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BIO430 2008

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  1. Innate immunity, malaria and Burikitt’s lymphomaMichele Bernasconi, PhDUniversity Children’s HospitalExperimental Infectious Diseases and Cancer ResearchAugust Forel Strasse 1CH-8008 Zurich BIO430 2008

  2. Innate immunity ↔ Adaptive immunity

  3. Innate immunity ↔ Adaptive immunity • Innate ( Nonspecific ) Immunity - The term, innate immunity, refers to the basic resistance to disease that a species possesses - the first line of defense against infection. The characteristics of the innate immune response include the following: • Responses are Broad-Spectrum (non-specific) • There is no memory or lasting protective immunity • There is a limited repertoire of recognition molecules • The responses are phylogenetically ancient • Potential pathogens are encountered routinely, but only rarely cause disease. The vast majority of microorganisms are destroyed within minutes or hours by innate defenses. The acquired specific immune response comes into play only if these innate defenses are breached.

  4. Receptors involved

  5. Receptors involved (adaptive imm.)


  6. Toll-like receptors • Two distinct pathways control the inducible synthesis of antimicrobial peptides in Drosophila adult flies. • The Toll receptor is activated by the cysteine-knot growth factor Spaetzle (Spz). The activated Toll receptor triggers phosphorylation of the inhibitory protein Cactus though the intermediates Tube and Pelle. Phosphorylated Cactus is degraded by the proteasome, thus allowing nuclear translocation of the transcription factor DIF, which induces synthesis of the antifungal peptide drosomycin. The antibacterial peptide diptericin is induced by a distinct pathway in which a putative membrane receptor activates a signaling complex comprising the Drosophila homologs of IKKβ and IKKγ (encoded by the genes ird5 and kenny, respectively). This complex induces phosphorylation and cleavage of Relish. Upon nuclear translocation, the Rel domain from Relish activates synthesis of diptericin. The caspase Dredd is also required for the induction of the antibacterial peptide genes. Note that it is not yet known whether Spaetzle directly interacts with Toll. Abbreviations: DD, death domain; KD, kinase domain; IL, interleukin; TIR, Toll/IL-1 receptor homology domain.

  7. Toll-like receptors Chiron, D., I. Bekeredjian-Ding, et al. (2008). "Toll-like receptors: lessons to learn from normal and malignant human B cells." Blood.

  8. Toll-like receptors - signaling

  9. Malaria • Plasodium vivax or falciparum

  10. Malaria • Plasodium vivax or falciparum

  11. Burkitt lymphoma • B cell lymphoma • Reciprocal translocation Ig-enhancers and chr 8 • c-myc: similar to myelocytomatosis viral oncogene (v-myc) Taub R, Morton C, Lenoir G, et al. Translocation of the c-myc gene into the immunoglobulin heavy chain locus in human Burkitt lymphoma and murine plasmacytoma cells. Proc Natl Acad Sci USA 1982;79:7837-7841

  12. Burkitt lymphoma • 1956 Denis Burkitt • 1964 Epstein and Barr identify virus Endemic Burkitt's lymphoma: a polymicrobial disease? Rosemary Rochford, Martin J. Cannon & Ann M. Moormann Nature Reviews Microbiology 3, 182-187 (February 2005)

  13. Burkitt lymphoma • Endemic BL & endemic malaria

  14. Malaria activate innate immune system • Malaria pigment hemozoin activates TLR9 • J Exp Med (2005) 201: 19-25. Toll-like receptor 9 mediates innate immune activation by the malaria pigment hemozoin. C Coban, KJ Ishii, T Kawai, H Hemmi, S Sato, S Uematsu, M Yamamoto, O Takeuchi, S Itagaki, N Kumar, T Horii, S Akira

  15. Malaria activate innate immune system

  16. Malaria activate innate immune system

  17. Malaria activate innate immune system • CIDR1a: cystein-rich inter-domain region 1a of the P. falciparum erythrocyte membraneprotein 1 (PfEMP1) • RBCs or CIDR1a bind to EBV positive Burkitt lymphoma cells (memory B cell) and activate proliferation

  18. Malaria activate innate immune system • CIDR1a: cystein-rich inter-domain region 1a of the P. falciparum erythrocyte membraneprotein 1 (PfEMP1) • RBCs or CIDR1a bind to EBV positive Burkitt lymphoma cells (memory B cell) and activate proliferation

  19. TLR expression and function during normal B cell differentiation and in B cell malignancies. Chiron, D., I. Bekeredjian-Ding, et al. (2008). "Toll-like receptors: lessons to learn from normal and malignant human B cells." Blood.

  20. Further reading Reviews • Chiron, D., I. Bekeredjian-Ding, et al. (2008). "Toll-like receptors: lessons to learn from normal and malignant human B cells." Blood. • Coban, C., K. J. Ishii, et al. (2007). "Manipulation of host innate immune responses by the malaria parasite." Trends in microbiology15(6): 271-8. • Krieg, A. M. (2007). "Development of TLR9 agonists for cancer therapy." The Journal of clinical investigation117(5): 1184-94. Original articles • Ewald, S. E., B. L. Lee, et al. (2008). "The ectodomain of Toll-like receptor 9 is cleaved to generate a functional receptor." Nature456(7222): 658-62. • Chaturvedi, A., D. Dorward, et al. (2008). "The B cell receptor governs the subcellular location of Toll-like receptor 9 leading to hyperresponses to DNA-containing antigens." Immunity28(6): 799-809. • Chene, A., D. Donati, et al. (2007). "A molecular link between malaria and Epstein-Barr virus reactivation." PLoS pathogens3(6): e80. • Coban, C., K. J. Ishii, et al. (2005). "Toll-like receptor 9 mediates innate immune activation by the malaria pigment hemozoin." J Exp Med201(1): 19-25.

  21. Akata cells • Sporadic Burkitt's lymphoma cell line • c-myc translocation • EBV positive • EBV can be reactivated by IgG cross-linking • Model system to study EBV reactivation to lytic infection • Model system to study innate immunity and EBV?

  22. qPCR / Real time quantitative PCR • Quantitative analysis of gene expression

  23. qPCR / Real time quantitative PCR • Quantitative analysis of gene expression

  24. Quantitative analysis of TLR9 expression in Akata cells • mRNA from Akata cells stimulated with different cytokines • Retro-transcription mRNA → cDNA • PCR with TaqMan probes • TLR9 • GAPDH (reference) • Data analysis