Histopathology and antibody Flashcards
What is the difference between Histopathologist and cytopathologists?
Histopathologist-interested in tissues-biopsies, specimens, frozen sections, post-mortems
Cytopathologists-interested in CELLS-smears, needle aspirates
What is the main role of histopathologist?
Diagnosis based on tissue
Assess cancer spread (stage)+monitor disease and treatment (in stuff like IBS/UC)
What are the 4 main samples hisotpathologist use?
Biopsies, resection specimens (from removal surgeries), frozen section, post mortems
What are the main information gathered from biopsies?
is it normal or not
Is it inflammed-and why
Is it a tumour
if yes-what type of tumour
What is a resection specimen? What do you check in them?
usually a large specimen-usually done after diagnosis
Always check the margins of specimen (see if all cancer has been removed, its stage etc)-if its not cancer-also important
What is a frozen section? What is the use?
Done during the surgery-and usually for cancer
Often margin check to see if its all out
and check if its the right cancer-and treatment is appropriate
How are tissue sections obtained and treated?
Labelled and placed in box with formallin-sets the tissue to watch
Then embed in parafin was and cut section-then microscope
Stains are the main use-gram, ZN, etc
But can also use AB to specific antibody
some molecular tests too
How are cytopathology samples obtained?
Looking for cells-not tissue (might be easier to get if organ hard to reach)
Use fine needle aspirations-
How are ABs made for therapeutic/diagnostic purposes?
Can attatch enzymes, probs, dyes, magnetic beads (to purifiy different cell types), Drugs (like BC-anti-her2)
Main reason to use them is specificity
Either-produced by patient Or manufactures (Immunised animals-take from (but multiclonal-and limited supply) (monoclonal Ab-can make tons) (and now make them from the gene directly + genetic engineering
What are the different therapeutic uses of ABs?
1) prophylactic against microbial infertion (in immunocompromised patients)
2) Anti Cancer therapy (the Anti-Her2)
3) Removal of T cells from BM grafts (Anti CD3 Ab)
4) Block cytokine activity-anti TNF for Rhumathoid arthiritis
5) Anti-calcitonin gene related peptide for migrane
6) -and more coming every months
main issue is their price and volatility
What are the different diagnostic uses of ABs?
Determine blood groups
Quantitative immunoassays (hormoones, AB, Ag)
Immunogiagnostics (disease, AID, allergy, Malignancy)
What is indirect labelling using Anti-anti-body?
Ab binds the AG-and a secondary Ab (anti-antibody) with a reporter that identifies the first one (or bring drug etc)
how do you produce monoclonal Ab?
Mouse is challenged with Antigen-take spleen cells to produce the Ab to that
Fuse them with B-cell cancers (myeloma)-create hybdridoma that produce the Ab but are immortal like cancer cells
select the right cell-and then have infinite supply
How do you produce Ab using DNA technology?
Isolate the genes encoding the variable region-and then fuse with a bacteriophage coat protein-cloning a random population gives rise to mix of bacteriophages-PHAGE DISPLAY LIBRARY
then just select the right one
How are AB used in quantitative tests?
Using ELISA test-has a capture Ab on plastic-then it binds the AG
Then another Ab binds the AG as well-and its linked with a dye that generates a colour easy to measure-and directly proportional to Ag present
How can ABs be used for rapid testing?
Sample is mixed with Abs-flow (Ab binds Ag)-and in the first strip Ab to Ag again that will bind the AB-AG complex and send signal
AFter-second line has Anti AB-binds those that didnt bind AG
What are immune complexes?
Usually signs as vagues pain and aches-immune complexes-being deposited in various parts of body
Size matters the most-and once membrane bound activate complement very well
causes Inflammation/complement activations Serum sickess Immune complex glomerulonephritis Immuni complex at other sites (skin, joints, lungs)
What are the 3 main things measured in an immunology lab?
Serum IG levels-ELISA, Serum electrophoresis, etc-check if compromised
Specific ABs or AGs-ELISA
Lymphocyte subsets-CD3/4/5 etc
How does serum electrophoresis measure Ab activity?
like normal electrophoresis
Has an albumin band at bottom (very abundant) and then several bands along the way in which different Abs will stop-measureing the size of each bands tells us which one is most abundant
In infected patients-large thick band in gamma bands-not compromised
In some-thin by very dark gamma band-moloclonal
How does flow cytometetry use Ab to identify the cells?
use AB with specific dyes that binds the Ags in the cells-they will bind the cells with their Ag-and then single cells passed by and their dye colour is measured-tells you what cells have one AG, another, or both
