Protective activity of glycolipid antigen against infection by Leptospira interrogans serovar canicola

Abstract

A protective glycolipid antigen (PAg) was extracted from Leptospira interrogans serovar canicola with chloroform/methanol/water (1 : 2: 0.8, by vol.) and partially purified by silica gel column chromatography. The PAg elicited a protective response in hamsters and in cyclophosphamide-treated mice subsequently challenged with homologous Lepfospira. The PAg band was detected as a single smear-like band, corresponding to a protein of 23-30 kDa, by silver-staining in SDS-PAGE. In immunoblots, this band reacted with a monoclonal antibody, A5, which agglutinated serovar cunicola and recognized a serovar-specific antigen. Furthermore, the PAg did not migrate on silica gel TLC, but was detected at the origin as a ninhydrin-and naphthol-positive spot. This suggests that PAg is a hydrophilic molecule with a carbohydrate chain that contains amino groups, possibly as amino sugars.

Immunodominant antigens recognized by the human immune response to infection by organisms of the species Leptospira interrogans serogroup Australis

“…The majority were found to be localized in the LPS-like component of the cell. Ono [7], Masuzawa [8], and Schoone [9] reached similar conclusions and identified serovar-specific epitopes within the groups Canicola and Icterohaemorrhagiae.…”

“…Two or three serum samples were sequentially obtained from six patients who became infected through drinking contaminated water [15]. They have been indicated with the arabic numbers 1, 7,8,9,12,17. Samples were collected: (a) immediately; (b) 18 months; and (c) 36 months after the epidemic outbreak.…”

Immunochemical Characteristics and Localization on Cells of Protective Antigen (PAg) Prepared from Leptospira interrogans Serovar lai

“…We have isolated the protective antigen (PAg) from lyophilized whole cells and the outer-envelope fraction of L. interrogans serovar lai, copenhageni, canicola, autumnalis, hebdomadis and australis by chloroformmethanol-water extraction. We reported that PAg protected hamsters from experimental infection of homologous serovar (12,14,15). Furthermore, PAgs showed no endotoxic activities and the biological safety of PAgs as vaccine has been demonstrated (13).…”

“…PAg was extracted from lyophilized cells with a chloroform-methanol-water (1:2:0.8, v/v/v) solution (5) described previously (12,14). Samples (1 mg/ml) of PAg were suspended in 2 M formic acid and heated at 100 C for 2 hr.…”

“…Immunoblotting was carried out according to the method of Towbin et al (19) and immunologically stained with anti-PAg MAb LW2 (10). The protective activity of the antigens was examined in golden hamsters according to previously described methods (12,14). Hamsters were given PAg intraperitoneally (i.p.)…”