The long-standing history of Corynebacterium parvum, immunity, and viruses

Exploiting bacterial-origin immunostimulants for improved vaccination and immunotherapy: current insights and future directions

Vaccination is a valid strategy to prevent and control newly emerging and reemerging infectious diseases in humans and animals. However, synthetic and recombinant antigens are poor immunogenic to stimulate efficient and protective host immune response. Immunostimulants are indispensable factors of vaccines, which can promote to trigger fast, robust, and long-lasting immune responses. Importantly, immunotherapy with immunostimulants is increasing proved to be an effective and promising treatment of cancer, which could enhance the function of the immune system against tumor cells. Pattern recognition receptors (PRRs) play vital roles in inflammation and are central to innate and adaptive immune responses. Toll-like receptors (TLRs)-targeting immunostimulants have become one of the hotspots in adjuvant research and cancer therapy. Bacterial-origin immunoreactive molecules are usually the ligands of PRRs, which could be fast recognized by PRRs and activate immune response to eliminate pathogens. Varieties of bacterial immunoreactive molecules and bacterial component-mimicking molecules have been successfully used in vaccines and clinical therapy so far. This work provides a comprehensive review of the development, current state, mechanisms, and applications of bacterial-origin immunostimulants. The exploration of bacterial immunoreactive molecules, along with their corresponding mechanisms, holds immense significance in deepening our understanding of bacterial pathogenicity and in the development of promising immunostimulants.

Bacterial Therapy of Cancer: A Way to the Dustbin of History or to the Medicine of the Future?

Bacteria are the constant companions of the human body throughout its life and even after its death. The history of a human disease such as cancer and the history of microorganisms, particularly bacteria, are believed to closely intertwined. This review was conceived to highlight the attempts of scientists from ancient times to the present day to discover the relationship between bacteria and the emergence or development of tumors in the human body. Challenges and achievements of 21st century science in forcing bacteria to serve for cancer treatment are considered. The future possibilities of bacterial cancer therapy, including the creation of bacterial microrobots, or "bacteriobots", are also discussed.

Innate Immunity Stimulation during the COVID-19 Pandemic: Challenge by Parvulan

Aim. We report an open spontaneous anecdotical retrospective survey of Corynebacterium parvum administration to 4000 fragile immune-depressed and multimorbid patients treated with a killed C. parvum strain to enhance innate immunity, integrating the adaptative immune response for long-standing antinfectious resistance. Methods. A total of 4000 patients (1900 men and 2100 women) with mild, moderate, or chronic disease, appealing to our Second Opinion Medical Consultation Network, signed an informed consent form and were injected subcutaneously with C. parvum. The treatment was followed up to 6 months, completing the short form of the medical outcome health survey questionnaire (SF-36) directly by the patients or their parents and monitoring their health status regularly via telemedicine (Skype, WhatsApp, mail, etc.) or outpatients visits. Results. The main efficacy endpoints, as assessed by the SF-36 questionnaire are: significant improvements in the mental and physical role functioning score ( $p<0.02$ ), better general health; social role performance ( $p<0.02$ ), vitality ( $p<0.03$ ), and a significant pain reduction ( $p<0.03$ ). A quick (48-72 hours) symptoms improvement and/or complete regression of the herpetic eruptions was observed in 1000 affected patients with disappearance or relieve of herpetic neuralgia (reduced in 80% of cases); also full recovery or frequency reduction (30%) of recurrent cystitis and prostatitis in 120 affected patients. Last but not least, a life quality improvement in 100 oncologic patients of overall 200 cases. A significant increase in the lymphocyte count ( $p<0.01$ ), mainly helper and killer lymphocytes, was noted 6 months after Parvulan injection vs. the baseline. The asymptomatic SARS-CoV-2 patients who were incidentally enrolled in our survey were tested at the sixth month for antibodies against SARS-CoV-2, and 14 patients had high levels of SARS-CoV-2 antibodies. The incubating COVID infections of the Parvulan-injected patients even if frail and multimorbid recovered in short term (48-96 hours) with a benign clinical course, without need of drugs administration except for the variants, such as Delta and Omicron, whose infections lasted on average one week and required some antipyretics and low-dose steroids for a few days. Conclusions. Our results confirm that C. parvum is quite safe and effective in supporting immune-compromised patients when epidemic or pandemic events increase the life risk and any kind of infection and complication rate. Further double-blind placebo evidence-based studies are urgently required, and our numerically substantial not sponsored spontaneous observation is exclusively intended to promote further evidence-based double-blind institutional studies.

The secret identities of TMPRSS2: Fertility factor, virus trafficker, inflammation moderator, prostate protector and tumor suppressor

The human TMPRSS2 gene is pathogenetically implicated in both coronaviral lung infection and prostate cancer, suggesting its potential as a drug target in both contexts. SARS-COV-2 spike polypeptides are primed by the host transmembrane TMPRSS2 protease, triggering virus fusion with epithelial cell membranes followed by an endocytotic internalisation process that bypasses normal endosomal activation of cathepsin-mediated innate immunity; viral co-opting of TMPRSS2 thus favors microbial survivability by attenuating host inflammatory responses. In contrast, most early hormone-dependent prostate cancers express TMPRSS2:ERG fusion genes arising from deletions that eliminate the TMPRSS2 coding region while juxtaposing its androgen-inducible promoter and the open reading frame of ERG, upregulating pro-inflammatory ERG while functionally disabling TMPRSS2. Moreover, inflammatory oxidative DNA damage selects for TMPRSS2:ERG-fused cancers, whereas patients treated with antiinflammatory drugs develop fewer of these fusion-dependent tumors. These findings imply that TMPRSS2 protects the prostate by enabling endosomal bypass of pathogens which could otherwise trigger inflammation-induced DNA damage that predisposes to TMPRSS2:ERG fusions. Hence, the high oncogenic selectability of TMPRSS2:ERG fusions may reflect a unique pro-inflammatory synergy between androgenic ERG gain-of-function and fusogenic TMPRSS2 loss-of-function, cautioning against the use of TMPRSS2-inhibitory drugs to prevent or treat early prostate cancer.

Oral vaccination stimulates neutrophil functionality and exerts protection in a Mycobacterium avium subsp. paratuberculosis infection model

Mycobacterium avium subsp. paratuberculosis (Map) causes paratuberculosis (PTB), a granulomatous enteritis in ruminants that exerts high economic impact on the dairy industry worldwide. Current vaccines have shown to be cost-effective against Map and in some cases confer beneficial non-specific effects against other pathogens suggesting the existence of trained immunity. Although Map infection is mainly transmitted by the fecal-oral route, oral vaccination has not been deeply studied. Therefore, the aim of this study was to compare the oral route with a set of mycobacterial and non-mycobacterial vaccines with a subcutaneously administered commercially available vaccine. Training effects on polymorphonuclear neutrophils (PMNs) and homologous and heterologous in vivo protection against Map were investigated in the rabbit infection model. Oral vaccination with inactivated or live vaccines was able to activate mucosal immunity as seen by elevation of serum IgA and the expression of IL4 in peripheral blood mononuclear cells (PBMCs). In addition, peripheral PMN phagocytosis against Map was enhanced by vaccination and extracellular trap release against Map and non-related pathogens was modified by both, vaccination and Map-challenge, indicating trained immunity. Finally, PBMCs from vaccinated animals stimulated in vitro with Map antigens showed a rapid innate activation cytokine profile. In conclusion, our data show that oral vaccination against PTB can stimulate neutrophil activity and both innate and adaptive immune responses that correlate with protection.

Nucleoside-modified messenger RNA COVID-19 vaccine platform

On March 11, 2020, the World Health Organization declared coronavirus disease 2019 (COVID-19) a pandemic; from that date, the vaccine race has begun, and many technology platforms to develop a specific and effective COVID-19 vaccine have been launched in several clinical trials (protein subunit, RNA-based, DNA-based, replicating viral vector, nonreplicating viral vector, inactivated virus, live attenuated virus, and virus-like particle). Among the next-generation strategies, nucleoside-modified messenger RNA vaccines appear the most attractive, not only to counteract emerging pathogens but also for the possible applications in regenerative medicine and cancer therapy. However, exactly as all innovative drugs, they deserve careful pharmacovigilance in the short and long term.

COVID-19 vaccine and boosted immunity: Nothing ad interim to do?

Today, Coronavirus Disease 2019 (COVID-19) is a global public health emergency and vaccination measures to counter its diffusion are deemed necessary. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the etiological agent of the disease, unleashes a T-helper 2 immune response in those patients requiring intensive care. Here, we illustrate the immunological mechanism to train the immune system towards a more effective and less symptomatic T-helper 1 immune response, to be exploited against SARS-CoV-2.