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Professor Klaus Okkenhaug

Professor Klaus Okkenhaug

Professor and Head of the Division of Immunology

Areas of Interest:

- Immunity

- Infection

- Cancer

- Immunodeficiency

- Cell Signalling

- PI3K

Department of Pathology
University of Cambridge
Tennis Court Road

Office Phone: 01223 333726


Klaus Okkenhaug has been Professor of Immunology in the Department of Pathology since October 2017. He obtained his B.Sc. in Biochemistry from the University of Victoria, British Columbia, Canada, followed by a Ph.D. in Immunology from the University of Toronto, where he studied CD28 signalling in Robert Rottapel's lab. In 1999, he moved to London, UK, where he joined Bart Vanhaesebroeck's group at the Ludwig Institute for Cancer Research as a Postdoctoral Fellow, working on the role of the PI3Kδ in immune responses. There he generated the PI3Kδ kinase-dead knock-in mouse, which showed a key role for this PI3K isoform in B cell and T cells, as well as in preventing colitis due to the role of PI3Kδ in regulatory T cells. Klaus joined the Laboratory of Lymphocyte Signalling and Development at the Babraham Institute as a Group Leader in 2003. His group investigates the role of cell signalling pathways in the immune system, with particular focus on the PI3K family of enzymes. In recent years, he has contributed to the description of a new primary immunodeficiency syndrome caused by activated PI3Kδ mutations (APDS) and his group demonstrated that deletion of PI3Kδ in regulatory T cells unleashes a potent anti-tumour response. 

Research themes


Research Interests


Our group focuses on how a group of enzymes called phosphoinositide 3-kinases (PI3Ks) are used by cells of the immune system to instruct and coordinate defences against pathogens. Cells of the immune system can express up to eight different forms of PI3K, which act as second messenger signalling molecules within cells that control diverse of cellular functions and genetic programmes.

We aim to dissect the unique roles played by individual forms of PI3K with particular focus on their roles in B cells and T cells. We also ask what the effect of inhibiting or enhancing the activity of individual forms of PI3K has on immunity to infections.

PI3K isoforms

Most of our work to date has focused on PI3Kδ. The activation of PI3Kδ is one of the first events that happen inside a T cell or B cell when it first is exposed to a foreign antigen. Because PI3Kδ is expressed at very low levels in other organs in the body, it is thought that targeting PI3K with drugs may be an effective way to suppress immune responses without some of the side effects associated with many immunosuppressive drugs in current use.

PI3K in immuity

We therefore work closely with colleagues in pharmaceutical companies who have developed specific inhibitors against PI3Kδ or other forms of PI3K to help predict and understand the effect of such drugs on the immune system.

Research Supervision

Group members: 

Anne-Katrien Stark

Andrew Conway Morris

Anita Chandra

Daisy Luff

Rafeah Alam

Fiorella Cugliandolo

Christina Courreges

Doreen Lau

Priya Schoenfelder

Krishnendu Chakraborty


  • Immunology

Key Publications

Selected Review Articles (all available for free by clicking on the title)


Lucas CL, Chandra A, Nejentsev S, Condliffe AM, Okkenhaug K.

Nat Rev Immunol. 2016 Nov;16(11):702-714. doi: 10.1038/nri.2016.93. Epub 2016 Sep 12. Review.

PMID: 27616589 Free PMC Article 


Okkenhaug K, Graupera M, Vanhaesebroeck B.

Cancer Discov. 2016 Oct;6(10):1090-1105. Epub 2016 Sep 21. Review.

Stark AK, Sriskantharajah S, Hessel EM, Okkenhaug K.

Curr Opin Pharmacol. 2015 Aug;23:82-91. doi: 10.1016/j.coph.2015.05.017. Epub 2015 Jun 18. Review.

Okkenhaug K.

Annu Rev Immunol. 2013;31:675-704. doi: 10.1146/annurev-immunol-032712-095946. Epub 2013 Jan 16. Review.

PMID: 2333095 Free PMC Article