hi,
just a few questions:
1. Some exams I've done state T cells as giving rise to Helper t cell, cytotoxic T cell and memory cells? Isn't it suppose to be activated t helper give rise to more activated t helper cell and memory helper t cell etc.
2. Also on a few of the vcaa exams, there has been questions about giving vaccines to viral infections, however aren't vaccine specifically suppose to make memory B cells that give rise to plasma cell which secrete antibodies. Don't antibodies aid in destroying cellular pathogen rather than non-cellular pathogens. How does vaccine work with viral infection?
3. is it correct to say a structural feature that occurred as hominids evolved into modern humans would be smaller teeth due transition of lifestyle - herbivore to omnivore
4. Do NK cells also release granzymes and perforins to initiate apoptosis and are they also involved in transplant rejection
5. How is pigment (from tattooing) identified as foreign by macrophages and why is there no adaptive response to the ink pigments by the body?
Thanks xx
1) I am not aware of VCAA saying T cells differentiate to give rise to Helper t cell, cytotoxic T cells - do you know what exams mentioned this?. I have found them defining that "T memory cells survive for many years and proliferate rapidly into Th and Tc cells when the body is exposed to a pathogen for the second time, mounting a quicker and stronger response".
Helper T cells will differentiate to produce more helper T cells and memory helper T cells, but VCAA doesn't seem to want you to make the distinction between the two types of memory T cells, and instead wants you to group them as 'T memory cells'.
2)Antibodies are still effective against viruses. The humoral immune system may be activated by viral antigens and antibodies specific to these viral antigens can be produced where they will bind to the virus itself function to:
- neutralise the virus (i.e. by antibody binding to a surface protein (of the virus) which enables the virus to bind to host cells, thus preventing the virus from binding to host cells and replicating).
- Agglutinate virus particles, preventing their movement through the body
- act as an opsonin and enhance phagocytosis of the virus
3) I would agree with this response
4) NK cells do release perforin and granzymes. NK cells do play a role in tissue rejection - but I think most questions will want you to talk about cytotoxic T cells.
5) This question is a bit odd - was there more context that came with it?