Host directed therapy

Question 1

Nosocomial infection

Answer 1

Infection you acquire in hospital

Question 2

Drug resistant infections

Answer 2

Resistance to first line antbiotics

Question 3

Goal host directed therapy:

Answer 3

Prevent replication of pathogen > Prevent death of host

- Killing the pathogen is not always the main goal

Question 4

Challenges host directed therapy

Answer 4

• Safety
• Efficcacy: Have to be affecting against pathogen you fight against
• Competing drugs

Question 5

ED50/ TD50

Answer 5

Dose required to produced a (therapeutic-/toxic- effect) in 50% of the population

Question 6

Therapeutic index

Answer 6

Toxic effect/ Efficiacy effect= How well works a drug

Question 7

When host therapy used?

Answer 7

• Viruses and intracellular bacteria (chlamydia)
• Immune modulation to enhance or suppress response to a pathogen (inhibit cytokines)
• Multi drug resistant pathogens > (resistance not expected)

Question 8

How target the pathogen in host directed therapy?

Answer 8

• Small molecules
• Large biologicals (Antibodies)
• Genetic engineering

Question 9

Plerixafor

Answer 9

Against binding CXCR4

Question 10

Maraviroc

Answer 10

Against binding CCR5

Question 11

Example HIV: host therapy

Answer 11

limit infection and host cell death with small molecules

• Block caspase I&raquo_space; No pyroptosis

Question 12

Two types of infection virus

Answer 12

• Successful infection

- Abortive infection (95%): CD4 cells that aren’t infected.

Question 13

Pyroptosis in HIV infection

Answer 13

High inflammatory programmed cell death of CD4

Question 14

Example mycobacterial infection ,

host therapy

Answer 14

Limitation of nutrients / dissemination with small molecules.

Not target bacteria directly but via host
- Prevent outgrow of blood vessels > Prevent granuloma growth in zebrafishes

Question 15

Pazipanib: Anti mycobacterial

also anti-tumor

Answer 15

VEGF inhibitor

VEGF = Vascular Endothelial Growth Factor

Question 16

Example Toll Like Receptor, host therapy

Answer 16

Immune modulation to enhance or suppress response to a pathogen with small molecules

Question 17

TLR: Function

Answer 17

Recognises pathogen associated molecular patterns
In endosome and at the surface.
Share the IRAK4 pathway

Question 18

Septic shock

Answer 18

Due to TLR4 that recognises LPS

Oplossing:
Block dimerisation of TLR4 < Doesn’t work for long treatment
No drug yet

Question 19

TLR as therapeutical target

Answer 19

TLR7&raquo_space;

Imiguimod&raquo_space; Against genital warts&raquo_space; Boosed immune system

Question 20

Example s. aureus infections, host therapy

Answer 20

Eradication of intracellular bacteria with large biologicals

Target small amount that are inside host cells (system effects) > Eradicate S. aureus out body with antibodies.

Question 21

ADC

Answer 21

Antibody drug conjugates: Antibody with drug > Bind receptor > Host caspase releasse drug > Cell killed

Question 22

AAC

Answer 22

Antibody Antibiotic conjugates: Antibody recognises pathogen.

Antibody binds bacteria > High concentration inside cell&raquo_space; Killing bacteria in cell

• If only a antibioticum given > Works but still some bacteria survive
• AAC: No bacteria alive anymore

Question 23

AAC pros

Answer 23

1. High [antibiotic] at the infectious site
2. AAC longer half life than normal antibioticum (normal antibioticum 4 hours)
3. Works only on bacteria , normal antibioticum kills everything what looks like.
4. Spares the commensal flora

Question 24

AAC cons

Answer 24

1. Application for a limited numer of pathogens (only intracellular) &laquo_space;So doesn’t work against every pathogen
2. Very expensive, more than normal antibiotics
3. Intravenous delivery

Question 25

CRISPR

Answer 25

Genetic code in bacteria where they place virus DNA | It's programmable : You give a copy of DNA you want to modify and put the system into a living cell.

Question 26

Bacteriophages

Answer 26

Place own genome into bacteria >> Mostly the bacteria dies >> Sometimes it survives and save a part of the virus DNA in their own genetic code called CRISPR >> In CRIPR it's stored till needed. - When virus attacks again > Bacterium quickly makes crRNA which bound mRNA of virus and makes it double RNA >> Danger signal

Question 27

Protein Cas9

Answer 27

Scan bacterium inside for signs of the virus invader, compares every bit of DNA When it finds virus it's activated and cuts out the virus DNA making it useless >> Protecting the bacteria against the virus attack - Cas9 is very precise

Question 28

Example HIV in CRISPR | Gene editing

Answer 28

Curing by gene editing: - Cut out HIV gene of patient cell and give to rat > Inject CRISPR > Removes 50% of the virus from cells all over the body - Crystal therapy might cure HIV and other retroviruses - Alle viruses that hide inside the human DNA could be eradicted this way

Question 29

Cons: CRISPR in HIV therapy

Answer 29

1. Need constantly target the virus with CRISPR, because virus mutates over time and can bind again 2. It's only activated when you have HIV, so not available as vaccin, Cas9 under death receptor 3. It's very specific on bases in DNA 4. Can get cancer when it binds wrong

Question 30

Example Malaria in CRISPR Prevent malaria by engineering the vector (musquitos) via large biomolecules and genetics.

Answer 30

- The musquitos become immune for the parasite | - Cas9 binds where normally the plasmodium binds

Question 31

Normal malaria infection: | Plasmodium and malaria cycle

Answer 31

Plasmodium consists of single cells and veroorzaakt Malaria Sporozoids into the skin > Hide for immune system > Become merozoids > multiple and burst into the blood stream >> Hide in membrane of infected cells , so immune system doesn't recognize them

Question 32

Transgenic anopheles stehensi

Answer 32

Coexpression of single chain antibodies resist plasmodium development

Question 33

HIV cycle

Answer 33

HIV enters cell >> Stimulate pyroptosis >> Release of pro-inflammatory cytokines >> Inflammation >> Recruitment of healthy CD4 cells >> Infection etc..

Question 34

Gene driving principle

Answer 34

Gene driving by gRNA and Cas9 - Guide RNA and Cas9 incorperated in DNA of plasmid were normally plasmodium binds - Transfer 'new' sequence to native chormosome - From heterogenous to homogenous >> Easy to transorm complete organisms In malaria: - 2 antibodies needed that recognise plasmodium > Prevent replication and prevent spread of pathogen