Important Facts Flashcards

Question

Classes of dendritic cells

Answer 1

Classical – CD11 b (drives CD4 response) and CD8 (in lymphoid tissues) or CD103 (peripheral tissues) which is involved in cross-presentation Plasmacytoid DCs – primarily function in viral infections, when they secrete type I IFN and play role in Ag presentation

Answer 2

ITAMs - involved in cell activation ITIMs - inhibit cellular response

Answer 3

T cells - CD4 and CD8 B cells CR2/CD21

Answer 4

T cells - CTLA-4, PD-1 B cells - CD22, FcyRIIB (contains an ITIM motif)

Answer 5

CD28 on the T cell - binds CD80/86 (aka B7-1/2) expressed on activated APCs CD80/86 expression is induced by TLRs and IFNgamma CD4 ehnances expression of CD80/86 by CD40-dependent pathway Tregs are dependent on CD80/86:CD28 mediated co-stimulation CD28 signaling amplifies signals induced downstream of the TCR and amplifies the NF-kB pathway PI3K is recruited to the CD28 tail —> activates Akt and Itk as well as PLCy Net result of CD28:B7 costim is increased expression of anti-apoptosis Bcl-2 and Bcl-XL promoting T cell survival, IL-2 production OTHER COSTIM: CD40L on T cells and CD40 on APCs (B cells, macs, DCs) CD40L activates APCs to make them more potent by enhancing B7 expression and IL-12 secretion (IL-12 promotes T cell differentiation)

Answer 6

Phosphorylation of ITAMs linked to CD3 or delta chains

Answer 7

NFAT - required for expression of genes encoding IL-2, IL-4, TNF; activated by calcium-calmodulin AP-1 - transcription factor composed of FOS and Jun NF-kB - TF activated in response to cytokine synthesis; important for TLR and cytokines Also miRNAs - small non-coding RNAs that are transcribed from DNA but not translated – inhibit expression of genes (Argonaute proteins assoc w miRNA to form RISC)

Answer 8

IL-2 = growth, survival, and differentiation cytokines for T cells (promotes proliferation and differentiation of CD8 T cells into CTLs); activates JAK/STAT, induces anti-apop Bcl-2, stims cell cycle progression through degradation of p27 IL-17 = most important cytokines for maintenance of memory CD4 and CD8 T cells (CD127 is IL-17 receptor on Tmem cells) IL-15 = also important for CD8 memory/survival of memory cells; produced by many cell types including DCs IL-12 = causes differentiation of Th0 cells to Th1 cells; produced by DC pop during innate immune response IL-4 = causes differentiation of Th0 cells to Th2 cells; involved in allergic rxns and response to helminths IL-5 = involved in allergic rxns and response to helminths IL-13 = involved in allergic rxns and response to helminths IL-1 = promotes differentiation of Th0 cells to Th17 cells IL-17 = produced by Th17 cells, interacts with macrophages IL-22 = interacts with macrophages IL-6 = promotes differentiation of Th0 cells to Th17 cells TGF-beta = promotes differentiation of Th0 cells to Th17 cells IFNgamma = secreted by CD8 T cells and Th1 cells; activates macrophages, tells B cells to switch to IgG, stims expression of proteins that enhance MHC Ag presentation Type I IFN - stimulates differentiation to cytotoxic T cells; produced by CD pop during innate immune response IL-21 = plays a role in induction of CD8 memory and prevention of exhaustion; produced by activated CD4 cells; contributes to generation of plasma cells, facilitates B cell selection events and B cell differentiation

Answer 9

CR2/CD21 receptor on B cells C3d complement fragment is recognized by CR2 —> enhances strength of BCR signaling

Answer 10

NF-kB and AP-1 (activated by CD40:CD40L signaling cascade)

Answer 11

Regulated by cytokines produced by T helper cells • IFNy —> B cells switch to IgG • IL-4 —> B cell switches to IgE • TGF-beta, BAFF, and APRIL —> B cell switches to IgA at mucosal sites CD40 signals work w cytokines to induce switch

Important Facts Flashcards

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