QUESTIONS

1. The following confusing statement describes how stimulation of Helper T cells is amplified.   A member of the monocyte/macrophage line processes & presents antigen.  Processing stimulates the production & secretion of ______(a)______.  Helper T cells are triggered by the presented Antigen & this substance (the blank above) to synthesize ______(b)______  and receptors for ______(b)______.  Stimulation of these receptors leads to helper T cell proliferation.
    
2. What primary immunodeficiency is said to have a high incidence in the Shar pei?
    
3. In the cyclic neutropenia that is classically associated with Gray collies:
   
   a) Are only PMNs involved?
   b) What is the mode of inheretance?
   c) How often does the neutropenia occur, how long does it last?
   d) How long do such patients usually live?
    
4. What is the usual name for the syndrome associated with smoke blue persian cats involving:
   
   a) eosinophilic granules in PMNs, basophils & eosinophils, b) enlarged melaninin granules in the skin, c) increased bleeding tendency and d)  abnormally light coat color & iris color?
    
5. Immune Mediated Polyarthritis is an example of which of the Gell & Coombs class?
    
6. There is an X-linked combined immunodeficiency which kills puppies off fairly quickly.  What breed tends toward this condition?
    
7. Why are immunologists all interested in Concanavalin A, phytohemagglutinin & pokeweed mitogen?
   
8. There is an in vivo test of CMI involving 2-4 dinitrochlorobenzene.  Describe  it.
    
9. What is a Hassall’s corpuscle?
    
10. Most peripheral lymph tissue have afferent & efferent lymphatics.  Does the thymus?
     
11. Do reptiles, amphibians or birds have lymph nodes?
     
12. How many tonsils does your basic mammal have?
     
13. In what section of the small intestine are you most likely to find Peyer’s patches?
     
14. What are M cells?
     
15. How does lysozyme work?
     
16. What is the difference between an Epitope & a Hapten?
     
17. What the hell does IgD do?
     
18. What is the Properdin Pathway?
     
19. What is the difference between an Isograft & an allograft?
     
20. Explain the prozone phenomenon & why you might get a falsely negative Coombs test because of it.
    
    
    
    
     

ANSWERS

1. A member of the monocyte/macrophage line processes & presents antigen.  Processing stimulates the production & secretion of  Interleukin 1.  Helper T cells are triggered by the presented Antigen & this substance (IL-1) to synthesize Interleukin 2  and receptors for Interleukin 2.  Stimulation of these receptors leads to helper T cell proliferation.
   
   
   
   
    
2. IgA deficiency( which can come as complete, partial or transient) has a relatively high incidence in the Shar pei.  IgA is measured by RIA and anything < 10 mg/dl is abnormal.  In the Shar pei, it is believed that there is a problem in the maturation & differentiateion of the IgA producing B cells.  The German Shepherd also is predisposed to IgA deficiency.
   
   
   
   
    
3. In cyclic neutropenia, all cellular blood elements are involved including platelets.  There is far more than neutropenia happening.  The mode of inheretance is autosomal recessive.  The neutropenia occurs every 8-12 days and lasts 2-4 days.  Patients generally do not live longer than 3 years.
   
   
   
   
    
4. We have described Chediak-Higashi syndrome.
   
   
   
   
    
5. Immune Mediated Polyarthritis is an immune complex deposition disease which fits in to class III.  “Hepatitis blue eye” from the hepatitis vaccine is another class III reaction.  Recall that the Afghan hound is predisposed.
   
   
   
   
    
6. The Basset Hound has a problem with X-linked CID.
   
   
   
   
    
7. These three substances are used in lymphocyte stimulation tests.  They are all plant lectins which bind to lymphocyte receptors & initiate blastogenesis.  ConA & Phyto. stimulate T cells while pokeweed does both B & T cells.
   
   
   
   
    
8. This 2,4 stuff sensitizes for contact allergy when it is applied to one’s skin.  If Cell mediated immunity is normal, a delayed hypersensitivity lesion appears in a few days.  If the lesion doesn’t appear, there’s a CMI deficiency.
   
   
   
   
    
9. The thymus is a multilobulated organ, having a cortex & a medulla.  There are more lymphocytes in the cortex.  HassallÕs corpuscles -also called “thymic corpuscles”, live in the medulla.  They consist of tightly wound nests of epithelial cells & they commonly undergo keratinization & mineraliation.
   
   
   
   
    
10. No.  The thymus has only efferent lymphatics.  As T cells mature, they migrate from the cortex to the medulla & then out to the peripheral T cell pool (only about 10% make it out because anything that might ever respond against self is removed).
    
    
    
    
     
11. These guys have no lymph nodes.  Guess they miss out.
    
    
    
    
     
12. Your basic mammal is packing 6 tonsils:  2 palatine, 2 lingual, & 2 pharyngeal.
    
    
    
    
     
13. You would most likely find peyer’s patches on the antimesenteric border of the ileum.
    
    
    
    
     
14. The peyer’s patch forms a dome-like bulge into the small intestine lumen.  The epithelium here is called lymphoepithelium and it is infiltrated with lymphocytes & M cells.   M cells are sort of flat with very folded surfaces. They are actively pinocytic and are sampling antigens in the lumen & presenting them to lymphcytes in the peyer’s patch.
    
    
    
    
     
15. Lysozyme is a muramidase found in tears, saliva, plasma & PMN granules.  It cleaves the murein ring which is a component of the Gram + cell wall.
    
    
    
    
     
16. An epitope is a naturally present incomplete antigen.  A hapten gets added later.  An epitope is generally only 4-6 amino acids in size, far too small to stimulate the immune system on lits own but it makes up part of the “determination group,” the portion of the antigen that will be recognized by a lymphocyte.
    
    
    
    
     
17. We don’t know that much about IgD.   It acts as a receptor on the B cell and helps the B cell recognize its antigen.
    
    
    
    
     
18. The properdin pathway is an alternate complement pathway involving CHO in the yeast cell wall, lipopolysaccharide in the Gram - cell wall, or aggregate antibodies.  (Should I review all the complement pathways?  I will if someone wants.  It seems like serious minutia.  It seems more important to get what complement does.)
    
    
    
    
     
19. An isograft comes from a genetically identical individual (it is also called a “syngraft”.)  An allograft comes from a  member of the same species.
    
    
    
    
     
20. Recall in the Coombs test you are looking for hemagglutination and you are testing different concentrations of patient serum.  After the serum is too dilute, you will not see agglutination but up to that point, you will.  Well there’s a point also where your red cells are so totally covered with antibodies that there is no room for any cross linking (the antibodies are packed too close together.)  Even though you have tons of anti red cell antibodies present you will not get hemagglutination until you have diluted the serum more.  When there’s room for cross-linking, you’ll see hemagglutination then you’ll get too diluted & won’t see hemagglutination.  Your results will look like this as dilution proceeds:  0 0 0 0  + + + + 0 0 0 .  The first group of zeros represents the “prozoneÓ”.