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Description
Flashcards by Maryam Nasir, updated more than 1 year ago
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Created by Maryam Nasir
over 7 years ago
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| Question | Answer |
| first line of defence | intact skin + mucus membrane |
| second line of defence | innate immunity |
| innate immunity | 1. not specific 2. rapid 3. preformed 4. fully active |
| third line of defence | adaptive immunity |
| adaptive immunity classification | cell-mediated and humoral/antibody-mediated |
| antibody functions | Opsonization neutralize toxins & viruses complement fixation prevent attachment of microbes catalytic ability |
| Cell mediated immunity is for | inhibiting fungi, parasites, intracellular bacteria kill virus infected cells kill tumor cells (new antigens) |
| Adaptive immunity characteristic | Specific Memory Diverse |
| Bridge b/w adaptive & innate immunity | macrophages + dendritic cells |
| first step of adaptive immunity activation | presentation of antigens to Th cells by APCs |
| Origin of host defences | recognition by specific immune cells activation of immune cells response that targets the offender |
| Which antigen activates B cells directly? | bacterial polysaccharides (T cell independent antigens) |
| T cell independent antigens | only IgM is produced |
| functions of B cells (during induction process) | present epitopes to Th cells (IgM receptor) |
| IgM receptor recognizes what compounds | CHO, lipids, DNA, RNA, foreign proteins |
| MHC II of B cells | recognize only peptide fragments |
| INNATE IMMUNITY | exists prior to exposure, non specific no improval after exposure no memory kill microbes activate adaptive immunity |
| host defences of innate immunity | 1. Barriers 2. Cells 3. Proteins 4. Processes (inflammation, phagocytosis) |
| Recognition by innate arm | pattern recognition receptors- recognize PAMPs |
| Innate arm receptors on surface of cells | TLR + Mannan binding lectin receptors |
| Innate arm receptors inside the cytoplasm | NOD + RIG-I helicase receptors |
| Toll Like Receptors (TLR) | 10 receptors Location: Macrophages, dendritic cells, mast cells |
| TLR Function | activate transcription factors, which increase production of proinflammatory cytokines |
| TLR-4 | recognizes LPS (gram -ve bacteria) LPS binds to LPS binding protein in plasma; LPS transferred to Macrophages surface receptor CD14 LPS stimulates TLR 4 |
| Function of TLR 4 | transmission of signals to nucleus to induce sysnthesis of IL 1, IL 6, IL 8, TNF, & B7 (costimulator) |
| TLR 2 | recognize Gram +ve bacteria & yeast |
| Mannan binding lectin | recognizes mannan on bacteria & yeast |
| Location of MBL (mannan binding lectin) | dendritic cells & macrohages |
| Function of MBL | activation of Complement system enhancement of phagocytosis In Acute phase reaction, MBL increased |
| Candida albicans recognition | by a C type lectin receptor (beta glucan recognized) |
| NOD receptors | Peptidoglycan recognized |
| NOD receptor location | macrophages, dendritic cells, epithelial cells |
| Function of NOD | recognition of intracellular pathogens like listeria |
| RIG I helicase receptor | nucleic acid of viruses recognized |
| Function of RIG I helicase receptor | viruses recognized and IFN alpha & beta formed |
| Effectors of innate immunity | Cellular: macrophages, dendritic cells, NKC (only for viruses) Non-cellular: complement, cytokines, proteins (APR), defensin |
| Pro-inflammatory cytokines | Inflammosome, IL 1 |
| Anti-inflammatory cytokines | IL 10, transforming growth factor beta (TGF beta) |
| APRs : CRP MBL | CRP: binds to CHO in S. pneumoniae MBL: binds to mannan of bacteria |
| Defensin | positively charged peptides; make pores and kill; antiviral too |
| Defensin location | GIT intestinal crypts (neutrophils & paneth cells- alpha) lower respiratory tract (beta defensin) |
| Alpha defensin | antiviral, doesn't let HIV bind to CXCR4 |
| APOBEC3G (apolipoprotein B RNA editing enzyme) | against retrovirus, |
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