White blood cells

[spherelin]

Hey guys
I know that B and T cells are classified as lymphocytes but are phagocytes/macrophages also lymphocytes too or are they another class of white blood cells?
There was a VCAA question asking what type of white blood cells are involved in the thrid line of defence of the immune system
and the choices were MAST CELLS, EOSINOPHILS, LYMPHOCYTES and MACROPHAGES.
I picked macrophages.... but it was lymphocytes... yeah.....so obviously macrophages aren't lymphocytes??
BUT THENN in the 2007 VCAA examiner report it said that phagocytes/macrophages were lymphocytes.
Or maybe i'm just fried. haha
okay help please?

[saheh]

Third line of defense: t and b cells, hence the answer lymphocytes
The others are second line
Macrophages etc are myeloid stem cells, whereas t/b/nk cells are lymphoid
I doubt they'd be called lymphocytes :/
I don't know too much about it all...
But if it's asking lymphocytes it should be referring to t/b cells

[spherelin]

but technically, aren't macrophages involved in 3rd line of defence too? because they engulf antigen-antibody complexes? but yeah, i now agree that lymphocytes are correct, haha it's more specific to the 3rd line thanks!

[Daenerys Targaryen]

lyphotcyes are B and T cells because they are in the lymph nodes?
and macropahes etc are phagocytes because they undergo phagocytosis when engulfing

[duquesne9995]

My understanding is:
- lymphocytes differentiate from lymphoid stem cells and include B cells (plasma + memory cells), T cells (helper, cytotoxic, suppressor, memory) and Natural Killer cells
- action of B and T cells in humoral and cell mediated immunity make up the specific immune defense
- macrophages are phagocytes and stem from myeloid stem cells. They are not lymphocytes.
- macrophages/phagocytes are part of the second line of defense because they engulf foreign material non-specifically. They do act as antigen presenting cells and that's where they facilitate third specific line, so I see what you mean but they are classified as second-line. I think these blurry lines are just attributed to the fact that it's biology

[spherelin]

aw thanks for that, I just have one more question, when your body is exposed to the same antigen the 2nd time... do your b and t MEMORY cells proliferate into their subgroups? is that why the 2ndary response is quicker?

[Daenerys Targaryen]

yup, also because it doesnt have to go throguh the whole begining process again (antigen presteing cells etc)

[spherelin]

oh okay, thanks for that, ALSO ONE MORE HHEHEHEHE, if they give us a graph of a primary response and a secondary response, would we say that the secondary response is higher because of B memory cells AND T memory cells?

[Daenerys Targaryen]

yea.