adaptive immunity (16)

what does PAMP stand for

pathogen associated molecular patterns

PAMPs are not present where

molecular signatures not present in normal mammals

what are PAMPs recognized by

PRRs

PRR stands for

pattern recognition receptors

types of bacterial PRRs

toll-like receptors

NOD-receptors

toll- like receptors bind what

many ligands

NOD-like receptors bind what

intracellular bacteria

types of viral PRRs

RIG-I/MDA5

cGAS/STING

PKR

RIG-I/MDA5 viral PRRs bind what

dsRNA

cGAS/STING viral PRRs bind what

cytoplasmic DNA

PKR viral PRRs bind what

dsRNA

function of PAMPs

stimulate an innate immune response and cytokine production

viral PAMPs are related to what

genome structure and replication cycle

viral PAMPs stimulate what

interferon (IFN) production

intracellular receptors for viral dsRNA

PKR and RIG-I

What does PKR do

inhibit translation

what does RIG-I do

activate cytokine and interferon production

intracellular receptor for viral dsDNA

cGAS/STING

what do cGAS/STING do

activate cytokine and interferon production

what is another part of the virion that can be recognized by innate immune sensors

capsid proteins

what does ISG stand for

interferon stimulated genes

what stimulates ISG

interferon binding

what does ISG do

make proteins that limit virus infection

how many ISGs are there

hundreds

tetherin

a transmembrane protein that is also a GPI-bound protein

what does tetherin do

inserts into budding virions and the plasma membrane to prevent their dissociation after egress

what can happen to tetherin-bound virions

can be endocytosed again independent of VAP

can lead to degradation of the virion

what triggers fever

pyrogenic (pro-inflammatory) cytokines

examples of fever-causing cytokines

IL-1B, TNF, IL-6

How do pyrogenic cytokines cause fever

stimulate the hypothalamus to produce prostaglandin

what does prostaglandin do in relation to fever

increases the body temperature set point

can interfere with the replication of bacteria

what temperature can lead to convulsions

40.6C

2 branches of adaptive immunity

humoral (antibody mediated) and cell mediated

what type of cells are in humoral immunity

B cells

target of humoral immunity

extracellular target

how does humoral immunity work

antibodies are secreted into the plasma and bind to targets to direct effector responses to clear infection

what type of cells in cell mediated immunity

t cells

target of cell mediated immunity

intracellular antigens

what does cell mediated immunity do

eliminates infected or damages cells

what percent of blood cells are lymphocytes

20-40%

3 main types of lymphocytes

B cells

T cells

NK cells

2 types of T cells

CD4+ T helper cells

CD8+ cytotoxic cells

what mediates the adaptive immune response

B cells and T cells

adaptive immunity has what kind of response

an anamnestic response (memory)

describe the memory response

they are more robust responses to the same antigen on subsequent exposures

clonal selection theory

-how adaptive immune system selects and activates the right lymphocytes (B and T cells) to respond to a specific antigen

-each B and T cell has one unique receptor- antigen selects cell with matching receptor

diversity in clonal selection theory

is encoded in the germline and expressed by recombination

recombination in clonal selection

genetic shuffling of B and T cells before they meet the antigen

creates diverse antigen receptos

what happens during deletion/education in clonal selection

auto-reactive B and T cells are removed in the bone marrow or thymus

where does lymphocyte recombination occur

primary lymphoid organs (bone marrow and thymus)

what is the purpose of receptor diversity

allow the immune system to recognize many different antigens

what percent of B and T cells are deleted during education

90%

what stimulates clonal proliferation

binding of a specific antigen

clonal proliferation

makes a population of B or T cells expressing the same receptor

where does clonal proliferation occur

secondary lymphoid tissue

what is an B cell receptor

a membrane bound immunoglobulin

it is an antibody

structure of B cell receptor

4 polypeptides in immunoglobulin assembled with disulphide bonds

2 heavy and 2 light chains

2 forms of B cell receptor

membrane-bound form

secreted form (antibody)

2 regions on an antibody

constant fragment (Fc)

variable fragment (Fv or Fab)

antibody signaling requires what

cross linking BCR (B cell receptor)

what part of the antibody determines antigen specificity

CDR

CDR

complementarity determining region

epitope

specific pattern on the antigen that the antibody CDR recognizes

immunogen

antigens that activate an immune response

why do plasma cells have extensive rough ER

they produce excessive amounts of antibodies (proteins)

what region of the antibody binds the antigen

the Fab region

what (on the antibody) physically touches the antigen

the CDR (on the Fab region)

what part of the antigen is recognized by the CDR

epitope

what generates diversity of immunoglobulins

recombination of V, D, and J segments

what is required for the recombination of V, D, and J segments

RAG1/2 (lymph