Editing Neisseria gonorrhoeae (section)

=== Antigenic variation ===
''N. gonorrhoeae'' evades the immune system through a process called [[antigenic variation]].<ref>{{cite journal | vauthors = Stern A, Brown M, Nickel P, Meyer TF | title = Opacity genes in Neisseria gonorrhoeae: control of phase and antigenic variation | journal = Cell | volume = 47 | issue = 1 | pages = 61–71 | date = October 1986 | pmid = 3093085 | doi = 10.1016/0092-8674(86)90366-1 | s2cid = 21366517 }}</ref> This process allows ''N. gonorrhoeae'' to recombine its genes and alter the [[antigenic determinants]] that adorn its surface,<ref name="Sherris" /> such as the Type IV pili.<ref>{{cite journal |vauthors=Cahoon LA, Seifert HS |date=September 2011 |title=Focusing homologous recombination: pilin antigenic variation in the pathogenic Neisseria |journal=Molecular Microbiology |volume=81 |issue=5 |pages=1136–1143 |doi=10.1111/j.1365-2958.2011.07773.x |pmc=3181079 |pmid=21812841}}</ref> Simply stated, the chemical composition of molecules are changed due to changes at the genetic level.<ref name="Hill_2016"/> ''N. gonorrhoeae'' is able to vary the composition of its pili and lipooligosaccharide. Of these, the pili exhibit the most antigenic variation due to chromosomal rearrangement.<ref name="Lev13th2" /><ref name="Sherris" /> The ''pilS'' gene is an example of this ability to rearrange, as its combination with the ''pilE'' gene is estimated to produce over 100 variants of the PilE protein.<ref name="Hill_2016" /> These changes allow for adjustment to local environmental differences at the site of infection, evasion of recognition by targeted antibodies, and inhibit the formation of an effective vaccine.<ref name="Hill_2016">{{cite journal | vauthors = Hill SA, Masters TL, Wachter J | title = Gonorrhea - an evolving disease of the new millennium | journal = Microbial Cell | volume = 3 | issue = 9 | pages = 371–389 | date = September 2016 | pmid = 28357376 | pmc = 5354566 | doi = 10.15698/mic2016.09.524 | doi-broken-date = 1 November 2024 }}</ref>

In addition to gene rearrangement, it is also [[Natural competence|naturally competent]], meaning it can acquire extracellular DNA from the environment via its type IV pilus, specifically proteins PilQ and PilT.<ref>{{cite journal | vauthors = Obergfell KP, Seifert HS | title = Mobile DNA in the pathogenic ''Neisseria'' | journal = Microbiology Spectrum | volume = 3 | issue = 3 | date = February 2015 | pmid = 25866700 | pmc = 4389775 | doi = 10.1128/microbiolspec.MDNA3-0015-2014 }}</ref> These processes allow ''N. gonorrhoeae'' to acquire and spread new genes, disguise itself with different surface proteins, and prevent the development of [[immunological memory]] – an ability which has contributed to antibiotic resistance and impeded vaccine development.<ref>{{cite journal | vauthors = Aas FE, Wolfgang M, Frye S, Dunham S, Løvold C, Koomey M | title = Competence for natural transformation in Neisseria gonorrhoeae: components of DNA binding and uptake linked to type IV pilus expression | journal = Molecular Microbiology | volume = 46 | issue = 3 | pages = 749–760 | date = November 2002 | pmid = 12410832 | doi = 10.1046/j.1365-2958.2002.03193.x | s2cid = 21854666 | doi-access = free }}</ref>