Biological activities of Brucella abortus lipopolysaccharides

Abstract

Purified lipopolysaccharide (LPS) from smooth (S) and rough (R) strains of Brucella abortus and lipid A isolated from S-LPS by mild acid hydrolysis were examined in several assays of biological activity. Brucella Sand R-LPSs and Brucella lipid A activated the complement cascade. Previously reported mitogenic activation by Brucella LPSs of spleen cells from endotoxin-resistant C3H/ HeJ mice was confirmed and also produced by isolated Brucella lipid A. Mitogenicity was not inhibited by polymyxin B, and amino acid analysis showed no binding of polymyxin B to Brucella LPS under conditions in which mitogenicity of phenol-water-extracted Escherichia coli LPS was inhibited. S and R Brucella LPSs and lipid A all produced equivalent polyclonal stimulation of C3H/HeJ and C3H/HeAU spleen cells. Crude and purified LPS from S but not from R B. abortus was toxic for outbred mice, with 50% lethal doses approximately six times greater than that for E. coli LPS. Sand R-LPSs were abortifacient in pregnant outbred mice. S Brucella LPS was lethal for carrageenen-pretreated C3H/HeJ and C3H/HeAU mice, whereas only C3H/HeAU mice were killed by E. coli LPS. The data are consistent with the hypothesis that the unique fatty acid composition of Brucella lipid A is responsible for its biological activity in endotoxin-resistant C3H/HeJ mice. The participation of the protein strongly bound to the lipid A cannot be excluded, but its mode of action, if any, is different from that of the lipid A-associated protein of enterobacterial LPS.

Urban outbreak of a Brucella melitensis infection in an Argentine family: Clinical and diagnostic aspects

“…Lipopolysaccharide contents of CYT and LPSfree CYT fractions were determined by Limulus lysate gelation activities (LLGA) as described by Sullivan and Watson [12] using E. coli LPS as standard. Brucella abortus S-LPS contents were estimated using the ratio reported by Moreno et al [13] between E. coli and B. abortus LPS gelating activities. This immune adsorption reduced the LPS concentration from 10 mg ml-1 in CYT to 9 × 10 3 mg ml-1 in LPS-free CYT [8].…”

Characterization of Brucella abortus lipopolysaccharide macrodomains as mega rafts

“…Another study has suggested that LPS can be exocytosed in culture supernatants after bacterial processing (Duncan et al ., 1986). Intracellular Proteobacteria such as Bartonella , Coxiella , Brucella , Chlamydia , Legionella , Porphyromonas and Rickettsia have unique properties, which can be attributed to distinct LPS structures (Moreno et al ., 1981;Neumeister et al ., 1998;Moriyon, 2004;Zahringer et al ., 2004). In contrast to the LPS of enterobacteria, the modified lipid A of the intracellular Proteobacteria confers low endotoxicity, deficient host cell activation and resistance to degradation by macrophages (Erridge et al ., 2002).…”

Characterization of Biological Activities of Brucella melitensis Lipopolysaccharide

“…Further, the O antigen of Brucella LPS is a homopolymer of perosamine (4,6dideoxy-4-formamido-d-mannopyranosyl) (3,27,37). The biological activities such as cytokine production and lethality of S-LPS and rough types of LPS (R-LPS) from various Brucella strains are reported to be lower than those of enterobacterial LPS (4,14,25,29). The lower endotoxicity seems to be responsible for the unique lipid A structure of Brucella LPS.…”