UCF PCB3233 Immunology Weigel Exam 2 2025

iCB3 is a ligand for - Correct Ans-CR3 and CR4 receptors on macrophages Scavenger receptors prefer negatively charged molecules such as - Correct Ans-nucleic acids, phosphate containing lipoteichoic acis (gram +) and LPS (gram -) CR3 and CR4 can also recognize - Correct Ans-LPS (gram -), lipophosphoglycan (protozoa), filamentous hemagglutinin, cell surface structures on yeast Mannose receptors recognize - Correct Ans-LPS (gram -), CPs and ManLam of bacteria When TLR's are engaged, what mechanism is engaged in the macrophage? - Correct Ans-A signal is sent to the nucleus to make and secret inflammatory cytokines What does TLR3 bind to? - Correct Ans-RNA viruses What does TLR4 bind to? - Correct Ans-LPS (gram - bacteria) What does TLR5 bind too? - Correct Ans-Flagellin What does TLR7 bind too? - Correct Ans-Single strained RNA What are the steps of the TLR4 signaling mechanism? - Correct Ans-Complex of TLR4, MD2, CD14 and LPS assembles on macrophage surface MyD88 binds TLR4 and activated IRAK4 to phosphorylate TRAF6, which leads to phosphorylation and activation of IKK . IKK phosphorylates IκB, leading to it's degradation and release of NFκB which enters the nucleus and activates transpition of genes for inflammatory cytokines which are synthesized in the cytoplasm and secreted via the ER What 5 genes are transcribed because of the TLR4 recognition? - Correct Ans-IL1, IL6, CXCL8, IL12 and TNFα IL1, IL6, CXCL8, IL12 and TNFα are all considered to be what? - Correct Ans-Inflammatory cytokines Describe neutrophils - Correct Ans-Common myeloid precursor granulocyte/macrophage progenitor neutrophil 40-75% of leukocytes effectors of innate immunity, specializing in capture, engulfment and killing of microbes, work in anaerobic conditions found in damaged tissue, short lived, die at site of infection, phagocytic cell that contain toxic substances in intracellular granules, 60% of hematopoietic activity in the bone marrow, where a large reserve is kept Another name for neutrophils is? - Correct Ans-Polymorphonuclear leukocyte (microphages) 4 classes of adhesion molecules - Correct Ans-Selectins are carbohydrate binding lectins which bind to vascular Addressins CD34 (contain carbohydrate groups) Integrins LFA1 bind to Ig superfamily proteins and extracellular matrix, strong adhesion, ICAM1 binds to LFA 3 4 steps of extravastion - Correct Ans-Extravasation=allowing neutrophils to exit the blood near site of infections. Cytokines/inflammatory mediators induce selectin expression on vascular endothelium to bind neutrophils. Transient interation between neutrophil and selectin on the endothelium. Rolling adhesion, tight binding, interactions between LFA1 to ICAM1, strong interaction induced by CXCL8 held on ECM proteoglycans, chemokine attraction, neutrophils squeeze between the endothelial cells ROLLING ADHESION TIGHT BINDING DIAPEDESIS AND MIGRATION How can you tell the difference between a general cytokine and a chemokine? - Correct Ans-All chemokines are cytokines, but NOT all cytokines are chemokines. CC or CXC while be in the name of chemokines, except IL8 which is a chemokines What are the 3 neutrophil granules? - Correct Ans-Primary (azurophilic) Secondary (specific) and tertiary (gelatinase) What is the respiratory burst associated with neutrophils? - Correct Ans-Transient increase in oxygen consumption, the purpose is to raise the pH of the phagosome so the granule contents can becomes active to kill pathogen Name 2 acute phase proteins and what can they do? - Correct Ans-C reactive protein can activate the complement pathway and bind with C1q , Mannose binding lectin activated the complement cascade and enhances complement fixation, can also serve as opsonin Describe Type I vs Types II interferons? - Correct Ans-Type I interferon is secreted when a human cell is infected with a virus, interfere with viral replication, alert immune system cells that an infection is present, make virally infected cells more vulnerable to killer lymphocyte attack, Type I interferon inducing proliferation of NK cells, Type II interferon (interferon gamma) secreted from NK cells, CD8T cells and CD4 TH1 cells What cells can produce Type I interferon? - Correct Ans-Almost all nucleated cells have the compacity to make type I interferon. Cytoplasmic sensors for viral RNAs What is the main innate immune cell activated by Type I interferons? - Correct Ans-NK cells of innate immunity secrete cytokines to kill infected cells IFNalpha and beta bind to circulating NK cell IFN receptor and activate the NK cells, which will attack the virus infected cell one at a time What are the two effector functions of NK cells? - Correct Ans-Inducing apoptosis of infected cells when NK cells are stimulated by IFNalpha or IFNbeta, secretion of cytokines which activates macrophages when NK cells are stimulated by IL12 What type of infection do NK cells typically fight against? - Correct Ans-Viral infections What type of response is created in a cell that an NK cell has targeted (virally infected)? - Correct Ans-Induce apoptosis What cytokine does an NK cell secrete to activate macrophages? - Correct Ans-Interferon gamma What happens to virally infected dendritic cells when NK cells outnumber them? - Correct Ans-When there are more NK cells then infected dendritic cells, the NK cells are cytotoxic to dendritic cells What happens to virally infected dendritic cells when they outnumber NK cells? - Correct Ans-When there are more infected dendritic cells then NK cells, the NK cells signal the dendritic cells to migrate to nearest secondary lymphoid tissue to activae the adaptive immune system. Describe IgG - Correct Ans-(IgG1, IgG2, IgG3, IgG4) found in vascular and extravascular spaces as well as secretions, most ABUNDANT Ig in blood, provides blk of immunity again blood bourne pathogens, ONLY antibody class to cross the placental barrier and provide passive innate immunity to developing and newborn infant Decribe IgA - Correct Ans-Found in external secretions, colostrum, milk and saliva being the first line of defense against microbes entering the mucosal surface and prevents colonization of mucosal surfaces and mediates phagocytosis, secretory IgA is dimeric and synthesized locally by plasma cells in mammary and salivary glands and along he respiratory, GI and genitourinary tracts, contain light chain and heavy chains, also contain J chains, which holds together the 2 four chain units, via disulfide bridges Describe IgM - Correct Ans-Is the first antibody to be produced by B cells, expressed as a 4 chain unit, 2 mew heavy chains and 2 light chains, also present as soluble molecule in blood J chain initiates polymerization of subunits, in circulation IgM is composed of 5 four chain units and has 10 binding sites, high avidity. Decribe IgE - Correct Ans-Present in seru