Mutagenesis of the Neisseria gonorrhoeae porin reduces invasion in epithelial cells and enhances phagocyte responsiveness

Porin (PorB), the major outer membrane protein of Neisseria gonorrhoeae, ha s been implicated in pathogenesis previously. However, the fact that porin deletion mutants are not viable has complicated investigations. Here, we de scribe a method of manipulating the porin gene site-specifically. N. gonorr hoeae MS11, which harbours the porB(1B) (P.1B) porin allele, was used to ge nerate mutants carrying deletions in the surface loops 1 and 5. An 11-amino -acid deletion in loop 1 impaired Opa(50)-dependent invasion into human Cha ng epithelial cells, whereas loop 5 deletion exhibited no apparent phenotyp e. In a second approach, the complete gonococcal porB(1B) was replaced by t he porB(Nla) gene of Neisseria lactamica, Such mutants were unable to induc e efficient uptake by epithelial cells but induced an enhanced respiratory response in HL60 phagocytic cells. The increased respiratory burst was acco mpanied by an enhanced phagocytic uptake of the mutant compared with the wi ld-type strain, Our data extend previous evidence for multiple central func tions of PorB in the infection process.