biol 230 unit 4 + comprehensive final

hypersensitivity

immune response above normal, overreaction

allergen

antigens that trigger a Th2 response

exposure: skin contact, injection, ingestion, inhalation

type I - anaphylactic reaction

immediate, IgE antibodies

localized anaphylaxis

hay fever, hives.

restricted to area.

systemic anaphylaxis

anaphylactic shock, complete reaction, life threatening

mediator in anaphylactic reactions

crosslinking of allergens to IgE

use of allergy shots in desensitization

inject allergen in increasing concentration over time.

desensitize by switching IgE to IgG production, tricking immune system into blocking allergic response.

type II - cytotoxic reaction

intermediate, antibody.

blood typing!

transfusion reactions

when wrong blood type is transfused and classical compliment is triggered due to differing antibodies.

type III - immune complexes

intermediate, antibody mediated.

neutrophils phagocytose smaller antibody-antigen immune complex trapped in blood vessels damaging tissues.

post-streptococcal glomerulonephritis relating to type III

inflammatory disease damaging kidney tissues after a bacterial infection

type IV - cell-mediated hypersensitivity reaction

delayed, cell mediated.

TH1, Tc response

type IV in TB mantoux test

when exposed to TB -> Th1 response. mantoux tests for Tc by injecting TB protein.

positive mantoux test

- signs and symptoms

- exposure to TB, no symptoms

- vaccinated with BCG

IGRA (interferon gamma release assay)

blood test separates vaccine and exposed groups.

TB antigen added to blood, interferon released if Tc activated by mantoux test

graft rejection

IV reaction due to foreign antibodies creating Tc response

auto immune disease

immune system attacks self

multiple sclerosis

type IV reaction.

caused by mono infection when CD8 is desensitized, transmigration into brain where myelin sheath is attacked. immune response to self.

HIV/AIDS

single stranded RNA, enveloped, retrovirus

seroconversion

change in serologic tests from negative to positive due to development of antibodies post-exposure

clinical AIDS

CD4+ count 20% below normal, venerable to opportunistic infections like kaposi sarcoma.

HIV latent state

HIV integrates into CD4 Th. after reverse transcription it never leaves & remains as reservoir

HIV testing

10 day period after exposure cannot be tested.

earliest: RNA test

45 days: western blot for presence of antibodies.

antigen/antibody tests most sensitive!

HIV portals of entry

direct contact/mucus membranes of genitals.

fomite (needles) with contaminated blood.

vaccine

suspension of all or part of microorganism to trigger active immune response

herd immunity

majority of population is resistant to antigen and pathogen cannot spread

attenuated vaccine

weakened whole bacteria/virus.

greater immune response, more effective but not as safe.

can revert to being virulent.

inactivated vaccine

"dead" bacteria incapable of infection but intact antigens still trigger immune response.

not always effective but very safe.

poliovirus

replicates in intestines. can cause paralysis if gets to spinal cord by blood.

salk vaccine

inactivated shot.

IgG stops paralysis but no IgA gut immunity to prevent replication.

sabin vaccine

attenuated oral.

IgA gut immunity stops replication and transmission.

use of salk versus sabin

salk used in polio free countries due to low risk if reverted.

sabin used in polio endemic countries where immunity needs to be easily distributed.

toxoid vaccines

exotoxin of pathogen inactivated

disrupted cell/acellular vaccines

most antigenic parts of a microorganism, not whole, used to stimulate immune response

recombinant vaccines

DNA for antigenic proteins put into yeast, purified, and only antigenic protein is ued in vaccine

antibody-sandwich (direct)

FC region of antibody attached to bottom of well, patient sample added and antigen binds. enzyme linked antibody binds to patient antigen. when substrate added, color change concludes positive for antigen.

indirect ELISAs

(enzyme-linked immunosorbent assay)

antigen attached to well. patient sample added for antibody to bind to antigen. enzyme linked antibody added to bind to patient antibody. color change concludes positive for antibody

sterilization

eradicate all microbial life

disinfection

eradicate all vegetative pathogens, not spores

antisepsis

eradicate vegetative pathogens on skin

degerming

scrubbing to remove microbes on skin

bacteriostatic

stopping bacterial growth

bactericidal

killing bacteria

asepsis

absence of pathogens

sepsis

presence of pathogens

boiling

disinfecting.

gets rid of some but not all microbes

autoclaving

sterilizing.

steam and pressure at high temps to kill all

thermal death point

lowest temp where all organisms killed in 10 min

thermal death time

shortest time all microbes are killed at a given temperature

pasteurization

moist heat treatment of milk to remove pathogens.

not sterilizing.

types of pasteurization

historic: originally used for wine.

high temperature, short time (flash).

ultra high temperature.

filtration

removes bacteria, not cidal or static

low temperatures

-80 C freezer, static. stops growth by stopping division

osmotic pressure

salt! static, stops division by plasmolysis (shrinking of call wall)

desiccation

static. drying fruit.

radiation

cidal.

UV disinfecting, gamma sterilizing

phenols, bisphenols, and phenolic

denature proteins, disrupt membranes.

harsh on skin, bac can develop resistance.

alcohols

denature proteins, disrupt cell membranes.

halogens

denature proteins.

Br, Cl, F, I

oxidizing agent

H2O2 denature proteins.

disinfectant and antiseptic.

surfactants

disrupt cell membrane.

removal of pathogens.

soaps degerm

heavy metals

denature proteins.

silver & arsenic

aldehydes

crosslinking between protein and DNA causes all movement to stop in cell.

can be sterilizing.

gaseous agents

sterilize by crosslinking proteins and nucleic acids.

ethylene oxide

tincture

disinfectant dissolved in OH increases effectiveness

factors effect disinfectants

temperature, surface, number of microorganisms

microbial structures from most resistant to least

endospores

mycobacterium

protozoan cysts

vegetative protozoa

gram neg bac

fungi

non enveloped viruses

gram pos bac

enveloped viruses

antibiotic

one organism inhibits another organism's growth

spectrum of microbial activity

number of different pathogens present

broad-spectrum antibiotics

activity against several different types of pathogens

inhibitors of cell wall synthesis

penicillin blocks cross links in peptidoglycan

inhibitors of protein synthesis

erythromycin binds to 50s subunit and blocks A site so no new tRNA can enter

(human ribosomes slightly larger and can block binding)

inhibitors of nucleic acid synthesis

ciprofloxacin targets enzyme to inhibit DNA replication

inhibitors of metabolic synthesis

sulfa drugs inhibit folic acid production so no nucleotides are produced.

competitive inhibitor blocking enzyme from binding

clavulanic acid in augmentin

inhibits penicillinase by irreversibly inactivating beta-lactamase which allows for penicillin resistance

drug inactivation

bac produce enzyme to block antibiotics

decreased permeability

microorganism blocks drug from entering cell

activation of drug pumps

protein structures on membrane pump drugs out of bacteria

alteration of binding site

change in sequence of the 50s subunit so drug cannot bind

alternative metabolic pathway

bacteria get enzymes to go around antibodies using a different synthesis pathway.

mutations caused by gene transfer!

effectiveness of antimicrobials

kirby-bauer: disc on lawn

minimal inhibitory concentration: how much needed to inhibit bac

ketoconazole

antifungal.

blocks production of membrane ergosterol

metronidazole

breaks up DNA in anaerobic protozoa and bac.

vaginal infections!

quinine derivatives

treebark! used against plasmodium (malaria) by inhibiting formation of digestive vacuole.

artemisinin

chinese wormwood used against plasmodium, free radicals caused by the cleavage of bonds oxidizes cells

arsenicals

melarsoprol used against early stage african sleeping sickness (Trypanosoma brucei) by inhibiting enzymes

eflornithine

used against late stage Trypanosoma brucei by competitive inhibition

nucleoside

nucleotide lacking a phosphate group

acyclovir

nucleoside analog looks like guanine. picked up by herpes and blocks replication

AZT (zidovudine)

analog against HIV looks like thymine to block reverse transcription

crixivan (indinavir)

protease (HIV enzyme) inhibitor.

GAG POL precursor protein inhibited from cleaving into proteins.

oseltamivir (tamiflu)

inhibits neuraminidase enzyme activity in influenza A by blocking release of virus after replication

antibiotic resistance contibution

not necessary, incorrect dosage, usage in animal feed

Bacillus anthracis

boil bacteria, endospore former, gram negative

cutaneous anthrax

skin lesions from handling animal skins.

not typically deadly

gastrointestinal anthrax

consumption of infected meat.

fatal, uncommon

inhalation anthrax

breathing in spores.

fatal if not treated due to spores germinating in alveoli and producing cytoxins

advantages of anthrax

not communicable, antibiotics and vaccine available

disadvantages to anthrax

easily aerosolized, fatal if not treated, cost of clean up

cytotoxin in anthrax progression

first symptoms similar to flu, once cytotoxin is produced drastic decline leads to fatality and inability of treatment