Microbes and virulence – Flashcards
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Unlock answers| Diagram the Inflammation response |
This needs to include: Mast cells, Histamine, Dendrites Neutrophil, integrin, Eselectin from membrane. Vasodilation causing heat, pain, redness, swelling Monocyte, macrophage. (non specific response) |
| Draw out the 3 complement protein activation |
1) Classical pathway -> Antigen/antibody 2) Alternative pathway -> Complement proten binds to pathogen 3) Lectin pathway-> Antibodies can bind to the lectin and manose on the pathogen |
| Define the T cells (Cellular response) |
Tc - Cytotoxic T cells (CD8) Th - Helper T cells (CD4) Th1 - Stimulates Macrophage growth, releases cytokines Th2 - Stimulates B cells to produce more antibodies |
| Allergy Immune response types |
Type I - Accute/immediate. Seconds Type IV, Delayed, cell mediated. Hours to show. |
| Describe a type I allergen response |
Antigen triggers a B cell response. IgE produced instead, the IgE is a receptor for Mast cells. Mast cells release histamine. |
| Define Type IV allergy response |
| ANtigen presenting cell reaction ocurs macrophages and t cells migrate to the locations. |
| What protein is required for opsonization? |
| C3b |
| How is opsonization carried out? |
| Antibodies and complement proteins bind to cell. Phagocytes recognize IgG and complement protein C3b and are drawn to the pathogen. Makes it easier for engulfment. |
| Name the 3 complement proteins we care about |
IgG - Prevalent. Long term protection, in blood and tissues IgM - Initial response, large sized IgE - Part of the mast cell response |
| What are the 4 main ways we use adaptive immunity |
Specificity (One responder to one stimulus) Diversity (Antibodies, light chain receptors vary) Tolerance (Recognizes self) Memory (Memory B&T cells) |
| What are regulatory T cells? |
| Regulate against autoimmune response |
| What are Natural Killer cells? |
| Respond to virally infected cells/cells missing MHCI proteins |
| What is opsonization? |
| A pathogen identified by the body and marked for phagocytosis. |
| What is an epitope? |
| The recognized portion of an antigen that antibodies can identify and bind with. Either shown on an antigen presenting cell or on the pathogen itself. |
| How do cytotoxic T cells kill the infected cells? |
| They release perforin to create holes in the cell, then send in Granzyme to the cell to stimulate aptopsis |
| What are the identifying factors for bacteria on skin cells? |
Drying, salty, pH 4-6, antimicrobial peptides in sweat glands, Lysozymes destroy cell walls (gram positive) Microflora include gram positive, few gram negative and fungi
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| What are the identifying factors for microbes in the oral cavity? |
Moist, anaerobic, antribacterial compunds Microflora: Biofilms of mixed cultures. High sugar increases, attachment, organic acids, gingivities, caries and cavities |
| What are the identifying features for bacteria in the respiratory tract? |
Mucus/mucuciliatory escalator carries out bacteria Microflora: Mixed culture/pathogens. Eyes: Contain lysozomes to help control bacteria. |
| What are the identifyiing features for bacteria in the GI tract? |
Nutrients, pH variations and Anoxic (No O2) Microflora Mixed culture, provides us with B12 and K
Stomach pH 2 (Heliobacter and Strptococcus live) Duodenum ph 4-5 Ilum and colon ph7
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| Draw the exposure chart |
| Exposure to pathogen -> Adherence (Skin or mucosa) -> invasion throug the epithelium -> Colonization and growth/virulence factors (further colonizing the invasion site)-> Splits to toxicity as toxins effect the local area or systemic area <--> Invasiveness growing out of the intial site furthering exposure -> Tissue damage/disease. |
| Explain the 5 steps of infection |
Incubation period (low # of organisms) Prodromal response (general/vague symptoms as organisms increase) Illness (Most severe symptoms, high #organisms) Decline (Decrease of symptoms and organisms) Convalescence (No signs or symptoms) |
| Define the difference between signs and symptoms. |
Signs - Evidence (Fever, rash, swelling) Symptoms - Subjective (pain, malaise, fatigue) |
| What are the 3 types of symbiosis |
Mutualism - Everyone benefits Commensalism - One benefts the other is neutral Parasitism - Host is harmed |
| Describe toll like receptors |
| Anchored in membranse of macrophages and dendrtes. Recognizes peptidoglycan, lipopolysaccharide and flagellin. |
| Describe nod like receptors |
| Cytoplasmic proteins that detect bacterial componants in cells |
| Describe rig like receptors |
| Cytoplasmic proteins that recognizes bacterial DNA viral dsRNA and ssRNA. |
| What are interferons? |
| When a cell recognizes it has been infected, interferons are released to neighboring cells to prime them for activaton in case they are infected stimulating PKR (antiviral protein) production. |
| What are the complement proteins used in the inflammation response? |
| C5a and C3a. They cause mast cells to release pro-inflammatory cytokines |
| How do bacteria avoid the bodies natural defenses? |
Biofilm growth Siderophores (Bind to iron) Avoidance of secretory IgA (Mucosal IgA) Pili turnover IgA proteases |
| How does a bacteria colonize? |
| Adhesions on the end of pili attach to a receptor. |
| How do pathogens invade the cellular barriers? |
1) Direct uptake (Pathogen induces the host cell to engulf it by endocytosis. Salmonella uses type III secretion sytem to inject in effector proteins) 2) Hiding in a host cell (Shigella directly transfers from cell to cell using actin) 3) Avoiding the complement system proteins (N gonorrhoeae binds the complement proteins to avoid the membrane attack complex) |
| What do Defensins do? |
| Disrupt the microbial membranes |
| What do interferons do? |
| Inhibit replication of viruses. |
| Describe the arrangement of antibodies/B cell receptor/T cell receptors |
| Consist of 2 heavy chains and 2 light chains. The tops of the heavy and light chains contain a variable antigen binding site region that will only activate with the proper epitope. |
| Describe the antibody growth curves |
| Lag period. IgM is released (5-15 days) IgG production picks up around 15 days and takes over the IgM. IgM is an indicator of current disease, IgG is an indicator of past disease. |
| Define primary and secondary immune responses |
Primary: IgM responds, IgG responds after 15 days and then declines Secondary: IgM responds, IgG responds more rapidly and with higher antibody production from plasma cells. More memory cells created. |
| Describe how vacines work with the primary and secondary responses |
Primary: Antigen injected, IgM response started. Secondary: Antigen injected again, IgG response is prevalent. |
| Describe the antigen ELISA test |
Antigen is attached to micro well Serum is added, the complimentary antibody binds to the antigen Enzyme linked antibody added, attaches to the complementary antibody Substrate added to well, any enzyme linked will change the color in the well. |
| What is Epidemiology? |
Measures a disease in a population Makes determinations regarding the cause of the disease Applies knowledge to control public health problems |
| What are the 3 types of epidemiological studies? |
Descriptive Analytical Experimental |
| What does the Descriptive studies branch of epidemiology look at? |
Physical aspects of an existing disease. # of cases Segments of affected population Location and time of cases. |
| What does the analytical studies branch of epidemiology look at? |
Cause and affect. Attempts to determine the probable cause, mode of transmission and methods of prevention Used in situations where Koch's postulates can't be applied. |
| What are the 2 sub branches of the analytical studies branch of Epidemiology? |
Retrospective - Looks at preceding events. Uses a control group Prospective - As the epidemic spreads. Determines susceptibilities and resistance. Determines if things can be changed to stop the spread. |
| What does the Experimental Studies branch of epidemiology look for? |
| Hypothesis testing. Find the reservoirs of infection, portals of entry and mechanisms of transmission. |
| Define Incidence and Prevalence |
Incidence: Number of *new* cases in a population during a specific time period.
Prevalence: Total number of people infected at a given time. Severity and length of the disease |
| Define Morbidity and Mortality. |
Morbidity: Number of individuals affected during a set period of time in relation to total pop.
Mortality: Number of deaths in a population during a specific time period. |
| Draw and lable the Epidemiological Triad |
Host <-> Infectious agent (infectivity, pathogenicty, virulence <-> Environment
All around the vector. |
| What are the main virulence factors of infectious agents? |
Adhesion factors biofilms/capsules Extracellular enzymes Toxins Immune evasion |
