Babys Immune System: Why Is It Weak At Birth
Our immune system comprises cells, tissues, organs, and proteins. While your babys immune system works in exactly the same manner as yours, it has limitations. Being young and immature, the system takes time to learn about the different adversaries and build an effective campaign against them.
The response to the first infection is neither as quick nor as strong. But, the system learns, and the next time the same bug enters, the system is ready to deal efficiently and effectively against it.
This unpreparedness of the immune system is why your baby is more prone to infections. As the baby grows, so does their immune system. The system soon recognizes the invaders and creates effective barriers to keep them away.
Proof of its effectiveness shows how we rarely suffer from chickenpox or measles more than once.
T Cell Development And The Neonatal T Cell Compartment
Early Life T Cell Development and Immunophenotypes
The T cell compartment in early life is uniquely positioned to respond to diverse immunological demands, such as balancing immunotolerance in utero and during microbial colonization with defense against pathogens . These divergent demands result in highly stimulus dependent T cell responses in early life . Human T cell development begins in utero, as the thymus starts producing T cells at 1214 weeks of gestation, and the neonatal T cell receptor repertoire is diversified by 26 weeks of gestation . Distinct waves of human T cell development occur in utero, yet the T cell compartment continues to evolve dynamically after birth. In contrast to other immune cell compartments that converge with adult immunophenotypes by 3 months of age, infant and adult T cell compartments remain phenotypically distinct at least for the first 2 years of life .
Innate-Like Functions of T Cells in Early Life
Mechanisms Regulating T Cells in Early Life
Immunotolerance and Regulatory T Cells in Early Life
T Helper Cell Responses in Early Life
As Scientists Probe The Mystery Of How Newborns Develop Immunity Order Rises From The Chaos
New studies take the most comprehensive look yet into immune system activity immediately after birth
Much about the immune system has long been mysterious to scientists. Its activity is incredibly complicated and varies greatly between individuals a deeper understanding of how the system works could lead to more and better vaccines, and even to a clearer distinction between health and disease.
Now three studies report finding new patterns amid the apparent chaosincluding in the crucial days just after birth, when the immune system faces many threats from the outside world for the first time.
European researchers last year an analysis of the immune systems of 100 infantshalf born prematurelybetween one and 12 weeks after birth. And in a study appearing this week in Nature Communications, a global consortium of researchers began laying a baseline for healthy immune system development by examining which genes, proteins and immune cells are active during a newborns first seven days. Massive molecular changes are occurring across the first week of life, says Ofer Levy, a staff physician and director of the Precision Vaccines program at Boston Children’s Hospital, who helped lead the most recent study. Over 1,000 genes changing, many proteins changing, hundreds of metaboliteswere talking about pretty radical shifts.
Understanding The Mothers Immune System During Pregnancy
Why are pregnant women considered to be more at risk from infections? This is due to a quirk of nature that takes place deep in the body.
50% of the fetuss genetic material comes from the father. The mothers immune system should fight and reject the fetus like any other intruder. This is where the quirk gets into the act.
To ensure that the fetus is not rejected by the mother, her immune system generates a tolerant immune memory of the fetal tissue. This is known as the paradox of pregnancy . The mothers immune system develops tolerance to paternally derived fetal antigens despite having an adequate defense against infections.
This results in a scenario of immunosuppression in both the mother and fetus, which carries over into early life. Since the mothers immune system is suppressed during this period, she is more susceptible to infections.
Immune System Of Newborn Babies Stronger Than Previously Thought
- King’s College London
- Contrary to what was previously thought, newborn immune T cells may have the ability to trigger an inflammatory response to bacteria, according to a new study. Although their immune system works very differently to that of adults, babies may still be able to mount a strong immune defense, finds the study.
Contrary to what was previously thought, newborn immune T cells may have the ability to trigger an inflammatory response to bacteria, according to a new study led by King’s College London. Although their immune system works very differently to that of adults, babies may still be able to mount a strong immune defense, finds the study published in the journal Nature Medicine.
Our immune system is made up of several different types of immune cells, including neutrophils which play an important role in the frontline defense against infection, and lymphocytes: B cells which produce antibodies, and T cells that target cells infected with viruses and microbes.
The team discovered that whilst T cells in newborn babies are largely different to those in adults, it is not because they are immunosuppressed rather, they manufacture a potent anti-bacterial molecule known as IL8 that has not previously been considered a major product of T cells, and that activates neutrophils to attack the body’s foreign invaders.
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Stay On Top Of Baby’s Vaccines
Washing your hands and scrubbing every surface of your home can only do so much. One of the most important things you can do to keep your baby healthy and avoid serious illness is to get her vaccines on schedule from birth and beyond into childhood.
And dont forget to stay on top of your own vaccines too. When in doubt about whether you’re up-to-date on your immunizations, check in with your doctor.
T Cell Responses To Pathogens And Vaccines In Early Life
Early Life T Cell Responses to Pathogens
Studies of fetal and neonatal immune responses to infections have greatly advanced our understanding of the functional capabilities of T cells in early life . Fetuses mount pathogen-specific CD8+ and CD4+ T cell responses against human immunodeficiency virus , cytomegalovirus , Trypanosoma cruzi, and Plasmodium falciparum . Fetuses exposed to P. falciparum and T. cruzi generate CD4+ T cell responses that release proinflammatory cytokines when re-stimulated, highlighting that adaptive T cell memory is elicited in utero . Moreover, infants exposed to P. falciparum in utero produce antigen-specific CD4+ and CD8+ T cell responses that undergo memory differentiation . These P. falciparum specific CD4+ T cell responses in cord blood correlate with protection against malaria infection in the first 2 years of life, suggesting that priming of pathogen-specific CD4+ T cell responses in utero may confer protection later in life .
Early Life T Cell Responses to Vaccines
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Ways To Boost Immunity In Infants
- Skin To Skin Contact Through skin to skin contact between mother and child, the baby is exposed to microorganisms that help the baby to develop immunity.
- Proper Sleep Time A proper sleep routine is essential for building immunity. Lack of sleep can reduce immune cells that help to kill harmful bacteria, making the infant’s body prone to diseases.
- Fiber and Nutrient-Rich Foods Once infants start on solid foods, it is advisable to give fruits and vegetables which are rich in fiber and contains nutrients that help boost immunity.
- BreastfeedingBreast milk is the best source nutrition for the baby. It provides all proteins, fats, and antibodies required for building the baby’s immunity. Breast milk also contains oligosaccharides which have prebiotic effect. These are non-digestible fibers which pass through the stomach and small intestine undigested and stimulates the growth of beneficial/good bacteria and decreases bad bacteria in the infant gut, thus helps build a strong immune system.
The Importance Of Scrubbingand Rubbing
Germs are like cooked rice: To remove them from your skin, you have to rub them off. That means running soapy hands under the faucet isnt enough, youll have to vigorously rub your hands together to get rid of germs. So, if you ever cant wash before holding your baby, rub your hands on your pants to reduce the germ transfer.
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About Infant Immune Systems
Perhaps our strongest instinct as parents is the need to protect our childrento shield them from harm, pain and illness. These days, were all thinking about our health and well-being more often than ever and how we can avoid putting ourselves and our kids at risk for disease.
In this post, well discuss how infant immune systems work what illnesses babies are most likely to get and how to boost an infant immune system. Well also share how the Western Washington Medical Group Family Practice can assist you further with your babys health.
Starting with the basics, everyone is born with an immune system of proteins and cells, which exist to prevent illness by defending the body from infection. When something like a virus is introduced to the body, the white blood cells respond by producing antibodies to fight it, and store that data for future defenses.
Babies are born with immature immune systems that develop as they age and become exposed to germs. Antibodies that protect newborns were passed to them through their mothers placenta during the last three months of her pregnancy. They also receive bacteria during birth, which helps build immunity-boosting bacteria in the gut.
As they continue to grow as infants, they receive additional antibodies through the breast milk of their mother and the germs that they are exposed to in the atmosphere. It takes time to develop their immune system, and even longer if they were born prematurely.
Transfer Of Protection From Mother
The main component of immune protection transferred from mother to child is antibody. This is transferred across the placenta to the foetus using the FcRn . Antibody is also transferred to the infant via breast milk. The main immunoglobulin class transferred is IgA, the transferred IgA works at mucosal surfaces, where it is able to prevent pathogen entry. However other important factors are transferred, including complement and commensal bacteria which may provide protection against asthma and allergy in later life .
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Passive Vs Active Immunity
There are two categories of immunity: passive and active immunity. These labels refer to how your body develops protection against a certain disease or toxin.
Passive immunity. This type of immunity occurs when a person is given antibodies — the body’s response to a pathogen — rather than producing them through their own immune system. Newborn babies get passive immunity from their mothers through the placenta before they’re born. A mother shares the antibodies that she has with her unborn baby.
Each baby’s passive immunity is unique because each mother’s immune system is unique. The exact kinds and amounts of antibodies in a baby’s blood are a reflection of its mother’s levels at birth. These differences can impact how long passive immunity lasts.
Active immunity. This type of immunity occurs when your body is exposed to a particular disease and develops antibodies to fend it off. Active immunity can happen in two ways: naturally or vaccine-induced.
When you’re exposed to a pathogen in the world, your immune system learns to “recognize” that pathogen and can protect you in the future. If you receive a vaccine, that’s a way to “teach” your immune system safely how to do the same thing — learn to recognize the pathogen and protect yourself from it if you’re ever exposed.
Babies begin to build active immunity shortly after birth as they are exposed to germs in the outside world and as they begin to receive the necessary immunizations to keep them healthy.
Ways To Reduce Your Babys Risk Of Sickness
There are things you can do to protect your baby during the first few months of life, Dr. Sabella says.
1. Limit outside exposures. You cant keep your baby in a bubble until they reach the six-month mark. But you can limit contact with other people. And ask visitors to wash their hands before touching the child.
The first two months of life, we really regard as a sacred time to try to limit exposures as much as possible because babies can get viruses from people who dont even know theyre contagious yet, he says.
2. Watch for fever. Its difficult for doctors to determine whether a virus or bacteria is causing an infants illness. So, they err on the side of caution. Any fever 100.4 degrees F or higher will likely land your baby in the hospital for IV antibiotic treatment, Dr. Sabella says. In some cases, doctors will order a spinal tap to rule out meningitis.
Our ability to distinguish between a virus and a bacterial infection right up front is limited, he says. We often have to do everything and treat it to rule out worst-case scenarios.
The whooping cough vaccine is particularly important. The illness is life-threatening for a child under six months of age. Babies should receive the vaccine first at two months, he says.
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The Immune System In Babies
A babys immune system is not fully developed when they are born. It gets stronger as the baby gets older. The immune system works throughout our lives fighting germs that can cause disease.
A mothers antibodies are shared with their baby through the placenta during the third trimester of pregnancy. The mothers antibodies help protect the baby from illnesses when the baby is born. The type of antibodies passed from mother to baby depends on the mothers own level of immunity.
After birth, more antibodies are passed to your baby from the colostrum and in breast milk.
How Long Does Mother’s Immune System Protect Baby
Studies are still ongoing in this subject, so there’s no precise answer. The exact amount of protection that a baby receives from its mother depends on the antibodies that the mother has in her immune system. Research indicates that a baby’s passive immunity lasts for around six months.
One study examined the passive immunity to measles in infants. It discovered that the babies’ immunity to the disease diminished over time, and none of them had immunity by the age of 9 months.
In other words, it isn’t like flipping a switch. There isn’t a cutoff date at which a baby is no longer protected by the passive immunity provided by its mother. Rather, immunity to certain pathogens slowly decreases over several months after birth.
Breast milk, however, contains antibodies that can extend a baby’s ability to fight infection.
Among other important elements, breast milk has the antibodies that a mother has in her body as well as those she makes in response to illnesses that she encounters while breastfeeding. This extra support for the developing immune system can help keep newborn babies healthy while their passive immunity wanes and their own immune systems continue to grow stronger.
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Lack Of Immune System
A baby with SCID has little to no immune system. The immune system is made up of cells that fight infection. All babies with SCID share the problem of being born with either no T cells or too few T cells. The numbers of normal T cells in your baby are extremely low or are not made at all.
T cells are essential for the immune system to work properly. If your baby catches a cold or other infections, he or she might not be able to fight it off like most other people. The cold could get worse and be life-threatening.
Doctors diagnosed your baby with SCID through newborn screening and additional testing. Newborn screening showed doctors that the T cells responsible for fighting infections were extremely low in your child.
Antibody Responses To Pathogens And Vaccines In Early Life
Early Life Humoral Responses to Pathogens
Potently neutralizing antibodies with limited rates of SHM have been observed in RSV infections in early life as well. Goodwin et al. analyzed antibodies isolated from memory B cells of infants hospitalized for RSV infection and observed that the majority of the RSV-specific antibodies did not have detectable SHM. Yet, antibodies from each of the infants demonstrated neutralizing activity against RSV and 4 out of 5 had highly potent neutralizing activity . Although the authors did not test whether these antibodies prevented RSV reinfection, this study demonstrated that, even with limited levels of SHM, antibodies generated in early life may still have substantial anti-pathogenic i.e., neutralizing capabilities.
Humoral Responses to Vaccines in Early Life
Notably, newborns can mount adult-like antibody responses following HepB vaccination . This highlights that certain stimuli may be better able to induce a protective immune response via vaccination in early life. In fact, when comparing adult and infant responses to HIV vaccines, we observed that children immunized with an oil-in-water emulsion adjuvant developed higher antibody titers than adults immunized with the same vaccine, yet no difference was observed between adults and infants when immunized with an Alum-adjuvanted vaccine . These results suggest that the choice of the vaccine adjuvant can significantly improve antibody responses early in life, as discussed below.
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