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Completed

NCT Number: NCT06837961

LC-Plasma on Immune Response and Reducing Symptoms of Upper Respiratory Infectious Diseases

The goal of this study is to evaluate the effects of LC-Plasma on the innate and acquired immune systems, including the activation of pDCs, which play a role in virus elimination, as well as to assess its efficacy in reducing clinical symptoms of upper respiratory infectious diseases in healthy adults. Researchers will compare LC-Plasma to placebo, participants will take a tablet containing LC-Plasma or placebo daily for 4 weeks.

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Key information

Conditions

Healthy Volunteer Immune Response

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Griffith University

Southport, Queensland, 4215, Australia

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Individuals who can provide a signed and dated informed consent form after confirming their willingness to participate.
  • Individuals willing to comply with all study procedures during the study period, including daily monitoring record compliance, cooperating with blood and urine sample collection and performing regular RATs.
  • Healthy people living in Australia aged 18-60 (both men and women).
  • Individuals who have received at least two doses of a SARS-CoV-2 vaccine, with at least two weeks having passed since the last dose.
  • Individuals who are not currently infected with SARS-CoV-2 and, if previously infected, have recovered and have been infection-free for at least four weeks.
  • Individuals who do not have any chronic or acute illnesses, including respiratory and/or gastrointestinal and/or other diseases, (e.g. hypertension, IBS, IBD, SLE, cancer, asthma, primary or secondary immunodeficiencies etc.), at the time of enrolment.

Exclusion criteria

  • Individuals medically prescribed medications that would affect the immune and/or the inflammatory response.
  • Individuals deemed unsuitable for participation by Griffith CTU staff and/or the study clinician.
  • Active smokers/vapers and/or individuals with nicotine or drug habits.
  • Individuals currently participating in (or planning to participate in) other clinical trials.
  • Women who are pregnant, planning to become pregnant during the study period, or are currently breastfeeding.
  • Individuals unable to abstain from alcohol for two days prior to blood and urine sample collection.
  • Individuals unable to refrain from consuming other lactic acid bacteria supplements.
  • Individuals who are known to be HIV, HTLV-1, or HCV positive (based on answers to the enrolment questionnaire).

Treatment and study plan

LC-Plasma

Dietary Supplement

1 tablet containing 50mg LC-Plasma is taken daily for 4 weeks

Placebo

Other

1 tablet containing 50mg MCC is taken daily for 4 weeks

Primary outcomes

  1. The degree of activation of plasmacytoid dendritic cells (pDCs)

    Time frame: Week 0 to week 4

    The degree of activation of plasmacytoid dendritic cells (pDCs) is measured using the indicators CD304+/CD123+, CD86+, or HLA-DR+

Secondary outcomes

  1. Activation of Cytotoxic T Lymphocytes (CTLs)

    Time frame: Week 0 to week 4

    The evaluation of CTLs responsible for virus elimination will be determined using the indicator (CD8+/CD3+/CD4-/IFN-γ+).

  2. Anti-viral Activity of PBMCs

    Time frame: Week 0 to week 4

    The anti-viral activity gene expression and IFN-α & β production capability of PBMCs, both unstimulated and mildly stimulated with CpG, will be measured.

  3. WURSS-24 Symptom Score

    Time frame: Week 0 to week 4

    Symptoms will be measured using the Wisconsin Upper Respiratory Symptom Survey (WURSS-24)

  4. Rapid antigen test (RAT)

    Time frame: Week 0 to week 4

    Rapid antigen test (RAT) for Flu A/B, RSV & SARS-CoV-2. Will be conducted by participants once per week, with additional tests if symptoms are present.

Other outcomes

  1. Safety: Occurrence of adverse events

    Time frame: Week 0 to week 4

    Occurrence of adverse events

  2. Safety: Confirmation of medical history during study period

    Time frame: Week 0 to week 4

    Confirmation of medical history during study period

Sponsors and collaborators

Lead sponsor

RDC Clinical Pty Ltd

Industry

Collaborators

  • Kirin Holdings Company, Limited

Registry information

Official study title

The Effects of Lactococcus Lactis JCM 5805 (LC-Plasma) Lactic Acid Bacteria on Immune Response and Reducing Symptoms of Upper Respiratory Infectious Disease in Australian Healthy Adults. Randomized Placebo-controlled Double-blind Parallel Group Study.

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Feb 20, 2025
Registry last updated
Nov 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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