may be very important in human leptospirosis, as shown by the extraordinarily high expression level of TLR2 in human monocytes [26].