Peter Bergman group

We study the role of antimicrobial peptides (AMPs) in mucosal immunity. The current focus is on respiratory tract infections and the intestinal barrier function.

AMPs are expressed in mucosal tissues and by immune-cells. They constitute important effector molecules in the innate immune system. AMPs have potent antimicrobial activity against bacteria, viruses and fungi. In addition, AMPs function as "alarmins", i.e they activate and recruit cells from the adaptive immune system to the site of infection. AMP expression is tightly regulated but recent knowledge has revealed that substances such as vitamin D and phenylbutyrate (PBA) can induce AMP-expression in mucosal tissues and immune-cells.

Our aim is to translate basic findings on AMP-expression and regulation into clinical practice. We work with mechanistic studies on human tissues and cells but also perform clinical trials where inducers of AMP-expression are investigated in humans.

Keywords: Antimicrobial peptides, innate immunity, clinical microbiology, clinical trials, vitamin D


Peter Bergman, MD, PhD, Docent, Associate Professor, Group Leader 

*Medical Degree, MD (Karolinska Institutet, Sweden, 2001) *PhD in Medical Biochemistry (Karolinska Institutet, 2005) *Resident Physician in Clinical Microbiology, "ST-läkare" (Karolinska University Hospital Huddinge, Sweden, 2007-2013) *Postdoc in Clinical Microbiology (Karolinska Institutet, Dept. of Med. and Dept. of Lab. Med., Sweden, 2008-2012) *Group leader, CIM, (2012- ). 

Phone: +46-8-585 879 42. Mobile: +46-708-141684

Salah Zangenah, MSc, BMA, Project student

*Biomedical Analyst, BMA (Umeå University, Sweden, 2003) *Master of Science in Medical Nuclide Physics (Uppsala University, Sweden, 2005) *Project student in Bacteriology (Karolinska Institutet, Sweden, 2010-present). 

Catharina Missailidis, MD, Specialist in Infectious Diseases, Project student

*Medical degree, MD (Uppsala University, 1998) *Research student (MTC, 2001-2002) *Research Assistant (Walter Reed Army Institute, Washington DC, 2002-2004), *Resident physician, Infectious diseases (Karolinska University Hospital, 2005-2010), *Specialist in Infectious diseases (2011). 

Associated students (current co-supervision)

Julia Uhlmann, MSc, PhD-student, CIM (together with Dr Linda Johansson)
Anna-Carin Norlin, MD, PhD-student, Dept of Laboratory Medicine (together with Prof Mats Remberger)
Frank Nylén, MSc, PhD-student, Dept of Medical Biochemistry and Biophysics (together with prof Birgitta Agerberth)
Rokeya Sultana Rekha, MSc, PhD-student, Dept of Medical Biochemistry and Biophysics (together with prof Birgitta Agerberth)
Andreas Cederlund, MSc, PhD-student, Dept of Medical Biochemistry and Biophysics (together with prof Birgitta Agerberth)

Associated students (previous co-supervision)

Marie Olliver, MSc, PhD (2012) (together with prof Birgitta Henriques-Normark)


Vitamin D and respiratory tract infections - a randomized and double blind clinical interventional study

Our aim in this project is to explore if small exogenous compounds, such as vitamin D, can be used to induce antimicrobial peptides in vivo in order to prevent or treat respiratory tract infections. To test our hypothesis, we have performed a randomized controlled trial including high-dose treatment with vitamin D for one year to 140 patients with frequent respiratory tract infections.

Pneumococcal vaccination and cellular immune mechanisms

Another way to prevent infections is by vaccination. In this project we aim to study the role of Th17-cells in mucosal immunity after pneumococcal conjugate vaccination.

Microbial translocation and vitamin D - the role of antimicrobial peptides

Microbial translocation of bacterial products across the intestinal barrier occurs in many diseases, including HIV, hepatitis and inflammatory bowel disease. Our aim is to study if it is possible to improve intestinal barrier function via induction of antimicrobial peptides.

Diagnostic and mechanistic aspects on invasive bacterial infections

In this project we study sepsis caused by the bacterium Capnocytophaga canimorsus, which may be transmitted to humans via bites or scratches from dogs or cats. Our aim is to understand how this bacterium can cause severe disease in humans. Invasion mechanisms, immune response and memory related to C.canimorsus infections are currently being investigated. The bacterial strains will be subjected to whole genome sequencing in collaboration with SciLife labs at KI. We are also evaluating novel diagnostic methods of C.canimorsus infection, with focus on MALDI-TOF.

Infections and autoimmune brain disease

Infections may initiate autoimmunity via molecular mimicry or by other mechanisms. Here we study the role of bacterial and viral infections in the cause of autoantibody mediated brain inflammation. We are currently studying the possible relation between influenza-vaccination and narcolepsy in children and adolescents. This is a collaborative project between KI and Finland (prof Markku Partinen).


  • CIM: Susanna Brighenti, Jan Andersson, Linda Johansson and Anna Norrby-Teglund
  • MBB: Birgitta Agerberth
  • MTC: Birgitta Henriques-Normark
  • Clinical Pharmacology: Linda Björkhem-Bergman, Lena Ekström, Jonatan Lindh
  • Clinical Microbiology: Volkan Özenci
  • Dept of Neuroscience, KI: Tomas Hökfelt

Financial support

  • Stockholm County Council (ALF)
  • The Foundation for Strategic Research (SSF)
  • Magnus Bergwall and Åke Wiberg foundations
  • Swedish Society for Medical Microbiology
  • Karolinska Institutet
  • Pfizer (Pneumococcal vaccination)
  • Finnish Academy/VR (Narcolepsy)

Selected publications

Vitamin D3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention study.
Bergman P, Norlin A, Hansen S, Rekha R, Agerberth B, Björkhem-Bergman L, et al
BMJ Open 2012 ;2(6):

CMV-associated encephalitis and antineuronal autoantibodies--a case report.
Xu X, Bergman P, Willows T, Tammik C, Sund M, Hökfelt T, et al
BMC Neurol 2012 Sep;12():87

Identification of blood and wound isolates of C. canimorsus and C. cynodegmi using VITEK2 and MALDI-TOF.
Zangenah S, Ozenci V, Boräng S, Bergman P
Eur. J. Clin. Microbiol. Infect. Dis. 2012 Oct;31(10):2631-7

Impaired release of antimicrobial peptides into nasal fluid of hyper-IgE and CVID patients.
Cederlund A, Olliver M, Rekha R, Lindh M, Lindbom L, Normark S, et al
PLoS ONE 2011 ;6(12):e29316

Studies on the antibacterial effects of statins--in vitro and in vivo.
Bergman P, Linde C, Pütsep K, Pohanka A, Normark S, Henriques-Normark B, et al
PLoS ONE 2011 ;6(8):e24394

Human monocytes promote Th1 and Th17 responses to Streptococcus pneumoniae.
Olliver M, Hiew J, Mellroth P, Henriques-Normark B, Bergman P
Infect. Immun. 2011 Oct;79(10):4210-7

Specificity in killing pathogens is mediated by distinct repertoires of human neutrophil peptides.
Cederlund A, Agerberth B, Bergman P
J Innate Immun 2010 ;2(6):508-21

The antimicrobial peptide LL-37 inhibits HIV-1 replication.
Bergman P, Walter-Jallow L, Broliden K, Agerberth B, Söderlund J
Curr. HIV Res. 2007 Jul;5(4):410-5

Induction of the antimicrobial peptide CRAMP in the blood-brain barrier and meninges after meningococcal infection.
Bergman P, Johansson L, Wan H, Jones A, Gallo R, Gudmundsson G, et al
Infect. Immun. 2006 Dec;74(12):6982-91

Improved outcome in shigellosis associated with butyrate induction of an endogenous peptide antibiotic.
Raqib R, Sarker P, Bergman P, Ara G, Lindh M, Sack D, et al
Proc. Natl. Acad. Sci. U.S.A. 2006 Jun;103(24):9178-83

The antimicrobial peptide cathelicidin protects the urinary tract against invasive bacterial infection.
Chromek M, Slamová Z, Bergman P, Kovács L, Podracká L, Ehrén I, et al
Nat. Med. 2006 Jun;12(6):636-41

Neisseria gonorrhoeae downregulates expression of the human antimicrobial peptide LL-37.
Bergman P, Johansson L, Asp V, Plant L, Gudmundsson G, Jonsson A, et al
Cell. Microbiol. 2005 Jul;7(7):1009-17

CD46 in meningococcal disease.
Johansson L, Rytkonen A, Bergman P, Albiger B, Källström H, Hökfelt T, et al
Science 2003 Jul;301(5631):373-5


Induction of the human cathelicidin LL-37 as a novel treatment against bacterial infections.
van der Does A, Bergman P, Agerberth B, Lindbom L
J. Leukoc. Biol. 2012 Oct;92(4):735-42

[Natural immunity--first line defense. New treatment against infections and autoimmune diseases in sight].
Bergman P, Gudmundsson G, Agerberth B
Lakartidningen ;105(34):2254-9

Open positions

We always want to get in touch with talented potential co-workers. If you are interested in doing research within our group, as a degree project or as a researcher, please contact the group leader Peter Bergman.