viral pathogens II

Question 1

HIV course

Answer 1

HIV wants to infect t cells, they have CD4 molecule
HIV recognises CD4 and T cells
killing T cells
drop in T cell numbers = stimulates more HIV to be produced, more replication.
opportunisitic infection will occur.
HIV causes immunodeficiency

Question 2

what is viral load set point

Answer 2

minimal number of viral RNA genomes/ml blood.

without immune system detecting it and virus still replicating

Question 3

describe immunodeficiency

Answer 3

viruses need to evade immune responses. they can be mediated by specific cells of the immune system
these immune cells will recognise and kill cells infected by virus
to evade this response, some viruses replicate in immune cells whose function is to recognise and kill infected cells
replication in immune cells will hide virus from immune cells, inhibiting immune cell function
inhibition of immune cell function = other pathogens can replicate in virus infected host, meaning disease occurs.

Question 4

how does HIV promote T cell killing

Answer 4

directly or indirectly
directly = by infecting T cells
not all t cells are permissive to HIV replication
permissive = allow replication of HIV. CD4 cells are small number within immune system
production of new viruses activates apoptosis which kills cells that apoptosis is activated in
non permissive = CD4 cells on surface, but dont allow virus to replicate as it is recognised by innate system. activates pyropoptosis

Question 5

pyropoptosis

Answer 5

causes inflammation = recruitment of more t cells to site of infection

1. HIV infection
2. release of pro inflammatory cytokines and cellular contents
3. inflammation
4. recruitment of healthy cd4t cells
5. migration of neutrophils and monocytes into tissue
6. cell death and release of proinflammatory cytokines and cellular contents

Question 6

HIV associated pathogens

Answer 6

1. virus = herpes or kaposi’s sarcoma herpesvirus
2. bacteria = mycobacterium tuberculosis, salmonella
3. fungus = candida
4. parasite = cryptosporidium

Question 7

AIDS

Answer 7

two routes of possible infection = primary infection and reactivation from latency
primary infection can be resolved by immune suppression and infection moves to sites in host that immune system doesnt access. in these sites the virus resides without replicating = latency
reactivation from latency occurs upon immunodeficiency

Question 8

kaposi’s sarcoma

Answer 8

cancer caused by herpes virus

spreads through all systemic organs

Question 9

viruses that cause cancer

Answer 9

human papilloma virus = skin cancer

epstein = lymphoma
hepatits B = carcinoma
hepatitis c = carcinoma

herpes virus 8 = lymphoma
human t lymphotrophic

merkel cell polyomavirus = carcinoma