Term
| What are the cells in innate immunity ? |
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Definition
| Phagocytes, Dendritic cells, NK cells |
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|
Term
| What are the cells in adaptive immunity ? |
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Definition
| CD8+ T cells, CD4+ T cells, B cells |
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Term
| Virally infected cells secrete what type of cytokines ? |
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Definition
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Term
| Immune responses to viruses vary according to ? |
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Definition
| The site where the virus is detected |
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Term
| Destruction of virus infected cells is done by what cells ? |
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Definition
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Term
| Macrophage phagolysosome serves as favorite niche for what pathogen ? |
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Definition
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Term
| What is difference b/w bactericidal and bacteriostatic ? |
|
Definition
Bactericidal is bacterial killing
Bacteriostatic is bacterial growth inhibiting |
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|
Term
| How does lactoferrin interfere in bacterial growth ? |
|
Definition
| A protein that binds iron, reducing the amount available to bacterial so that they are unable to grow |
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|
Term
| How does lysozyme weaken bacteria ? |
|
Definition
| A protein that weakens the cell wall of some bacteria by cleaving specific bonds in the peptidoglycan layer (cell wall). |
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|
Term
| Are extracellular bacteria sequestered within cells ? |
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Definition
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Term
| In innate immune system, how is extracellular bacteria eliminated ? |
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Definition
| Phagocytosis is primary mechanism |
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|
Term
| What is opsonin mediated phagocytosis ? |
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Definition
| Deposition of opsonins enhances recognition of bacteria via receptors that are specific for the opsonin |
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|
Term
|
Definition
| Refers to any host protein that binds to bacteria, and is recognized specifically leading to phagocytosis |
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|
Term
| Opsonins are generally what type of proteins ? |
|
Definition
| Proteolytically derived complement proteins or IgG antibodies |
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|
Term
| Opsonin mediated phagocytosis occurs after only what 2 things happen ? |
|
Definition
| Complement system has been activated or after B cells differentiate into plasma cell secreting IgG Abs |
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|
Term
|
Definition
|
|
Term
| What does opsonin do to bacteria ? |
|
Definition
| Facilitate recognition of bacteria but do not alter process by which organism is destroyed |
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|
Term
| Complement system eliminates bacteria in which two ways ? |
|
Definition
1) Complement fragments serve as opsonins
2)Generation of MAC causes destruction of bacterium by osmotic lysis |
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|
Term
| Complement activated by the classical pathway requires ? |
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Definition
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|
Term
| How does adaptive immunity deal with extracellular bacteria ? |
|
Definition
Activated B cells differentiate to plasma cells that secrete antibodies
Mostly done by IgG and IgM Abs |
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|
Term
| B cell activation requires what ? |
|
Definition
| CD4+ T cells and the cytokines they secrete |
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|
Term
| Which two Abs activate classical pathway of complement ? |
|
Definition
IgM and IgG Ab isotypes
IgM more effective b/c of its pentameric structure |
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|
Term
| Which CD4+ T-cell derived cytokines enhance killing by phagocytes ? |
|
Definition
| Type 1 cytokines, IFNgamma, TNF |
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|
Term
| Is phagocytosis a primary mechanism for eradication of viral infections ? |
|
Definition
|
|
Term
| Viruses may be phagocytosed when they are found in what 3 fluids ? |
|
Definition
B L I
Blood, Lymph, Interstitial Fluid |
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|
Term
| NK cells interact with infected cells how ? |
|
Definition
| Interact directly via NK activating receptor or indirectly via FcgammaR |
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|
Term
| NK cells kill virally infected cells how ? |
|
Definition
Via ADCC (Ab dependent cell mediated toxicity)
Granules containing perforin are released and this induces osmotic lysis of the infected cell |
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|
Term
| Why are NK cells most effective during early phase of infection ? |
|
Definition
| B/c increased expression of class 1 MHC following IFNalpha/beta signalling by virally infected cells "shuts off" NK mediated activity |
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Term
| For effective viral immunity, CD4+ T-cells must differentiate to ? |
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Definition
| Th1 subset secreting IL-2, b/c IL-2 is responsible for differentiation of naive CD8+ T cells to CTL |
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|
Term
| Are B cells THE key players in viral immunity ? |
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Definition
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|
Term
| Which Ab can neutralize free virus as well as play a key role in ADCC by NK cells ? |
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Definition
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|
Term
| Cytotoxic CD8+ T cells (CTLs) and NK cells kill virally infected cells in what same way ? |
|
Definition
| Release of granules containing perforin which leads to osmotic cell lysis |
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|
Term
| What cytokine is needed to change pCTL to CTL ? |
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Definition
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|
Term
| What cytokine provides a stimulating signal for both NK cells and IL-2 for CD8 T cell expansion ? |
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Definition
|
|
Term
| pCTL --> CTL requires what 3 things ? |
|
Definition
Antigen contact with an infected cell
IL-2
IFNgamma |
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|
Term
| NK cell cytotoxicity is inhibited by ? |
|
Definition
Excessive class 1 MHC expression on target cell
This is done by KIR (killer inhibitory receptor) on NK cell interacting with MHC Class 1 on target cell |
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|
Term
| How does upregulation of class 1 MHC on target cell affect CTL and NK cell cytotoxicities ? |
|
Definition
Increases CTL cytotoxicity
Inhibits NK cell cytotoxicity |
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|
Term
| The key cells in immunity to intracellular bacteria are ? |
|
Definition
| Cytokine activated macrophages |
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|
Term
| Mycobacterium tuberculosis escape killing how ? |
|
Definition
Prevent phagosome/lysosome fusion and replicate within the phagosome
So lysosomal enzymes cannot destroy the microbe |
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|
Term
| What cells are important in protecting against Mycobacterium Tuberculosis ? |
|
Definition
| Cytokine (IFNgamma, TNF) activated macrophages |
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|
Term
| What notable feature is present in immune response to Mycobacterium Tuberculosis ? |
|
Definition
|
|
Term
|
Definition
| An aggregation of macrophages surrounded by CD4+ T lymphocytes secreting Type 1 cytokines, particularly IFNgamma |
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|
Term
| Granuloma formation enhances immune response how ? |
|
Definition
| Cytokines secreted by activated T cells are available to large numbers of infected macrophages |
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|
Term
| Individuals at risk for disease like Mycobacterium Tuberulosis are those that ? |
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Definition
| Have CD4+ T cell defects or in those whom differentiation of naive CD4+ Thp cells results in polarization to Th2 cells secreting Type 2 cytokines rather than Type 1 cytokines |
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|
Term
| Another name for fungal infections ? |
|
Definition
|
|
Term
| Fungal infections usually pose a serious threat to who ? |
|
Definition
| Immunocompromised individuals like AIDS patients as well as those receiving immunosuppressive drugs or chemotherapy |
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|
Term
| What are "opportunistic fungi" ? |
|
Definition
| Are part of normal flora in environment and are relatively harmless to healthy hosts |
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|
Term
| Two common opportunistic fungi ? |
|
Definition
| Candida Albican and Aspergillus (mold) |
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|
Term
| Fungi transmitted from human to human cause superficial infections such as ... |
|
Definition
| Ringworm and athlete's foot |
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|
Term
| What airborne fungi can cause disease in humans that is found in pigeon droppings ? |
|
Definition
|
|
Term
| Fungi are usually destroyed how ? |
|
Definition
|
|
Term
| Individuals with defect in what cell type sustain serious fungal infections ? |
|
Definition
| Neutrophils, b/c cannot do phagocytosis |
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|
Term
| Phagocytosis is more efficient in presence of ? |
|
Definition
| Opsonins, IgG, or complement fragments |
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|
Term
| When fungi hyphae are too large for phagocytosis, how can they be destroyed ? |
|
Definition
| Activated neutrophils can still destroy them by secretion of an array of proteolytic molecules into the local microenvironment |
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|
Term
| Which cytokines play a significant role in immunity to Candida species ? |
|
Definition
| Cytokines secreted by activated CD4+ T cells like IFNgamma |
|
|
Term
| IFNgamma augments production of ? |
|
Definition
| Reactive oxygen intermediates, nitric oxide, and reactive nitrogen intermediates |
|
|
Term
| How does Candida albicans (yeast and fungi) invade ? |
|
Definition
| May invade the underlying basement membrane by forming budding protrusions termed "hyphae" |
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|
Term
| Both yeast infections Candida Albicans and Vaginitis are referred to as ? |
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Definition
|
|
Term
| Chronic mucocutaneous candidiasis is due to? |
|
Definition
| "Hole in the repertoire" , b/c individuals lack T cells with antigen specific TCRs |
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|
Term
| Streptococcus pneumoniae protects itself from phagocytosis how ? |
|
Definition
| By presence of a polysaccharide capsule |
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|
Term
| The polysaccharide capsule that Streptococcus pneumoniae has prevents what cells from being activated ? |
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Definition
| CD4+ T cells, b/c polysaccharides are not processed for presentation with class 2 MHC, so that is why pneumoccocal polysaccharide is a T-independent antigen |
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|
Term
| The polysaccharide capsule that Streptococcus pneumoniae has allows what cells to be activated ? |
|
Definition
| Gamma/Delta TCR+ T cells, which do not depend on class 1/2 MHC presentation |
|
|
Term
| A lack of what can lead to multiplication of Streptococcus Pneumoniae bacteria ? |
|
Definition
| Lack of opsonins, mainly IgG |
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|
Term
| Do immune responsess to T-independent antigens generate memory T cells ? |
|
Definition
| No, so each infection can be potentially life threatening |
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|
Term
|
Definition
| A heterogeneous group of infectious agents composed mainly of nucleic acid surrounded by a protein coat |
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|
Term
| EBV encodes what cytokine like molecule which inhibits development of effective anti-viral cytotoxic T cells needed to kill virally infected cells ? |
|
Definition
|
|
Term
| What is causative agent of AIDS ? |
|
Definition
|
|
Term
| What is causative agent of AIDS ? |
|
Definition
|
|
Term
| How does HIV disable the immune system ? |
|
Definition
| By destroying the CD4 T-cells directly or indirectly |
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|
Term
| (Macrophage) M tropic strains of HIV-1 bind to what to gain entry into cells ? |
|
Definition
|
|
Term
| T-tropic strains of HIV bind to what receptor to gain entry into cells ? |
|
Definition
| CXCR4 (receptor for CXC chemokine SDF-1 (stromal cell derived factor 1) |
|
|
Term
| When can you tell if individual is seropositive with HIV ? |
|
Definition
| When Abs are detected in serum |
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|
Term
| Effectiveness of Abs is limited to ? |
|
Definition
| Free viral particles, not to those viral particles sequestered within a cell |
|
|
Term
| Following infection, cell conjugates form, resulting in ... |
|
Definition
|
|
Term
| Syncytia formation is related to HIV how ? |
|
Definition
| It may contribute to decrease in uninfected CD4+ T cells observed during HIV infection |
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|
Term
| What is a useful marker for disease progression in CD4+ T-cells ? |
|
Definition
| Decline in CD4 T cell numbers |
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|
Term
| What is a "trojan horse" when talking about bacteria ? |
|
Definition
| Bacteria may enter the lung inside a macrophage |
|
|
Term
| How do you detect Myco. Tuberculosis ? |
|
Definition
| A skin test is used to confirm exposure. Consists of intradermal challenge of PPD (purified protein derivative) |
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|
Term
| Upon PPD skin test challenge, previously infected TB patients develop what ? |
|
Definition
| Develop a cutaneous reaction (due to reactivation of memory CD4+ T cells) and this is referred to as a DTH (delayed-type hypersensitivity) rxn and a Mantoux rxn |
|
|
Term
| What is the vaccine given to prevent TB in third world countries ? |
|
Definition
|
|
Term
| Some bacteria escape removal from intestine by peristalsis how ? |
|
Definition
|
|
Term
| Shigelle dysenteriae infects what cells ? |
|
Definition
| Epithelial cells in the intestinal lumen |
|
|
Term
| How does Shigella escape expulsion from GI tract by peristalsis ? |
|
Definition
| Binds to M cells and endocytoses within these cells and replicates here |
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|
Term
| Cryptococcus neoforman is a common infection in ? |
|
Definition
|
|
Term
| What protects Cryptococcus neoforman from phagocytosis ? |
|
Definition
| Polysaccharide capsule surrounding the organism |
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|
Term
| Shigella species induce apoptosis in which cells ? |
|
Definition
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