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MICR 304 Immunology & Serology. Lecture 12 Innate Lymphocyte Chapter 2.3; 4.22; 7.28; 10.5. Overview of Today’s Lecture. General characteristics of innate lymphocytes B1 cells gd T cells NKT cells. Key Players in Immunology. Innate Ly. General Characteristics of Innate Lymphocytes.
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MICR 304 Immunology & Serology Lecture 12 Innate Lymphocyte Chapter 2.3; 4.22; 7.28; 10.5
Overview of Today’s Lecture • General characteristics of innate lymphocytes • B1 cells • gd T cells • NKT cells
Key Players in Immunology Innate Ly
General Characteristics of Innate Lymphocytes • First in development • Less variability in antigen receptor • Fast responses • Do not need to undergo clonal expansion • Rather non-peptide antigens
Ligands are self antigens, carbohydrates, phosphocholin Main Features ofSelected Innate Lymphocytes
B1 Cells • Comprise 5% of all B cells • CD5+ and CD5- subsets • Development precedes development of conventional B cells • Found in pleural and peritoneal cavity function in defense of body cavities? • Respond to certain autoantigens • Recognize common bacterial antigens • Phosphocholine • Carbohydrates • Produce highly cross reactive IgM (“natural antibodies”)
Specialized T-cells In particular found in gut associated lymphoid tissue (GALT) and in skin Substantially fewer V gene segments Often no positive or negative selection Do not express CD4 or CD8 Interface between innate and adaptive immune system Some can recognize antigen directly without MHC presentation Respond to self-antigens released upon tissue injury and promote healing (release growth factors) Lyse tumor cells gd T Cells
Limited variability of the gd TCR • Only partially compensated by increased junctional diversity • Gene locus for d chain is entirely within the a chain locus Va: 70 - 80 Ja:: 61 Vb: 52 Db:2 Jb:6 - 7
NK T Cells • Natural killer like T cells • Many express CD4, some lack CD4 and CD8 • Express NK1.1 receptor found on NK cells • Express a TCR • Invariant a chain in TCR • Exist in thymus and peripheral lymphoid organs • Recognize glycolipid antigens bound to CD1d on target cell • Release large amounts cytokines • IL4 and IFN-g, also IL10 • Able to induce apoptosis • May regulate TH1/TH2 ratio
Additional Resources Accessed 5/10/2008 • http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f25-11_pleural_membrane_c.jpg • http://www.kidney.ab.ca/treatments/images/peritoneal.jpg