Structural requirements for initiation of Limulus amebocyte lysate gelation by lipoteichoic acids

Lipoteichoic acids (LTAs) of varying chemical composition from five streptococcal species and one lactobacillus species initiated gelation of Limu lus amebocyte lysate. Preincubation with antisera specific for the poly(glycerol phosphate) (PGP) chain or, when appropriate, with antisera, specific for a carbohydrate substituent inhibited gelation initiated by lipoteichoic acid, but did not inhibit l ipopolysaccharide-ini t ia ted gelation. Higher specific activities were found for those LTAs with higher D-alanine or carbohydrate substitution or with a shortened PGP chain, which suggested that those structural features which decreased the relative hydrophilicity or charge to mass ratio appeared to increase the specific activity.