Lecture 39: The Immune System

Identify invaders, eliminate or neutralize threat

these are the two challenges of fighting off bad things in our body

innate immune system

is immune system is in all multicellular plants and animals, 1st line of defense, always on, in the epithelial lining around host cells to destroy pathogens

generic

The innate system recognizes _____ elements common to many pathogens

evasion

In the innate immune system , the limited set of elements recognized makes _____ possible

specific

The adaptove immune system recognizes ____ features in individual pathogens

Toll-like receptors

these are expressed in macrophages and dendritic cells, expressed mostly on plasma membrane, but some on internal membranes, bind PAMPs to fight pathogens

macrophages and dendritic cells

Toll like receptors are expressed in ____ and ____ cells

mostly on plasma membranes, but some on internal membranes

where are Toll Like receptors expressed (location)

internal

receptors on the internal compartments of toll-like receptors identify _____ pathogens

Leucine

Leucine residues are positioned towards the inside of the C where they congregate together

The toll-like receptor contains many ____-rich repeats that curve into a C-shape

PAMPS

Toll-like receptors bind _____

PAMPS

these are pathogen associated moelcular patterns, found on invading organisms and are a critical component

invading organisms

PAMPS are found primarily on ______ ______ and are usually a critical component of that organism

Dimerization, fever, endocytosis

When toll like receptor binds the PAMP, it causes _______________, which initiaes signal transduction to have __________, inflammation, and ____________ of the pathogen

adaptive immune system

this immune system is focused on fighting specific pathognes, has humoral (antibodies) and cellular (killer T cells)

humoral immune response (antibodies)

cellular immune response (killer T cells)

what are the two systems in the adaptive immune system

antibodies

these are called immunoglobulins, they bind antigens, and we make a lot of them in order to specifically target antigens

antigens

antibodies bind ______

antigen

this is the foreign macromolecule that antibodies bind to

epitope

this is the site of the antigen where the antibody binds to

Fab, Fc

these are the 2 subunits of an antibody

Fab

ab= antigen binding

these fragments bind the antigen on the antibody

Fc

c= constant

these fragments mediate the effector response for the immune system

2 light chains, 2 heavy chains

these are the chain components of an antibody

disulfide bonds

these are the bonds that bond the Fab and Fc units together

immunoglobulin fold

this is a beta sandwich held together bya disulfide bond

IgG

4 per heavy chain

2 per light chain

this antibody has 12 immunoglobulin domains

Fab

The antigens bind on which subunits?

IgG

what is the most common antibody in serum

IgA (dimer)

this immunoglobulin is found in external secretions such as tears or saliva

IgM (pentamer)

this immunoglobulin is the first responder

IgD (monomer)

This immunoglobulins function is not clear, but seems to be key in activating basophils

IgE (monomer)

this immunoglobulin acts in allergic responses

flexible

antibodies are ____________(flexible/stiff)

crosslinking, two spots

antibodies being flexible are good because it allows from _________-________________ and for the natibody to bind an antigen in ________ ____________

Avidity

this is how two binding sites helps on antibodies, by allowing the bond to stay present for a lot longer

on the ends of the Fab subunits

Where are the variable regions on an antibodY?

hypervariable loops

these are found on the loops on the end of each beta sandwich, allows different antigens to bind to different antibodies (specificity)

pre-determined, doesn’t, amplified

Specificity of antibodies is ______-______________, as the body __________(does/doesn't) know beforehand what it is going to bind to, and when an antigen enters, an ab is selected, then ____________

some or all

antigens may interact with ____ or ____ groups

recombination

We get millions of antibodies from so few genes via __________________ in antibody producing cells

variable, antibodies

By recombining different _________________ regions, we can get various different combinations of those regions to get almost infinite amount of ______________

V,D,and J

generation of the light chain combines 1_ , 1_, and 1_ region

D

the generation of the heavy chain is similar to the generation of the light chain, except it also includes a __ region

C

Different ____ regions correspond to different classes of antibodies

B cells

these are antibody producing cells, each one undergoes a different recombination, and each B cell has a set variable region

V(D)J recombination

this type of recombination is what happpens in B cells that allows specific B cells to use variable regions to get specific antibodies that bind to specific antigens

IgM

all antibodies are originally _____(IgM)

one, cell surface

wach immature B cells produces ____ kind of antibody, nad thousands of copies of this antibody are attached to the _____ _____

phosphorylation, activated, proliferate

when B cells are activated, the IgM is on the outside of the cell, and the antigen binds to the antibody leading to _______________ inside of the B cell, which allows teh B cell to be ______________, and it starts to ______________

class switching

this is what happens after the proliferation of a certain B cell, which allows the IgM antibody to switch to IgG, IgA etc

does not

class switching (does/does not) change antigen specificity

variable, constant

in class switching, the ____ region stays the same, but the _____ region changes

recombination

OVERVIEW:

precursor cells undergo _______ to produce immature B cells

selection and activation

immature B cells under go ____ and ______ to become activated B cells

class switching

after B cells are activated they can undergo _____ _____