Summary: Over the past decade, compelling evidence has unveiled previously overlooked adaptive characteristics of innate immune cells. Beyond their traditional role in providing short, non‐specific protection against pathogens, innate immune cells can acquire antigen‐agnostic memory, exhibiting increased responsiveness to secondary stimulation. This long‐term de‐facto innate immune memory, also termed trained immunity, is mediated through extensive metabolic rewiring and epigenetic modifications. While the upregulation of trained immunity proves advantageous in countering immune paralysis, its overactivation contributes to the pathogenesis of autoinflammatory and autoimmune disorders. In this review, we present the latest advancements in the field of innate immune memory followed by a description of the fundamental mechanisms underpinning trained immunity generation and different cell types that mediate it. Furthermore, we explore its implications for various diseases and examine current limitations and its potential therapeutic targeting in immune‐related disorders.

Onychomycosis is a chronic fungal infection of nails, commonly caused by dermatophyte fungi, primarily species of Trichophyton. Because of the limited drug arsenal available to treat general fungal infections and the frequent failure of onychomycosis treatment, the search for new therapeutic sources is essential, and topical treatment with natural products for onychomycosis has been encouraged. Propolis, an adhesive resinous compound produced by honeybees (Apis mellifera), has shown multiple biological properties including significant antifungal and anti-biofilm activities in vitro. In spite of promising in vitro results, in vivo results have not been reported so far. This study assessed an ethanol propolis extract (PE) as a topical therapeutic option for onychomycosis, including its characterization in vitro and its applicability as a treatment for onychomycosis (from bench to clinic). The in vitro evaluation included analysis of the cytotoxicity and the antifungal activity against the planktonic cells and biofilm formed by Trichophyton spp. We also evaluated the capacity of PE to penetrate human nails. Patients with onychomycosis received topical PE treatments, with a 6-month follow-up period. The results of the in vitro assays showed that PE was non-toxic to the cell lines tested, and efficient against both the planktonic cells and the biofilm formed by Trichophyton spp. The results also showed that PE is able to penetrate the human nail. The results for PE applied topically to treat onychomycosis were promising, with complete mycological and clinical cure of onychomycosis in 56.25% of the patients. PE is an inexpensive commercially available option, easy to obtain and monitor. Our results indicated that PE is a promising natural compound for onychomycosis treatment, due to its ability to penetrate the nail without cytotoxicity, and its good antifungal performance against species such as Trichophyton spp. that are resistant to conventional antifungals, both in vitro and in patients.

The increasing incidence in systemic fungal infections in humans has increased focus for the development of fungal vaccines and use of monoclonal antibodies. Invasive mycoses are generally difficult to treat, as most occur in vulnerable individuals, with compromised innate and adaptive immune responses. Mortality rates in the setting of our current antifungal drugs remain excessively high. Moreover, systemic mycoses require prolonged durations of antifungal treatment and side effects frequently occur, particularly drug-induced liver and/or kidney injury. The use of monoclonal antibodies with or without concomitant administration of antifungal drugs emerges as a potentially efficient treatment modality to improve outcomes and reduce chemotherapy toxicities. In this review, we focus on the use of monoclonal antibodies with experimental evidence on the reduction of fungal burden and prolongation of survival in in vivo disease models. Presently, there are no licensed monoclonal antibodies for use in the treatment of systemic mycoses, although the potential of such a vaccine is very high as indicated by the substantial promising results from several experimental models.

Aim: Elucidate the antifungal efficacy of biologically synthesized silver nanoparticles with ethanolic propolis extract (AgNPs PE) against the planktonic forms and biofilms of clinically important ...

Myeloid innate immune cells, including macrophages, neutrophils, myeloid-derived suppressor cells, and dendritic cells, represent major components of the tumor microenvironment (TME), exhibiting remarkable plasticity and dual roles in cancer progression and immune regulation. In recent years, microbial-induced innate immune memory, also termed "trained immunity" (TRIM), has emerged as a novel strategy to reprogram myeloid cells into an immunostimulatory, antitumor state. In this review, we explore the intricate landscape of myeloid cells in cancer and examine how microbial ligands, such as the Bacillus Calmette-Guérin vaccine and β-glucan, reprogram both bone marrow progenitors and tissue-resident myeloid cells to enhance inflammatory and antitumor responses. Notable findings include the hematopoietic stem and progenitor cell reprogramming by Bacillus Calmette-Guérin for sustained anticancer immunity, and the enhanced granulopoiesis and neutrophil-mediated tumor killing mediated by β-glucan-induced TRIM. These mechanisms synergize with immunotherapies, such as immune checkpoint inhibitors, by reshaping the immunosuppressive TME and enhancing adaptive immunity. However, challenges remain, including the structural complexity of microbial products, the lack of predictive biomarkers, and the need for optimized dosing and delivery strategies. Addressing these gaps by introducing precise characterization of microbial-derived ligands, biomarker-driven patient selection through large-scale clinical trials, as well as the development of novel approaches for targeted therapy will be essential to harness the full potential of microbial-induced TRIM, ultimately paving the way for more effective and durable cancer immunotherapies. SIGNIFICANCE STATEMENT: Tumor-promoting myeloid cells within the tumor microenvironment remain a major barrier to effective cancer immunotherapy. Microbial-induced trained immunity offers a novel strategy to reprogram myeloid cells into an antitumor state. This review provides a comprehensive overview of myeloid cell populations in cancer and the mechanisms underlying microbial-induced trained immunity. It also highlights preclinical and clinical evidence demonstrating the efficacy of microbial-based strategies in overcoming immunosuppression and synergizing with existing immunotherapies, offering a promising approach to improve cancer treatment outcomes.