Immunoglobulin M (IgM), is one of the several forms of antibodies which is found mainly in the blood and lymph fluid, is the first antibody to be made by the body to fight new infections. . IgM is a Pentameric molecule comprising 5 Y-shaped units together with a polypeptide chain with ten antigen biding sites.
Immunoglobulin G( IgG) is a type of antibody representing more than 70% of serum antibodies in humans. It is the most common type of antibody found in blood circulation and it protects the body against bacterial and viral infections. IgG is a monomeric molecule comprising a Y-shaped unit with just two antigen binding sites.
In this article, get to understand more details about the Immunoglobulin M (IgM) and Immunoglobulin G (IgG), their structure, types, molecular weight and other related details.
The difference
Definition
Immunoglobulin G or IgG is the antibody that is found most abundantly in the human body. It is found in all body fluids and it protects the human body against bacterial and viral attack. Immunoglobulin M or IgM on the other hand, is found mainly in the lymph fluid and in the blood. It is the first antibody that is produced in case of an exposure to a particular bacteria or virus.
Structure
IgM is a Pentameric molecule comprising 5 Y-shaped units together with a polypeptide chain with ten antigen biding sites. On the contray, IgG is a monomeric molecule comprising a Y-shaped unit with just two antigen binding sites.
Presence
IgM is produce whenever the human body is exposed to bacteria virus, bacteria or a toxin. IgG on the contrary, is present in the body by default for long-term response of the body to a disease.
Types
There is only one type of IgM whereas; there are four different types of IgG that are; IgG 1, IgG 2, IgG 3 and IgG 4.
Size and Abundance
IgM is the largest antibody which is abundantly found in lymph and blood, whereas IgG is the smallest antibody that is found in all body fluids.
Percentage of presence
IgM account just 10 percent of the complete quantity of the serum whereas, IgG occupies 75 percent of the complete quantity of the serum.
Production
IgM is a temporary antibody that disappears within two or three weeks. One the hand, once IgG is produced in the body it lasts forever, providing lasting immunity to the person.
Molecular weight
IgM has a molecular weight of 900000MW 0r 900kDa while IgG has a molecular weight of 150000MW or 150 kDa.
Placenta Crossing
Because of the larger size, IgM is not able to cross the placenta, even though it’s the first antibody produced in the human embryo while IgG is smaller in size and may cross the placenta and supplies mother’s resistance to creating the embryo.
Presence in the Colostrum
IgM is absent in the colostrums whereas IgG is present in the colostrums.
Effect of High levels
High levels of IgM in the body can contribute to parasitic infections, kidney impairment, rheumatoid arthritis, hepatitis, monocluosis etc. on the contrary, high levels of IgG protects the body against long term diseases like HIV, multiple sclerosis and so on.
Antigen Binding Sites
IgM has 10 binding sites for antigens whereas; IgG has two binding sites for antigens.
Also Read: Difference Between B-Cells And T-cells
Difference Between IgM and IgG In Tabular Form
| Basis Of Comparison | Immunoglobulin M (IgM) | Immunoglobulin G (IgG) |
| Definition | Immunoglobulin M or IgM on the other hand, is found mainly in the lymph fluid and in the blood. It is the first antibody that is produced in case of an exposure to a particular bacteria or virus. | Immunoglobulin G or IgG is the antibody that is found most abundantly in the human body. It is found in all body fluids and it protects the human body against bacterial and viral attack. |
| Structure | IgG is a monomeric molecule comprising a Y-shaped unit with just two antigen binding sites. | IgM is a Pentameric molecule comprising 5 Y-shaped units together with a polypeptide chain with ten antigen biding sites. |
| Presence | . IgG is present in the body by default for long-term response of the body to a disease. | IgM is produce whenever the human body is exposed to bacteria virus, bacteria or a toxin. |
| Types | There are four different types of IgG that are; IgG 1, IgG 2, IgG 3 and IgG 4. | There is only one type of IgM. |
| Size and Abundance | IgG is the smallest antibody that is found in all body fluids. | IgM is the largest antibody which is abundantly found in lymph and blood. |
| Percentage of Presence | IgG occupies 75 percent of the complete quantity of the serum. | IgM account just 10 percent of the complete quantity of the serum. |
| Production | IgG is produced in the body it lasts forever, providing lasting immunity to the person. | IgM is a temporary antibody that disappears within two or three weeks. |
| Molecular Weight | IgG has a molecular weight of 150000MW or 150 kDa. | IgM has a molecular weight of 900000MW 0r 900kDa. |
| Placenta Crossing | IgG is smaller in size and therefore, may cross the placenta and supplies mother’s resistance to creating the embryo. | IgM is larger size and therefore, it is not able to cross the placenta, even though it’s the first antibody produced in the human embryo. |
| Presence in the colostrums | IgG is present in the colostrums. | IgM is absent in the colostrums. |
| Effect of High Levels | High levels of IgG protect the body against long term diseases like HIV, multiple sclerosis and so on. | High levels of IgM in the body can contribute to parasitic infections, kidney impairment, rheumatoid arthritis, hepatitis, monocluosis etc. |
| Antigen Binding Site | IgG has two binding sites for antigens. | IgM has 10 binding sites for antigens. |
Also Read: Difference Between Lymph And Blood
Summary
Immunoglobulin G or IgG is the antibody that is found most abundantly in the human body. It is found in all body fluids and it protects the human body against bacterial and viral attack. Immunoglobulin M or IgM on the other hand, is found mainly in the lymph fluid and in the blood. It is the first antibody that is produced in case of an exposure to a particular bacteria or virus.