The function of Atlantic salmon (Salmo salar L.) antibodies under extremes of pH and osmolarity

The ability of anti-MBP Atlantic salmon antibodies to bind to MBP was investigated using ELISA under a range of pHs (3-10) and osmolarities (100-1,000 mOsml(-1)) to determine the optimum binding conditions required for Atlantic salmon antibodies. The pH optimum was between pH 7-8 with pH 7.4 giving the highest level of antibody binding. However, the decrease in optical density was in excess of 60% at pHs 6.0 and 9.0 and in excess of 99% at pHs of 3.0 and 10.0. The optimum osmolarity required for antibody binding was in the range 100-400 mOsml(-1) with 330 mOsml(-1) giving the highest level of antibody binding. Above 400 mOsml(-1) there was a rapid decrease in antibody binding with the OD dropping by over 50% at all dilutions. This decrease was maintained at all osmolarities over 400 mOsml(-1).