Gonococci possessing only certain P.II outer membrane proteins interact with human neutrophils

Area of Science:

• Microbiology
• Immunology
• Bacterial Pathogenesis

Background:

• Neisseria gonorrhoeae outer membrane Protein II (P.II) mediates interactions with host cells.
• Understanding P.II variants' roles in neutrophil evasion and interaction is critical for gonorrhea pathogenesis.

Purpose of the Study:

• To investigate the role of individual P.II variants of Neisseria gonorrhoeae in vitro interactions with human neutrophils.
• To determine how P.II expression influences gonococcal adherence, neutrophil activation, and phagocytic killing.

Main Methods:

• In vitro assays using seven single P.II variants of Neisseria gonorrhoeae FA1090 and human neutrophils.
• Assessment of bacterial adherence, luminol-dependent chemiluminescence (CL) for neutrophil respiratory burst stimulation, and phagocytic killing.

Main Results:

• Nonpiliated gonococci lacking P.II (P.II-) exhibited poor adherence, minimal neutrophil stimulation (CL), and were not killed by neutrophils.
• Most P.II-expressing gonococci (P.II+) adhered to, stimulated, and were killed by neutrophils.
• One variant, P.IIa, did not mediate these interactions, acting similarly to P.II- gonococci.
• P.II's stimulatory effect on neutrophils was dominant over pili.
• No correlation was observed between colony opacity phenotype and neutrophil interaction.

Conclusions:

• Most, but not all, P.II proteins are essential for Neisseria gonorrhoeae interaction with human neutrophils.
• P.II proteins mediate gonococcal adherence, neutrophil respiratory burst stimulation, and phagocytic killing.
• Specific P.II variants can modulate the host-pathogen interaction, impacting bacterial survival and immune evasion.