Chapter 52 Immune Sytem By: Group D: Daniel Cazares del Castillo, Fabian Abarca, Justin Cruz, Jayce Frank, William Hoover, Alberto Rodriguez

Vocab Pattern recognition receptors- that can either be soluble or on the surface of blood cells, recognize PAMP's Macrophages- large irregularly shaped cells that kill microorganisms by ingesting them through phagocytosis. neutrophils- the most abundant circulating leukocytes accounting for 50-70% of the peripheral blood leukocytes natural killer cells- do not attack invading microbes directly instead they kill the cells of the body that have been infected with viruses. complement system- effective chemical defense membrane attack complex- aggregated complement proteins, inserts itself into the pathogen's plasma membrane forming a pore. antigen- is a molecule that provokes a specific immune response monocytes- give rise to macrophages neutrophils- phagocytic cells eosinophils- important in the elimination of helminths basophils- are not phagocytic cells but rather secrete histamines dendritic cells- important in the activation of T cells. B cells- respon to antigens by secreting proteins called antibodies.

Vocab continued humoral immunity- B cell mediated response producing secreted antibodies T cells- do not secrete antibodies bone marrow- not only the source of stem cells it is where B cells mature thymus- primary lymphoid organ located just above the heart cytokines- secrete low molecular weight proteins HIV- mounts a direct attack on T cells

Immune System: Innate VS. Adaptive Immunity Overview Innate Immunity: is ancient and recognizes molecular patterns; adaptive immunity involves genetic rearrangements to attack specific pathogens. the molecular patterns that innate immunity recognizes include bacterial lipopoly and peptidoglycan, as well as viral RNA and DNA. The inflammatory response begins with histamine release and involves a variety of molecules and signals that attract neutrophils, increase permeability, activate the complement system, and trigger fever Adaptive Immunity: is able to recognize individual pathogens and mount a specific response. Lymphocytes, produced in bone marrow, must acquire their specific receptors and undergo selection for selfreactivity in primary organs. These mature but naive lymphocytes circulate to secondary lymphoid organs, where they may encounter foreign antigens. B cells produce circulating antibodies (humoral immunity); T cells kill pathogens or help other cells respond to them (cell-mediated immunity).

Cell-Mediated Immunity T cells can be called cytotoxic T cells (Tc) or helper cells (Th). To be activated, both of these T cell types must recognize peptide fragments bound to MHC proteins, but the two cell types may be distinguished by (1) recognition of different classes of MHC proteins, which have distinct cell distributions, and (2) differing roles of the T cells after they are activated. In humans, the name given to the proteins encoded by the MHC complex is human leukocyte antigens (HLAs) MHC proteins on the tissue cells enable your T cells to distinguish itself from its nonself, an ability called self versus nonself recognition.

Cell-Mediated Immunity There are two classes of MHC proteins. MHC class I proteins are present on every nucleated cell of the body. MHC class II proteins, however, are found only on antigenpresenting cells(in addition to MHC class I). Most of the time, the peptides bound to MHC proteins are derived from self-proteins from the individual's own cells. Activated cytotoxic T cells recognize "altered-self" cells, particularly those that are virally infected or tumor cells. Because not all viruses can infect dendritic cells, the dendritic cells must ingest viruses or tumor cells and then, through a mechanism referred to as cross- presentation, place the viral or tumor peptides on MHC class I proteins.

Cell-Mediated Immunity Th cells secrete proteins called cytokines. They do this in response to foreign antigens. When T cells encounter the nonself MHC- peptide complexes present on transplanted tissue, the TCRs on many of the T cells can weakly bind to these complexes using cross- reactivity. Many cells release cytokines including Th cells.

Humoral Immunity and Antibody Production The B-cell receptors for antigen are the immunoglobulin molecules present as integral proteins in the plasma membrane. Each B cell exhibits about 10 5 immunoglobulin molecules of identical specificity for a particular epitope of an antigen. Each plasma B cell is a miniature factory producing soluble antibodies of the same specificity as the membrane-bound antibodies of the parent B cell.These antibodies enter the lymph and blood circulation as well as extracellular fluid,and they bind to the appropriate epitopes of antigen encountered anywhere into the body.

True or False T/F: Hematopoetic are adult stem cells that are found in the Immune System T/F: Innate immunity is nonspecific T/F: T cells are helper cells T/F: When T cells encounter the nonself MHC-peptide complexes present on transplanted tissue, the TCRs on many of the T cells can weakly bind to these complexes using cross-reactivity. T/F: the immune system is comprised only of Innate Immunity

Multiple Choice Cells that target and kill bocy cells infected by viruses are: a. macrophages b. natural killer cells c. monocytes d. neutrophils