This year's thematic is the seventeenth Immunological Investigations' thematic issue, and is entitled, "Micro and Nanoparticles in Immune Modulation". This topic was suggested by the editorial board last year. Applications using nano and microparticles occur in many medical fields and it is important to review how these particles affect the innate and the acquired immune system. The elegance of these systems intrigues both novice and experienced scientists, and attempts to modulate the immune system, either by up or downregulating it, can cause changes in many important aspects. Thus, in this issue, we focused on Micro and Nanoparticles in Immune Modulation. Like the effects and uses of nano and microparticles, this thematic is broad in scope. This thematic is a collection of articles on micro and nanoparticles that includes "Particulate matter, asian sand dust delays cyclophosphamide-induced type 1 diabetes in NOD mice" (Morita et al. 2019), "Bovine milk exosomes affect proliferation and protect macrophages against cisplatin-induced cytotoxicity" (Matic et al. 2020), "Exosomes represent an immune suppressive T cell checkpoint in human chronic inflammatory microenvironments" (Shenoy et al. 2020), "Immunosuppressive effect of "melanoma-derived exosomes on NY-ESO-1 antigen-specific human CD8 + T cells is dependent on IL-10 and independent of BRAF V600E mutation in melanoma cell lines" (Shu et al. 2020), Vaccine efficacy induced by 2009 pandemic H1N1 virus-like particles differs from that induced by split influenza virus" (Lee et al. 2019), "Metal nanoparticles in infection and immunity" (Crane 2020), "Microspheres encapsulating immunotherapy agents target the tumor-draining lymph node in pancreatic ductal adenocarcinoma" (Han et al. 2020), "Cytokine-encapsulated biodegradable microspheres for immune therapy" (Egilmez 2020), "Design and öptimization of PLGA particles to deliver immunomodulatory drugs for the prevention of skin allograft rejection" (Shahzad et al. 2019), "Biological function and immunotherapy utilizing phosphatidylserine-based nanoparticles" (Glassman et al. 2020) and "Mesenchymal stem cell-derived extracellular vesicles: a novel cell-free therapy" (Jafarinia et al. 2020). Several Immunological Investigation articles in the past 3 years have focused on the use on nanoparticles or microparticles in immunomodulation or as tools for immunologists, and these included "Poly lactic-co-glycolic acid nanoparticles containing human gastric tumor lysates as antigen delivery vehicles for dendritic cell-based antitumor immunotherapy" (Kohnepoushi et al. 2019), "Ïmmune correlates of protection induced by virus-like particles containing 2009 H1N1 pandemic influenza HA, NA or M1 proteins, immunological investigations" (Moon et al. 2019), "A "novel PspA protein vaccine intranasal delivered by bacterium-like particles provides broad protection against pneumococcal pneumonia in mice, immunological investigations" (Wang et al. 2018), and "Immunomodulatory activities of curcumin-stabilized silver nanoparticles: efficacy...
