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IMM250H1 Lecture Notes - Lecture 2: Pattern Recognition Receptor, Gram-Positive Bacteria, Headache

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raspberrypig77
23 Apr 2018
School
UTSG
Department
Immunology
Course
IMM250H1
Professor
Dana Philpott

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Document Summary

True pathogen: causes disease in healthy people with normal immune defenses. Opportunistic pathogens: can cause disease when person has lowered immune system. Pathogen: a pathogen has the inherent ability to cross anatomical barriers and breach the innate host defenses that normally limit infection, pathogens possess genes encoding virulence factors. Case study: h. pylori: helical bacterium with polar flagella that was isolated from stomach of individuals with gastritis, this is uncommon because the stomach is very acidic which should prevent bacterium from forming in there. So, warren drank a culture of bacteria obtained from a man with gastritis and that he treated with antibiotics. After a week, warren started feeling sick and he actually had h. pylori. Then he started taking antibiotics and the infection cleared: h pylori is part of the normal microbiota of most people. Infectious diseases are a dominant cause of death: acute respiratory infections, diarrheal infections, hiv/aids, tuberculosis .

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Related Questions

1. Why is the process of gene rearrangement used in creating antibodies and T-cell receptors (TCRs) so important?

A. This is how our systems produce memory of pervious exposures, a key trait in adaptive immune responses.

B. Without it, we would need a single gene for every antibody and TCR required to mount all the possible responses need ed during our lives

C. interactions with antigens stimulate cells to initiate these processes, building the best and strongest response possible to the antigen

D. this is the same DNA altering process that leads to cancer. Understanding it leads to better treatments for cancer

2. Which of the following is NOT an antimicrobial substance?

A. keratin

B. Lysozyme

C. Defensins

D. Lactoferrins

E. Peroxidases

3. Which of the following is NOT an outcome of fever?

A. Direct destruction of microbes

B. increased release of pro-inflammatory cytokines

C. increased production of lymphocytes

D. increased phagocytic killing by leukocytes

E. increased production of interferons

4. Which of the following pattern recognition receptors is/are anchored in the host cell membrane?

A. Only C-type lectin receptors (CLRs)

B. Only RIG-like receptors (RLRs)

C. TLR and CLRs

D. Only toll-like receptors (TLRs)

E. NLRs and RLRs

F. Only NOD-like receptors (NLRs)

5. Fever allows the body to fight microbial invaders by which of the following mechanisms?

A.Fever plays all of these roles in the body

B. Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells

C. Fever increases the inflammatory response, but reduces the production of interferons unless the invader is a dsRNA virus

D. A moderate fever reduces the inflammatory response but stimulates phagocytic activity in neutrophils and eosinophils

E. Fever increases the multiplication of lymphocytes and enhances the release of substances that attract basophils that then engulf the microbial invader

6. According to the clonal selection theory

A. Each B cell is already programmed to produce a specific antibody

B. B cells producing autoantibodies are eliminated in the thymus

C. Self-reactive T cells are killed in the thymus AND B cells producingautoantibodies are eliminated in the thymus

D. Seld-reactive T cells are killed in the thymus

7. Apoptosis

A. is a form of programmed cell death AND is induced in target cells by effector T cytotoxic cells

B. refers to the transformation of B cells into plasma cells

C. is induced in target cells by effector T cytotoxic cell AND results specifically in T cell death

D. results specifically in T cell death AND refers to the transformation of B cells into plama cells

8.

indicate whether you think the statements are true or false, and explain your reasoning. In each of your answers, provide 1-2 specific examples that support your position. (Each of your four answers is worth five points):

A) Memory cells require fewer distinct signals to be activated than naïve cells require.

B) Both B cells and T cells undergo ‘clonal selection’ after they are activated by antigen.

C) A B cell is only able to present antigen to a T cell that includes the epitope to which the

B cell’s receptor bound.

D) T cells can recognize peptide antigens in the context of MHC I and MHC II regardless of

whether they are Thelper or Tcytotoxic cells.

E) B cells and T cells can both still make productive antigen receptors via V(D)J

recombination even if no P-nucleotides are introduced during the process.

F) Allelic exclusion takes place when a naïve T or B cell encounters its specific non-self antigen for the first time and determines whether or not to become activated.

G) B cells have more chances to make a productively rearranged antigen receptor than T cells do.

H) A majority of immature T cells developing in the thymus will survive both positive and negative selection.

I) The reason why T cells are the only type of white blood cell that requires maturation in a specialized organ outside the bone marrow is because they are the only ones that must have antigen processed and presented to them before they can be activated.

True / False Questions

01. _____ Antibody is composed of 2identical long heavy chains and 2 identical shorter lightchains.

02. _____ Variable (V) and constant(C) regions are part of both heavy and light chains.

03. _____ Variable regions for heavyand light chains from the same antibody molecule are alwaysidentical.

04. _____ Variable region of lightchains are encoded by the DNA sequences that contain rearranged V,D, and J segments.

05. _____ Fc part of the antibody isnot important, F(ab’)2 fragment has the same binding andeffector capacity.

06. _____ Fab fragments are generatedby alternative splicing.

07. _____ J chain is used as asurrogate light chain during pre-B cell receptor testing forsuccessful V(D)J rearrangement.

08. _____ Binding of the antigen byantibody is stabilized by disulfide bonds.

09. _____ RAG1/2 are always expressedin B cells at high level, because B cells need RAG1/2 to constantlyrearrange their V regions.

10. _____ “N” (non template)nucleotides are added by TdT.

11. _____ The 12/23 rule is appliedduring class switching.

12. _____ For B cells, V(D)Jrecombination occurs only in the bone marrow.

13. _____ The process of somatichypermutation helps to improve specificity of the antibody.

14. _____ In late pro-B cells, Vsegment is rearranged with DJ segments.

15. _____ Failure to eliminateself-reactive B cells may lead to serious autoimmune diseases.

16. _____ Mature, naïve B cellsexpress IgD and any of the other classes of antibody (IgM, IgG,IgA, or IgE) on their surfaces.

17. _____ B1 cells are present in theperitoneal cavity, pleural spaces and brain.

18. _____ AID (activation inducedcytidine deaminase) is expressed only in B cells and it canintroduce breaks in double stranded DNA.

19. _____ Different classes (isotypes)of antibodies have different effector functions, which aretriggered by special receptors expressed by a variety of cells.

20. _____ Plasma cells are terminallydifferentiated cells that produce large quantities ofantibodies.

21. _____ Repeated exposure to thesame antigen eventually leads to immunological exhaustion and lackof immunity, because there is no room for new plasma cells in thebone marrow.

22. _____ Germinal centers arespecialized sites within the bone marrow where Ig genes ofactivated B cells undergo affinity maturation.

23. _____ B cells can present antigensto T helper cells.

24. _____ Co-stimulatory molecules arerequired for efficient generation of memory B cells.

25. _____ Lymphocytes migrate to thelymphoid tissues in response to chemokines.

26. _____ Class switching duringgerminal center reaction is a random process.

27. _____ T cell independent responsescan generate strong and long lasting B cell memory.

28. _____ Fc receptors that arepresent on many different cell types are crucial for removal of thepathogens.

29. _____ The ideal vaccine should bedesigned to mimic the natural course of infection without causingsymptoms of the disease.

30. _____ The protective immunity canbe generated against any pathogen because there is virtuallyunlimited number of possible V regions, thus any antigen can berecognize by an antibody.