The tradition of kimchi is as rich and varied as the culture itself in South Korea. With over 150 types of kimchi, each region and family adds its own touch, turning a simple dish into a symbol of heritage and identity. 

Every November, countless households come together to make kimjang kimchi, preparing not just food for the winter, but memories, connection, and care that carry them through the cold months.

According to Professor Park, the fact that the average Korean enjoys about 100 grams of kimchi every day shows how deeply this food is woven into daily life. And with historical records showing that Koreans have been eating kimchi in its current form for around 700 years.

The Lactobacillus sakei proBio65 strain 

The Lactobacillus sakei proBio65 strain (proBio65) has its roots in the time-honored tradition of Korean fermented kimchi.

Known for its remarkable ability to soothe inflammatory skin conditions like Atopic Dermatitis (eczema), its promise doesn’t end with skin health. 

To explore whether proBio65 could positively influence the immune system, the research team used an in vitro screening system1 by co-culturing freshly isolated mesenteric lymphocytes2 with this probiotic.

1. An in vitro screening system is a laboratory-based method for evaluating biological, chemical, or drug compounds outside of a living organism, typically using cells, tissues, or proteins in controlled environments like petri dishes. 

2. Mesenteric lymphocytes are specialized immune cells located in the mesenteric lymph nodes (MLNs) within the tissue connecting the intestines to the abdominal wall. They act as a critical "firewall," filtering gut-derived antigens and maintaining tolerance. 

The research team observed a marked increase in the expression of the Foxp33 transcription regulatory factor, followed by an upregulation of anti-inflammatory cytokine4 transcription factors. 

3. FOXP3 (Forkhead Box P3) is a master regulator transcription factor essential for the development and function of regulatory T cells (Tregs)5. It acts as a molecular switch, inducing Treg differentiation to maintain immune homeostasis, prevent autoimmunity, and induce tolerance to self-antigens. FOXP3 controls Treg function by suppressing effector T cell activity and cytokines. 

4. Cytokines are small signaling proteins released by immune and non-immune cells that act as messengers, regulating immune responses, inflammation, and cell communication. They orchestrate the body's defense against infection by coordinating cell movement to damaged areas and controlling cell growth and death.  

5. Core Functions of Tregs:

• Maintaining Self-Tolerance: Tregs prevent autoimmune diseases by recognizing and suppressing self-reactive T cells that escape the thymus.
• Immune Suppression: They act as "moderators" to calm the immune system after an infection, preventing chronic inflammation or autoimmune diseases.
• Peripheral Tolerance: Tregs reduce inappropriate responses to foreign antigens, such as allergens and commensal microbiota.

In vitro, the Lactobacillus sakei proBio65 strain demonstrated a high IL-10/IL-126 production ratio and significantly enhanced Foxp3 expression.

6. IL-10/IL-12 refers to an immunoregulatory circuit where IL-10 (an anti-inflammatory/immunosuppressive cytokine) and IL-12 (a pro-inflammatory cytokine) act in opposition to control immune responses, inflammation, and autoimmune disease. They act as a "double-edged sword" regulating pathogen elimination and preventing autoimmunity, with their balance used as a prognostic marker for cancer and infection. 

How Vaccines and proBio65 Work Together

A. The Internal Adjuvant

proBio65 acts like a natural, internal adjuvant, working from deep within the gut to prepare the body to respond to a vaccine.

The word “adjuvant” comes from the Latin, “adiuvare”, meaning “to help” — a fitting origin for something that quietly empowers our defenses. 

Instead of acting like a traditional chemical adjuvant—mixed into a vaccine vial to trigger a local alarm at the injection site—proBio65, acting as “amplifiers,”  supports the body on a global level.

It helps create an optimal cellular environment so that when a vaccine antigen appears, the immune system is ready to respond with remarkable speed, accuracy, and strength.

How Adjuvants Work

When a vaccine contains only purified fragments of a virus or bacteria, the immune system may not see it as a serious threat. 

That’s where adjuvants step in, transforming a faint signal into a clear call to action through several mechanisms:

Awakening Innate Immunity (Macrophage “Drill Sergeant”) 

Before your body can build lasting protection, its first line of defense must be called to attention. 

Adjuvants do exactly this: they awaken the “innate” immune system so it can train and empower the “adaptive” (long-term) immune system.

The Action: 

proBio65 energizes macrophages—the relentless “Pac-Man” cells that hunt down and consume foreign invaders.

The Adjuvant Effect: 

By driving these cells to become intensely active and efficient, proBio65 makes sure vaccine antigens are rapidly devoured, processed, and urgently “presented” to the rest of the immune system, instead of drifting through the body unnoticed. 

It transforms a passive response into a powerful call to action.

Empowering Humoral Immunity (Rapid-Response Antibody Generator)

Most vaccines share one vital mission: to help your body produce Immunoglobulin G (IgG) antibodies, the protective sentinels that stand guard against future threats. 

On their own, your defenses can take weeks to reach full strength.

The Action: 

proBio65 propels B-cells to mature and generate IgG antibodies at a dramatically accelerated pace.

The Adjuvant Effect: 

It acts like a temporal amplifier—compressing time so your body can raise its shield of circulating antibodies much sooner. 

This rapid response is especially critical when facing aggressive, fast-replicating viruses, turning a vulnerable window into a moment of strength.

“Noise Cancellation” for Laser-Focused Immunity

A scattered, overreactive immune system is not a fertile ground for vaccines. 

When your defenses are distracted by constant false alarms (i.e., allergies and chronic background inflammation) a vaccine’s message can be lost.

The Action: 

proBio65 supports immune regulators such as Foxp3 and Treg cells, helping to quiet allergic hypersensitivity and calm unnecessary inflammation.

The Adjuvant Effect: 

While traditional adjuvants simply turn the volume up on the immune response, proBio65 acts as a “smart adjuvant.”

It first clears away the background noise, silencing false alarms so your immune system can listen with total clarity. 

With the static removed, your immune cells can devote 100% of their focus to what truly matters: building strong, precise, and lasting protection from the vaccine.

~As an internal adjuvant, proBio65 empowers the body with a powerful dual-action advantage: it becomes a shield, quieting distracting inflammatory “noise,” and a sword, training macrophages and B-cells to recognize and strike vaccine targets with greater speed and precision.

B. The "False Alarm" Prevention 

proBio65 helps your immune system find its natural balance, a state known as immune homeostasis or immunomodulation.

In the world of immunology, balance is everything. 

An immune system that’s too quiet can’t protect you from infections. One that’s too loud creates chaos—false alarms like allergies, chronic inflammation, and autoimmune flares. 

When your body is stuck in chronic low-grade inflammation or hypersensitivity, your immune system is already tired and distracted:

• It wastes energy chasing harmless targets like food proteins, pollen, or even your own tissues.
• It may struggle to respond properly to vaccines—either ignoring them, overreacting to them, or triggering dangerous inflammatory storms.

ProBio65 steps in to quiet the noise and restore clarity. It supports your immune system with three powerful “silencers” that bring you back to center:

Empowering the Peacekeepers (Foxp3 and Treg Cells)

In laboratory studies on gut immune cells, proBio65 significantly increased Foxp3, a key transcription factor that leads to the creation of Regulatory T cells (Tregs). 

These Tregs are like the peacekeepers of your immune system, actively calming unnecessary reactions and shutting down false alarms.

Shifting the Chemistry Toward Calm (IL-10 vs. IL-12)

proBio65 promotes a higher ratio of IL-10—an anti-inflammatory, healing cytokine—compared to IL-12, which drives aggressive inflammation. 

This shift helps your body move from a state of tension and overreaction into one of resilience and controlled strength.

Relieving the Burden of Allergies (IgE and Mast Cells)

For those struggling with allergies, proBio65 has been clinically shown to reduce IgE levels and prevent mast cells from releasing histamine. 

By easing these allergic “false alarms,” it frees your immune system to do what it was meant to do: protect you from real threats.

Together, these actions create a powerful, dual-story for proBio65:

The Shield

proBio65 calms the background noise—soothing chronic inflammation, quieting allergies, and reducing unnecessary immune stress.

The Sword

At the same time, by clearing the clutter and supporting clean macrophage activity, proBio65 enables your body to launch a sharp, focused, and rapid IgG antibody response when a vaccine or real threat appears.

~This is the promise of proBio65: not just to push your immune system harder, but to help it become wiser—calmer when it should be calm, and fiercely effective when it truly matters.

Author’s Note

World Immunization Week 2026: For every generation, vaccines work.

This is Part 4: In-House Research on Immunity of a 4-part series, created to ignite meaningful conversations about how we protect our health in an increasingly complex world.

Probiotics have been hailed as “natural” immune boosters in recent years, while vaccines remain among the most rigorously tested and impactful public health tools ever created. Both have a place in the story of human health—but they are not interchangeable.

As you read, you’ll discover how these two approaches fit into a bigger vision of well-being. When we understand the unique roles of both vaccines and probiotics, we are better equipped to build a future where health is not a privilege, but a shared legacy.

Part 1 | Part 2 | Part 3