NRGN and gonorrhea: In support of this finding, immunization of mice with the similar 4CMenB vaccine significantly increased Ng clearance in the mouse model of gonorrhea (P < 0.0001), and sera from 4CMenB-vaccinated mice cross-reacted with several proteins of the Ng outer membrane, including MtrE, BamA, Opa, and PilQ, suggesting that these are the cross-protective proteins (Connolly et al., 2018).