Human bodies come into contact with billions of microbes daily, including harmful bacteria and viruses that are potentially deadly. Any possible place on earth less sanitized than a sterile lab-like environment has microbes that are hostile to human life. The smallest bacterial invader can enter the body from something as simple as breathing, and without natural immunity; it would be able to reproduce out of control, cause cell damage, and even death. This may sound like a terrifying world to live in, but luckily, anyone with a properly functioning immune system is fully prepared to thrive in it.  hopkinsmedicine
The immune system is one of the most complex networks in the human body, second only to the brain. The largest organs directly involved are the spleen and the thymus gland. Those organs are connected through a system of lymphatic vessels, where fluids, nutrients, messenger molecules and cells can travel quickly throughout the body to respond to any necessary immunological red flags. The essence of the immune system is that the spleen and thymus gland are control centres where the production of cells needed to fight off foreign invaders take place, and the lymphatic circulatory system serves a dual purpose as the pathway for cellular communication, and for transporting materials throughout the body to fight infections. There are many different kinds of immune cells that play different and nuanced roles in this process.  hopkinsmedicine
The importance of a well-functioning immune system cannot be overstated. It's the primary line of defense in protecting humans from illness and allowing them to stay in good health. Humans cannot survive long without it, and even compromised or low functioning immune systems can put them at a higher risk of becoming seriously sick or feeling chronically unwell. This arguably makes it the single most essential component of good health.
Many factors contribute to immune function, including diet, personal care and cleaning products, genetics factors, environmental toxins, gut microbiome health, age, chronic stress and/or fatigue, and sleep quality. There can be supportive effects from nutrition, proper rest and stress management, or reversely, harmful effects from anything that depletes the body of energy, compromises skin or gut barriers, and/or causes chronic inflammation.  harvard.edu
Amazingly, Chlorella is one of very few substances that manages to both positively support the immune system, as well as mitigate some negative effects from other sources. The multi-faceted manner in which Chlorella can potentially support the body's immune function is uniquely helpful, and this specific area of research is continuing. Many of the studies that directly focus on Chlorella and immune function have been done on animals or in vitro, and further study is being done on humans. . researchgate.net However many study results have still been promising, and the research so far on humans has overall shown positive results . researchgate.net
While research on the topic of Chlorella's effects on immune function is still continuing, the more general study of Chlorella and its properties has been ongoing since the 1950's and is well developed. We can identify the substances it contains, the specific effects those have on the human body, and some of the synergist effects in the unique makeup of nutrients it contains. There is ample evidence from this previous body of research that supports the usefulness of Chlorella as an immunological aid.
Strong immune systems overall require a balanced, varied, and nutritionally dense diet, free or at the very least limited in toxins . harvard.edu While the complexity of immunity requires a wide array of nutrients, there are a handful of specific nutrients that play a more key role than others. Vitamin C, D, selenium, zinc, iron and protein have all been highlighted as particularly essential for good immune health . harvard.edu Unfortunately, iron, vitamin D, and even zinc are commonly under consumed, even in developed nations [4, 5]. Those who choose to follow a vegan or vegetarian diet are also at an especially high risk of being low on these essential nutrients since the highest concentrations tend to be from animal foods . Amazingly, Chlorella is perhaps one of the only individual whole- foods that is a good source of every single one of the afore mentioned immunity nutrients .
Chlorella also has additional features that indicate its helpfulness in supporting immune health. It has antimicrobial, antioxidant, and anti-inflammatory properties, all of which decrease the body's level of chronic stress and inflammation [7, 8, 9]. Chronic inflammation is cause for concern because any inflammation is a marker that there is potential illness, which stimulates the immune system into action. Immune systems require large amounts of energy and nutrients when activated, which can temporarily divert them from other important bodily processes to keep us safe. Short-term, this is a sensical solution since fighting off illnesses is the body's main priority for staying alive, but an issue arises when our immune system is overworked from fighting chronic low-grade inflammation. The causes of inflammation are vast and complex, but the result is a fatigued immune system using up exorbitant amounts of nutrition and energy to respond to the inflammation, and correspondingly having less resources to support other bodily functions, leading to decreased overall wellbeing. There is a myriad of unpleasant symptoms associated with chronic inflammation, including: sleep issues, body aches, low energy, headaches, indigestion, and worsened mental health. 
No doubt, keeping inflammation in check is necessary to maximize wellbeing and immunity. The ways in which Chlorella assists with combating this problem is multifaceted. The anti-microbial characteristics of the algae may be able to fight off some potentially dangerous microbes, which could dampen or even prevent the body from experiencing an inflammatory immune response . The antioxidant aspects of Chlorella also may act as a preventative measure for slowing inflammation before it has the chance to develop. Antioxidants alleviate oxidative stress in the body from free radicals, which are capable of harming the body and causing inflammation. The antioxidants bind to these reactive radicals and render them inert. Lastly, the anti-inflammatory chemicals within the Chlorella directly respond to already existing inflammation and calm the body's immunological overreaction. 
There are some positive findings indicating chlorella's usefulness as an immunological aid [13, 14, 15]. There has been a fair amount of research in agricultural settings to determine whether Chlorella could be used as a replacement for frequently used antibiotic medications, with positive results . In one study, Chlorella was able to increase body mass, level of white blood cells, and lymphocytes in chickens: all indicators of healthy immune function . Many other studies testing immune effects have been done on mice. They have mostly determined through various measures that Chlorella does indeed have immune boosting effects in mice that were subjected to immunity suppressing situations [17, 18].
There has been research on humans into Chlorella's usefulness in alleviating allergic reactions, or as an immunological aid for fibromyalgia patients with positive results [19, 20]. Additional studies examining a unique substance it contains called Chlorella Growth Factor (CGF) look particularly promising . springer In the meantime, it's safe to say that Chlorella is an excellent source of many important nutrients that are required for good immune health, and that it has a very positive future with a growing body of evidence to support its use as a natural supplement for this purpose.
BioGenesis Chlorella is organically grown in the pristine Great Barrier Reef region of northern Australia. Bathed in golden sunshine the Chlorella thrive in the fresh spring water ponds. We have developed an innovative advanced energy efficient hydrodynamic growth system that replicates a natural river flow. When harvested we apply an advanced biodynamic technology to gently crack the hard outer cell wall making the nutrients fully available.
Australia’s only Licenced Chlorella grower. No.9298. Produced in a USA FDA accredited Bio Secure site.