Epitope mapping of monoclonal antibodies specific for the directly cross-linked mesodiaminopimelic acid peptidoglycan found in the anaerobic beer spoilage bacterium Pectinatus cerevisiiphilus.

Nineteen monoclonal antibodies (Mabs) were isolated based on reactivity with disrupted Pectinatus cerevisiiphilus cells. All of the Mabs reacted with cells from which the outer membrane had been stripped by incubation with sodium dodecyl sulphate, suggesting the peptidoglycan (PG) layer was involved in binding. Mab reactivity with purified PG confirmed this. Epitope mapping revealed the Mabs in total recognize four binding sites on the PG. Mabs specific for each of the four sites also bound strongly to disrupted Pectinatus frisingensis, Selenomonas lacticifix, Zymophilus paucivorans, and Zymophilus raffinosivorans cells, but weakly to disrupted Megasphaera cerevisiae cells. No antibody reactivity was seen with disrupted cells of 11 other species of Gram-negative bacteria. These results confirm that a common PG structure is used by several species of anaerobic Gram-negative beer spoilage bacteria. These results also indicate that PG-specific Mabs can be used to rapidly detect a range of anaerobic Gram-negative beer spoilage bacteria, provided the bacterial outer membrane is first removed to allow antibody binding.