This document provides an introduction to non-IgG antibodies, including IgA, IgD, IgE, and IgM. It discusses the structure, functions, and properties of each antibody class. IgA plays a role in mucosal immunity. IgD is found on B cell surfaces. IgE mediates allergic reactions. IgM is involved in primary immune responses. The document also offers related antibody engineering services and products from Creative Biolabs.

1. A Brief Introduction to
Non-IgG Antibody
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2. Contents
01 What is Non-IgG Antibody
03
02 Introduction to IgA
04
Introduction to IgD Introduction to IgE
05 Introduction to IgM 06 Related Services & Products

3. What is Non-IgG Antibody
PART.01

4. Immunoglobulin (Ig), also known as antibody (Ab),
functions as part of the immune system to identify
and neutralize foreign objects such as pathogenic
bacteria and viruses. The antigen-binding sites at
both tips of the antibody come in an equally wide
variety, and the remainder of the antibody is
relatively constant. It only occurs in a few variants,
which define the antibody's class or isotype: IgA,
IgD, IgE, IgG, or IgM.
Introduction to Immunoglobulins

5. IgA is the predominant antibody in mucous
secretions such as saliva, tears, milk and intestinal
juice. It is involved in preventing pathogens from
entering through mucosal barriers. It can be found
in a monomeric or dimeric form.
IgA
IgD
Found predominantly on the surface of B-cells, it
has a similar structure to IgG, but with an extended
hinge region that is very susceptible to proteolytic
digestion.
IgE
IgE has two additional constant domains in place
of the hinge region. It plays an important role in
defense against parasites, and is also a key
mediator of Type I hypersensitivity reactions or
allergies.
IgM
IgM is the predominant antibody in the primary
immune response, which can present as a
pentamer or hexamer in solution and as a
monomer on the surface of B-cells.
Introduction to Non-IgG Antibody

6. Introduction to IgA
PART.02

7. Immunoglobulin A (IgA) is an antibody that plays a crucial role in the immune function of mucous
membranes. IgA mainly exists in the form of dimers in secretions, and sIgA is formed by the
polymerization of two or more IgA monomers. A typical sIgA is mainly composed of two IgA
monomers, a J chain, and a secretory component.
Introduction to IgA
 Molecular weight: 320,000 (secretory)
 H-chain type (MW): alpha (55,000)
 Serum concentration: 1 to 4 mg/mL
 Percent of total immunoglobulin: 10-20%
 Glycosylation (by weight): 10%
 Distribution: intravascular and secretions
 Function: protect mucus membranes

8. Classification of IgA
IgA1：IgA1 is dominant in serum, accounting for 85% of the
total IgA concentration in serum. IgA1 shows broad
resistance to several proteases, but some can affect or splice
on the hinge region. IgA1 shows a good immune response to
protein antigens, but a low degree of immune response to
polysaccharides and lipopolysaccharides.
IgA2：IgA2 accounts for only 15% of the total IgA in serum,
and it mainly exists in the mucous membranes of the airways,
eyes, and gastrointestinal tract to combat polysaccharides
and lipopolysaccharide antigens. It also shows excellent
resistance to proteolysis and many bacterial proteases, and
plays an important role in fighting bacterial infections.
3D structure of secretory IgA1 and
IgA2
Pictures from Wikipedia

9. Therapeutic Potential of IgA
Pictures from KEGG

10. Introduction to IgD
PART.03

11. Immunoglobulin D (IgD) is an antibody synthesized late in the ontogeny. It is composed of two light (L)
chains and two heavy (H) chains. The heavy chain and the light chain are connected by disulfide bonds,
forming a conformation similar to the shape of the letter Y.
Introduction to IgD
 Molecular weight: 180,000
 H-chain type (MW): delta (70,000)
 Serum concentration: 3 to 40 μg/mL
 Percent of total immunoglobulin: 0.25%
 Glycosylation (by weight): 13%
 Distribution: lymphocyte surface

12. Secreted IgD exists and plays an elusive function in blood,
mucosal secretions, and on the surface of innate immune
effector cells. IgD apparently is also able to bind to basophils
and mast cells and activate these cells to produce
antimicrobial factors that are functional in respiratory immune
defence in humans.
Functions of Secreted IgD
IgD secretion enhances mucosal immune surveillance. [1]
[1] Gutzeitet C; et al. The enigmatic function of IgD: some answers at last[J]. Eur. J. Immunol., 2018, 48(7): 1101-1113.

13. Introduction to IgE
PART.04

14. Immunoglobulin E (IgE) is an antibody that has been found only in mammals. IgE primarily defends against
parasitic invasion and is responsible for allergic reactions. Monomers of IgE consist of two heavy chains (ε chains)
and two light chains, with the ε chain containing 4 Ig-like constant domains (Cε1-Cε4).
Introduction to IgE
Picture from WikiVet
 Molecular weight: 200,000
 H-chain type (MW): epsilon (73,000)
 Serum concentration: 10 to 400 ng/mL
 Percent of total immunoglobulin: 0.002%
 Glycosylation (by weight): 12%
 Distribution: basophils and mast cells in
saliva and nasal secretions
 Function: protect against parasites

15. Function of IgE
[1] Henrike C.H. B, Thomas E, et al. IgE – the main player of food allergy[J]. Drug Discovery Today: Disease Models, 2017, 17-18: 37-44.
The role of IgE in the context of IgE-mediated allergy.[1]

16. Introduction to IgM
PART.05

17. Immunoglobulin M (IgM) is the largest antibody that is produced by the immune system of vertebrates. It can
attack against a wide variety of antigens and take part in many steps of the primary and adaptive humoral
immune response. The predominant form of IgM in human serum is pentamer which is composed of five
monomers connected with the joining-(J) chain.
Introduction to IgM
Pictures from Wikipedia
 Molecular weight: 900,000
 H-chain type (MW): mu (65,000)
 Serum concentration: 0.5 to 2 mg/mL
 Percent of total immunoglobulin: 10%
 Glycosylation (by weight): 12%
 Distribution: mostly intravascular
 Function: primary response

18. Functions of IgM
[1] Srini V. K, Gregg J. S, et al. Natural IgM in Immune Equilibrium and Harnessing Their Therapeutic Potential[J]. J Immunol, 2012, 188(3): 939-945.

19. Comparison of Five Classes of Immunoglobulins
Pictures from Wikipedia

20. Related Services & Products
PART.06

21. Related Services at Creative Biolabs

22. Related Products at Creative Biolabs

23. THANKS
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