Dot blot showing the reactivity of meningococcal lysates with MAb 3/9-2. Representative meningococci of the Bavarian carrier isolate collection were used, including all strains harboring the gene for NmeDI. A1, positive-control strain 2120 (ST-11) (5); A2, negative-control strain MC58 (ST-74; donated by Richard E. Moxon, Oxford, England). Strains positive for the gene for NmeDI all reacted with MAb 3/9-2 (eight ST-11 complex strains, two ST-8 complex strains, four ST-44 complex strains, and one ST-914 strain), i.e., A3, B4 to -6; D2, -3, -5, and -6; E2 to -6; and F1 and -2. Genetically diverse strains lacking the gene for NmeDI did not react with MAb 3/9-2.