Chemical and biological properties of endotoxin from leptospira interrogans serovars canicola and icterohaemorrhagiae

RESUMO

Endotoxin-like activity was extracted with phenol-chloroform-petroleum ether (PCP) from Leptospira interrogans serovars icterohaemorrhagiae and canicola. Chemical analysis of leptospiral cells obtained from the PCP extract i9ndicated the following distribution of lipopolysaccharide (LPS), protein and polysaccharide in mg/ml:3.0, 4.5 anmd 1.0 for icterohaemorrhagiae and 3.,3, 5.6 and for canicola. The preparations presented several biological activities: positive Limulus test (1.0 pg/ml) for icterohaemorraahagiae and canicola PCP extract and 0.5 pg/ml for E. coli 0111:B4 LPS, lethality for chicken embryos (LD 50 45, 25 and 1.0) for ecterohaemorrhagiae, canicola and E. coli 0111:B4 LPS, pyrogenicity in rabbits with an average increase in rectal temperature of 0.6 grade C, 0.9 grade C and 2.2 grade C for canicola, icterohaemorrhagiae and E. coli 0111: B4 LPS, reacted with complement inhibiting the lysis of sheep red blood cells 62%, 75% and 90% for 2.0 ug/ml of icterohaemorrhagiae, canicola PCP extract and E. coli 0111:B4 LPS. The PCP extract showed no cytotoxicity on chicken embryo fibroblasts and epithelial cells