Immunology- B & T cells

IgM

Produced first exposure to antigen by SL (short lived)

Circulates in blood/extracellular fluid

During next infection it will be made in lower

Binds to surface of B-cells (immature)

IgG (G1=proteins, G2=polysaccharides, G3=proteins, G4=food allergens)

Produced by memory cells (that will become SL plasma cell)

Produced by LLPC(long term antibody)

For future exposures

In circulation

CAN CROSS THE PLACENTA

Lasts 6months in baby

Low during 1st infection

IgA

Produced by SLPC

Secretory= pharangeal mucosa membranes, Breast milk

1% of antibody in infants (when mom is infected she passes this to baby)

Travels through blood to mucosas

IgE

Binds to basophils/ mast cells to increase specificity for future infections

Can bind to parasites (eosinophils recognition of pathogen)

Involved in allergies

IgD

Is not secreted, is on B cell surface

For recognition and activation of cell

Allows Bcell to do antigen presentation (antigen binds on it and then is digested to present on MCH II)

Higher on mature naive Bcells

Types of antigen

Proteins, lipids, sugars, nucleic acid

Proteins antigens defense

B cells— antigen presentation through antigen presenting cells (MCHII) to Thelper cells

Produce IgM and IgG or others antibodies

Memory by Bcells

Non-protein antigens (lipids & sugars) defense

No antigen presentation

The antigen binds to B cell receptor (IgD, maybe IgM) —- cross linking of receptors

Directly activates Bcell and starts differentiation into SLPC

Plasma cells will produce only IgM

NO memory cell formed, when infected again same pathway will happen

First Infection= antigen presentation

Antigen presentation to Th cells

Th cells find & activate B cells

B cell found and activated—-

Divide into memory B cells

SLPC & LLPC

SLPC= produce …

LLPC= produce …

SLPC= produce IgM, IgA (if mucosal), one cell for every Ig

LLPC= produce IgG

After pathogen is killed, LLPC…

LLPC make IgG

Second infection:

IgG (from LLPC) in blood attack pathogen, basophils enchanted with IgE attack pathogen

Bcell will be activated IgG (by SLPC)

Food sensitivity

Food sensitivity/intolerance= IgG/IgA response

Delayed response

Ex. Gluten

Food allergies

IgE

Immediate response

Ex: peanuts, shellfish, eggs

Basophils with IgE in surface

Antibody class switching

After B-cell activation (during division)

Induced by cytokines by Th cell

Monoclonal antibodies

Can be injected into a person

Ex. Gamma globulin therapy

Gamma globulin therapy

Treatment that involves the injection of antibodies to a specific antigen (typically IgG) 3 to 6 months

Ex. Rh factor (blood), Respiratory syncytial virus, measles

Rh factor problem in pregnancy

When mom (-) and dad (+) there’s a chance that baby has a different Rh factor than mom and during birth any blood contact between mom & baby will activate mom immune response, making antibodies for it (Bcells) could present problems in a future pregnancy

When Rh factor is administered to moms

Last trimester and after birth, when contact happens the antibodies will act on the protein before moms complement cascade is activated and antigen presentation happens

Rh factor

A protein on red blood cells, activates antigen presentation

Blood types

A, B, AB, O

Involves antigens in RBC but are carbs and don’t create memory that’s why you can receive blood from others

The body will produce antibodies for the opposite antigen

Blood types- antibodies

A- ANTIBODIES for B

B- antibodies for A

AB- no antibodies

O- antibodies for A & B

Tc (CD3, CD8)

Divide into Effector cell= specific recognition of antigens on the surface of infected cells (has T-cell receptor), kills infected/ foreign/ cancerous cells, releasing perforin & granzymes

Memory T cell= requires re-stimulation to divide

5years (half life)

Th0 (CD3, CD4)

T helper resting cells (naive)

Control/activate immune response

Receive antigen by presentation from CDC, macrophages, basophils or B-cells

Involves MHC II, and CD8 (APC) and TCR & CD28 (Th)

Once activated differentiates

Th1

Intracellular infections (virus)

Activates Tcytotoxic, NK

Th2

Extracellular parasites (fungi, protozoa, worms)

Activates eosinophils, B cells

Th17

Mucosal infections

Th22

Skin infections

Th22

Skin infections

T-cell cancer therapy (CAR-T cell chimeric antigen receptor)

-obtain blood from cancer patient identify antigen

-Tc cells engineered to have a T-cell receptor that can identify cancer antigen

-T cells are reintroduced in patient where the modified Tcells can attack the cancer