Microbiology Exam #4

Innate = Defenses against any pathogen; present at birth; good against pathogen; no memory

Adaptive = Defenses against or resistance to a specific pathogen; specific reaction to a pathogen; acquired through exposure; memory response

Receptors on macrophages that recognize pathogens by looking for PAMPs (Pathogen Associated Molecular Patterns - peptidoglycan, endotoxin, flagella protein, double stranded RNA)

Physical = skin (sebum), epidermis (consists of tightly packed cells with Keratin), mucous membranes (mucous traps microbes), ciliary escalator (microbes trapped in mucous are transported from lungs), lacrimal apparatus (washes eye), saliva (washes off microbe), urine (flows out), vaginal secretions (flows out)

Chemical = fungistatic fatty acid in sebum, low pH of skin, lysozyme in perspiration, tears, saliva, & urine, low pH of gastric juice, low pH of vaginal secretions

Blood consists of plasma & formed elements (RBCs, WBCs, T cells, B cells, & Platelets)

2 Types:

• 1.  Granulocytes
• Neutrophils - phagocytosis
• Basophils - histamine, allergies, inflammation
• Eosinophils - kills parasites, allergies

• 2.  Agranulocytes
• Monocytes (Macrophages) - phagocytosis
• Dendritic Cells - phagocytosis, present antigen to adaptive immune cells, bridge to 3rd line of defense
• Natural Killer Cells - destroy target cells, kill abnormal cells

Chemotaxis = Chemotactic chemicals produced (chemokines) along a gradient causing movement of phagocytes to microbes - movement toward a chemical signal

Adherence = Attachment of phagocyte's membrane to microbe; opsonization (coating of microbe by antibodies or complement); toll-like receptors cause activation of phagocyte to release cytokines

Ingestion = Pseudopods engulf microbes & fuse together forming phagosome; pH is lowered inside the phagosome

Digestion = Phagosome fuses with lysozome creating the phagolysozome; lysozome degrades peptidoglycan while other enzymes break down other cell components; after microbe is digested, vesicle becomes a residual body & expels waste outside the cell; also presents antigens to the 3rd line of defense

• Inhibit Adherence =  M protein, capsules
• Kill Phagocytes; = Leukocidins
• Lyse Phagocytes =  Membrane attack complex
• Escape Phagosome
• Prevent Phagosome-Lysozome Fusion
• Survive in Phagolysozome

Body's response to cell damage characterized by redness, heat, pain, swelling

Vasodilation = increased permeability of blood vessels; release of acute phase proteins (histamines, kinins, prostaglandins, leukotrienes) causes increased leakiness of vessels to allow migration of leukocytes to site of damage; blood clots can form around abcess to prevent dissemination of infection

Phagocyte Migration & Phagocytosis = phagocytes normally flow with blood through vessels; can adhere loosely & then bind tightly when stimulated; then follow chemokine gradient & can squeeze through endothelial cells to move into tissues; adhere to microbes & phagocytose them

Tissue Repair = final stage; new cells are produced by the supporting tissues and/or the functioning tissue; can be abnormal if fibroblasts are activated to produce scar tissue

Complement System = defensive system consisting of over 30 proteins produced by the liver and found circulating in blood serum and within tissues throughout the body

Complements the cells of the immune system in destroying microbes; not adaptable and does not change over the course of a person's lifetime (belongs to the innate immune system)

• Inactive C3 splits into activated C3a and C3b.
• C3b binds to the surface of a microbe, and receptors on phagocytes attach to the C3b.  Thus C3b enhances phagocytosis by coating a microbe, opsonization promotes attachment of a phagocyte to a microbe.
• C3b also initiates a series of reactions that result in cytolysis.
• The transmembrane channels of the MAC result in cytolysis.
• C3a and C5a bind to mast cells and cause them to release histamine and other chemicals that increase blood vessel permeability during inflammation.  C5a also functions as a very powerful chemotactic factor that attracts phagocytes to the site of an infection.

• Classical = Initiated when antibodies bind to antigens
• Alternative = Does not involve antibodies; activated by contact between certain complement proteins and a pathogen
• Lectin = When macrophages ingest bacteria, viruses, and other foreign matter by phagocytosis, they release cytokins that stimulate the liver to produce lectins, proteins that bind to carbs

Class of similar antiviral proteins produced by certain animal cells, such as lymphocytes and macrophages, after viral stimulation; interferes with viral multiplication

Alpha & Beta Interferon = produced by virus-infected host; induces uninfected cells to produce antiviral proteins that prevent viral replication

Gamma Interferon = produced by lymphocytes; induces neutrophils and macrophages to kill bacteria; causes macrophages to produce nitric oxide that appears to kill bacteria as well as tumor cells by inhibiting ATP production

Inhibit cell wall synthesis; form pores in plasma membranes, resulting in lysis; destroy DNA and RNA

Produced by nearly all plants and animals, and bacterial resistance to AMPs has not yet been seen

B Cells = type of WBC; differentiates into andtibody-secreting plasma cells and memory cells; recognize antigens and make specific antibodies against them

T Cells = type of WBC; develops from a stem cell processed in the thymus gland that is responsible for cell-mediated immunity; contact with an antigen complementary to a TCR can cause certain types of T cells to proliferate and secrete cytokines rather than antibodies

Globulin proteins aka immunoglobulins (Ig); made in response to an antigen

Structure = antibody monomer has 4 protein chains joined by disulfide links and other bonds to form a Y-shaped molecule; the two sections located at the ends of the y's arms are called variable regions

IgG = enhances phagocytosis; neutralizes toxins and viruses; protects fetus and newborn

IgM = especially effective against microorganisms and agglutinating antigens; first antibodies produced in response to initial infection

IgA = localized protection of mucosal surfaces

IgD = serum function not known; presence on B cells functions in initiation of immune response

IgE = allergic reactions; possibly lysis of parasitic worms

• Collection of genes that encode molecules of genetically diverse glycoproteins that are found on the plasma membranes of mammalian nucleated cells
• Identifies the host and its use here prevents the immune system from making antibodies that would be harmful to the host

Agglutination = antibodies cause antigens to clump together

Opsonization = the antigen, such as a bacterium, is coated with antibodies that enhance its ingestion and lysis by phagocytic cells

Neutralization = IgG antibodies inactivate microbes by blocking their attachment to host cells and neutralize toxins in a similar manner

Activation of Complement System = triggered by either IgG or IgM antibodies which llyses the microbe, which then attracts phagocytes and other defensive immune system cells to the area

Antibody-Dependent Cell-Mediated Cytotoxicity = resembles opsonization in that the target organism becomes coated with antibodies; however, destruction of the target cell is by immune system cells that remain external to the target

Helper T Cell = coordinates and regulates the immune response by secreting interleukins; regulate other t cells, b cells, leukocytes (macrophages and granulocytes); can recognize an antigen presented on the surface of a macrophage

Cytotoxic T Cell = destroys infected cells as well as pathogens by releasing destructive compounds that will kill the pathogen; secretes toxins and digestive enzymes as well

Supressor T Cell = inhibit and regulate the immune response

Natural Killer Cell = can attack cancer and some pathogens

Dendritic Cells = present all types of antigens, but present viral antigens efficiently

Macrophages = present bacterial antigens well 

B Cells = present peptides of soluble protein antigens, such as protein toxins, that they have internalized via their antigen receptors

• Not immunologically specific; they do not need to be stimulated by an antigen
• They first contact the target cell and determine whether it expresses MHC class I self-antigens; if it does not they kill the target cell

A small protein released from human cells that regulates the immune response; directly or indirectly may induce fever, pain, or T cell proliferation

• The capacity of the body's immune system to remember an encounter with an antigen due to the production of circulating antibodies and expanded clones of long-lived B and T cells during the primary response
• Ensures that subsequent infections with the same pathogen will provoke a faster, stronger, longer secondary immune response

Naturally Acquired Active Immunity = develops when a person is exposed to antigens, becomes ill, and then recovers.  One acquired, immunity is lifelong for some diseases

Naturally Acquired Passive Immunity = involves the natural transfer of antibodies from mother to her infant.  Antibodies in a pregnant woman cross the placenta to her fetus

Artificially Acquired Active Immunity = result of vaccination; introduces vaccines into the body


Artificially Acquired Passive Immunity = involves the injection of antibodies (rather than antigens) into the body.  These antibodies come from an animal or person who is already immune to the disease

A suspension of organism or fractions of organisms that is used to induce immunity

Live Attenuated Vaccines = includes a live virus that has mutated so that it has reduced ability to grow in human cells and is no longer pathogenic to humans

Inactivated Killed Vaccines = Includes virus particles that have been treated with formalin, heat, or irradation so that they are no longer able to replicate

Subunit Vaccines = use only those antigenic fragments of a microorganism that best stimulate an immune response

Conjugated Vaccines = involves attachment of a polysaccharide to a protein

Nucleic Acid (DNA) Vaccines = plasmids of "naked" DNA injected into muscle results in the production of the protein antigen encoded in the DNA; the protein antigens are carried to the red bone marrow and stimulate both humoral and cellular immunity

Antibodies that recognize a single, specific epitope of an antigen of interest

When a hybridoma is grown in culture, its genetically identical cells continue to produce the type of antibody characteristic of the ancestral B cell

Useful because they are uniform, highly specific, and they can be produced readily in large amounts

Precipitation Reactions = involve the reaction of soluble antigens with IgG or IgM andtibodies to form large, interlocking molecular aggregates called lattices; used in precipitin ring test and immunodiffusion tests

Agglutination Reactions = involve either eithe particulate andtigens or soluble antigens adhering to particles; these antigens can be linked together by antibodies to form visible aggregates; used in direct agglutination tests and indirect agglutination tests

Antigen-antibody reaction in which the harmful effects of a bacterial exotoxin or a virus are blocked by specific antibodies

Antibodies that do not produce a visible reaction, such as precipitation or agglutination, can be demonstrated by the fixing of complement during the antigen-antibody reaction

Indirect = detects antibodies in a patient's sample rather than an antigen such as a drug; antigen is adsorbed to well, patient serum is added and complementary antibody binds to antigen, enzyme-linked anti-HISG is added and binds to bound antibody, enzyme's substrate is added and reaction produces a product that causes a visible color change

Direct = tests to detect the presence of drugs in urine; antibody is adsorbed to well, patient sample is added and complementary antigen binds to antibody, enzyme-linked antibody specific for test antigen is added and binds to antigen, forming sandwich, enzyme's substrate is added, and reaction produces a product that causes a visible color change

Refers to an antigenic response beyond that which is considered normal; aka allergy

Hypersensitivity responses occur in individuals who have been sensitized by previous exposure to an antigen; aka allergen

Type 1 (Anaphylactic) = IgE binds to mast cells or basophils; causes degranulation of mast cell or basophil and release of reactive substances such as histamine - anaphylactic shock from drug injections and insect venom; common allergic conditions such as hay fever or asthma

Type 2 (Cytotoxic) = antigen causes formation of IgM and IgG antibodies that bind to target cell; when combined with action of complement, destroys target cell - transfusions reactions, Rh incompatibility

Type 3 (Immune Complex) = antibodies and antigens form complexes that cause damaging inflammation - arthus reactions, serum sickness

Type 4 (Delayed Cell-Mediated, or Delayed Hypersensitivity) = antigens activate Tc that kill target cell

• Used to identify and compare HLAs (human leukocyte antigen)
• Certain HLAs are related to an increased susceptibility to specific diseases
• Medical application of HLA typing is to identify such susceptibility and in transplant surgery

Condition in which one's own immune system cannot discriminate between foreign and self antigens

Specific immunological eradication of a graft

Hyperacute Rejection = preexisting antibodies in recipient, Ag-Ab complex, mismatched blood groups

Acute Rejection = due to difference in MHC I and II alleles, happens in 10 - 14 days and is cell-mediated,

Chronic Rejection = due to difference in minor histocompatibility antigens, slow progressive (months to years), both humoral and cellular immunity

Graft Vs Host Rejection = lymphocytes in a graft attacking the recipient, if immunocompromised

• Privileged Sites and Privileged Tissue
• Stem Cells
• Grafts
• Bone Marrow Transplants

• Some cancer cells can produce proteins that shut down the immune system in the area around the tumor
• Some cancers occur in places that the immune system has a hard time getting to such as the brain

Congenital = the inability, due to an individual's genotype, to produce specific antibodies or T cells

Acquired = the inability, obtained during the life of an individual, to produce specific antibodies or T cells, due to drugs or disease

• Retrovirus that has two identical strands of RNA, the enzyme reverse transcriptase, and an envelope of phospholipid
• Spread by dendritic cells that cary it to the lymphoid organs where it contacts cells of the immune system; viral DNA becomes integrated into the chromosomal DNA of the host cell

T Cells

Causes the immune system to shut down

• Causative Agent = S. aureus
• Identifying Characteristic = Localized infection, with or without pus

• Causative Agent = S. aureus
• Identifying Characteristic = Highly contagious, vesicular rash; passed through direct contact

• Causative Agent = S. aureus
• Identifying Characteristic = Staph toxins enter blood stream; results in fever, rash, and shock

• Causative Agent = S. pyogenes
• Identifying Characteristic = Reddish patches on skin or mucous membranes with fever

• Causative Agent = S.pyogenes; MRSA
• Identifying Characteristic = Bacteria invade tissue and destroy it

• Causative Agent = Pseudomonas aeruginosa
• Identifying Characteristic = Ear infection - swimmers ear

• Causative Agent = P. aeruginosa
• Identifying Characteristic = Opportunistic

• Causative Agent = Propionibacterium
• Identifying Characteristic = Most common skin disease; G- rods; metabolize sebum in hair follicles

• Causative Agent = HPV
• Identifying Characteristic = Skin cells proliferate and cause benign growths; spread by direct contact

• Causative Agent = Variola virus
• Identifying Characteristic = Enters respiratory tract and causes pustular rash; passed by aerosols, no tx

• Causative Agent = Varicella virus
• Identifying Characteristic = Vesicular rash; latent in nervous system

• Causative Agent = Varicella virus
• Identifying Characteristic = Vesicular rash; latent in nervous system - reactivates across single dermatome

• Causative Agent = HSV-1
• Identifying Characteristic = Vesicles around mouth (also in GI Tract); 90% infected; can cause encephalitis

• Causative Agent = Measles virus
• Identifying Characteristic = Macular rash; Koplik's spots in mouth diagnostic indicator; MMR vaccine

• Causative Agent = Rubella virus
• Identifying Characteristic = German measles; transmitted respiratory route; milder rash; major concern during pregnancy

• Causative Agent = Human Parvovirus B19 HHV-6,7
• Identifying Characteristic = Mild macular rash on face (slapped face); high fever; rash on body

• Causative Agent = Trichophyton (hair, skin, nails); Microsporum (hair, skin); Epidermophyton (skin, nails)
• Identifying Characteristic = Tinea capitis (head); Tinea pedis ringworm, athletes foot, jock itch, etc; metabolize keratin

• Causative Agent = Candida albicans
• Identifying Characteristic = Yeast infection; thrush; commonly found in immunosuppressed

• Causative Agent = Mites Sarcoptes scabiei
• Identifying Characteristic = Burrow under skin; papules and itching

• Causative Agent = Pediculus humanis (lice)
• Identifying Characteristic = Itchiness due to sensitization to louse saliva

• Causative Agent = Hemophilus influenzae (bacteria); can be viral too
• Identifying Characteristic = Inflammation of the conjunctiva of the eye; aka pink eye

• Causative Agent = Chlamydia trachomatis
• Identifying Characteristic = G- coccoid; swelling and pus; birth canal or wrimming; Trachoma - scar

• Causative Agent = Neisseria gonorrhoeae
• Identifying Characteristic = Acquired during birth; acute infection with pus; blindness; newborns tx with antibiotics

• Causative Agent = HSV-1
• Identifying Characteristic = Inflammation of cornea

• Causative Agent = Acanthamoeba
• Identifying Characteristic = Fresh water, usually in contact lens wearers who make own saline

• Causative Agent = Opportunistic G- bacteria
• Identifying Characteristic = Inflammation of the urethra

• Causative Agent = E. coli, Staphylococcus saprophyticus
• Identifying Characteristic = Inflammation of the bladder

• Causative Agent = Opportunistic G- bacteria
• Identifying Characteristic = Inflammation of the ureters

• Causative Agent = E. coli
• Identifying Characteristic = Inflammation of the kidneys

• Causative Agent = Leptospira interrogans
• Identifying Characteristic = Transmitted by urine contaminated water from animals (dogs, rats); causes fever, chills, and can lead to liver and kidney issues

• Causative Agent = Neisseria gonorrhoeae
• Identifying Characteristic = Attaches to mucosal cells using fimbriae; results in painful urination and pus discharge in men; can cause blindness if passed to infant during birth

• Causative Agent = Chlamydia trachomatis
• Identifying Characteristic = Inflammation of urethra; chlamydia most common STI; mild symptoms; also causes blindness in infants

• Causative Agent = N. gonorrhoeae; C. trachomatis
• Identifying Characteristic = Bacterial infection of the female pelvic organs; can result in blockage of uterine tubes and sterility

• Causative Agent = Treponema pallidum
• Identifying Characteristic = Spirochete; not grown in media; has 4 distinct stages =  primary - sore at site of infection, secondary - rash on skin and mucous membranes, latency - can last years, tertiary - presence of gummas (skin lesions); also affect cardiovascular and nervous systems

• Causative Agent = C. trachomatis
• Identifying Characteristic = Disease of tropics; initial lesion and then blockage of lymphatic system leading to swollen genitals

• Causative Agent = Gardenella vaginalis
• Identifying Characteristic = Infection of the vagina (no inflammation); diagnosis based on increased pH; fishy odor and presence of clue cells (vaginal epithelial cells coated with bacteria)

• Causative Agent = Herpes Simplex Virus type II (also HSV-1)
• Identifying Characteristic = Fluid filled vesicles on genitals; virus goes latent in nerve cells; virus can cause recurrent lesions upon reactivation

• Causative Agent = HPV
• Identifying Characteristic = 1/4 of women infected; linked with cervical cancer; causes wart like growths on genitals in females; asymptomatic in males

• Causative Agent = Candida albicans
• Identifying Characteristic = Lesions in vagina with itching and irritation; treated with OTC medications

• Causative Agent = Trichomonas vaginalis
• Identifying Characteristic = Protozoan infection of vagina; raises pH

Pathogen-associated molecular patterns

Physical

Lysozyme

Neutrophils

Macrophages

Opsonization

Phagolysosome

True

Opsonization and cell lysis

IFN-gamma

B cells

T cells

True

True

True

False

MHC II---antigen presenting cells

Perforin and Granzyme

True

True

Agglutination, opsonization, neutralization, complement activation - cell lysis, antibody-dependent cell-mediated cytoxicity

Attenuated vaccine

Subunit vaccine

True

True

Agglutination

Mast cells and basophils

Cytotoxic

Blood type and HLA type

False

CD4+ T cells

True

Leptospirosis

Increased pH and clue cells

Syphilis

Pelvic inflammatory disease

Impetigo

Lice

Fifth Disease

Small pox

Necrotizing fasciitis