Development of mouse hybridomas for production of monoclonal antibodies specific to Burkholderia mallei and Burkholderia pseudomallei.

Burkholderia mallei and B. pseudomallei are designated category B biothreat agents on the "select agents" list established by the NIH and CDC. Development of monoclonal antibodies (MAbs) that could effectively differentiate these two closely related species of bacteria and other non-pathogenic Burkholderia bacteria is urgently needed. Splenocytes from mice immunized with various antigen preparations from either B. mallei (American Type Culture Collection [ATCC] 23344) or B. pseudomallei (ATCC 23343) were used for production of hybridomas. Using a three-step cross-screening protocol, a total of 10 hybridomas were selected that produced MAbs which specifically recognized B. mallei 23344 but did not bind B. pseudomallei, Pseudomonas aeruginasa, or any of the other nine Burkholderia species tested. All 10 MAbs targeted to the lipopolysaccharide (LPS) molecules of B. mallei and reacted strongly with 12 out of 15 different strains of B. mallei tested. A total of 14 hybridomas that produced MAbs reacting with B. pseudomallei 23343, but not with B. mallei, P. aeruginasa, or any other nine non-pathogenic Burkholderia species were also selected. All 14 MAbs appeared to react with a proteinase K-sensitive 200-kDa band by immunoblotting analysis. Surprisingly, these 14 MAbs that were raised against the ATCC 23343 strain failed to react to any of the other 13 different strains of B. pseudomallei examined. In conclusion, our B. mallei-specific MAbs can effectively recognize 80% of the different B. mallei strains tested, and all the B. pseudomallei-specific MAbs appeared to react with a unique antigen present only in the ATCC 23343 strain, but not in any other strains of B. pseudomallei tested.