Immunoglobulin overview

Immunoglobulin (an antibody), is a glycoprotein molecule produced by white blood cells. Immunoglobulins antibodies play a crucial role in detecting and attaching themselves to certain antigens like bacterial and viruses. These antibodies also contribute to the destruction of those antigens. As such, they form an essential immune response component.

There are five major Immunoglobulin types in placental mammals, depending on amino acid sequence variability exhibited in the antibody heavy chain’s constant region. They include IgA, IgD, IgE, IgG as well as IgM antibodies. Each of these antibody types has a distinct structure, hence a unique function and response to antigens.

IgA antibodies are mainly located in highly sensitive body areas that are exposed to external foreign substances. These areas include the nose, air way, digestive tract, vagina, ears, as well as eye surface. saliva, tears, and blood also contain IgA antibodies


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On the other hand, IgG antibodies are present in any body fluid. The IgM antibodies are exclusively found in theblood and the lymph fluid.

IgE antibodies are located inside the lungs, skin, as well as mucous membranes. Lastly, IgD antibodies are found in the belly and chest tissues.

Here, we shall focus on IgG.

What Role Does Immunoglobulin G (Igg) Play in The Human Body?
What Role Does Immunoglobulin G (Igg) Play in The Human Body?

What is Immunoglobulin G (IgG)?

Immunoglobulin G (IgG) is a monomer; the simplest antibody type in the human serum. Besides, accounting for 75% of the entire immunoglobulin in a human body, it is the predominant type of immunoglobulin in humans.

The white blood cells release IgG antibodies in the form of a secondary immune response to fight antigens. Due to its predominance in a human’s body and great antigen specificity, IgG has been of great use in immunological studies as well as scientific diagnostics. It is used as a standard antibody in both areas.

Generally, IgG are glycoproteins, each comprising four polypeptide chains with two similar copies of every of the two polypeptide chain types. The two types of polypeptide chain are light (L) and heavy, gamma (γ). The two are connected by disulfide bonds as well as noncovalent forces.

The difference between immunoglobulin G molecules comes in terms of their amino acid sequence . However, inside every individual IgG molecule, the two L chains are indifferent, same case with the H chains.

The major role of an IgG molecule is to create a commotion between a human body’s effector systems and an antigen.

How many subclasses does Immunoglobulin G (IgG) contain?

Immunoglobulin G (IgG) contains four subclasses that differ in terms of disulfide bond number as well as the hinge region length and flexibility. These subclasses include IgG 1, IgG 2, IgG 3 and IgG 4.

(1) IgG 1

IgG1 accounts for approximately 60 to 65% of the entire main IgG. In other words, it is the most common isotope in human serum. Notably, this class of immunoglobulin is rich in antibodies that help to fight against harmful proteins and polypeptide antigens. An example of the proteins that IgG 1 counteracts is the diphtheria, tetanus bacteria toxins and viral proteins.

Newborns have a measurable level of IgG1 immune response. It’s during the infancy stage that the response reaches its normal concentration. Otherwise, failure to achieve the concentration at that stage is an indication that the child could be suffering from hypogammaglobulinemia, an immune disorder that occurs as a result of insufficient levels of all gamma globulin types.

(2) IgG 2

immunoglobulin g subclass 2 comes second in terms of the most common isotopes in human serum. It accounts for about 20 to 25% of Immunoglobulin G. The role of immunoglobulin g subclass 2 is to help the immune system fight against polysaccharide antigens like Streptococcus pneumoniaeorHaemophilus influenzae.

A child achieves the normal “Adult” concentration of immunoglobulin g subclass 2 by the time she turns six or seven years old. The deficiency of IgG2 is characterized by frequent respiratory system infections and is mostly prevalent among infants.

(3) IgG 3

Similarly, to IgG 1, Immunoglobulin G isotopes belonging to subclass IgG3 are rich in antibodies. These antibodies help the immune response to overcome harmful protein and polypeptide antigens in the human body.


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5% to 10% of total IgG in the human body are IgG3 type. However, although they are less predominant as compared to IgG1, sometimes IgG3 have a higher affinity.

(4) IgG 4

The percentage of IgG 4 of the total IgG is normally below 4%. It’s also worth noting that this subclass of Immunoglobulin G is available in extremely low levels among children under the age of 10. Therefore, the diagnosis of immunoglobulin g subclass 4 deficiency can only be possible for kids who are at least ten years old and the adults.

However, scientists have not yet been able to identify the exact function of immunoglobulin g subclass 4. Initially, scientists linked IgG4 deficiency to food allergies.

Nevertheless, a study done recently shows that patients with sclerosing pancreatitis, interstitial pneumonia or cholangitis had high IgG4 serum levels. Therefore, research findings have left confused about the exact role of immunoglobulin g subclass 4.

Immunoglobulins sharing the same subclass have approximately 90% similarity in homology, not considering their flexible regions. On the other hand, those that belong to different subclasses share only 60% similarity. But generally, the concentration levels of all the four IgG subclasses change with age.

Immunoglobulin G (Igg) Functions and Benefits

IgG antibodies play a crucial role in the secondary immune response as IgM antibody takes care of the primary response. Specifically, immunoglobulin g antibody keeps infections and toxins off your body by binding pathogens such as viruses, bacteria and fungi.

Although it is the smallest antibody, it is the most abundant in a mammal’s body, including human’s. it accounts for up to 80% of the entire antibodies present in the human body.

Due to its simple structure, IgG is able to penetrate a human placenta. In fact, no other Ig class can do this, thanks to their complex structures. As such, it plays a very crucial role in protecting a newborn during the initial months of conception. This is one of the key immunoglobulin g benefits.

What Role Does Immunoglobulin G (Igg) Play in The Human Body?
What Role Does Immunoglobulin G (Igg) Play in The Human Body?

The IgG molecules react with Fcγ receptors present on the macrophage, neutrophil and natural killer cell cells surfaces, rendering them powerless. Besides, the molecules have the ability to stimulate the complement system.

The complement system is part of the immune system and its major role is to enhance the antibody and phagocytic cell capacity to remove microbes and injured cells from a human body. The system also improves the ability of the antibodies and the cells to destroy the cell membrane of pathogens and inflame them. This is another of immunoglobulin g benefits.


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Your body produces immunoglobulin g antibody in a delayed response to curb an infection. The body can retain this antibody for an extended period to assist in not only fighting the pathogens responsible of the infection but also facilitate the removal of the destroyed ones from your system.

Due to the high serum endurance, IgG are the most effective antibodies for passive immunization. As such, IgG is mostly an indication that you had an infection or a vaccination recently.

IgG Powder Uses and Application

IgG powder is a refined dietary supplement that serves as a rich immunoglobulin G (IgG) source. It offers the highest concentration of IgG to help your body have a robust immune response, especially if you have frequent and substantial allergen-related issues.

One of the key ingredients of IgG Powder is bovine colostrum which supplies a full range of naturally occurring immunoglobulins. These immunoglobulins are specific to various human antibodies, including Immunoglobulin G (IgG). Therefore, immunoglobulin g colostrum is an effective means of boosting the human body immunity to fight diseases.

With immunoglobulin g colostrum as its major component, IgG Powder can provide as much as 2,000 mg of IgG per serving. The powder will also supply your body with protein (4 g per serving)

Particularly, the immunoglobulin g colostrum in the powder has been tested and proved to assist people in maintaining a strong intestinal immune system. It achieves this by binding a vast array of microbes and toxins located in the gut lumen.


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Therefore, the immunoglobulin g benefits include:

  • Improved immune modulation
  • Stronger gut-immune (GI)barrier
  • Normal inflammatory balance maintenance
  • Newborn immune health support
  • Mucosal immunity boost, thanks to non-allergenic concentrated Immunoglobulin supply
  • Microbial balance maintenance

Suggested use 

There’s no exact IgG powder dosage that’s scientifically proven to be the ideal. However, health experts suggest that one or several scoops of the powder per day are okay. Add the IgG powder to 4 ounces of water/your favorite beverage or as recommended by your doctor.

What Role Does Immunoglobulin G (Igg) Play in The Human Body?
What Role Does Immunoglobulin G (Igg) Play in The Human Body?

Immunoglobulin G (Igg) Deficiency

An Immunoglobulin G (IgG) deficiency refers to a health condition characterized by insufficient Immunoglobulin G production by the body. When a person has IgG deficiency, he/she is at an increased risk of getting infections because their immune system is weak.

Unfortunately, immunoglobulin g deficiency can affect you at any point in your life, no age is exempt from this condition.

Nobody has managed to identify the exact cause of immunoglobulin g deficiency. Nevertheless, it is highly suspected that it is something to do with genetics. Also, medical experts believe that there are some medications and medical conditions that can cause IgG deficiency.

The diagnosis of immunoglobulin g deficiency starts by taking a blood test to assess the immunoglobulin levels. Then other complex tests involving antibody level measurement to assess the response of the body to particular vaccinations are conducted on an individual suspected to have the condition.

Immunoglobulin G Deficiency Symptoms

A person with immunoglobulin g deficiency will most likely exhibit the following symptoms:

  • Respiratory infections such as sinus infections
  • Digestive system infections
  • Ear infections
  • Infections causing a sore throat
  • Pneumonia
  • Bronchitis
  • severe and possibly fatal infections (in rare cases though)

In some cases, the above infections can interfere with the normal functions of the airway and the lung. As a result, victims experience breathing difficulties.

Another point to note about these infections caused by IgG deficiency is that they can attack even people who have been vaccinated against pneumonia and flu.

How to treat an IgG deficiency?

The treatment of IgG deficiency has different approaches, each depending on the severity of the symptoms and infections. If the symptoms are mild, meaning that they prevent you from carrying on with your regular activities/ tasks, immediate treatment might be sufficient.

However, if the infections are severe and frequent, ongoing treatment could be the best solution. This long-term treatment regimen could involve daily antibiotic intake to fight off the infections.

In severe cases, immunoglobulin therapy might come in handy.

The therapy helps in boosting the immune system, thus helping the body to fight the infections better. It involves injecting a mixture of antibodies (immunoglobulins) or a solution of under a patient’s skin, into the muscle or into his/her nerves.


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The use of IgG powder could also see someone recover from IgG deficiency.

What Role Does Immunoglobulin G (Igg) Play in The Human Body?
What Role Does Immunoglobulin G (Igg) Play in The Human Body?

Immunoglobulin G Side Effects

After an immunoglobulin therapy, your body is likely to react adversely to immunoglobulin g.

The most common immunoglobulin g side effects include:

  • Fast heartbeat
  • Earache
  • Fever
  • Cough
  • Diarrhea
  • Dizziness
  • Headache
  • Painful joints
  • Body weakness
  • Pain at the injection site
  • Throat Irritation
  • Vomiting
  • The infrequent immunoglobulin g side effects include:
  • Breathing difficulty
  • Wheezing
  • Malaise
  • Cramps

When the immunoglobulin igG is too high

Too high IgG levels can be seen in systemic lupus erythematosus, atrophic portal vein, cirrhosis, chronic active hepatitis, rheumatoid arthritis, subacute bacterial endocarditis, multiple myeloma, non-Hodgkin lymphoma, hepatitis, cirrhosis, and mononucleosis.

Extremely IgG level of immunoglobulin can also be noticed in IgG-, some viral infections (such as HIV and cytomegalovirus), plasma cell disorders, IgG monoclonal gamma globulin disease and liver disease.

When the immunoglobulin igG is too low

immunoglobulin g low levels put person at a higher risk of developing repeated infections. immunoglobulin g low levels can be seen in antibody deficiency, immunodeficiency syndrome, non-IgG multiple myeloma, heavy chain disease, light chain disease or nephrotic syndrome.

The extremely low levels of the antibody can also be notices in certain types of leukemia, severe burn injuries, allergic eczema, kidney disease, sepsis, malnutrition, pemphigus, muscular tonic and malnutrition cases.

When the immunoglobulin IgG is positive

If the immunoglobulin IgG is positive for an infection antigen such as Covid-19 or dengue, it is an indication that the person under the test could have been infected with the associated virus within recent weeks. Also, immunoglobulin g positive result shows the possibility that the person received a vaccine recently to protect them from the virus.

Therefore, immunoglobulin g positive result is an indication of increased risk of a person to an infection related to the antigen that contributes to the positive test. This is particularly if the positive result isn’t as a result of a vaccine.

Why Is Immunoglobulin G (Igg) Indispensable In Life Activities?

Immunoglobulin G (IgG) is indispensable in life activities because it plays the most significant role in keeping people healthy and able to go on with their life activities as compared to other Immunoglobulins.

Notably, IgG antibodies are present in all body fluids, say tears, urine, blood, vaginal discharge and the like. Considering this, it’s no surprise that they are the most common antibodies, accounting for 75% to 80% of the entire number of antibodies in the human body.


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The antibodies protect the body parts /organs that are in contact with these fluids from bacterial and viral infections. So, without or with insufficient levels of IgG, you might not be able to attend to satisfactorily attend to your day-to-day life activities due to recurring infections.

Additionally, IgG is crucial for human reproduction. Being the smallest of all antibodies and having a very simple structure, it is the only antibody that can penetrate the placenta in a pregnant woman. Therefore, it is the only antibody that can protect an unborn child from viral and bacterial infections. Without it, many unborn children will be at high risk of developing various health conditions, some of which could be life-threatening or lifelong.

Is There Any Interoperability Between Immunoglobulin G And Lactoferrin?

Both immunoglobulin G and lactoferrin are both key natural components of bovine milk (from humans and cows). Just like immunoglobulin G, studies show that lactoferrin is also involved in various protective functions in the human body.

It helps the body to fight pathogenic microorganisms like bacterial, viral, as well as fungal infections. In other words, it boosts the immune function of the human body. So, lactoferrin supplements can complement immunoglobulin G powder in this function.

However, lactoferrin has an additional function; iron binding and transportation.

What Role Does Immunoglobulin G (Igg) Play in The Human Body?
What Role Does Immunoglobulin G (Igg) Play in The Human Body?

More Information About Immunoglobulins

When to test immunoglobulins? 

At some point, your doctor may recommend that you undergo an immunoglobulin test, especially of he/she suspects that you have too low or extremely high immunoglobulin levels. The test is aimed at establishing the level (amount) of immunoglobulin in your body.

Mostly, an immunoglobulin test is recommended if you have:

  • Recurrent infections, especially sinus, lung, stomach, or intestine infections
  • Persistent/chronic diarrhea
  • Mysterious weight loss
  • Mysterious fevers
  • skin rashes
  • serious allergic reactions
  • HIV/AIDs
  • Multiple myeloma
  • Family immunodeficiency history

Your doctor may also find it wise to recommend an immunoglobulin test for you if you fell sick after travel.


An immunoglobulins blood test is used to assist in the diagnosis of various health conditions such as:

  • Bacterial and viral infections
  • Immunodeficiency: This is a condition characterized by a reduced capacity of the human body to fight diseases and infections
  • autoimmune disorders like rheumatoid arthritis and lupus
  • cancer types like multiple myeloma
  • Newborn baby infections

How the test is carried out?

This test usually involves measuring the three most prevalent types of immunoglobulin; IgA, IgG, and IgM. The three are measured together to give your doctor a picture of the effectiveness of your immune response.

Your blood sample will be the specimen for this test. Therefore, a lab technician will penetrate a needle into a section of your arm to reach one of the underlying veins. Then, technician allows the blood to collect into the tube or vial attached to the needle.

Alternatively, the doctor may opt to use a sample of your cerebrospinal fluid (CSF) instead of blood for the test. For clarification, cerebrospinal fluid is the fluid surrounding a person’s spinal cord and brain. Your technician will use a procedure called lumbar puncture to extract the fluid from your spine.

The extraction of the fluid sample can be quite painful. However, the experts involved in such procedures local anaesthesia to make the affected body site insensitive to pain. So, the first thing your lab technician will do is to inject an anaesthetic drug shot into your back to numb all the pain.

Then, lab expert will ask you to lie on your side on a table and then pull up your knees to your test. Alternatively, you may be asked to sit on the table. When you are in either of the two positions, the technician will be able to locate your two lower spine vertebrae.

What follows is that the technician will insert a hollow needle in the middle of your third and fourth lumbar vertebrae. Then, a small quantity of your cerebrospinal fluid will collect into the hollow needle. After a few seconds, the technician will draw out the needle together with the fluid collected inside it.


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Finally, the fluid sample will be put on an immunoglobulin-specific detection kit for testing.

What Role Does Immunoglobulin G (Igg) Play in The Human Body?
What Role Does Immunoglobulin G (Igg) Play in The Human Body?

Final words

Immunoglobulin G (IgG) is among other important immunoglobulins in the human body. Others are IgA, IgD, IgE, as well as IgM. However, out of the four types of immunoglobulins, IgG is the smallest but most common and important in the body. It is present in any body fluid to support the immune system in its fight against pathogens (bacteria and viruses).

Too low or high level of immunoglobulin G is bad for your health. In case of an immunoglobulin g deficiency, an IgG powder buy and use could be a step to your recovery.


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