THE HUMORAL IMMUNE-RESPONSE OF ATLANTIC SALMON AND RABBIT AGAINST CARBOHYDRATE CELL-WALL ANTIGENS OF RENIBACTERIUM-SALMONINARUM

The humoral immune response of Atlantic salmon and rabbit against carb ohydrate cell wall antigens of Renibacterium salmoninarum was studied after immunisation with whole bacterial cells (WC) and trypsinised cel ls (TC). Trypsination was shown to remove all proteins from the R. sal moninarum cells, and TC thus represents the carbohydrate skeleton of t he bacterial cells. A galactose-rich polysaccharide (GPS) and peptidog lycan (PCT) are the quantitatively most important carbohydrate constit uents of the Renibacterium cell wall. Antibodies to GPS were readily d etectable in sera from rabbits immunised with TC, but not in sera from Atlantic salmon immunised with TC or WC. On the other hand, sera from Atlantic salmon immunised with TC showed relatively high titres of an tibodies to PG, whereas sera from rabbits immunised with TC hardly con tained antibodies to PG;. The TC preparate contained mannose and gluco se in its cell wall in addition to the monosaccharide constituents fro m GPS and PC;. This indicates the presence of additional polysaccharid e(s) and/or glycolipid(s) that may also be immunogenic which is also s uggested by the immunological data presented. (C) 1998 Academic Press.