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Stimulating the Body’s DefencesProbiotics show promise in boosting immunity and reducing respiratory tract infections in infants and young children

Dr Shikha Pundir Senior Research Scientist, Paediatrics

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IntroductionA healthy immune system is critical for good health throughout the different stages of life, from infancy and childhood to adulthood and older age. The immune system is a complex set of organs and biological processes designed to protect the body from potential threats of invasion and to maintain the healthy functioning of the body. While the immune system is complex, one way to categorise its components is in terms of the innate (natural) and the adaptive (acquired) immune systems (Figure 1).

The innate immune system includes physical and chemical barriers, commonly known as the first line of defence, essential to keep viruses, bacteria, parasites, and other foreign agents from entering the body and causing an unfavourable reaction. Physical barriers include skin, eyes and hair, and are further supported by chemical and microbiological barriers which aid in the repelling of undesirable organisms. If a pathogen invades these physical barriers, it can encounter other elements of the innate immune system, such as special white blood cell types (as shown in Table 1) that constantly survey the blood stream for potential

threats. For example, monocytes can identify foreign antigens (molecules that are capable of initiating immune response) and engulf invading pathogens through a process known as phagocytosis1. Activation of the innate “non-specific” immune response generally results in swift inflammatory responses that alert the rest of the immune system to the presence of a threat. Thereafter, this inflammatory response activates a series of proteins present in the blood and enhances the function of phagocytic cells to clear the pathogens and damaged cells1. Interestingly, another feature of the innate immune system is our own populations of microorganisms that live on our epithelial surfaces (our microbiome). They can actively compete with, and often destroy pathogens before they become harmful2.

If a pathogen manages to avoid the innate immune defences, a highly specific, adaptive immune response is triggered. The adaptive immune system is a more targeted response that will adapt to the presence of new or specific antigens never encountered before. It will then develop “immune memory” to make a much more efficient response the next time that antigen is present. Unlike innate immunity, which responds to pathogens via pre-set “hard wired” antigen receptors, the adaptive immune system can learn to recognise new antigens and it keeps a record of antigens from previous encounters. Hence it is also referred to as acquired immunity. While the generation of the initial

NeutrophilsMonocytesEosinophilsBasophilsNatural Killer cells

T lymphocytesB lymphocytes

Humoral Immunity

Cell-mediated Immunity

Human Immune System

Innate Immune Responses• First line of defence• Non-specific and fast

Adaptive Immune Responses• Follows innate response• Highly specific and slow• Produces antigen-specific memory

The Immune System

Mucosal Immunity lgA, lgM

Figure 1: Complexities of the immune system

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Table 1: Examples of different types of immune cells and their function

Neutrophils

• Group of white blood cells responsible for innate immunity, such as Neutrophils, Eosinophils and Basophils

Eosinophils

• Ingest microorganisms and kill them

Basophils

• Release cytokines and modulate inflammatory response to allergy and asthma

Monocytes

• Target parasites and bacteria• Release during allergic

inflammation and increase blood flow to infection site

Lymphocytes

B-cells(B Lymphocytes)

T-cells(T Lymphocytes)

• A type of phagocytic cell found in the blood stream which develops into a macrophage when it migrates to tissues

Granulocytes

• Responsible for adaptive immunity

• Develop in the bone marrow or thymus

• Responsible for humoral immune response by secreting antibodies

• Responsible for cell mediated immune responses by neutralising infected cells. There are three main classes of T-cells – cytotoxic, helper and suppressor (regulatory) cells. Cytotoxic cells destroy or kill infected cells, while helper cells stimulate antibodies and macrophages to destroy any intracellular pathogens

adaptive response to a new antigen can take several days, response to the subsequent infection tends to be faster and more sophisticated. Adaptive immunity is a complex, antigen-specific response mediated by T and B lymphocytes (or T- and B-cells) that develop in red bone marrow and either mature there (B-cells) or in the thymus (T-cells)3. These cell types underpin the two mechanisms by which adaptive immunity works - humoral and cell-mediated immune responses.

Humoral immunity is an immune response mediated by the production of antigen-specific antibodies produced by B-cells. These antibodies bind to the antigens and can block the function of the antigen or neutralize the pathogen. In contrast to this, cell-mediated immunity is facilitated by T-cell subtypes - T helper (Th cells) and cytotoxic T-cells. Activated B- and T-cells either kill the pathogen directly or secrete antibodies which enhance the phagocytosis of pathogens by innate immune cells, thereby disrupting the infection.

During the adaptive immune response, most of the white blood cells die as the immune response is completed. However, memory cells (memory Th cells, memory cytotoxic T-cells, and memory B-cells) are formed that have long lifespans often lasting for decades3,4. This means, if the antigen reappears, cell-mediated and humoral immunity can work together to facilitate efficient and fast responses.

Mast cells • Similar to basophils, release histamines and heparin and mediate allergy and inflammatory responses

Natural killer cells • Mediate anti-tumor and anti-viral responses

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Figure 2: Basic components of the immune system

Innate immunity Adaptive immunity

BasophilNeutrophil B-cell

T-cellCytokines

Antibodies

Eosinophil

Mast cell Natural killer cell

Antigen presentation

Hours DaysTime of response

Dendritic cell

Macrophage

DEVELOPMENT, STIMULATION AND REGULATION OF THE IMMUNE SYSTEM

In recent years it has become well established that the human body is inhabited by trillions of commensal, or beneficial bacteria, together known as the human microbiota. Bacteria live on the skin, in the respiratory tract, and throughout the gastrointestinal (GI) tract, maintaining a mutual symbiotic relationship with the host. An important feature of commensal bacteria is to interact with the immune system5,6. For example, commensal gut bacteria can prevent the colonisation of pathogenic bacteria and infection via mechanisms that can involve the immune system7. The importance of the gut as an immune organ is highlighted by the fact that majority of immune cells are located around the gut8. The microbiota has a central role in the immune development of the newborn infant9 and this interaction is maintained throughout life. Therefore establishing a healthy intestinal microbiota results in a healthy gut and is also an important factor in maintaining healthy immune function and providing protection against harmful pathogens9. Establishment of the microbiota in the first few years of life is a successive and complex process10. It begins during birth and is determined by several factors including genetics, environment and diet11.

POTENTIAL BENEFITS OF PROBIOTICS

Early life nutrition is an important factor shaping infant immunity, metabolism and gut health for babies. Diet is an important influencer of the gut microbiota and in turn has an impact on immune homeostasis and therefore the health of an individual. One approach to boost healthy gut bacteria is through dietary administration of prebiotics and probiotics. (For more information on prebiotics and probiotics see NZMP SureStartTM White Paper “The Probiotic Effect”).

Probiotics are live micro-organisms that offer a health benefit to the host12. Most probiotics belong to bacterial species found naturally in the gastrointestinal microflora and are often referred to as “friendly bacteria” or “good bacteria”. Probiotic bacteria typically come from two major genera - Bifidobacterium or Lactobacillus. Within each genus, there are different species, and within each species exist different strains or subspecies (varieties). Amongst the numerous probiotic strains studied for a variety of health benefits, Bifidobacterium (genus) animalis subspecies lactis (species) and Lactocaseibacillus (genus) rhamnosus (species) (previously known as Lactobacillus rhamnosus) are two of the most popular probiotics. A large body of in vitro and in vivo data has suggested a positive role for probiotic strains in improving immunity and providing protection against infection, especially in vulnerable groups such as in infants and in the elderly13,14.

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BENEFITS OF SURESTART™ BIFIDOB HN019™ FOR GUT HEALTH, IMMUNITY DEVELOPMENT AND PROTECTION

Probiotics are well known for their positive effect on immunity and for protecting against illness and prevention of infections. However, the health benefits of probiotics are strain specific, and the functional benefits identified for each probiotic strain cannot be generalised for all other strains. The exclusively breastfed infant harbours a greater diversity of gastrointestinal Bifidobacteria, and the appearance of these bacteria are regarded as a sign of a healthy gut microbiome15. Therefore much attention has been focused on the use of specific strains of Bifidobacterium as probiotics.

Bifidobacterium animalis subspecies lactis is a naturally occurring bacterial species, first isolated from fermented milk. The Bifidobacterium animalis subspecies lactis HN019™ strain, commercially known as SureStart™ BifidoB HN019™, was first isolated from yogurt. A proprietary strain developed and patented by Fonterra, SureStart™ BifidoB HN019™ is a well-characterized and safe probiotic strain with well documented probiotic effects in people across all stages of life. Systematic and robust clinical studies have been conducted to demonstrate its benefits in the area of gut microbial health, protection against infection and immune modulation, with no reports of adverse effects16,17.

SUPPORT FOR THE IMMUNE SYSTEM

A healthy intestinal function is important for the overall health of a human. The human gastrointestinal tract is home to a variety of microorganisms, known as the gut microbiota, that are involved in complex interaction with the immune system. It is well recognised that diet can help shape the composition of the gut microbiota by promoting the growth of certain healthy bacterial groups such as Bifidobacteria and Lactobacilli. Maintaining a healthy balance of the bacteria which make up the microbiota therefore has a positive impact on good gut health and the immune health of an individual.

SureStart™ BifidoB HN019™ has been shown to survive the low pH of the stomach and bile acids of the gastrointestinal tract, making it a suitable candidate for probiotic use. The daily dietary consumption of SureStart™ BifidoB HN019™ can substantially increase its concentration in the lower

gastrointestinal tract which further helps to improve the overall immune health of an individual18,19. A study by Irwinda et al. showed supplementation of SureStart™ BifidoB HN019™ in pregnant women significantly increased its concentration in the faecal microbiota of the intervention group compared to the control group, suggesting that SureStart™ BifidoB HN019™ can survive in the gastrointestinal tract 20. This is in line with the definition of probiotic bacteria, that they are live bacteria that survive in the GI tract. A further study showed that the colonisation of SureStart™ BifidoB HN019™ was transient, suggesting that regular consumption of the strain would be optimal18. This strain is safe and well tolerated by infants. A cohort study of 160 infants from birth to at least 6 months of age reported that SureStart™ BifidoB HN019™ was present in greater numbers in infants who had been fed with supplemented infant formula for 3 months17,21, suggesting that this supplementation approach may further help to promote the infant’s healthy immune system.

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PROTECTION AGAINST GASTROINTESTINAL TRACT INFECTIONS

Diarrhoea and respiratory infections are the most common preventable diseases in infants and are commonly caused by viruses and bacteria22,23. Of all the age groups, young infants are more susceptible to gastrointestinal infections due to the immature or developing immune system. During an intestinal infection the gut epithelium releases chemokines and pro-inflammatory molecules provoking epithelial barrier dysfunction and persistent diarrhoea24. Preclinical studies suggested that SureStart™ BifidoB HN019™ could provide a natural defence mechanism against invasion of pathogenic bacteria causing gastrointestinal infections19. It appeared to exert a strong adhesive activity to human gut epithelial cells and decreases the adhesion of pathogens. Extensive pre-clinical studies suggest the anti-pathogenic effect of SureStart™ BifidoB HN019™ to be particularly effective against Rotavirus and Escherichia coli infections25. SureStart™ BifidoB HN019™ also enhanced the resistance to Salmonella typhimurium by decreasing inflammation and bacterial adhesion to the intestine in an animal model24. More recently, a large community-based randomised clinical trial of more than 300 children between the ages of 2 and 5 years showed a reduction in the incidence of diarrhoea and fever among the group who consumed SureStart™ BifidoB HN019™ compared to the placebo group26.

PROTECTION AGAINST RESPIRATORY TRACT INFECTIONS

To demonstrate the protective benefits of SureStart™ BifidoB HN019™ for children’s health, a randomised, double-blind, placebo-controlled community-based trial was conducted. The study involved 64 children between 9 and 15 months of age, who were randomly assigned to either consume a standard follow-on formula, or the same follow-on formula supplemented with the probiotic SureStart™ BifidoB HN019™, or the follow-on formula with another probiotic over a period of 3 months27. Results showed that parents reported the infants who received SureStart™ BifidoB HN019™ had 50% fewer symptoms of respiratory tract infections such as colds and flu over the winter. This finding was reflected in the observation that the infants who received SureStart™ BifidoB HN019™ also had reduced antibiotic use compared to the control infants. Interestingly, the other probiotic was not as effective, illustrating the point that probiotic benefits cannot be generalised to all probiotics, and therefore must be shown for each probiotic strain.

The beneficial effect of SureStart™ BifidoB HN019™ on respiratory tract infections confirms an earlier study performed with 624 young children between 1-4 years of age. The children received either a fortified milk, or the same milk supplemented with SureStart™ BifidoB HN019™ and prebiotic galacto-oligosaccharides (GOS). The study showed that consumption of this prebiotic and probiotic combination significantly reduced the incidence and prevalence of dysentery23,28. Furthermore, the study showed a clinically meaningful reduction in the incidence of pneumonia (24%) and severe respiratory tract infections (35%) and also reduced the risk of anaemia23 in the supplemented group compared to the control group.

Taken together these studies support the substantial role of SureStart™ BifidoB HN019™ in improving immunity and providing protection against gastrointestinal tract and respiratory tract infections.

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Less than 24 months of age Greater than 24 months of age

Day

s w

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seve

re il

lnes

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Trial A

Control BifidoB 019

p = 0.05

p = 0.03

Figure 3: Impact of supplementation time with SureStart™BifidoB HN019™ on reduction of

childhood illnesses27

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ConclusionIt is evident that common infectious diseases are a major cause of poor health among young children, which is a concern for parents. Therefore, identifying potential strategies to improve immune function through early life nutrition and to help reduce the risk of disease in this age group is a major focus for health. SureStart™ BifidoB HN019™ has been shown in scientific studies to support a healthy gut microflora, thereby enhancing immunity and helping to protect against illness and infection, particularly in infants and young children.

REFERENCES1. Nye KE (2004) The basics of immunology for the non-immunologist. In: Diet Hum. Immune Funct. Humana Press, pp 3–152. Rutherfurd-Markwick KJ, Gill HS (2004) Probiotics and immunomodulation. In: Diet Hum. Immune Funct. Humana Press, pp 327–3443. Delves PJ (2019) Innate and adaptive systems of immunity. In: Autoimmune Dis. Elsevier, pp 45–614. Gombart AF, Pierre A, Maggini S (2020) A review of micronutrients and the immune system–working in harmony to reduce the risk of infection. Nutrients 12:2365. Bäckhed F, Ley RE, Sonnenburg JL, Peterson DA, Gordon JI (2005) Host-bacterial mutualism in the human intestine. Science (80- ) 307:1915–19206. Wu HJ, Wu E (2012) The role of gut microbiota in immune homeostasis and autoimmunity. Gut Microbes 3:4–147. Hooper L V., Littman DR, Macpherson AJ (2012) Interactions between the microbiota and the immune system. Science (80- ) 336:1268–12738. Thursby E, Juge N (2017) Introduction to the human gut microbiota. Biochem J 474:1823–18369. Belkaid Y, Hand TW (2014) Role of the microbiota in immunity and inflammation. Cell 157:121–14110. Collado MC, Rautava S, Aakko J, Isolauri E, Salminen S (2016) Human gut colonisation may be initiated in utero by distinct microbial communities in the placenta and amniotic fluid. Sci Rep. https://doi.org/10.1038/srep2312911. Bäckhed F, Roswall J, Peng Y, et al (2015) Dynamics and stabilization of the human gut microbiome during the first year of life. Cell Host Microbe 17:690–70312. Food and Agricultural Organization of the United Nations & World Health Organization (2006) Probiotics in food: Health and nutrition properties and guidelines for evaluation. Rome

13. Kerr JA, Long C, Clifford SA, Muller J, Gillespie AN, Donath S, Wake M (2017) Early-life exposures predicting onset and resolution of childhood overweight or obesity. Arch Dis Child archdischild-2016-31156814. Gopal P., Dekker J., Prasad J., Pillidge C. (2005) Development and commercialisation of Fonterra’s probiotic strains - ProQuest. Aust J Dairy Technol 60:173–18215. Murphy K, Curley D, O’callaghan TF, O’shea CA, Dempsey EM, O’toole PW, Ross RP, Ryan CA, Stanton C (2017) The composition of human milk and infant faecal microbiota over the first three months of life: A pilot study. Sci Rep. https://doi.org/10.1038/srep4059716. Dekker JW, Wickens K, Black PN, Stanley T V., Mitchell EA, Fitzharris P, Tannock GW, Purdie G, Crane J (2009) Safety aspects of probiotic bacterial strains Lactobacillus rhamnosus HN001 and Bifidobacterium animalis subsp. lactis HN019 in human infants aged 0-2 years. Int Dairy J 19:149–15417. Oswari H, Prayitno L, Dwipoerwantoro PG, Firmansyah A, Makrides M, Lawley B, Kuhn-Sherlock B, Cleghorn G, Tannock GW (2013) Comparison of stool microbiota compositions, stool alpha1-antitrypsin and calprotectin concentrations, and diarrhoeal morbidity of Indonesian infants fed breast milk or probiotic/prebiotic-supplemented formula. J Paediatr Child Health 49:1032–103918. Gopal PK, Prasad J, Gill HS (2003) Effects of the consumption of Bifidobacterium lactis HN019 (DR10TM) and galacto-oligosaccharides on the microflora of the gastrointestinal tract in human subjects. Nutr Res 23:1313–132819. Sanders ME (2006) Summary of probiotic activities of Bifidobacterium lactis HN019. J Clin Gastroenterol 40:776–78320. Wibowo, N., Bardosono, S., & Irwinda R (2016) Effects of Bifidobacterium animalis lactis HN019 (DR10TM), inulin, and micronutrient fortified milk on faecal DR10TM, immune markers, and maternal micronutrients among Indonesian pregnant women. Asia Pac J Clin Nutr. https://doi.org/10.6133/APJCN.122016.S221. Dwipoerwantoro PG, Mansyur M, Oswari H, Makrides M, Cleghorn G, Firmansyah A (2015) Growth of Indonesian infants compared with world health organization growth standards. J Pediatr Gastroenterol Nutr 61:248–25222. Jones G, Steketee RW, Black RE, Bhutta Z a., Morris SS (2003) How many child deaths can we prevent this year? Lancet 362:65–7123. Sazawal S, Dhingra U, Hiremath G, Sarkar A, Dhingra P, Dutta A, Verma P, Menon VP, Black RE (2010) Prebiotic and probiotic fortified milk in prevention of morbidities among children: Community-based, randomized, double-blind, controlled trial. PLoS One. https://doi.org/10.1371/journal.pone.001216424. Liu C, Zhang ZY, Dong K, Guo XK (2010) Adhesion and immunomodulatory effects of Bifidobacterium lactis HN019 on intestinal epithelial cells INT-407. World J Gastroenterol 16:2283–229025. Shu, Quan; Qu, Freeman; Gill HS (2001) Probiotic treatment using Bifidobacterium lactis HN019 reduces weanling diarrhea associated with rotavirus and Escherichia coli infection in a piglet model. J Pediatr Gastroenterol Nutr 33:171–17726. Hemalatha R, Ouwehand AC, Forssten SD, Geddan JJB, Mamidi RS, Bhaskar V, Radhakrishna K V. (2014) A community-based randomized double blind controlled trial of Lactobacillus paracasei and Bifidobacterium lactis on reducing risk for diarrhea and fever in preschool children in an urban slum in India. Eur J Nutr Food Saf 4:325–34127. Dekker J, Xu L, Hong Q, Xiaoyang S (2017) Bifidobacterium animalis subsp. lactis HN019 protects against respiratory tract infections in Chinese infants. J Pediatr Gastroenterol Nutr 64:76028. Sazawal S, Dhingra U, Sarkar A, Dhingra P, Deb S, Marwah D, Menon VP, Black RE (2010) Efficacy of milk fortified with a probiotic Bifidobacterium lactis HN019 (DR-10 TM ) and prebiotic galacto-oligosaccharides in prevention of morbidity-a community based double masked randomized trial. apiycna.org

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