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The Role of CD1a Polymorphisms in Mycobacterium tuberculosis Susceptibility

This study explores the association between polymorphisms in the CD1a gene and susceptibility to Mycobacterium tuberculosis (Mtb). Analyzing healthy individuals, the research examines how variations in the promoter region of CD1a may influence its expression and, consequently, the immune response to tuberculosis. By genotyping CD1a polymorphisms and assessing dendritic cell surface expression, we aim to determine if CD1a deficiency correlates with increased tuberculosis risk. Our findings may shed light on the genetic factors affecting immune responses to Mtb.

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The Role of CD1a Polymorphisms in Mycobacterium tuberculosis Susceptibility

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  1. Polymorphisms in CD1a and susceptibility to mTb Emily Ford 5/29/2012

  2. Acknowledgments: • Thomas Hawn ChetanSeshadri MeeraShenoy Glenna Peterson Rick Wells

  3. NA 1/34 McMichael AJ, JR Pilch, G Galfre, DY Mason, JW Fabre, C Milstein. 1979. Eur J Immunol 9 (3): 205-210. A human thymocyte antigen defined by a hybrid myeloma monoclonal antibody. 1984 – Nobel Prize - Niels K. Jerne, Georges J.F. Kohler, Cesar Milstein

  4. “The dissection of the immune response by the hybridoma technique” Milstein C. Nobel prize lecture. 1984.

  5. Cluster of Differentiation (CD)

  6. Cluster analysisof the original 139human antibody/antigen complexes Bernard, A and L Boumsell (1984). Human Immunology 11: 1-10. IUIS-WHO Nomenclature Subcommittee (1984). Bull WHO 62 (5): 809-811.

  7. CD1 • Sequence lies on chromosome 1 • Significant sequence homology with MHC-I • Associates with beta 2-microglobulin • Expressed on antigen presenting cells (APCs) CD1D CD1A CD1C CD1B CD1E Porcelli S, MB Brenner et al. (1989). Nature 341 (6241): 447-450. Brigl M and MB Brenner. (2004). Annu Rev Immunol22: 817-890.

  8. MOLT-4 (CD1) IDP2 IDP2 IDP2 IDP2 IDP2 Brenner MB, J McLean et al. (1987.) Nature 325: 389-394

  9. CD1-expressing cells can be recognized and lysed by specific CTLs IDP2 BK6 CD1-transfected cells Cytotoxic CD4-8- T cells CD1a CD1c Porcelli S, MB Brenner et al. (1989). Nature 341 (6241): 447-450.

  10. CTLs will respond to MTb in the presence of CD1 ? APC DN1 DN1 DN1 DN1 Porcelli, S, CT Morita, MB Brenner. (1992). Nature 360: 593-597

  11. CD1 presents lipid antigens Beckman EM, SA Porcelli et al. 1994. Nature 372: 691-4

  12. CD8+ CD1-responsive T cells can cause intracellular lysis of mycobacteria Stenger S, RJ Mazzaccaro et al. 1997. Science 276: 1684-1687.

  13. CD1 family structure Van Rhijn I, DM Zajonc et al. (2005). CurrOpinImmunol17(3): 22-29.

  14. Overview and homology w/ known MHC presenting processes Sugita, M, DB Moody et al. 1998. Clinical Immunology and Immunopathology87 (1): 8-14.

  15. Tb: How is it so good at getting around our immune system?

  16. Are SNPs in CD1a Associated with Expression? Chromosome 1 158,223,927 158,228,059 • Experimental Method • Collect blood from healthy individuals in Seattle (N=21) • Genotype for CD1a polymorphisms • Generate dendritic cells and analyze surface expression of CD1a Peripheral Blood Mononuclear Cells CD1- Monocytes CD1+ dendritic cells GM-CSF IL-4 rs389293 rs1230716 rs3181029 rs858998 rs411089 rs2269714 rs440419 Untranslated region Coding region C Seshadri, not yet published

  17. Distribution of CD1a expression in Seattle cohort CD1a CD1c Donor 3 Donor 4 Donor 5 C Seshadri, not yet published

  18. CD1A Expression Stratified by SNP C Seshadri, not yet published Genotypic Test = Kruskal-Wallis rank test Recessive Test = Wilcoxon rank sums test

  19. Is CD1a-deficiency Associated with Tuberculosis? • Combined Cohort Analysis • 762 Cord Blood Controls • 385 Pulmonary TB • 307 Meningeal TB

  20. Hypothesis: differences in the promoter region of CD1a may affect its expression Chromosome 1 – 5000kb Promoter Intron Exon

  21. 1. Makeplasmids containing CD1a variants CD1a “HI” 1kb CD1a “LO” PGL4 1kb

  22. 2. Try to get it into a cell Lipofection Electroporation cell cell

  23. Results

  24. The end!

  25. If there’s time – mysterious CD1d

  26. How did they move into dendritic cells? • They first had to make their own CD1 expressing cells, then technology developed • Ralph Steinman – PNAS from 1980s? • Dendritic cells were very hard to study! (rare, difficult to isolate) • Wesley Van Voorhees was his phd student • GM-CSF IL-4 method to make dendritic cells (legend of figure 1) Nature paper

  27. Human thymocytes NA 1/34

  28. Human thymocytes NA 1/34 HTA1/CD1

  29. Other T-cell types also recognize CD1 • Reminder of T cell subsets CD4+ CD4-8- CD8+

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