The potential role of bovine leukemia virus (BLV), a zoonotic deltaretrovirus, in human breast carcinogenesis remains controversial, and evidence from seroepidemiological studies is limited. This study aimed to evaluate BLV IgG seroprevalence in women with malignant breast cancer and benign breast lesions and to explore the possible association between BLV exposure and breast cancer development. In this cross-sectional comparative study, a total of 124 women aged ≥18 years who presented to Ankara Etlik City Hospital between May and July 2024 were included. The malignant group comprised 82 women with histopathologically confirmed breast cancer, while the control group included 42 women with benign breast lesions. Serum samples were analyzed for BLV-specific IgG antibodies using a commercial enzyme-linked immunosorbent assay kit. Overall BLV IgG seroprevalence was 12.9% (16/124), with rates of 13.4% in the malignant group and 11.9% in the benign group, showing no statistically significant difference (p = 0.812). In the malignant group, BLV IgG seropositive patients were significantly older than seronegative patients, and seropositivity increased with age (p < 0.01). Although higher BLV IgG seropositivity were observed in invasive mucinous carcinoma cases, this association did not reach statistical significance in logistic regression analysis. Hematological parameters were evaluated to investigate potential systemic immune or inflammatory responses associated with BLV exposure; however, no significant associations were identified between BLV IgG seropositivity and these parameters. These findings suggest that BLV exposure, as reflected by humoral immune response, is not directly associated with breast cancer development but may represent cumulative or long-term exposure. Further large-scale, multicenter studies integrating molecular and serological approaches are warranted to clarify the potential role of BLV in human breast cancer etiology.

The SEN virus (SENV), a DNA virus that has been linked to blood transfusion, is a major cause of post-transfusion hepatitis. SENV-D and SENV-H are non-A to E hepatitis viruses. The present study was conducted to investigate the prevalence of SENV-D/H among dialysis patients and blood donors as control group in Diyala province/Iraq. This study includes 120 participants: 80 dialysis patients who have been attending the Ibn-Sina Dialysis Center-Diyala Directorate of Health were previously diagnosed with the disease, and 40 individuals as controls were selected at random from blood donors at the Central Blood Bank during the period from 1/5/2025 to 30/11/2025. Full information had been taken directly from the patients, and the information had been arranged in an informative formula sheet, which includes age and gender. All study subjects were screened for nested polymerase chain reaction. The SENV-D prevalence was 10 (12.50%) and 0.00% for dialysis patients and controls, respectively, and SENV-H was 5 (6.25%) and 1 (2.50%) for dialysis patients and controls, respectively. The SENV co-infection rate of genotypes D and H was 3 (7.50%) in the dialysis group, and no cases in the control group were found. A very strong association was found between the distinct SENV genotypes and Hepatitis B virus (HBV) or Hepatitis C virus (HCV) status. Positivity for SENV was also correlated with high serum Aspartate Aminotransferase (AST) and Alanine aminotransferase (ALT). SENV-D and SENV-H were more prevalent among hemodialysis patients than in normal blood donors. The presence of SEN-V in both groups indicates its categorization as a blood-borne virus and suggests risk for transmission by blood exposure.

This study aimed to characterize Epstein-Barr virus (EBV) serological markers and EBV DNA profiles in a healthy examination cohort from Chongqing, China, and to examine their associations with routine hematological and biochemical parameters. This retrospective cross-sectional study included adults undergoing routine health examinations in Chongqing between 2019 and 2024. EBV serology (EA-IgA and VCA-IgA) was assessed in 4,535 individuals using ELISA, and EBV DNA was measured in 6,508 individuals by quantitative PCR. Hematological indices and liver and renal function markers were compared across EBV antibody subgroups and EBV DNA status. Multivariable linear regression analyses were performed with adjustment for age and sex. VCA-IgA seroprevalence was significantly higher than EA-IgA (13.38% vs. 6.09%, p < 0.001), with both peaking in the 41-50-year age group. EBV DNA was detected in 7.24% of individuals, with positivity increasing with age (≥61 years: 12.09%) and being higher in males than females (7.81% vs. 6.06%, p = 0.010). Among EBV DNA-positive individuals, 86.17% had low viral loads (<104 copies/mL). After adjustment, EBV seropositivity and EBV DNA positivity were independently associated with statistically significant differences in leukocyte subsets and hepatic and renal markers; however, all median values remained within established clinical reference ranges. EBV infection markers in this inland Chinese health examination population exhibited distinct age- and sex-related distributions and showed independent associations with subtle physiological variations rather than overt pathology. Importantly, EBV serological markers and EBV DNA demonstrated differential association patterns, indicating that they convey complementary and nonredundant biological information in assessing EBV infection status.

BK polyomavirus (BKPyV) is highly prevalent and clinically relevant in immunocompromised populations, underscoring the need for reliable serological tools to support epidemiological monitoring and clinical follow-up. This study aimed to generate a recombinant VP1-based enzyme-linked immunosorbent assay (ELISA) using a baculovirus-Sf9 insect cell system and to explore its application in a human serum cohort. Recombinant VP1 was produced by baculovirus-mediated expression, purified by nickel-nitrilotriacetic acid affinity chromatography, and used to establish an indirect IgG ELISA. A plasmid-based transient expression approach in Sf9 cells was evaluated only as a feasibility experiment and did not yield sufficient VP1 for assay development. Analytical performance was assessed using a polymerase chain reaction (PCR)-defined serum panel (n = 30), and the assay was subsequently applied to 149 sera with unknown BKPyV status. Baculovirus-mediated expression generated high-purity VP1 with an average yield of approximately 1.55 mg/mL from a 10 mL culture. PCR-confirmed positive sera showed markedly higher optical density values than PCR-negative sera, with very good analytical discrimination in this small validation set (area under the curve = 0.996). In the cohort analysis, overall seroreactivity was 89.7%, antibody reactivity increased with age, and higher ELISA signals were observed in renal transplant and hemodialysis patients than in healthy individuals. Detectable reactivity in young children may reflect early exposure or passive maternal antibodies. These findings indicate that insect cell-derived BKPyV VP1 is a suitable antigen for serological assays and a practical platform for preliminary seroepidemiological applications, which require confirmation in larger independent validation cohorts.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has led to a global health crisis by triggering extensive systemic and immune dysregulation. Granulocytes, including neutrophils, eosinophils, and basophils, are critical components of the innate immune system that play dual roles in protection and pathogenesis during infection. In this review, we examine the multifaceted roles of granulocytes in COVID-19 and their impact on disease severity through excessive inflammation, cytokine storm, and tissue damage. Neutrophil extracellular traps (NETs) and the overactivation of neutrophil subtypes contribute to the development of thrombosis and acute respiratory distress syndrome. In contrast, eosinophils and basophils modulate T helper 2-type and allergic responses that may influence recovery or disease progression. We further summarize the therapeutic strategies targeting granulocyte activation and signaling pathways, including IL-1, IL-6, IL-17, IL-5 receptor, granulocyte-macrophage colony-stimulating factor inhibitors, and antihistamines, emphasizing their clinical outcomes, approval status, and the global regions in which they are studied. Understanding the regulatory mechanisms of granulocyte activation and inhibition provides new insights into COVID-19 immunopathology and opens pathways for targeted immunomodulatory therapy. These findings underscore the importance of balancing protective immune functions with controlled anti-inflammatory interventions to mitigate the severe complications of SARS-CoV-2 infection.

The immunological properties of recombinant hepatitis B surface antigen (rHBsAg), prepared using yeast (Saccharomyces cerevisiae [SC]) and Chinese hamster ovary (CHO) cells, were evaluated through in vitro and invivo assays to support the efficacy of recombinant hepatitis B vaccines. In vitro, antigenicity was assessed by measuring the affinity of rHBsAg to anti-HB antibodies using surface plasmon resonance. In vivo, mice were intraperitoneally injected with 3 µg of simulated vaccines containing anti-HB antibodies absorbed onto aluminum hydroxide adjuvant. Humoral responses were evaluated by measuring serum anti-HB antibody titers and seroconversion rates on days 7, 14, 21, and 28. Cellular immune responses were assessed based on cytokine (Interferon-γ-IFN-γ) and (Tumor Necrosis Factor-α- TNF-α) production from splenic lymphocytes on day 28 postimmunization. A recombinant Huh-7-HBsAg cell line, developed to analyze cellular immune responses, was established through cytotoxicity and apoptosis assays. In vitro, the equilibrium dissociation constant (KD) of rHBsAg from CHO cells was significantly lower than that from yeast cells, indicating stronger antibody affinity. In vivo, rHBsAg-CHO induced faster and higher antibody titers compared with rHBsAg-SC. Cellular responses showed higher levels of TNF-α and IFN-γ for rHBsAg-CHO. In addition, the rHBsAg-CHO group exhibited higher late apoptosis rates in target cells. The rates induced in the rHBsAg-CHO and rHBsAg-SC groups were 25.0% and 19.2%, respectively. In conclusion, this study demonstrates that the immunological properties of rHBsAg vary based on the expression systems and provides nonclinical data supporting the evaluation of vaccine efficacy.

Background: Interleukin-37 (IL-37) can prevent liver damage and may be an important candidate for use as a novel therapeutic tool in hepatitis B virus (HBV) infection. This study aimed to evaluate the serum levels of IL-37 in individuals with chronic HBV (CHB) infection, those who spontaneously cleared (SC) HBV infection, compared with healthy control (HC) subjects. Materials and Methods: This case-control study included 30 patients with CHB (17 males, 13 females; mean age, 50.13 ± 14.51), 30 subjects with SC HBV infection (16 males, 14 females; mean age, 51.50 ± 16.85), and 42 HC subjects (22 males, 20 females; mean age, 53.52 ± 14.44). Blood samples were collected, and then serum IL-37 levels were measured using an enzyme-linked immunosorbent assay kit. Results: Our results showed that serum IL-37 levels were significantly higher in the CHB (96.99 ± 13.39 pg/mL) than in the HC group (37.85 ± 2.99 pg/mL, p = 0.02). No statistically significant differences were found in IL-37 serum levels between CHB group and SC group (91.93 ± 17.11 pg/mL, p = 0.43). Correlation analysis showed a significant negative correlation between serum IL-37 levels and age in SC subjects (p = 0.02, R = -0.42). Conclusion: Our results suggest that increased production of IL-37 may biologically act as a negative feedback loop to attenuate the release of pro-inflammatory cytokines and subsequently alleviate disease symptoms in CHB. The negative correlation between the cytokine and age may indicate that higher levels of IL-37 in younger individuals may lead to the spontaneous clearance of HBV.

Evaluating the impact of cardiac surgery on humoral and cellular immunity in pediatric congenital heart disease patients with prior Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection or vaccination is crucial for postoperative care planning. This study enrolled 61 pediatric patients undergoing cardiac surgery with cardiopulmonary bypass at a single institution. Measurements were taken before the operation, immediately postoperation, and during the first follow-up examination at least 1 month later. The evaluations included SARS-CoV-2-specific immunoglobulin G (IgG) and neutralizing antibodies for humoral immunity assessment, as well as specific and nonspecific T-cell immune responses to gauge T-cellular immunity and functionality. The results demonstrated that the serum titers of IgG and neutralizing antibodies remained comparable postsurgery to preoperative levels. Nevertheless, significant decreases in specific and nonspecific T-cell immune responses, along with a decline in CD3+ T-cell numbers, were observed immediately following surgery. This was followed by a gradual recovery of immune response to preoperative levels approximately 1 month later. These findings suggest that in the first month following cardiac surgery in pediatric patients, residual specific antibodies, potentially derived from the original production or plasma transfusion, may provide partial protection against COVID-19 infection. Subsequently, T-cellular immunity gradually recovers and resumes its protective role. The study provides important insights into the dynamics of immune recovery following cardiac surgery in this vulnerable patient population, which may be essential for optimizing postoperative management and reducing the risk of COVID-19 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, has been spreading and changing globally. Adjuvant-based vaccines can improve vaccine protection by enhancing the immune response. Bacterial flagellin is a potent adjuvant and promotes protective immune responses. Here, we successfully expressed and purified the S1 subunit of SARS-CoV-2. The adjuvanticity of flagellin (FliC) of Salmonella Typhimurium in mice was determined by combining it with the recombinant S1 subunit vaccine. FliC-adjuvanted S1 vaccine could induce significantly enhanced S1-specific Immunoglobulin G (IgG), IgG1 and IgG2a titers, SARS-CoV-2-neutralizing antibodies, and levels of Th1 type (TNF-α and IFN-γ) and Th2 type (Interleukin-5 (IL-5), IL-4, IL-10, and IL-13) cytokines in splenocytes compared with the S1 alone group. Additionally, the titers of S1-specific IgG antibodies in the FliC adjuvant group could maintain a high level for at least 2 months. These results indicated that the FliC-adjuvanted S1 subunit vaccine could trigger strong humoral and cellular immune responses, which could promote the ongoing development of COVID-19 vaccines.

The Heartland virus (HRTV) is a tick-borne human pathogenic phlebovirus that primarily causes leukopenia and thrombocytopenia. It is transmitted by Amblyomma americanum type of tick, that is, notable for their aggressive biting behavior, affinity for human hosts, and high prevalence. Developing vaccines or immunizations against HRTV is gaining importance as a public-health preventive strategy. The current study was planned to prioritize a multi-epitope stable mRNA vaccine model against HRTV from lead B-cell and T-cell epitopes (with IC50 < 100 nM) of HRTV proteome following advanced immunoinformatics approaches. Model constructs were designed by linking the most potent, nonallergenic epitopes along with incorporation of human ribosomal protein adjuvant for immune response enhancement. The immunogenic potential of the coding vaccine molecule was examined via molecular docking against toll-like receptors immune receptors followed by normal mode analysis and molecular dynamics simulations-based energy minimization, molecular stability, and flexibility assessments. A robust, stable circular mRNA precursor of multi-epitopes vaccine model was designed by incorporating the Kozak consensus sequence, a start codon, and essential elements such as MHC class I trafficking domain (MITD), tPA, Goblin 5' and 3' Untranslated Region (UTRs), and a poly (A) tail. This strategic amalgamation ensures elevated immunogenicity and predicts a promising circular mRNA vaccine model against HRTV. The immune simulation predicted that the designed model vaccine is capable to elicit cell-mediated and humoral immune responses. The predicted circular mRNA vaccine precursor model is promising against HRTV to examine experimentally for its immunogenicity and safety features.