Testicular sperm maturation is critical for establishing male fertility. Spermatozoa undergo remodeling of sperm proteins and changes in lipid and ribonucleic acid composition during transport in the epididymal ducts, which play an important role in sperm maturation. The anatomy, epithelial cell types, physiological functions, and epigenetic inheritance of the epididymis are explored, and recent findings in epididymal research are analyzed. Suggesting possible directions for future research on the epididymis. Using the keywords “epididymis”, “sperm”, and “sperm maturation”, a search of the epididymis was performed through databases and official websites of journals related to reproduction. The epididymis was searched in databases and on the official websites of journals related to reproduction. This review introduces the characteristics of the epididymis, as well as the biological functions of cell types such as principal cells, clear cells, and basal cells, providing a detailed description of the overall physiological functions of the epididymis. It highlights current research hotspots in the field of epididymis, including single-cell analysis, epigenetics, and extracellular vesicles, aiming to offer a comprehensive understanding for beginners. The review emphasizes the importance of the epididymis, its impact on sperm maturation and subsequent embryo development, and how it advances research on epididymal diseases while providing new directions for the study and treatment strategies of infertility.

As the most severe novel infectious disease in this century, coronavirus disease 2019 (COVID-19) faces tremendous challenges due to the hysteresis of drugs and vaccine development. Elucidating the panoramic mechanism of coronavirus-host immune interaction is a strategy for disease surveillance, diagnosis, treatment, prevention, and immunity assessment of COVID-19. A robust carbon nanotube (CNT)-based photic vaccine technology contributes to address the core scientific issues of these challenges. This perspective states the latest prevention and control strategy of CNT-based photic vaccine and its broad-spectrum resistance to high transmissible and pathogenic variants. Furthermore, this perspective covers the potential immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) under the CNT-based photic vaccine intervention and finally evaluates its efficacy and the underlying interactive mechanisms. In the future, findings of the highly efficient and conservative T cell epitopes depending on an intelligent chem-physical modulation would provide a promising basis for the development of next generation vaccines. Ideally, these next generation vaccines are prone to be with the function of dynamic allostery responding to the chem-physical changing and present the allosteric epitopes which are affinity to the viral variation.

Aim: Antigen (Ag) presentation by Ag-presenting cells (APCs) is the first step in the generation of adaptive humoral and cellular immune responses. However, there have been few studies on the effects of flavonoids on APC function. In this study, we examined the effects of five polymethoxyflavones, two isoflavones, and one flavanol on CD11c⁺ dendritic cell function.

Methods: CD11c⁺ dendritic cells were differentiated from bone marrow cells by culturing with granulocyte macrophage-colony stimulating factor. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The Ag-presenting ability was determined by a mixed lymphocyte reaction assay. Expressions of MHC class II, CD40, CD80, and CD86 molecules on CD11c⁺ cells were determined by flow cytometric analysis. Lipopolysaccharide-induced inflammatory cytokines productions were determined by enzyme-linked immunosorbent assay.

Results: The flavonoids used in the study did not show strong toxicity to CD11c⁺ cells. Nobiletin, heptamethoxyflavone, and genistein enhance Ag-presenting function. Nobiletin and heptamethoxyflavone increased the expression of MHC class II and CD80 molecules. A direct correlation between APC function and lipopolysaccharide-induced cytokine production was not found.

Conclusions: The results of the in vitro study indicate that flavonoids, nobiletin, heptamethoxyflavone, and genistein regulate innate dendritic cell function.

Aim: The clinical symptoms of autoantibody (AAb)-mediated autoimmune diseases (AID) usually correlate with the AAb-titer. Immunoglobulins (Igs) of the IgG type are actively recycled by the neonatal crystallizable fragment receptor (FcRn). The most common Ig type of AAb is IgG. This explorative study evaluates the safety and tolerability of a fully human anti-FcRn monoclonal antibody (mAb) in patients with thyroid autoimmunity (TA).

Methods: Adverse events (AEs) and serious AEs (SAEs) were documented and coded according to the standardized Medical Dictionary for Regulatory Activities (MedDRA). AEs were followed up, and seriousness, as defined by the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH)-guideline E6, was documented. All AEs were analyzed for a possible underlying cause, and if not identified, were graded as side effects (SEs). Additionally, safety-relevant serological parameters (liver function and blood cell counts) were evaluated. Furthermore, laboratory parameters influenced by other anti-FcRn agents in clinical studies were considered.

Results: Of 31 patients with TA, 19 were administered the anti-FcRn mAb subcutaneously once weekly for 12 weeks, while 12 were on placebo. Compared to placebo, there was no increased occurrence of AE and/or SE in the mAb group. mAb treatment increased total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol. A mAb treatment-induced transient decrease in serum albumin strongly correlated with an increase in total cholesterol ( r = –0.893, P = 0.012). Overall compared to placebo, there were no significant changes in blood cell counts, complement factors, or liver enzymes. Serological changes were transient and spontaneously normalized after treatment completion. Two SAEs were deemed no-drug induced (dysthyroid optic neuropathy and a post-COVID infection associated autoimmune encephalomyelitis).

Conclusions: The anti-FcRn mAb is a safe and well-tolerated therapy for AAb-mediated AID.

Rheumatoid arthritis (RA) is a complex autoimmune disorder characterized by a spectrum of hypersensitivity reactions, encompassing Type II, Type III, and Type IV responses. Firstly, RA is marked by Type II hypersensitivity reactions driven by autoantibodies, such as rheumatoid factor (RF) and anti-(cyclic) citrullinated protein antibodies (ACPAs). These autoantibodies serve not only as serological markers for RA but also actively participate in inflammation, bone erosion, and clinical outcomes, with concurrent activation of the complement system involving C1q, C3, and C5 components specifically linked to RA progression and bone damage. Secondly, RA exhibits traits of Type III hypersensitivity, marked by the formation of immune complexes inciting inflammatory reactions. Immunoglobulin G (IgG) autoantibodies like RF and ACPA play pivotal roles in immune complex formation and the ensuing inflammatory responses. RA also demonstrates Type IV hypersensitivity propelled by CD4⁺ T cells, encompassing T helper 1 (Th1) and Th17 subsets. Th1 cells release interferon (IFN)-γ, promoting proinflammatory cytokines, while Th17 cells secrete IL-17, IL-22, and granulocyte-macrophage colony-stimulating factor (GM-CSF), contributing to synovial inflammation, bone and cartilage damage, and angiogenesis. RA concurrently exhibits features of Type II, Type III, and Type IV hypersensitivity. It is crucial to comprehend the presence and complex interplay of hypersensitivity responses and specific immune cell subsets in RA to create precise and efficient therapeutic approaches for the management of this incapacitating autoimmune condition. Thus, in this review, we aim to provide a comprehensive overview of the hypersensitivity features of RA.

Aim: Severe dengue is correlated with a decrease in the circulating complement regulator, factor H (FH) and prior work has shown that dengue virus (DENV) infection induces FH mRNA but not FH protein release. Here, the mechanisms of this phenomenon were defined.

Methods: HEK293 cells were infected with DENV-2 and changes in FH mRNA and protein were analyzed by real time reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and fluorescent microscopy. Additionally, cells were stimulated with size fractionated supernatants from DENV-infected cells, supernatant containing DENV non-structural protein-1 (NS1) without virus particles, and infections performed with or without the toll-like receptor-4 (TLR4) antagonist, TAK-242. Mass spectrometry was used to define the protein content of the fractionated supernatant, and treatment of cells with sialidase or heparinase was used to define cell-associated FH protein.

Results: DENV-infection induced full-length FH mRNA and cell-associated FH protein. Microscopy demonstrated membrane and intracellular-associated FH with a cytoskeletal and perinuclear localisation, in both DENV positive and uninfected neighboring bystander cells. Fractionation of cultured supernatant from DENV-infected cells demonstrated that secreted factors > 50 (kilodaltons) kDa induced FH mRNA and this could be blocked with TAK-242 but was not simulated by the TLR4 agonist, DENV NS1. Mass spectrometry detected DENV envelope, membrane and NS1, complement component 5 (C5), and complement FB, and indicated a > 20-fold increase in C4, inter-alpha-trypsin inhibitor heavy chain H2 (ITIH2), and alpha-2-macroglobulin in the > 50 kDa fraction from DENV-infected compared with conditioned media from uninfected cells. Sialic acid levels were unchanged and cleavage did not affect release of FH from DENV-infected compared to uninfected cells. In contrast, sulphated glycosaminoglycans (GAGs) were reduced in the cultured supernatant and cell lysates following DENV-infection, and heparinase cleavage released significantly more FH from DENV-compared with uninfected cells.

Conclusions: Following DENV-infection, secreted molecules induce FH that remains intracellular and with increased binding to cell surface heparan sulphate. The mediators of induction of FH mRNA act in trans and via TLR4 but this is not likely to be via DENV NS1. The retention of FH in the local environment of the infected cell could benefit the virus by negating local complement killing of cells, and/or benefit the host by inhibition of heparan sulphate-mediated DENV infection to restrict viral spread.

The skin, as the first physical barrier for invading pathogens, also serves as an immunologically active organ. Breaching the skin barrier is thus essential for pathogens to enter the body. The skin contains various immune responsive cells that initiate both the innate and adaptive immune response upon invasion. Activated immune cells help to regulate cytokine response and their differentiation to promote or suppress the crucial immune response against invading pathogens. Human herpes simplex viruses (HHSVs) are the oldest pathogen that can escape immune surveillance of the human host by a well-developed escape mechanism within ganglia, as their evolutionary strategy. In primary infection, a non-specific defense of the host initiates the response against the invading virion. The initial direct antiviral action of the host is regulated by activated macrophages, via the release of cytokines like tumor necrosis factor (TNF), and type-1 interferon (IFN-1). The host-derived cytokines including IFN-12, TNF, and IFN-1 in turn induce natural killer (NK) cells to release IFN-γ. Their positive feedback with synergistic interactions collectively releases nitric oxide (NO) and reactive oxygen species (ROS) against the invading virus. Simultaneously, the combination of cytokines, macrophages, and other cells activates the immune system to eliminate the pathogen. However, the virus has also evolved various mechanisms to counter the host defense strategies. This review will highlight virus-mediated skin infections, especially by HSV, and portray a detailed role of virus-induced cytokines in host-immunity to challenge the invading virion during mucocutaneous HSV infection. Further, this review will discuss the viral-interference on host defense to provide a simplistic overview of the complications of cutaneous HSV infection.