Primarily there are three different types of immunity:
This is designed to keep out infections and includes skin, mucus and tears.
This is mediated by certain cells, which have the ability to recognise antigens. This recognition is only between self and non-self, i.e. these cells can recognise that a foreign body has entered the system but cannot make out which particular pathogen is involved. For example, these cells would not be able to distinguish an influenza virus from a hepatitis virus but can make out that a viral infection has occurred. A majority of commonly occurring infections like common cold are controlled through this mechanism.
This comprises the third line of defence. In this case white blood cells recognise an antigen individually. In this situation it takes comparatively longer for the response to take effect but it also results in a memory of the antigen. This means that if the same antigen re-infects, memory of the antigen will ensure that an immune response will be generated and the antigen will be immediately removed. The mechanism of adaptive immunity is made use of in the process of vaccination.
Natural Immunity in babies.
Natural Immunity refers to a state where a ababy is immune to a disease and yet has never had the disease or any vaccination against it. The natural immune response is a pre-programmed first line of defence that is primarily responsible for eliminating or containing pathogens at the site of entrance into the host. Natural immune system serves well and protects most animals with its enormous variety of defence mechanisms. It becomes stronger and more capable of handling threats when it is successful in containing an infection on its own.
So boosting your baby’s natural immunity is a very effective method of arresting the onset of various diseases. Unfortunately the role of natural immunity in helping fend off a host of diseases has so far gone largely unrecognised.
Building natural immunity is especially important in babies whose immune systems are not fully equipped to deal with a large number of diseases. A strong immune system would provide a baby with the natural defences to fight off many diseases.
The gastrointestinal system and body defences.
One of the major sites from where harmful agents like microorganisms and toxins can gain entry is the gastrointestinal system. The gastrointestinal system is the largest surface area of the body that communicates directly with the internal milieu. It could very well be labelled as an intricate defence network, allowing entry of nutrients and keeping out toxins and other harmful agents. In that sense it is the body’s largest immune organ.
The gastrointestinal tract has two lines of defences. It is composed of:
The Mucosal Barrier: It is the first line of defence. It absorbs essential nutrients and excludes access to foreign substances.
Mechanical barrier: It is a tight junction of epithelial cells.
Chemical barrier: It comprises gastric acid.
Other defences: Mucus and peristalsis
The Gut Associated Lymphoid Tissue (GALT).
This is the second line of defence. It removes antigens that have penetrated the mucosa and therefore protects the body against harmful pathogens.
Immunity in Pregnancy.
The immune system is trained to differentiate between self and non-self. It recognises a body cell as one of its own and in a similar vein recognises a foreign antigen as a threat. In pregnancy the developing foetus has cells from the father as well. If the mother’s immune system were to function exactly like it does when she is not pregnant, the foetus would be recognised as non-self and rejected. Nature has devised a way to get around this problem. Modifications occur in the mother’s immune system during pregnancy. Some of the specific immune responses in the mother are down regulated or toned down. In their stead non-specific responses are activated. One more significant development during pregnancy is that antibodies pass from the mother to the foetus through the placenta. This means that the developing foetus will be automatically protected against some of the infections the mother has been exposed to or vaccinated against.
Development of the baby’s immune system.
The ball sets rolling even before a baby is born. The immune system develops as a result of a combination of factors. This includes inborn resistance to diseases, maternally acquired antibodies and active exposure to germs.
The immune system starts developing when the foetus is just five weeks old. Immediately after a baby is born, it is exposed to the risk of infection. Exposure to infectious agents kickstarts her immune system and it starts producing antibodies just six days after birth.
A developing foetus receives antibodies from the mother through the placenta. Immediately after she is born it also receives antibodies through breast milk. This passive immunity conferred on the infant by the mother starts fading after 6 – 8 months by which time its own immune system would have taken over.
By the time a baby is 1 year old, she has already developed immunity to some diseases. Even then its immune system is not fully equipped to deal with the whole range of diseases she is up against. This is primarily because over this short span of time, the baby does not get exposed to many of the diseases and therefore its immune system has not been primed to deal with these diseases.
A newborn’s immune system.
A newborn’s immune system is quite immature and ineffective. she cannot readily keep infection at bay. However, nature has made adequate provision for newborn babies. She receives disease fighting antibodies from you. These antibodies find their way through the placenta into her body during pregnancy. These antibodies linger on for several months and protect her from many common illnesses. Breastfeeding bestows on the baby disease-fighting abilities and that’s why it is important.
Caesareans and baby immunity.
Babies delivered through Caesarean section may have weaker immune systems. There are many studies suggesting that babies delivered vaginally have higher white blood cell counts in the immediate neonatal period. It is also believed that babies delivered through Caesarean section have aberrations in their gut flora (bacteria and other microorganisms in the intestines). The gut flora is believed to play a crucial role in the development of immune processes within an organism. Studies also suggest that both innate and adaptive immune responses seem to have some relation with the mode of delivery. These responses seem to be affected not only in the immediate neonatal period but also beyond that time.
Colostrum and breastfeeding.
Colostrum is a type of milk produced by the mother in late pregnancy. It is the first milk a mother produces after delivery and is extremely important for the baby. The highest concentration of antibodies is found in Colostrum. Antibodies such as IgA, IgM and IgG are