@article{mbs:/content/journal/micro/10.1099/00221287-138-6-1229, author = "Kokka, Robert P. and Vedros, Neylan A. and Janda, J. Michael", title = "Immunochemical analysis and possible biological role of an Aeromonas hydrophila surface array protein in septicaemia", journal= "Microbiology", year = "1992", volume = "138", number = "6", pages = "1229-1236", doi = "https://doi.org/10.1099/00221287-138-6-1229", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-138-6-1229", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "The biochemical, immunological, and biological properties of an S layer purified from an Aeromonas hydrophila strain (AH-342) involved in a case of bacteraemia were investigated. The S layer selectively removed from the cell surface was composed of a single acidic (pI 4·65) protein subunit (surface array protein, SAP) with a molecular mass of approximately 52 kDa. Amino acid analysis of this 52 kDa protein indicated a molecule composed of 498 amino acids with 46% hydrophobic residues. No cysteine residues were detected. The first 35 residues of the N-terminus were sequenced by Edman degradation; only 4–24% homology was noted between this sequence and those previously published for SAPs of Aeromonas salmonicida (A450) and a strain of A. hydrophila (TF7) originally isolated from a moribund fish. Polyclonal antibodies raised against AH-342 SAP were genospecific, reacting only against S layers produced by A. hydrophila strains and not those from Aeromonas veronii. Acute serum from the bacteraemic patient from whom AH-342 was isolated reacted strongly with the SAP of AH-342 in immunoblot studies. Purified SAP, when intraperitoneally co-inoculated with SAP− strains of A. hydrophila into Swiss-Webster mice, could reduce the 50% lethal dose by approximately 30–70 fold. The results suggest that the SAP of A. hydrophila strains may play an important role in systemic dissemination after invasion through the gastrointestinal mucosa.", }