IDENTIFICATION OF A BOVINE SERUM MANNAN-BINDING PROTEIN REACTIVE WITHA RA CHEMOTYPE STRAIN OF SALMONELLA SEROVAR TYPHIMURIUM

To study the relationship between a bovine serum mannan-binding protei n (MBP) and a serum protein reactive with a Ra chemotype strains of Sa lmonella sorovar Typhimurium (Ra-reactive factor, RaRF), both proteins were isolated by use of their affinity for yeast mannan and the Salmo nella cells followed by affinity chromatography on mannobiose-Sepharos e 4B. Both purified proteins showed a major protein band with a molecu lar weight of 33,000 and a few faint bands in sodium dodecyl sulfate-p olyacrylamide slab gel electrophoresis under reducing conditions. In W estern blotting with rabbit anti-bovine MBP antibody, the major subuni t of both proteins were found to be immunologically identical. Similar findings were also obtained with purified human MBP and RaRF. From th ese findings, bovine and human serum MBP are suggested to be electroph oretically and immunologically the same as their corresponding RaRF.