Characteristics of toxic shock syndrome toxin 1-induced lectin-like activity and inhibitor(s) in rabbit serum.

In adult rabbits intravenously injected with toxic shock syndrome toxin 1 (TSST-1) or staphylococcal enterotoxin B, serum lectin-like activity (detectable by cation-dependent agglutination of bacteria) developed. This activity was sensitive to heat, trypsin, and formaldehyde but resistant to neuraminidase or galactose oxidase. Formaldehyde-fixed Propionibacterium acnes or Escherichia coli cells reactive with plant lectins provided sensitive targets for titration of serum agglutination activity that was competitively blocked with D-galactose, D-glucose, D-mannose, and alpha-L-fucose. The lectin-like activity, partially purified by affinity chromatography, was a protein of approximately 76,000 Da with an isoelectric point of 5.4. Both lectin-positive and normal serum contained agglutination inhibitors that were absorbed by protein A-producing staphylococci. S protein may be the origin of this lectin-like activity. In vitro exposure of peripheral-blood mononuclear cells to TSST-1 (1.0 micrograms/mL) and to lectin-positive serum induced rapid cell clumping and subsequent "activation" to a larger blast form expressing receptors for buccal epithelial cells. The interaction of toxin/lymphokine-activated mononuclear cells with glycoproteins and/or other antigens selectively expressed by tissues in various organ systems may play a role in target cell pathology in rabbits dying with toxic shock syndrome.