Sub theme 4.7
Molecular immunology and immunopathology of the lung

Goals of research: general outline
Scientific achievements
Future plans: special goals and approach
Running projects
Associated staff

Workgroup leaders   Department
Prof.dr.  R.W.  Hendriks   Pulmonary Diseases

Goals of research: general outline

The lung is continuously exposed to the outside world and is a portal of entry for viral, bacterial, and fungal infection. Throughout evolution, an extensive defense mechanism has been developed that protects humans from these potentially lethal assaults and at the same prevents reactivity to harmless antigens. Nevertheless, the incidence of lung diseases such as asthma and sarcoidosis has risen dramatically over the last 50 years and pneumonia is a leading cause of death among young children and the elderly worldwide.

Next to antibacterial peptides, such as defensins, mannose binding protein, lysozyme and activation of complement, the innate immune system consists of phagocytic cells (alveolar macrophages, neutrophils and eosinophils) and natural killer (NK) cells. They have the capacity to recognize and neutralize bacterial antigen or virus-infected cells, whereby they make use of pattern recognition receptors, such as Toll-like receptors (TLRs) to recognize conserved bacterial or viral motifs. The adaptive specific cellular immune response provides humans with B and T lymphocytes that carry immunoreceptors that are highly specific for antigens that these cells have not encountered before. Dendritic cells (DCs) are professional antigen-presenting cells (APC) that are located at sites where maximal microbial encounter occurs. They are essential for the transport of antigens (from the airway mucosa and interstitium to the draining lymph nodes) and thereby initiate the activation of lymphocytes. In this way, the adaptive immune system has the capacity to strengthen and to regulate the innate defense mechanisms and to build specific immunological memory so that subsequent challenges with the same pathogen are efficiently overcome.

Until recently, research themes in the research laboratory of the department of pulmonary medicine (headed by Prof. B.N. Lambrecht till October 2007) included fundamental studies to unravel DC function, as well as research on the pathology of various respiratory disorders, in particular asthma. Dr. R.W. Hendriks started as head of the research laboratory in October 2007 and has a background in development and differentiation of lymphocytes. Therefore, the research program “Molecular Immunology and immunopathology of the lung” is now gradually changing towards a more integrated program studying the role of both the innate and the adaptive immune system of the lung.

Our aims are to:

  • To elucidate the role of DCs in directing and maintaining an acute or chronic localized immune response in the lung, e.g. in influenza virus infection, in asthma or in mesothelioma. 
  • To characterize the signal transduction pathways that are downstream of (i) the antigen receptors and are essential for developmental progression and repertoire selection of lymphoid cells, and (ii) TLRs and are essential for activation of B cells and DCs.
  • To study the in vivo differentiation program of lymphoid cells in health and disease.

Molecular approaches become increasingly important to unravel the pathogenesis of pulmonary diseases. Over the last years technical expertise has been acquired in animal models, using cellular immunology, flow cytometry, cell sorting, image analysis as well as molecular biology, genome-wide expression analysis, chromatin immunoprecipitation and retroviral transduction.

Scientific achievements
  • The role of DC was studied in the pathogenesis of atopic asthma, a disease caused by a dysregulated adaptive immune response to inhaled allergens, leading to eosinophilic airway inflammation. We showed that plasmacytoid dendritic cells (pDC) provide intrinsic protection against inflammatory responses to harmless inhaled antigen. In these studies, both myeloid (mDC) and pDC take up antigen in the lung and present it in an immunogenic or tolerogenic form to draining lymph node T cells. pDC did not induce T cell division but suppressed the generation of effector T cells induced by myeloid DC [De Heer et al., J. Exp. Med. 2004]. We also found that activation of peroxisome proliferators-activated receptor-gamma in DCs inhibits the development of eosinophilic airway inflammation in a mouse model of asthma [Hammad et al., Am J. Pathol. 2004]. Selective removal of pDCs during allergen challenge enhanced airway inflammation, whereas adoptive transfer of cultured pDCs before allergen challenge suppressed inflammation. pDCs were antiinflammatory irrespective of their maturation state [Kool et al. J. Immunol. 2009]. Taken together, these findings indicate a specialized immunoregulatory role for pDCs in airway inflammation. Enhancing the anti-inflammatory properties of pDCs could be employed as a novel strategy in asthma treatment. Furthermore, we found that extracellular ATP triggers and maintains asthmatic airway inflammation by activating DCs [5], that alum adjuvant boosts adaptive immunity by inducing uric acid and activating inflammatory DCs, and that house dust mite allergen induces asthma via TLR4 triggering of airway structural cells [8].  In addition, in a collaborative study we were able to show that Btk is dispensable for TLR-mediated activation of mast cells [Zorn et al., Cell. Signal. 2009].
  • We identified a division of labor between different DC subsets during pulmonary influenza infection, whereby clearance of influenza virus from the lung depends on langerin+CD11b- but not pDC [7]. CD11chigh DCs are essential for the organization of inducible bronchus-associated lymphoid tissue, a form of tertiary lymphoid organs induced in the lung following influenza virus infection [10].
  • Based on the observation that DCs are able to induce protective immunity in a mouse model of mesothelioma, we study the potential of tumor-pulsed autologous DCs to prevent mesothelioma recurrences (Phase I study is now completed). 
  • We have found that SLC pre-B cell receptor components had the capacity to induce constitutive B cell receptor internalization, secondary immunoglobulin light-chain rearrangement, and a severe developmental arrest of immature B cells, dependent on the downstream adaptor protein Slp65. During B cell development silencing of surrogate light chain genes is not essential for the limitation of pre-B cell proliferation, but is required for the prevention of constitutive activation of B cells [3]. The pre-B cell receptor downstream signaling molecules Btk and Slp65 act as tumor suppressors [1,2] and play an important role in repertoire selection. B cell receptor repertoire was also studied in a mouse model for chronic lymphatic leukemia generated in the lab [Ter Brugge et al., Blood 2009].
  • We have defined roles for transcription factors Gata3 en CTCF in T cell development in the thymus, as well as in differentiation of various T helper subsets [9]. In particular, we focused on the regulation of the proinflammatory subsets Th2 [5,6,9] and Th17 and regulatory T cells [4]. Chromatin immunoprecipitation analysis revealed multiple CTCF binding sites in the Th2 cytokine locus. Using conditional targeting in vivo we showed that CTCF is essential for Gata3-dependent regulation of Th2 cytokine gene expression [9].

Future plans: special goals and approach

Fundamental research will be focused on various signaling molecules:

  • B lymphocytes play an important role, both in protection to infection (e.g. influenza) and in the pathology of autoimmune disease. Several interstitial lung diseases, including sarcoidosis, have an autoimmune component. Therefore, we want to study B cell receptor repertoire formation in the lung. We have recently obtained grants from the Reumafonds, which enable us to investigate the role of SLC-expressing B cells in repertoire selection during B cell development in autoimmunity in general (also in the context of rheumatoid arthritis and SLE). In this project, we aim to set up single cell-derived Ig heavy and light chain cloning to analyze BCR repertoire. We are currently using genome-wide expression profiling to identify the role of the transcription factor CTCF and the signaling molecules Slp65 and Btk in pre-B cells.
  • Also in an ongoing project studying the immune response to influenza in the lung, we want to focus on B cell activation and BCR repertoire selection during (terminal) B cell differentiation. We will perform studies in vivo, using mouse models that have BCR signaling disorders, including Btk knock-out with defective B cell activation, various Btk transgenic and SLC transgenic mice with autoimmunity.
  • TLR/NF-kB signaling. The function of A20, a regulator of the NF-kB pathway, will be studied in a collaboration with the Department for Molecular Biomedical Research in Gent (R. Beyaert). Using conditional targeting, we will investigate A20 function in DCs and mast cells, both in vitro and in vivo, e.g. in asthma models (Marie Curie fellowship M. Kool). As we hypothesize that Btk and A20 will have opposing effects, in a later phase we want to include Btk KO and Tg models in these studies.

Next to the projects described above, several directly disease-centered projects are running, whereby we are directing our efforts mainly towards investigating the role of the T cell compartment in disease pathology:

  • Sarcoidosis. By analysis of peripheral blood and lung biopsy specimens from sarcoidosis patients, we have recently found evidence for defects in regulatory T cells, as well as for the involvement of the Th17 T cell lineage, which produces the proinflammatory cytokine IL-17, in granuloma formation. We have set up an animal model for beryllium-induced granuloma formation, which should enable us to unravel the molecular mechanisms involved in the inflammatory response.
  • We also plan to perform parallel studies in chronic obstructive pulmonary disease (COPD) patients as well as patients with community-acquired pneumonia, to investigate a possible role of the Th17 cytokines IL-17 or IL-22 in the onset or maintenance of inflammation.
  • Mesothelioma. Development of DC-based immunotherapy that induces effective CD8 CTL responses. In this context, we also aim to investigate how the effects of negative regulators of these responses, including myeloid-derived suppressor cells and regulatory T cells can be dampened. To this end, we will not only use our mesothelioma mouse model, but we have also recently started a clinical study in mesothelioma patients in which DC-mediated immune therapy is combined with low doses of cycloheximide. 

Most recent publications
  1. Kersseboom R, Middendorp S, Dingjan GM, Dahlenborg K, Reth M, Jumaa H, and Hendriks, RW (2003). Bruton’s tyrosine kinase cooperates with the B-cell linker protein SLP-65 as a tumor suppressor in pre-B cells. J. Exp. Med 198: 91-98. (IF=15.2)
  2. Jumaa H, Hendriks RW and Reth M (2005). B cell signaling and tumorigenesis. Annual Rev. Immunol. 23:415-45. (IF= 41.1)
  3. Van Loo PF, Dingjan GM, Maas A and Hendriks, RW (2007). Surrogate-light-chain silencing is not critical for the limitation of pre-B cell expansion but is for the termination of constitutive signaling. Immunity. 27:468-680. (IF= 20.6)
  4. Mantel PY, Kuipers H, Boyman O, Rhyner C, Ouaked N, Rückert B, Karagiannidis C. Lambrecht BN, Hendriks RW, Crameri R, Akdis CA, Blaser K and Schmidt-Weber C. (2007). GATA3-driven Th2 responses inhibit TGF-beta1-induced FOXP3 expression and the formation of regulatory T cells. PLoS Biol. 5:e329. (IF=12.7).
  5. Idzko M, Hammad H, van Nimwegen M, Kool M., Willart MA, Muskens F, Hoogsteden HC, Luttmann W, Ferrari D, Di Virgilio F, Virchow JC Jr, Lambrecht BN. (2007). Extracellular ATP triggers and maintains asthmatic airway inflammation by activating dendritic cells. Nat Med. 13:913-9. (IF= 27.6).

  6. Kool M, Soullié T, van Nimwegen M, Willart MA, Muskens F, Jung S, Hoogsteden HC, Hammad H, Lambrecht BN (2008). Alum adjuvant boosts adaptive immunity by inducing uric acid and activating inflammatory dendritic cells. J Exp Med. 205:869-82. (IF=15.2)
  7. GeurtsvanKessel CH, Willart MA, van Rijt LS, Muskens F, Kool M, Baas C, Thielemans K, Bennett C, Clausen BE, Hoogsteden HC, Osterhaus AD, Rimmelzwaan GF, Lambrecht BN. Clearance of influenza virus from the lung depends on migratory langerin+CD11b- but not plasmacytoid dendritic cells. J Exp Med. 2008 205:1621-34 (IF=15.2)
  8. Hammad H, Chieppa M, Perros F, Willart MA, Germain RN, Lambrecht BN. House dust mite allergen induces asthma via Toll-like receptor 4 triggering of airway structural cells (2009). Nat Med. 15:410-416 (IF= 27.6)
  9. Ribeiro de Almeida C, Heath H, Krpic S, Dingjan GM, van Hamburg JP, Bergen I, van de Nobelen S, Sleutels F, Grosveld F, Galjart N, Hendriks RW (2009). Critical role for the transcription regulator CCCTC-binding factor in the control of Th2 cytokine expression. J Immunol. 182:999-1010 (IF= 6.0).
  10. GeurtsvanKessel CH, Willart MA, Bergen I, van Rijt LS, Muskens F, Elewaut D, Osterhaus AD, Hendriks RW,  Rimmelzwaan GF, Lambrecht BN. Dendritic cells are crucial for maintenance of tertiary lymphoid tissue in the lung of influenza virus infected mice. J Exp Med. 2009 (in press, IF=15.2)