Molecular immunological heterogeneity of the salmonella zuerich [1, 9, 12, (46), 27] cell-wall polysaccharides

Abstract

Extraction of O specific polysaccharide from S. zuerich leads to three fractions (ZA, ZB, ZC). Polysaccharide ZB carries specificities 1, 27, and 46, present on the Salmonella cells. It exhibits a factor 27 that is very similar to that present on the S. typhi T 2 1 - 27 + polysaccharide, a factor 1 that is close to that present on S. senftenberg polysaccharide, and a factor 46 that gives a very weak cross-reaction with anti-46 antibodies. Polysaccharides ZA and ZB are immunologically different and ZB contains two distinct fractions: ZB 1 - devoid of O factor 1 and carrying the specificities 46 and 27 mostly, if not completely, on the same molecule (46, 27); and ZB 1 + carrying O factors 1, (46), 27. Zb 1 + is composed of at least two different molecules: [1, (46)], precipitable with anti-1 antibodies but only coprecipitable with anti-46 antibodies; and (1, 27) precipitable with both anti-1 and anti-27 antibodies. Molecules [1, (46)] precipitate only part of the anti-1 antibodies precipitable by (1, 27). The smaller precipitation of anti-27 antibodies (when factor 27 is present together with factor 1 on the same molecule) and the coprecipitation, instead of precipitation, of anti-46 antibodies (when factors 46 and 1 are present on the same molecule) may be explained by a sterical hindrance between O-factors 1 and 27, and 1 and 46. The molecular, immunological heterogeneity of the polysaccharides extracted from S. zuerich would result from the presence on the cells of two kinds of O polysaccharides: one with, the other without O factor 1, which is related to the presence of a side-chain of an α- D-glucosyl residue. A structure for S. zuerich polysaccharide is proposed.