TABLE 1

The 18 meningococcal strains used to test for SBA

Strain [reference(s)]Location (yr)MLSTa (clonal complex)Relative strain expression of MenB-4C antigenb:Detection of OMV (PorA P1.4)c
FHbp (peptide ID)NadANHba
Reference strains
    H44/76 (FHbp strain) (35)Norway (1976)32 (32)++ (1)Absent±No
    5/99 (CH245) (NadA) (35)Norway (1999)1349 (8)+ (23)++±No
    SK016 (CH526) (PorA P1.4) (37)North Carolina (2001)103 (103)+ (25)Absent±Yes
FHbp subfamily A isolates (n = 7)
    CH865, college outbreakRutgers University, New Jersey (2016, 2 cases)11 (11)± (19)Absent±No
    B11, M4407 (CH258) (43)Minnesota (1996)6160 (41/44)+ (19)Absent++No
    B2 (CH740)Georgia (2003)13 (269)++ (19)Absent+No
    H44/76 mutant (FHbp subfamily A) (37)Norway (1976)32 (32)++ (22)Absent++No
    03s-0673 (CH862)California (2003)32 (32)++ (23)+++No
    B9 (CH687)Georgia (1997)136 (41/44)++ (24)Absent++No
    03s-0451 (CH862)California (2003)1364 (32)+ (76)++No
FHbp subfamily B isolates (n = 8)
    H44/76 mutant (50% FHbp expression) (16)Norway (1976)32 (32)+ (1)Absent+No
    CH840, college outbreak (18)University of California, Santa Barbara (2013, 5 cases)32 (32)++ (1)+++No
    CH852, college outbreak isolate (44)College in Rhode Island (2015, 2 cases)9069 (364)++ (1)Absent++Yes
    CH860, hyperendemic isolate (38)Quebec, Canada (2009)269 (269)++ (15)Absent++No
    CH861, hyperendemic isolate (38)Quebec, Canada (2013)269 (269)++ (15)Absent++No
    CH855, college outbreak isolate (45)Ohio University (2010, 13 cases)269 (269)+ (15)++++No
    CH819, college outbreak isolate (18, 46)Princeton University (2013, 9 cases)409 (41/44)+ (276)Absent+No
    CH863, college outbreak isolateSanta Clara University (2016, 3 cases)New (32)++ (510)+++No
  • a MLST, multilocus sequence typing.

  • b Antigen expression was measured by flow cytometry using live bacteria and monoclonal or polyclonal mouse sera, as previously described (37). The following symbols are used to represent the quantitation of antigen expression: ±, <20% expression compared to that of a positive-control strain tested in parallel; +, 20 to 80% expression compared to that of a positive-control strain tested in parallel; ++, >80% expression compared to that of a positive-control strain tested in parallel. Expression of FHbp was compared with that by strain H44/76 (subfamily B) or M44/07 (subfamily A), depending on the subfamily of the test isolate. Expression of NadA was compared to that by strain 5/99, and expression of NHba was compared to that by strain M4407. All of these strains are naturally high-level expressers of the respective antigen being measured (35, 43). Absent, no detectable binding and absence of an NadA gene.

  • c OMV (PorA P1.4) was detected with a specific mouse monoclonal antibody, and the strain variable region sequence type was inferred by gene sequencing (see Table S1 in the supplemental material).