Immunomodulators

Immunity is a vital component of the interface between the individual & their world, and an expression of homeostasis & relationship between our bodily health, emotional well-being, and mental vision & perspective.

Although some herbs can indeed stimulate immune responses, most can be best described as immune modulators, in that they facilitate greater immune system flexibility in the body’s natural response to disease. It’s best to use caution when prescribing herbs strictly as immune stimulants (eg. “natural antibiotics” – just kill the bug!) if we are to practice herbal medicine holistically.

Immune stimulants lead to a non-specific stimulation of our immunological defences. They generally do not effect our immune memory cells, and because their pharmacological effects fade relatively quickly, they must be administered at regular intervals or continuously. These herbs are more akin to conventional drug therapies for infections, and are valuable options when wanting to boost the body’s innate immune mechanisms in immunocompromised patients and in autoimmune disease.

Immune modulation denotes any effect a herb will have on immune system responsiveness. For example, these herbs may stimulate T-supressor cells (thereby reduce immune resistance), and stimulate macrophages and natural killer cells. Others will enhance the production of antibodies within acting as antigens themselves. Immunomodulators have potential contributions to the treatment of malignancies as they play a central role in supporting those cells involved in our immunological defenses.

As we continue to uncover the healing potential of these plants, the semantics of our reductionist medical model make it difficult to accurately describe and comprehend their uniquely normalizing effects. Herbalist Christopher Hobbs identifies 3 levels of herbal immune activity which are described below:

1. Deep Immune Activation

Herbs in this group are also referred to as Deep Immune Tonics or Immune Modulators. The pharmacology of these herbs tends to point to saponins and polysaccharides as key contributors to their function. They are used where there is a chronic problem or where the immune system needs feeding and strengthening, and usually used in combination with other body system tonic herbs where a weakness has been identified. Some herbal examples include:

• Astragalus membranaceus (Astragalus)
• Codonopsis tangshen (Codonopsis)
• Ganoderma lucidum (Reishi mushroom)
• Lentinus edodes (Shitake mushroom)
• Trametes versicolor (Turkey tail)
• Ligustrum lucidum (Privet)
• Schisandra chinensis (Schizandra)

1. Surface Immune Activation

These are many plants perhaps more well known as Antimicrobials, or “immune-boosters” that often act directly on a bacteria or virus, while also stimulating the function of the immune system as a whole. Active pharmacological compounds are many and complex, however Volatile oils are common. Some herbal examples include:

• Allium sativum (Garlic)
• Baptisia tinctoria (Wild Indigo)
• Echinacea sp. (Echinacea)
• Thuja occidentalis (Thuja)
• Usnea sp. (Old Man’s Beard)

1. Adaptogenic action or Hormonal Modulation

Herbs in this group work through some hormonal modulation of the immune response. The field of Psychoneuroimmunology describes the numerous endocrine functions that can be effected by stress, our mental/emotional health, and it is largely at this levels the herbs demonstrate their actions. For example, adaptogens exert their effects through saponins (steroidal & triperpendoi) via the adrenal glands which is foundational component of healthy immune status. Herbal examples include:

• Eleutherococcus senticosus (Siberian ginseng)
• Panax ginseng (Chinese/Korean Ginseng)
• Glycyrrhiza glabra (Licorice)

• Adapted from David Hoffman’s ‘Medical Herbalism’.