Home Ingredients ImmuseLC-Plasma (Lactococcus lactis strain Plasma)
Immune SupportRespiratory Health

ImmuseLC-Plasma (Lactococcus lactis strain Plasma)

Lactococcus lactis subsp. lactis JCM 5805 (strain Plasma)
Evidence Level
Moderate
3 Clinical Trials
4 Documented Benefits
3/5 Evidence Score

Heat-killed lactic acid bacterium uniquely shown to activate plasmacytoid dendritic cells (pDCs) — innate immune cells producing antiviral interferon. Meta-analysis of RCTs supports reduced cold-like symptom days.

Studied Dose 100 billion (10¹¹) heat-killed L. lactis strain Plasma/day standard RCT dose. Kirin iMUSE® + ImmuseLC-Plasma brands. YOGURT: 100 billion cells/100 g serving. Trials 4-12 wk cold/flu season.
Active Compound Heat-killed (paraprobiotic/postbiotic) Lactococcus lactis strain Plasma cells; activates TLR9 / pDC pathway to induce IFN-α production

Benefits

Plasmacytoid dendritic cell activation

LC-Plasma uniquely activates pDCs — the innate immune cells most specialized for antiviral defense. Both live and heat-killed forms induce IFN-α production. The meta-analysis confirmed significant pDC activation (CD86 and HLA-DR expression on pDCs) across multiple RCTs of healthy adults.

Supported by Trial 1, Trial 2

Reduced cold-like symptom days

meta-analysis pooled data on common cold-like symptoms — sore throat, runny nose, cough, feverishness — and found reduction in cumulative symptom days for the LC-Plasma group vs placebo. Sugimura 2013 (foundational RCT) also reported fewer days of common cold-like symptoms during the yogurt consumption period.

Supported by Trial 1

Type I interferon induction

A 2025 confocal microscopy study confirmed LC-Plasma is uniquely internalized by pDCs (via phagocytosis) and induced significant IFN-α production (73.8 ± 2.5 pg/mL at recommended dose) — exceeding levels reported in serum of hospitalized COVID-19 patients. Other tested postbiotic strains showed no internalization or IFN-α response.

Supported by Trial 3

Postbiotic stability advantage

As a heat-killed paraprobiotic/postbiotic, LC-Plasma doesn't require cold-chain storage or live-cell viability. The activity is preserved through normal manufacturing and remains effective when incorporated into shelf-stable foods, beverages, and supplements — a practical advantage over conventional live probiotics for immune support.

Supported by Trial 1, Trial 3

Mechanism of action

1

TLR9 / pDC pathway activation

LC-Plasma is uniquely phagocytosed by plasmacytoid dendritic cells (pDCs) — a relatively rare immune cell population specialized for sensing viral nucleic acids and producing massive amounts of type I interferons. Most lactic acid bacteria activate myeloid DCs, not pDCs. LC-Plasma's distinctive cell wall components engage TLR9 and other intracellular pattern recognition receptors.

2

Type I interferon (IFN-α/β) cascade

Activated pDCs secrete IFN-α/β, which establish an antiviral state in surrounding cells: upregulating MHC class I, activating NK cells, priming cytotoxic T lymphocytes, and inducing antiviral effector proteins (PKR, OAS, Mx). This produces 'innate immune training' that primes defenses against viral pathogens including rhinovirus and coronaviruses.

3

Mucosal immune priming

Oral consumption of LC-Plasma provides direct contact with gut-associated lymphoid tissue (GALT), where pDCs can be activated and migrate to draining lymph nodes. This may explain the systemic immune effects from oral administration despite the heat-killed status precluding gut colonization.

Clinical trials

1
Kato 2025 — LC-Plasma Meta-Analysis (Individual Participant Data)
PubMed

Individual participant data meta-analysis (Kato et al 2025, Frontiers in Immunology, doi:10.3389/fimmu.2025.1696989).

RCTs of oral LC-Plasma vs placebo in healthy adults. Searches through June 2024 across PubMed, Cochrane, J-Dream III, UMIN-CTR, and ICTRP.

Significant LC-Plasma effects on pDC activity (CD86 and HLA-DR expression on pDCs in peripheral blood). Reduced cumulative number of days with common cold-like symptoms (sore throat, runny nose, cough, feverishness). Authors concluded oral LC-Plasma activates pDCs and mitigates common cold-like symptoms in healthy adults — strongest pooled evidence for the immune mechanism translating to clinical outcomes.

2
Sugimura 2013 — Foundational LC-Plasma Yogurt RCT
PubMed

Randomized, placebo-controlled, double-blind trial (Sugimura, Jounai, Ohshio, Tanaka, Suwa, Fujiwara 2013, Clin Immunol 149(3):509-518).

Healthy adult volunteers consuming yogurt fermented with L. lactis JCM5805 (LC-Plasma) vs placebo yogurt for 12 weeks.

Yogurt containing LC-Plasma activated pDC activity in vivo (peripheral blood pDC CD86 and HLA-DR expression). Effect was greater in subjects with low baseline pDC activity. IFN production capacity increased from baseline. Common cold morbidity risk was suppressed in the LC-Plasma group vs placebo. Established the foundational case that LC-Plasma activates pDCs in humans, not just in vitro.

3
2025 IFN-α Comparative Study — LC-Plasma Uniqueness
PubMed

Comparative postbiotic mechanism study (2025).

Five commercially available postbiotic products containing heat-killed bacterial strains tested for pDC activation and IFN-α induction. Confocal Z-stack imaging used to confirm bacterial internalization.

Among 5 tested postbiotic strains, ONLY LC-Plasma demonstrated significant internalization by pDCs and induced measurable IFN-α (73.8 ± 2.5 pg/mL at recommended dose). This effect was not observed with other strains, even at higher loads (1×10¹¹ cells). L. paracasei MCC1849 adhered to cell surface but was not internalized. IFN-α level induced by LC-Plasma exceeded serum levels in hospitalized COVID-19 patients, suggesting a meaningful antiviral immune contribution.

Side effects and drug interactions

Common Potential side effects

Generally very well-tolerated; heat-killed status removes most safety concerns associated with live probiotics.
Mild GI symptoms occasionally reported in early trials.
No serious adverse events reported in the published RCTs.
Theoretical: very rare hypersensitivity reactions to bacterial cell wall components.
Lactose-containing dairy carriers (yogurt, milk drinks) may cause symptoms in lactose-intolerant individuals — switch to capsule or lactose-free format.

Important Drug interactions

No documented clinically significant drug interactions in published trials.
Theoretical: as an immune activator, caution in patients on immunosuppressive medications (e.g., transplant recipients, autoimmune disease patients on biologics) — though no clinical concerns have been reported.
Antibiotics do NOT affect LC-Plasma efficacy because the cells are heat-killed; this is a key practical advantage over live probiotics.
Compatible with vaccines based on current evidence.

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Frequently asked questions about ImmuseLC-Plasma (Lactococcus lactis strain Plasma)

What is ImmuseLC-Plasma (Lactococcus lactis strain Plasma)?

Heat-killed lactic acid bacterium uniquely shown to activate plasmacytoid dendritic cells (pDCs) — innate immune cells producing antiviral interferon.

What does ImmuseLC-Plasma (Lactococcus lactis strain Plasma) do?

LC-Plasma is uniquely phagocytosed by plasmacytoid dendritic cells (pDCs) — a relatively rare immune cell population specialized for sensing viral nucleic acids and producing massive amounts of type I interferons. Most lactic acid bacteria activate myeloid DCs, not pDCs. In clinical research, ImmuseLC-Plasma (Lactococcus lactis strain Plasma) has been studied for plasmacytoid dendritic cell activation, reduced cold-like symptom days, type i interferon induction.

Who should take ImmuseLC-Plasma (Lactococcus lactis strain Plasma)?

ImmuseLC-Plasma (Lactococcus lactis strain Plasma) may be most relevant for people interested in immune support, respiratory health. It has been clinically studied for plasmacytoid dendritic cell activation, reduced cold-like symptom days, type i interferon induction. As with any supplement, consult your healthcare provider before starting, especially if you have medical conditions or take prescription medications.

How long does ImmuseLC-Plasma (Lactococcus lactis strain Plasma) take to work?

Most clinical trial effects appear over weeks of consistent use; individual response varies. Acute or same-day effects (where applicable) typically appear within hours, but most cumulative benefits — particularly those affecting biomarkers, mood, sleep quality, or chronic symptoms — require 4-12 weeks of regular use to fully assess. If you don't notice benefit after 12 weeks at the appropriate dose, it may not be your responder.

When is the best time to take ImmuseLC-Plasma (Lactococcus lactis strain Plasma)?

For immune support, ImmuseLC-Plasma (Lactococcus lactis strain Plasma) can typically be taken in the morning with breakfast. For acute illness use, follow product labeling — dosing frequency and timing may differ from preventive use. Always check product labeling and follow personalized guidance from your healthcare provider.

Is ImmuseLC-Plasma (Lactococcus lactis strain Plasma) worth taking?

ImmuseLC-Plasma (Lactococcus lactis strain Plasma) has moderate clinical evidence (Evidence Level 3/5 on NutraSmarts) — meaningful trial support exists, though results are less consistent than top-tier ingredients. Whether it's worth taking depends on your specific goals, what you've already tried, your budget, and your overall supplement strategy. The honest framing: no supplement is essential for most people, and lifestyle factors (sleep, exercise, diet, stress management) typically produce larger effects than any single supplement. ImmuseLC-Plasma (Lactococcus lactis strain Plasma) is most worth trying if its evidence-supported uses align with your specific goals.

What is the recommended dosage of ImmuseLC-Plasma (Lactococcus lactis strain Plasma)?

The clinically studied dose for ImmuseLC-Plasma (Lactococcus lactis strain Plasma) is 100 billion (10¹¹) heat-killed L. lactis strain Plasma/day standard RCT dose. Kirin iMUSE® + ImmuseLC-Plasma brands. YOGURT: 100 billion cells/100 g serving. Trials 4-12 wk cold/flu season.. Always follow product labeling and consult a healthcare provider for personalized dosing recommendations.

What is ImmuseLC-Plasma (Lactococcus lactis strain Plasma) used for?

ImmuseLC-Plasma (Lactococcus lactis strain Plasma) is studied for plasmacytoid dendritic cell activation, reduced cold-like symptom days, type i interferon induction. LC-Plasma uniquely activates pDCs — the innate immune cells most specialized for antiviral defense. Both live and heat-killed forms induce IFN-α production.