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. 2018 Oct 10;3(5):e00331-18. doi: 10.1128/mSphere.00331-18

TABLE 6.

ELISA reactivity and human serum bactericidal activity of murine antisera raised to P9-17 OM and NaDOC-OM, tested against homologous P9-17 and heterologous FA1090 strainsa

Immunogen Dose
(µg)/mouse
Adjuvant Homologous P9-17
Heterologous FA1090
Geometric mean
ELISA titer × 103
reciprocal (95%
confidence limits)
hSBA titer Geometric mean
ELISA titer × 103
reciprocal (95%
confidence limits)
hSBA titer
P9-17 OM 3 × 1 µg Saline 367 (26, 5102) 1,024 47 (23, 97) 1,024
3 × 10 µg Saline 581 (40, 8466) 4,096 63 (27, 146) 2,048
3 × 1 µg Al(OH)3 221 (129, 379) 1,024 33 (15, 71) 256
3 × 10 µg Al(OH)3 52 (18, 149) 2,048 164 (59, 458) 1,024
P9-17 NaDOC-OM 3 × 1 µg Saline 3 (0.3, 27) 256–512 1 (0.3, 4) 256
3 × 10 µg Saline 112 (30, 421) 256–1,024 10 (2, 39) 256
3 × 1 µg Al(OH)3 12 (2, 71) 256 18 (4, 74) 256
3 × 10 µg Al(OH)3 22 (8, 66) 256 108 (25, 466) 256
None No antigen dose Saline No reactivity 16–32 No reactivity 16
No antigen dose Al(OH)3 No reactivity 16 No reactivity 4
a

Murine antisera were tested individually in solid-phase ELISA against the homologous immunizing P9-17 OM and against a heterologous FA1090 OM preparation. Data represent the geometric means of the reciprocal ELISA titers (× 103) of n = 5 animals per immunization group, with the 95% confidence limits in parentheses. Sham-immunized animals showed no reactivity in ELISA against the OM preparations (the absorbance at λ450 nm of antisera tested at a starting dilution of 1/100 was <0.1; i.e., the level was similar to that measured for the no-serum background controls). Pooled antisera raised to P9-17 OM and NaDOC-OM and corresponding sham-immunized control sera were tested for their ability to induce complement-mediated killing of homologous N. gonorrhoeae strain P9-17 (homologous allele 10-encoded Ng-ACP) and FA1090 (heterologous allele 6-encoded Ng-ACP), using an hSBA. The data presented represent the reciprocals of the highest serum dilution at which ≥50% killing was observed. No killing was observed with any of the antisera tested with normal human serum that had been decomplemented by heat inactivation (titers of <4). The titers are expressed as the median values from two or more independent experiments.