Immunology 1

Question 1

what are the main cells of the adaptive immune response, and how do they interact with the environment?

Answer 1

B and T lymphocytes - sense and respond to their environment via antigen specific cell surface receptors

Question 2

two main types of immunity and how they differ

Answer 2

innate: no learning, no specificity or random diversity in cells. adaptive: can have a memory, infomration rich responses

Question 3

non specific host defences: 4 main categories and examples

Answer 3

anatomic: skin and mucous membranes. physiologic: temperature, pH, chemical mediators. phacocytic/endocytic barriers. inflammatory barriers.

Question 4

T cell receptors: how they bind to antigens

Answer 4

can’t bind free floating antigens (like B cells can), but only when they are chewed up into short peptides and presented on Class I (CD8) or Class II (CD4) MHC molecules.

Question 5

CD4 vs 8? MHC Class?

Answer 5

4 = helper, MHC Class II. 8 = cytotoxic, MHC Class I

Question 6

two main branches of the adaptive immune system?

Answer 6

humoral response (B cells making
antibody), and the cellular response (T helper cells and T cytotoxic cells).

Question 7

extracellular vs. intracellular microbes: which type of immune cells + MHC Class?

Answer 7

humoural immunity for extracellular pathogens. CD4 helper cells (Class II) for phagocytosed microbes. intracellular (Viruses) via CD8, Class I

Question 8

virus infected cell: what happens + what cells are involved

Answer 8

viral proteins shown on outside of infected cell via Class I - cytotoxic CD8 T cell

Question 9

CD4 regulatory/helper cells can see

Answer 9

presented on antigen presenting cells, which are the only ones that have Class II MHC. include macrophages + Bcells + dendritic cells

Question 10

which antigens go on Class I vs II MHC?

Answer 10

endogenous antigens (viral peptides) on class I. exogenous (bacteria) on Class II.

Question 11

what is critical for initiating adaptive immune response

Answer 11

movement of microbes/antigen into the draining lymph node - since lots of lymphocytes are in the lymph nodes and “sample” the antigens that are delivered there

Question 12

what happens during maturation of B lymphocytes? when does it happen?

Answer 12

occurs in the absence of antigen: produces antigenically B cells so each expresses an antibody with single antigenic specificity

Question 13

what happens during clonal selection of B lymphocytes

Answer 13

occurs when a given antigen binds to a B cell whose membrane bound antibody molecules are specific for epitopes of that antigen. then you get clonal expansion = get a bunch of memory and effector (plasma) B cells

Question 14

what is the cellular basis of immunological memory?

Answer 14

clonal expansion of B or T cells with particular specificities and the production of long lived memory cells with this same specificity

Question 15

antibodies: all consist of what structure containing what? two regions?

Answer 15

four chain structure with 2 heavy chains + 2 light chains. N terminus = variable region. C terminus = constant region

Question 16

antibodies: what pairs with what and how is it stabilized?

Answer 16

each light chain pairs with one heavy chain: attached via interchain disulfide bonds. the two heavy chains also pair with each other, via interchain disulfide bonds

Question 17

antibodies: each heavy/light chain made up of ___ of? stabilized by?

Answer 17

domains of ~110 aas with significant homology to one another, stabilized via intrachain disulfide bonds

Question 18

light chain: what domains? what domains in heavy chain?

Answer 18

each light chain has 2 domains: VL (variable light) and CL (constant light). heavy chain has one variable domain, VH, and several constant domains numbered sequentially CH1, CH2, etc.

Question 19

within the light and heavy chain variable regions, there are ___ regions of? forms what?

Answer 19

three regions of extreme variability = hypervariable regions. when folded, these 3 regions are brought together = antigen binding region (so total of 6 hypervariable loops. two of these sites per antibody