What are Immunoglobulins? (IgG)?
Immunoglobulin G (IgG) is a type of antibody that is present in all body fluids. IgG makes up about 75-80% of the body’s antibodies. These immune cells are part of the secondary response to a foreign invader, called an antigen, and are created to target a specific harmful microorganism. They circulate in the blood and lymphatic systems, and also reside in the mucous membranes to act as a barrier against invaders.
The immunoglobulin structure consists of four polypeptide chains with two of the same heavy chains linked by covalent and non-covalent bridges. The light and heavy chains both have areas with similar amino acids and also with a variable region. This variable region is where the antibody meets the antigen and where the IgG is able to neutralize the threat.
There are four main types of immunoglobulin, each plays a slightly different role in the body’s immune system:
IgG1 – 60 to 65% of the IgG in the body and is responsible for thymus-mediated immune response. This IgG can activate an immune system cascade to fight specific pathogens.
IgG2 – 20 to 25% of the IgG in the body, responsible for protection against sugar-based antigens. A deficiency in this type of IgG is associated with reoccurring respiratory infections.
IgG3 – 5-10% of the IgG in the body, responsible for protection against protein-based antigens.
IgG4 – Less than 4% of the total IgG. Elevated levels of IgG4 have been linked to food allergies, pancreatitis, and pneumonia. It is the least understood of all the immunoglobulins.
Even though these immunoglobulins all have slightly different roles, they are all needed for proper immune system function.
The Role of IgG and the Immune System
IgG is the major immunoglobulin in the body’s fluids, including the lymph fluid, blood, and cerebrospinal fluid. It is part of the humoral, or fluid-related, immune system. These types of immune cells can be retained in the body for a long period of time and therefore are useful for passive immunization. When a specific IgG is detected in the blood or other fluid, this can indicate a prior infection or vaccination.
IgG is one of the few antibodies that can cross the placenta, making it part of the immune protection infants receive from their mothers’ immune system during the first months of life.
Our body’s first line of immune defense against unhealthy organisms is the intestinal tract. IgG has been found to resist break down by the digestive enzymes within the digestive tract (due to the glycoproteins and trypsin inhibitors), therefore IgG enters the intestinal wall fully intact where it can defend the lining against invading organisms, and prevent the absorption of foreign proteins. IgG is also a factor in increasing the immune system activity level. This substance is important in stabilizing and restoring a damaged intestinal tract so it can function once again at its optimum capacity for nutrient absorption and utilization.
restoring a damaged intestinal tract so it can function once again at its optimum capacity for nutrient absorption and utilization.
Health Effects of Bovine Immunoglobulin
The antibodies derived from bovine milk, found in high quantities in non-denatured whey protein and colostrum, have many similar characteristics with the IgG found in mother’s milk. Therefore, they may be active against the diseases in humans. The bovine milk antigens are resistant to the peptic digestion process, allowing it to directly target the immune system even while still inside the GI tract.
For this reason, bovine IgG is believed to be biologically active and useful in modulating the immune system to help fight disease. Bovine immunoglobulins also have anti-microbial properties allowing it to start attacking pathogens right away.
In fact, bovine IgG has been found to help prevent digestive tract infections, respiratory infections and inflammation.
Bovine IgG may also be helpful in common respiratory infections, particularly in children. One study found that IgG was able to bind to and neutralize a common childhood virus called RSV, particularly during the first year of life. This study found similar effects with bovine immunoglobulin and the influenza virus.
The interesting thing about IgG is that it starts acting against pathogens as soon as it enters the GI tract. Studies have shown that 20% of immunoglobulins can pass through the entire GI tract. Several studies have found that immediately after consumption of IgG, it begins to act upon common human pathogens, such as E.coli, salmonella, staphylococcus, and streptococcus. This means that it can lower the risk of GI infections before they even occur, which may be particularly beneficial for people who are already immunocompromised.
Immunoglobulins may also help maintain gut integrity. Leaky gut, also known as increased intestinal permeability, is a trigger of disease and autoimmunity. When the gut is leaky, it allows allergens and pathogens to pass though the digestive system unchecked, causing an immune response. IgGs are able to calm the inflammatory reaction, preventing the immune system from over-reacting, which may decrease the risk of autoimmune disease. IgG has also been used to reduce the inflammatory response in people with various types of inflammatory bowel disease.
In order to get the most benefit from bovine IgG, it must come from minimally processed whey protein, like our Vital Whey. Heating and processing of the delicate immuno-proteins causes them to denature or be destroyed, therefore they lose their functional abilities to modulate the immune system. Regular consumption of active immunoglobulins can help support naturally healthy immunity.