CARACTERIZACIóN Y EVALUACIóN in vivo E in vitro DEL LIPOPOLISACáRIDO DE Aeromonas hydrophila

aeromonas hydrophila isolated from a septicemic disease outbreak in tilapia (piaractus brachypomusoreochromis niloticus) was used to prepare crude (29.5 mg/ml) and semipurified (106.5 mg/ml) lipopolysacharide extracts (lps) based on the phenol-hot water protocol (westphal and jann, 1965). protein contents were 2.3% and 0.1% for the crude and the semipurified extracts, respectively, while the polysacharides ranged from 15 to 26%. sds-page showed 14 kd bands for the central oligosacharide and lipid a of the lps. mice (n=3) (25 ~ 35 g) that were intraperitoneally injected (25 mg crude lps) showed after the first hour bristled fur, tachypnea and loss of appetite. congestion (liver, lung), hemorrhages (kidney, lung), leukocytes margination -mainly pmn neutrophils-(liver, lung) were the most remarkable microscopic features. these effects were more evident than those found in controls injected with e. coli lps (sigma？). crude lps at 10, 20 and 30 mg/ml induced in vitro proliferation of murine mononuclear cells (2 x 105 in 200 ml dmem) by use of tritiated thymidine. both the crude a. hydrophila and the control e. coli lps extracts showed dosed-dependent increasing counts per minute. the a. hydrophila lps elicited a proliferation very similar to the one induced by the control.