1. CLASSES OF
IMMUNOGLOBULIN
• PHYSICAL PROPERTIES
• STRUCTURES
• FEATURES AND FUNCTIONS

2. 5 CLASSES OF
IMMUNOGLOBULIN
1. IgG
2. IgA
3. IgM
4. IgD
5. IgE

3. PHYSICAL PROPERTIES
PHYSICAL
PROPERTY
IgG IgA IgM IgD IgE
No. of 4 chain
units
150,000 160,000
(each
monomer)
900,000 180,000 190,000
Heavy chains γ α μ δ ε
Light chains κ or λ κ or λ κ or λ κ or λ κ or λ
Other peptide - J ± S J - -
Subclasses γ1, γ2, γ3,
γ4
α1, α2 - - -
Serum
concentration
12.5 mg/ml
(80%)
2.1 mg/ml
(13%)
1.25 mg/ml
(8%)
40 μg/ml
(<1%)
0.4 μg/ml
(0.003%)
IMMUNOGLOBULINS

4. STRUCTURES

5. FUNCTIONS & FEATURES
•IgG
• Most abundant Ig of internal body fluids
particularly extravascular where it combats
microorganisms and their toxins
• Produced particularly during secondary
immune responses
• Major Ab in the blood, but it is able to enter
tissue spaces and coat antigens, speeding
antigen uptake

6. FUNCTIONS AND FEATURES
•IgA
• Major Ig of external secretions
• Present in tears, saliva, nasal secretions,
bronchial and digestive tract mucus and
mammary gland secretions (secretory IgA)
• Concentrates in body fluids to guard the
entrances of the body

7. FUNCTIONS AND FEATURES
•IgM
• Largest Ab
• Tends to remain in the blood, where it can
lead to efficient killing of bacteria
• Key Ig of the primary responses; produced
early in immune responses; effective first line
defense vs. bacteremia
• Very effective agglutinator

8. FUNCTIONS AND FEATURES
• IgD
• Present in minute concentrations in blood and other body fluids
• Remains membrane-bound
• Detected on the surface of many early B cells in conjunction with
IgM
• Antigen receptor on early B cells
• Somehow regulates the cell’s activation

9. FUNCTIONS AND FEATURES
•IgE
• Found in trace amounts in the blood, but it
still triggers allergies
• Protects against parasites by releasing
mediators that attract eosinophil
• Functions with mast cells as a “gatekeeper”
regulating the exit of cells and plasma into
extravascular sites

10. End.
Prepared by: DELA ROSA, Kathleen M.