Materials and Methods

Bacterial Strains. Neisseria gonorrhoeae strains 56 and 220 were kindly providedby Dr. Herman Schneider (Walter Reed Army Institute of Research, Washington, DC) and have been extensively characterized (1, 2, 13). Strain 56 is sensitive to lysis by normal human sera (ser'); 220 is serum resistant (serr). The Neisseria meningitides prototype strains for LOS serotypes have also been described previously (19-22). The meningococcal strains used in this study are of the following serotype classifications (19, 23): 126E (C: 3: P1. 2: L1, 8), 35E (C: 20: P1. 1: L2, 5), 1381 (C: 2a: P1. 2: L3), 891 (C: 11: L4), 118V (C:?: L2, 4), 6155 (B: 2a: P1. 2: L7, 3). Culture procedures for each Neisseria were described [1, 19].

Lipooligosaccharides. LOS were extracted from saline-washed or acetone-dried organisms by the hot phenol-water method (13, 24). Stock solutions of LOS used in solid-phase RIA (SPRIA) were prepared as described previously (2). Briefly, LOS was dissolved in 50 mM Na0H, heated for 1 h at 37 C, then carefully neutralized with 50 mM HCl and stored at 4 C. Monoclonal Antibodies. mAbs were kindly provided by Drs. Michael A. Apicella (06B4, 3fll) andJulie Westerink (1F10), State University ofNew York, Buffalo; and William W Young, Jr.(1132), University of Virginia Medical School, Charlottesville, VA. The preparation and characteristics of mAbs 06B4 (2), 3F11 (1-4), and 1B2 (25) have been reported. mAb 1F10 was prepared as described (3); it is specific for meningococcal group A polysaccharide. mAbs 06B4 and 3F11 were prepared from cells of mice immunized with a gonococcal strain and mAb 1F10 was prepared from cells ofmice immunized with a group A meningococcal strain. mAb 1B2 was prepared from immunocytes of mice that had been inoculated with the N-acetyllactosamine glycosphingolipid, lacto-N-norhexaosylceramide, nLc6Cer,(Galpl-