Mycobacterium indicus pranii therapy induces tumor regression in MyD88- and TLR2-dependent manner

Mycobacterium w - a promising immunotherapeutic intervention for diseases

Immunomodulating agents interact with the immune system and alter the outcome of specific immune processes. As our understanding of the immune system continues to evolve, there is a growing effort to identify agents with immunomodulating applications to use therapeutically to treat various diseases. Mycobacterium w (Mw), a heat-killed mycobacterium, is an atypical mycobacterial species that possesses strong immunomodulatory properties. Mw was initially evaluated as an immune-therapeutic against leprosy, but since then Mw has generated a lot of interest and been studied for therapeutic applications across a host of diseases, such as pulmonary tuberculosis, tuberculous pericarditis, sepsis, lung cancer, and more. This article summarizes a large body of work published in the past five decades, describing various aspects of Mw and its potential for further therapeutic development.

Mycobacterium Indicus Pranii (MIP) Vaccine: Pharmacology, Indication, Dosing Schedules, Administration, and Side Effects in Clinical Practice

Mycobacterium indicus pranii (MIP), previously called Mw vaccine, is a one-of-a-kind immunomodulatory vaccine. It was indigenously developed in India for use in leprosy. MIP is heat-killed Mycobacterium w, which is a non-pathogenic atypical mycobacterium belonging to Class IV of Runyon classification. It shares epitopes with Mycobacterium leprae and Mycobacterium tuberculosis, which forms the rationale behind its use in leprosy and tuberculosis. MIP activates both innate and acquired immunity. It induces a Th1 and Th17 immune response along with downregulation of Th2 pathway and activates macrophages and dendritic cells. MIP vaccine is safe with adverse effects such as local site erythema, swelling, and rarely fever and other systemic reactions. Apart from leprosy, MIP has been used in dermatological diseases such as warts and psoriasis. Clinical trials have evaluated the efficacy of MIP in a plenitude of non-dermatological conditions such as category II tuberculosis, Gram-negative sepsis, non-small cell lung cancer, human immunodeficiency virus (HIV), muscle-invasive bladder cancer, and very recently, coronavirus 2019 (COVID-19). In vitro and animal studies have also demonstrated its utility in leishmaniasis, melanoma, and as a vaccine for the prevention of pregnancy. The PubMed database was searched using "Mycobacterium indicus pranii, MIP, Mycobacterium w" as the keyword in title. This comprehensive review provides useful information for healthcare professionals about immunotherapeutic potential of MIP vaccine, its composition, dosing schedule, administration, and side effects besides its efficacy in various indications other than leprosy.

Augmenting Vaccine Efficacy against Delta Variant with 'Mycobacterium-w'-Mediated Modulation of NK-ADCC and TLR-MYD88 Pathways

Mycobacterium-w (Mw) was shown to boost adaptive natural killer (ANK) cells and protect against COVID-19 during the first wave of the pandemic. As a follow-up of the trial, 50 healthcare workers (HCW) who had received Mw in September 2020 and subsequently received at least one dose of ChAdOx1 nCoV-19 vaccine (Mw + ChAdOx1 group) were monitored for symptomatic COVID-19 during a major outbreak with the delta variant of SARS-CoV-2 (April-June 2021), along with 201 HCW receiving both doses of the vaccine without Mw (ChAdOx1 group). Despite 48% having received just a single dose of the vaccine in the Mw + ChAdOx1 group, only two had mild COVID-19, compared to 36 infections in the ChAdOx1 group (HR-0.46, p = 0.009). Transcriptomic studies revealed an enhanced adaptive NK cell-dependent ADCC in the Mw + ChAdOx1 group, along with downregulation of the TLR2-MYD88 pathway and concomitant attenuation of downstream inflammatory pathways. This might have resulted in robust protection during the pandemic with the delta variant.

Type 1 interferon mediated signaling is indispensable for eliciting anti-tumor responses by Mycobacterium indicus pranii

Introduction

The evolving tumor secretes various immunosuppressive factors that reprogram the tumor microenvironment (TME) to become immunologically cold. Consequently, various immunosuppressive cells like Tregs are recruited into the TME which in turn subverts the anti-tumor response of dendritic cells and T cells.Tumor immunotherapy is a popular means to rejuvenate the immunologically cold TME into hot. Mycobacterium indicus pranii (MIP) has shown strong immunomodulatory activity in different animal and human tumor models and has been approved for treatment of lung cancer (NSCLC) patients as an adjunct therapy. Previously, MIP has shown TLR2/9 mediated activation of antigen presenting cells/Th1 cells and their enhanced infiltration in mouse melanoma but the underlying mechanism by which it is modulating these immune cells is not yet known.

Results

This study reports for the first time that MIP immunotherapy involves type 1 interferon (IFN) signaling as one of the major signaling pathways to mediate the antitumor responses. Further, it was observed that MIP therapy significantly influenced frequency and activation of different subsets of T cells like regulatory T cells (Tregs) and CD8+ T cells in the TME. It reduces the migration of Tregs into the TME by suppressing the expression of CCL22, a Treg recruiting chemokine on DCs and this process is dependent on type 1 IFN. Simultaneously, in a type 1 IFN dependent pathway, it enhances the activation and effector function of the immunosuppressive tumor resident DCs which in turn effectively induce the proliferation and effector function of the CD8⁺ T cells.

Conclusion

This study also provides evidence that MIP induced pro-inflammatory responses including induction of effector function of conventional dendritic cells and CD8⁺ T cells along with reduction of intratumoral Treg frequency are essentially mediated in a type 1 IFN-dependent pathway.

Potential of Mycobacterium tuberculosis chorismate mutase (Rv1885c) as a novel TLR4-mediated adjuvant for dendritic cell-based cancer immunotherapy

For clinical application by dendritic cell (DC)-based cancer immunotherapy, a proper adjuvant system to elicit a strong anticancer immune response is needed. Here, we investigated the potential of chorismate mutase (TBCM, Rv1885c), a putative Mycobacterium tuberculosis (TB) virulence factor, as an immunoadjuvant in DC-based tumor immunotherapy. First, we found that TBCM functionally activated DCs by upregulating costimulatory molecules, increasing the secretion of proinflammatory cytokines, enhancing migration and inducing the Th1-type immune response in a dose-dependent manner via TLR4-mediated signaling. In addition, subcutaneous injection of TBCM-activated DCs loaded with cell lysates led to reduced tumor mass, enhanced mouse survival and lowered tumor incidence in lung carcinoma (LLC) cell-bearing mice. This is mainly mediated by functional cytotoxic T lymphocyte-mediated oncolytic activity and inhibition of cancer proliferation- and metastasis-related genes. Moreover, TBCM-induced DCs can also generate memory CD4 T cells and exert long-term tumor prevention effects. In conclusion, our findings suggest that TBCM (Rv1885c), a novel TLR4 agonist, could be used as an immunoadjuvant for DC-based cancer immunotherapy.

Cytokine Storm and Immunomodulation in COVID-19

COVID-19 has become a major pandemic in recent times. The exact pathophysiology and understanding of cytokine storm and immunomodulation are evolving. Various cytokines have been implicated in the pathophysiology of COVID-19. Immunosuppressant immunomodulators like steroids, canakinumab, anakinra, tocilizumab, sarilumab, baricitinib, ruxolitinib, bevacizumab, and itolizumab have been tried. Immunostimulant immunomodulators like interferons (IFNs) and Mycobacterium w (Mw) have also been repurposed. Considering the role of multiple cytokines implicated in COVID-19, molecules working on the majority of the targets, may hold a promising future prospect

A Randomized Trial of Mycobacterium w in Severe Presumed Gram-Negative Sepsis

BACKGROUND

Mycobacterium w, an immunomodulator, has been shown to resolve early organ failure in severe sepsis.

RESEARCH QUESTION

Does Mw improve survival in patients with severe presumed gram-negative sepsis?

STUDY DESIGN AND METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group study conducted in ICUs of five tertiary care centers in India. We included consecutive patients (age ≥ 18 years) with presumed gram-negative sepsis in the study within 48 h of the first organ dysfunction. Patients in the treatment arm received 0.3 mL/d of Mw intradermally for 3 consecutive days, whereas the control arm received matching placebo. The primary outcome was 28-day all-cause mortality. The secondary outcomes were ventilator-free days, days receiving vasopressor therapy, ICU and hospital length of stay, nosocomial infection rate, antibiotic use duration, and delta Sequential Organ Failure Assessment (SOFA) score.

RESULTS

We included 202 patients with severe sepsis (101 Mw, 101 placebo). The use of Mw significantly reduced the mortality (9/101 vs 20/101; estimate difference, 0.11 [95% CI, 0.01-0.21]; P = .04). We found no difference in ventilator-free days, days receiving vasopressor drugs, ICU length of stay, and the hospital length of stay. The time to mortality (median, 13 days vs 8.5 days) was significantly longer in the Mw than in the placebo arm. The delta SOFA score, rate of nosocomial infections, and antibiotic use duration were similar in the two arms. We found Mw to reduce significantly the odds (OR, 0.37 [95% CI, 0.15-0.9]) of mortality after adjusting for culture-positive sepsis, baseline SOFA score, age, and sex.

INTERPRETATION

The use of Mw was associated with a significant reduction in mortality in patients with severe presumed gram-negative sepsis. Further studies are required to confirm our findings.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02330432; URL: www.clinicaltrials.gov.

A randomised trial of Mycobacterium w in critically ill patients with COVID-19: ARMY-1

PURPOSE

We investigated whether Mycobacterium w (Mw), an immunomodulator, would improve clinical outcomes in coronavirus disease 2019 (COVID-19).

METHODS

We conducted an exploratory, randomised, double-blind, placebo-controlled trial of hospitalised subjects with severe COVID-19 (pulmonary infiltrates and oxygen saturation ≤94% on room air) conducted at four tertiary care centres in India. Patients were randomised 1:1 to receive either 0.3 mL·day-1 of Mw intradermally or a matching placebo for three consecutive days. The primary outcome of the study was the distribution of clinical status assessed on a seven-point ordinal scale ranging from discharged (category 1) to death (category 7) on study days 14, 21, and 28. The co-primary outcome was a change in SOFA (sequential organ failure assessment) score on days 7 and 14 compared to the baseline. The secondary outcomes were 28-day mortality, time to clinical recovery, time to reverse transcription PCR negativity, adverse events, and others.

RESULTS

We included 42 subjects (22 Mw, 20 placebo). On days 14 (OR 30.4 (95% CI 3.3-276.4)) and 21 (OR 14.9 (95% CI 1.8-128.4)), subjects in the Mw arm had a better clinical status distribution than placebo. There was no difference in the SOFA score change on days 7 and 14 between the two groups. We did not find any difference in the mortality, or other secondary outcomes. We observed no adverse events related to the use of Mw.

CONCLUSIONS

The use of Mw results in better clinical status distribution on days 14 and 21 compared to placebo in critically ill patients with COVID-19.

Mycobacteria-Based Vaccines as Immunotherapy for Non-urological Cancers

The arsenal against different types of cancers has increased impressively in the last decade. The detailed knowledge of the tumor microenvironment enables it to be manipulated in order to help the immune system fight against tumor cells by using specific checkpoint inhibitors, cell-based treatments, targeted antibodies, and immune stimulants. In fact, it is widely known that the first immunotherapeutic tools as immune stimulants for cancer treatment were bacteria and still are; specifically, the use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) continues to be the treatment of choice for preventing cancer recurrence and progression in non-invasive bladder cancer. BCG and also other mycobacteria or their components are currently under study for the immunotherapeutic treatment of different malignancies. This review focuses on the preclinical and clinical assays using mycobacteria to treat non-urological cancers, providing a wide knowledge of the beneficial applications of these microorganisms to manipulate the tumor microenvironment aiming at tumor clearance.