Quirin Hammer team – Innate Immune Regulation

The team investigates molecular mechanisms that regulate innate immune cell responses.

Illustration of innate immune cells.
Illustration of the team's work on recognition of aberrant or virus-infected cells by innate immune cells. By: Quirin Hammer

The Quirin Hammer team is part of the Kalle Malmberg research group at the Center for Infectious Medicine (CIM).

About our research

The team explores signals that regulate the activation of immune cells with a focus on cytotoxic effector cells of the innate immune system. Innate immune cells with cytolytic properties such as natural killer (NK) cells represent the first line of defense against virus infections and developing cancers. NK cells respond to a broad range of viruses and tumor cells using partly overlapping and partly very distinct pathways.

Central aspects of our research are to delineate the molecular signals that allow NK cells to recognize virus-infected cells and to study by which means NK cells discriminate between healthy and tumor-transformed cells. For this, we employ a broad range of in silico, cellular, as well as molecular biology techniques and study samples from patients with ongoing disease. In parallel to understanding the signals that initiate and restrict NK cell activation, we aim at exploiting such recognition pathways for cell therapy against cancer.

Quirin Hammer and Pouria Momayyezi. Photo: Tyler Sandberg

Team leader

Quirin Hammer

Postdoctoral researcher
H7 Department of Medicine, Huddinge

Quirin's research at KI focuses on investigating the molecular mechanisms with which NK cells detect virus-infected or tumor-transformed cells.

Quirin Hammer completed his PhD at the German Rheumatism Research Centre and the Humboldt University of Berlin in 2018. During his PhD, he studied host-pathogen interactions between human natural killer cells and cytomegalovirus.

When not at work, Quirin enjoys learning chess, having coffee and socializing.

Team members

Pouria Momayyezi received his medical degree from KI in 2015 and is currently a resident in Hematology at the Karolinska University hospital.

His PhD studies concern next-generation NK-cell immunotherapy, specifically prolonging the survival of transferred NK cells in patients receiving immunotherapy. In his spare time, he enjoys cooking, reading, watching football and experiencing different forms of art, preferably with friends and family.

Simone Schiele

Erasmus+ student

Simone Schiele studies Pharmaceutical Biotechnology in Jena, Germany, and is currently completing her master's degree. She joined the Hammer team for an Erasmus+ traineeship, investigating NK cell recognition of cytomegalovirus. In her spare time, Simone enjoys dancing, long walks in nature, and photography.


  • Chiara Romagnani, Berlin, Germany
  • Amir Horowitz, New York City, United States of America
  • Mattia Mori, Siena, Italy
  • Francesco Spallotta, Rome, Italy
  • Martin Messerle, Hannover, Germany

Research support

  • Marie Skłodowska-Curie Actions (EU)
  • Hedlunds Stiftelse
  • Groschinsky Minnesfond
  • Karolinska Institutet Foundation for Virus Reserach
  • Region Stockholm
  • Stiftelsen Lars Hiertas Minne
  • Petrus och Augusta Hedlunds Stiftelse
  • Stiftelsen Tornspiran



NK cell frequencies, function and correlates to vaccine outcome in BNT162b2 mRNA anti-SARS-CoV-2 vaccinated healthy and immunocompromised individuals.
Cuapio A, Boulouis C, Filipovic I, Wullimann D, Kammann T, Parrot T, Chen P, Akber M, Gao Y, Hammer Q, Strunz B, Pérez Potti A, Rivera Ballesteros O, Lange J, Muvva JR, Bergman P, Blennow O, Hansson L, Mielke S, Nowak P, Söderdahl G, Österborg A, Smith CIE, Bogdanovic G, Muschiol S, Hellgren F, Loré K, Sobkowiak MJ, Gabarrini G, Healy K, Sällberg Chen M, Alici E, Björkström NK, Buggert M, Ljungman P, Sandberg JK, Aleman S, Ljunggren HG
Mol Med 2022 02;28(1):20 

SARS-CoV-2 Nsp13 encodes for an HLA-E-stabilizing peptide that abrogates inhibition of NKG2A-expressing NK cells.
Hammer Q, Dunst J, Christ W, Picarazzi F, Wendorff M, Momayyezi P, Huhn O, Netskar HK, Maleki KT, García M, Sekine T, Sohlberg E, Azzimato V, Aouadi M, , , Degenhardt F, Franke A, Spallotta F, Mori M, Michaëlsson J, Björkström NK, Rückert T, Romagnani C, Horowitz A, Klingström J, Ljunggren HG, Malmberg KJ
Cell Rep 2022 03;38(10):110503

An optimized platform for efficient siRNA delivery into human NK cells.
Palacios D, Momayyezi P, Huhn O, Ask EH, Dunst J, Malmberg KJ, Hammer Q
Eur J Immunol 2022 Apr;():

Extent of Cytomegalovirus Replication in the Human Host Depends on Variations of the HLA-E/UL40 Axis.
Vietzen H, Rückert T, Hartenberger S, Honsig C, Jaksch P, Geleff S, Hammer Q, Romagnani C, Segura-Wang M, Puchhammer-Stöckl E
mBio 2021 03;12(2):

Natural killer cell immunotypes related to COVID-19 disease severity.
Maucourant C, Filipovic I, Ponzetta A, Aleman S, Cornillet M, Hertwig L, Strunz B, Lentini A, Reinius B, Brownlie D, Cuapio A, Ask EH, Hull RM, Haroun-Izquierdo A, Schaffer M, Klingström J, Folkesson E, Buggert M, Sandberg JK, Eriksson LI, Rooyackers O, Ljunggren HG, Malmberg KJ, Michaëlsson J, Marquardt N, Hammer Q, Strålin K, Björkström NK,
Sci Immunol 2020 08;5(50):

TOX is expressed by exhausted and polyfunctional human effector memory CD8+ T cells.
Sekine T, Perez-Potti A, Nguyen S, Gorin JB, Wu VH, Gostick E, Llewellyn-Lacey S, Hammer Q, Falck-Jones S, Vangeti S, Yu M, Smed-Sörensen A, Gaballa A, Uhlin M, Sandberg JK, Brander C, Nowak P, Goepfert PA, Price DA, Betts MR, Buggert M
Sci Immunol 2020 07;5(49):

NK cell receptor NKG2D enforces proinflammatory features and pathogenicity of Th1 and Th17 cells.
Babic M, Dimitropoulos C, Hammer Q, Stehle C, Heinrich F, Sarsenbayeva A, Eisele A, Durek P, Mashreghi MF, Lisnic B, Van Snick J, Löhning M, Fillatreau S, Withers DR, Gagliani N, Huber S, Flavell RA, Polic B, Romagnani C
J Exp Med 2020 08;217(8):


Remodeling of secretory lysosomes during education tunes functional potential in NK cells.
Goodridge JP, Jacobs B, Saetersmoen ML, Clement D, Hammer Q, Clancy T, Skarpen E, Brech A, Landskron J, Grimm C, Pfefferle A, Meza-Zepeda L, Lorenz S, Wiiger MT, Louch WE, Ask EH, Liu LL, Oei VYS, Kjällquist U, Linnarsson S, Patel S, Taskén K, Stenmark H, Malmberg KJ
Nat Commun 2019 01;10(1):514

Natural killer cell specificity for viral infections.
Hammer Q, Rückert T, Romagnani C
Nat Immunol 2018 08;19(8):800-808

Peptide-specific recognition of human cytomegalovirus strains controls adaptive natural killer cells.
Hammer Q, Rückert T, Borst EM, Dunst J, Haubner A, Durek P, Heinrich F, Gasparoni G, Babic M, Tomic A, Pietra G, Nienen M, Blau IW, Hofmann J, Na IK, Prinz I, Koenecke C, Hemmati P, Babel N, Arnold R, Walter J, Thurley K, Mashreghi MF, Messerle M, Romagnani C
Nat Immunol 2018 05;19(5):453-463