Alison K. Criss


  • BA, Williams College
  • PhD, Harvard University
  • Postdoc, Northwestern University

Primary Appointment

  • Associate Professor, Microbiology, Immunology, and Cancer Biology


Research Interest(s)

Cellular and molecular mechanisms of Neisserial pathogenesis

Research Description

Our laboratory studies N. gonorrhoeae, an obligate human bacterial pathogen that causes the sexually transmitted infection gonorrhea. Gonorrhea has existed within the human population for all of recorded history and remains the second-most commonly reported bacterial sexually transmitted infection in the world today. Gonorrhea continues to be a major public health problem because of rapid acquisition of antibiotic resistance (the CDC identified N. gonorrhoeae as a highest priority superbug threat in 2013), the lack of protective vaccines, the fact that previously infected individuals remain susceptible to re-infection, and the predisposition of infected individuals to acquisition of HIV.

Since N. gonorrhoeae has no niche outside of humans, the biology of this organism is exquisitely tailored to life in the human urogenital tract. Not only is N. gonorrhoeae able to exploit the nutritional and environmental conditions at this site, but the bacterium also has an extraordinary ability to thwart challenges by the host immune response. N. gonorrhoeae evades humoral immune recognition by undergoing extensive variation of its surface structures, including high-frequency sequence changes in the N. gonorrhoeae pilin gene that lead to antigenic variation of the type IV pilus. N. gonorrhoeae is also highly adept at surviving confrontations with the innate immune system. Acute gonorrhea is a highly inflammatory disease characterized by the production of an exudate containing large numbers of neutrophils. Although neutrophils are the body's first defenders against bacterial and fungal challenge, neutrophils are ineffective at killing N. gonorrhoeae, and gonorrheal exudates contain viable, infectious bacteria.

Our research is currently centered on identifying how N. gonorrhoeae resists neutrophil clearance. We are addressing how neutrophils recognize N. gonorrhoeae, which antimicrobial activities neutrophils direct against N. gonorrhoeae, and how N. gonorrhoeae withstands or thwarts these activities. We use a combination of cell biology, molecular biology, bacterial genetics and biochemistry to address these questions. The insights gleaned from these studies will help us to understand in general how the mucosal innate immune system defends against infection and how pathogens exploit mucosal defenses to aid in colonization and transmission.

Thin-section transmission electron micrograph of N. gonorrhoeae-infected neutrophil.

Fluorescence/phase-contrast image of human neutrophils infected with strain FA1090 N. gonorrhoeae for 60 minutes. Green particles are intracellular bacteria; red/yellow particles are extracellular bacteria.

Selected Publications

  • Jean S, Juneau R, Criss A, Cornelissen C. Neisseria gonorrhoeae Evades Calprotectin-Mediated Nutritional Immunity and Survives Neutrophil Extracellular Traps by Production of TdfH. Infection and immunity. 2016;84(10): 2982-94. PMID: 27481245
  • Martin J, Ball L, Solomon T, Dewald A, Criss A, Columbus L. Neisserial Opa Protein-CEACAM Interactions: Competition for Receptors as a Means of Bacterial Invasion and Pathogenesis. Biochemistry. 2016;55(31): 4286-94. PMID: 27442026 | PMCID: PMC4980159
  • Ragland S, Schaub R, Hackett K, Dillard J, Criss A. Two lytic transglycosylases in Neisseria gonorrhoeae impart resistance to killing by lysozyme and human neutrophils. Cellular microbiology. 2016. PMID: 27597434
  • Juneau R, Stevens J, Apicella M, Criss A. A thermonuclease of Neisseria gonorrhoeae enhances bacterial escape from killing by neutrophil extracellular traps. The Journal of infectious diseases. 2015;212(2): 316-24. PMID: 25605868 | PMCID: PMC4490236
  • Smirnov A, Solga M, Lannigan J, Criss A. An improved method for differentiating cell-bound from internalized particles by imaging flow cytometry. Journal of immunological methods. 2015;423 60-9. PMID: 25967947 | PMCID: PMC4522237
  • Handing J, Criss A. The Lipooligosaccharide Modifying Enzyme LptA Enhances Gonococcal Defense Against Human Neutrophils. Cellular microbiology. 2014. PMID: 25537831
  • Johnson M, Ball L, Daily K, Martin J, Columbus L, Criss A. Opa+ Neisseria gonorrhoeae exhibits reduced survival in human neutrophils via Src family kinase-mediated bacterial trafficking into mature phagolysosomes. Cellular microbiology. 2014. PMID: 25346239 | PMCID: PMC4402142
  • Ball L, Criss A. Constitutively Opa-expressing and Opa-deficient neisseria gonorrhoeae strains differentially stimulate and survive exposure to human neutrophils. Journal of bacteriology. 2013;195(13): 2982-90. PMID: 23625842 | PMCID: PMC3697530
  • Johnson M, Criss A. Fluorescence microscopy methods for determining the viability of bacteria in association with mammalian cells. Journal of visualized experiments : JoVE. 2013;. PMID: 24056524 | PMCID: PMC3814296
  • Johnson M, Criss A. Neisseria gonorrhoeae phagosomes delay fusion with primary granules to enhance bacterial survival inside human neutrophils. Cellular microbiology. 2013. PMID: 23374609 | PMCID: NIHMS444867
  • Smirnov A, Daily K, Criss A. Assembly of NADPH oxidase in human neutrophils is modulated by the opacity-associated protein expression state of Neisseria gonorrhoeae. Infection and immunity. 2013. PMID: 24343654 | PMCID: PMC3957997
  • Stohl E, Dale E, Criss A, Seifert H. Neisseria gonorrhoeae metalloprotease NGO1686 is required for full piliation, and piliation is required for resistance to H2O2- and neutrophil-mediated killing. mBio. 2013;4(4). PMID: 23839218 | PMCID: PMC3735123
  • Criss A, Seifert H. A bacterial siren song: intimate interactions between Neisseria and neutrophils. Nature reviews. Microbiology. 2012;10(3): 178-90. PMID: 22290508 | PMCID: PMC3569855
  • Johnson M, Criss A. Resistance of Neisseria gonorrhoeae to neutrophils. Frontiers in microbiology. 2011;2 77. PMID: 21747795 | PMCID: PMC3128980
  • Criss AK, Erickson LD. The Complement Cascade and Bacterial Complement Resistance TBL MedEdPORTAL. .