Search Results (83)

Background: Immune checkpoint inhibitor therapy in patients with lung cancer and metastatic melanoma is associated with exacerbation of autoimmune-related diseases. The efficacy of treatment targeting the programmed cell death receptor-1 (PD-1) checkpoint relies upon a feedback loop between interferon gamma (IFN-γ) and the interleukin-12 isoform, IL-12p40. Paradoxically, both cytokines and the anti-PD-1 antibody worsen psoriasis. We previously reported an immunomodulating peptide, designated IK14004, that inhibits progression of Lewis lung cancer in mice yet uncouples IFN-γ from IL-12p40 production in human immune cells. Methods: Immune cells obtained from healthy donors were exposed to IK14004 in vitro to further characterise the signalling pathways affected by this peptide. Using C57BL/6 immunocompetent mice, the effect of IK14004 was tested in models of lung melanoma and psoriatic skin. Results: Differential effects of IK14004 on the expression of IFN-α/β, the interleukin-15 (IL-15) receptor and signal transducers and activators of transcription were consistent with immune responses relevant to both cancer surveillance and immune tolerance. Moreover, both melanoma and psoriasis were inhibited by the peptide. Conclusions: Taken together, these findings suggest mechanisms underlying immune homeostasis that could be exploited in the setting of cancer and autoimmune pathologies. Peptide administered together with checkpoint blockers in relevant models of autoimmunity and cancer may offer an opportunity to gain further insight into how immune tolerance can be retained in patients receiving cancer immunotherapy. Full article

Background/Objective: Virus-based vaccine vectors have been widely utilised in commercial vaccines, predominantly for virus infections. They also offer promise for bacterial diseases, for which many vaccines are sub-optimal or ineffective. It is well-established for chlamydial infections, including ovine enzootic abortion, that the major outer membrane protein (MOMP) antigen is protective. Immune responses strongly associated with controlling Chlamydiae include cellular interferon-gamma (IFN-γ) production. Methods: A study was conducted to compare the ability of a modified Orf virus vector directly with a modified sheep maedi visna virus vector to deliver the C. abortus antigen ompA and stimulate vaccine-induced responses in sheep. The Orf virus-based vaccine (mORFV-ompA) was found to be more effective in stimulating MOMP-specific antibodies and cellular antigen-driven IFN-γ in immunised sheep. This mORFV-ompA vaccine was assessed in a follow-up immunogenicity investigation in sheep, where the cellular and humoral immune responses elicited following immunisation with the live or inactivated vaccine were determined. Sheep were immunised intramuscularly with a live mORFV-ompA (n = 10) or an inactivated mORFV-ompA (n = 10). An additional group of 10 sheep served as unvaccinated controls. Results: Serological anti-MOMP antibodies and cellular recall responses of peripheral blood mononuclear cells to the native C. abortus antigen were assessed. Immunisation with either the live or inactivated mORFV-ompA-induced anti-MOMP immunoglobulin-G. Antigen-specific cellular responses, characterised by the secretion of IFN-γ and interleukin (IL)-17A, with negligible IL-10 and no IL-4, were detected in lymphocyte stimulation assays from both mORFV groups. No antibody responses to the mORFV platform were detected following immunisations. Conclusions: Both live and inactivated vaccines have the potential to be a platform technology for deployment in sheep. This addresses a notable gap in veterinary vaccine development where the induction of both humoral responses and cellular responses is required without using an adjuvant. The successful use of the MOMP candidate antigen suggests potential utility for bacterial disease deployment. Full article

Compounds in sand fly saliva elicit specific immune responses that may play a role in the establishment of canine Leishmania infection. Although canine antibodies to anti-sand fly saliva antigens have been extensively studied, little is known about cellular immune responses against Phlebotomus perniciosus salivary proteins. This study aimed to explore humoral and T-cell-mediated immunity against P. perniciosus salivary proteins in dogs (n = 85) from Mallorca (Spain), a leishmaniosis-endemic area, and find correlations with demographic (age, sex, and breed) and parasite-specific immunological parameters. Anti-sand fly saliva IgG was examined using a P. perniciosus whole salivary gland homogenate (SGH) ELISA and recombinant salivary protein rSP03B ELISA. Interferon gamma (IFN-γ) release whole blood assays with L. infantum soluble antigen (LSA), SGH, and rSP03B were also performed. Positive correlations were found between IgG levels in the SGH and rSP03B tests and between concentrations of SGH IFN-γ and rSP03B IFN-γ. While concentrations of SGH IFN-γ and rSP03B IFN-γ were low and produced only by a minority of dogs (less than 20%), high levels and frequencies of LSA IFN-γ as well as anti-saliva IgG for SGH and rSP03B were detected in a majority of dogs (61% and 75%, respectively). LSA IFN-γ levels were positively correlated with age and Leishmania-specific antibodies. In conclusion, dogs from a leishmaniosis-endemic area presented high humoral immunity against P. perniciosus salivary proteins, but their cellular immunity to these proteins was low and less frequent. Full article

Objectives: Iodine and selenium are key elements for thyroid. There is also evidence of their immunoregulatory potential. However, the current state of knowledge of potential interactions among iodine—selenium—thyroid—immune system is not sufficient. The aim of the study was to evaluate iodine and selenium statuses and examine the relationship between them and the functioning of the thyroid and immune system in a group of women of reproductive age, without previously diagnosed disease. Methods: The study involved a group of 60 women aged 19–40 from southern Poland. The concentrations of iodine and selenium were determined in serum samples using the ICP-MS and AAS methods, respectively. Thyroid function was assessed by determining serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), and anti-thyroid peroxidase antibodies (anti-TPO) by electrochemiluminescence methods. Glutathione peroxidase 3 (GPX3) and ferric ion reducing antioxidant power (FRAP) in serum were measured by spectrophotometric methods. Immune functions were evaluated by analyzing cytokine levels using ELISA tests, including interferon-γ, interleukin-4, interleukin-17, and transforming growth factor-β. Results: No significant correlations between selenium and thyroid or immunological parameters were observed. The level of iodine in serum positively correlated with free thyroxine, indicating its importance for maintaining normal thyroid function, as well as with FRAP in serum, suggesting a protective role of iodine-mediated antioxidant activity on thyroid function. Conclusions: Our results underline the complexity of the system of correlations between iodine–selenium–thyroid–immune function. Nevertheless, understanding them may turn out to be crucial for developing preventive and therapeutic strategies in the context of thyroid diseases. Full article

Background/Objectives: Q-VAX vaccine, approved in Australia, prevents Q fever. However, individuals with prior Coxiella burnetii (Cb) infection have an increased risk of adverse reactions, requiring pre-vaccination screening by an intradermal hypersensitivity skin test for cell-mediated immune memory and a serological assay for anti-Cb antibodies. The week-long interval for skin test assessment limits efficient vaccination. This study evaluated a standardized interferon-γ release assay (IGRA) as a potential skin test alternative. Methods: Immune assays were compared in Australian populations with different incidences of prior Cb exposure. Cell-mediated immunity was assessed by the Q-VAX skin test and IGRA. Serological status was evaluated with established diagnostic assays. Hypothetical vaccine eligibility decisions using combined IGRA and serology results were compared with actual clinical decisions made using current guidelines. Results: All tests performed better in detecting prior infection than in detecting prior vaccination. Only the IGRA identified all individuals with a known history of Q fever. Agreement between the skin test and IGRA was limited. Moderate agreement was observed between hypothetical vaccine eligibility determinations based on IGRA plus serology results and actual clinical decisions. IGRA-positive but serology- and skin test-negative individuals received Q-VAX without clinically significant side effects, suggesting that elevated IGRA responses alone are not predictive of susceptibility to vaccine reactogenicity. Conclusions: The IGRA is not yet a suitable skin test replacement when assessing eligibility for Q fever vaccination, despite the significant limitations of the latter. We offer recommendations for designing future studies that might allow the development of appropriate guidelines for IGRA use in vaccine eligibility screening. Full article

Background/Objectives: The aim of our study was to investigate B cell and T cell responses in people with multiple sclerosis (PwMS) treated with ocrelizumab, a humanized anti-CD20 antibody, who were vaccinated with second and/or booster doses of various vaccine brands against COVID-19. Additionally, we detected the outcomes related to COVID-19 in PwMS after vaccination, based on follow-up for at least 12 months. Methods: We enrolled 91 PwMS on ocrelizumab and 42 healthy controls (HCs) in a prospective, single-center study, conducted at the Clinic of Neurology, UCCS, between January 2022 and October 2024. The serological responses were measured using the spike receptor-binding domain (RBD) Architect SARS-CoV-2 IgG Quant kit (Abbot), and cellular responses were measured by quantifying IFN-γ secretion in blood incubated with SARS-CoV-2 antigens. Results: A total of 58.2% (53/91) of PwMS on ocrelizumab and 100% of the HCs (42/42) were seropositive after a second or booster vaccination (p < 0.001), irrespective of the vaccine brand received. Anti-spike antibody levels were significantly lower in PwMS on ocrelizumab compared to the HCs (p < 0.001), again irrespective of the vaccine type. Interferon-γ responses were detected in 95.6% of the PwMS receiving ocrelizumab therapy and 97.6% of HCs after vaccination (p = 0.570). In our cohort, PCR-confirmed SARS-CoV-2 infections after vaccination occurred in a similar proportion of the PwMS (45/91, 49.5%) and HCs (15/32, 46.9%) (p = 0.139). Most of the PwMS (36/45, 79.2%) and HCs (13/15, 87.8%) had COVID-19 of mild severity. Conclusions: PwMS treated with ocrelizumab developed diminished humoral and robust cellular responses following two and three SARS-CoV-2 vaccinations. The obtained immunity after SARS-CoV-2 vaccination may translate into lower incidence and severity of COVID-19. Full article

Background/Objectives: Chlamydia trachomatis (Ct) is the leading bacterial cause of sexually transmitted infection globally. If undiagnosed or left untreated, these infections can lead to serious complications such as infertility, ectopic pregnancies, and chronic pelvic pain. Despite the high prevalence and potential for serious health complications, no vaccine has been licensed. Pigs offer a valuable biomedical model for chlamydia research: they have an overall high degree of similarity to humans and serve as natural hosts for Chlamydia suis (Cs), a close relative of Ct. Thus, in this study, the pig model was used to evaluate a vaccine candidate against Ct. Methods: The vaccine candidate consists of chlamydial-protease-like activity factor (CPAF) protein adjuvanted with STING (Stimulator of Interferon Genes) pathway agonist cyclic-di-AMP (c-di-AMP). Pigs received two doses intramuscularly followed by two intranasal doses. Each week, the systemic T cell response was assessed via IFN-γ and IL-17 ELISpots, as well as multi-parameter flow cytometry on 0, 14, and 28 days post vaccination (dpv). The humoral immune response was analyzed by measuring CPAF-specific antibody levels and avidity via ELISAs. Results: Vaccination with c-di-AMP adjuvanted CPAF triggered low-level systemic IFN-γ and multifunctional IFN-γ⁺TNF-α⁺ CD4 T cell responses. Despite the rather low systemic effector cytokine production, robust anti-CPAF IgG responses were detected in serum, vaginal swab eluates, and oviduct flushes. Genital Ct challenge 42 dpv resulted in only transient infection, precluding a confident assessment of vaccine efficacy of the tested CPAF/c-di-AMP vaccine candidate. However, after challenge, vaccinated pigs exhibited boosted systemic anti-CPAF IFN-γ and mucosal IgG responses compared to unvaccinated pigs. Conclusions: Thus, while vaccine efficacy remains elusive, the CPAF/c-di-AMP vaccine candidate was immunogenic: it elicited a low-level systemic cell-mediated response and robust humoral immune responses. Future studies will incorporate a STING agonist directly conjugated to CPAF as well as addition of other Th1-inducing adjuvants to enhance cellular immunity. Full article

Background/Objectives: Long-term studies on the immune response following multiple doses of SARS-CoV-2 mRNA vaccines remain limited. Methods: Secondary analyses of data from a cohort of non-immunocompromised subjects who received two doses of BNT162b2 (primary vaccination) and a booster with mRNA-1273 nine months later. Antibodies targeting the receptor-binding domain of the S1 subunit of the SARS-CoV-2 spike (anti-RBD) were measured at eight time points during follow-up; the SARS-CoV-2-specific T cell response was measured 16 and 25 months after primary vaccination using an interferon-γ release assay. Results: During the 9-month follow up period after primary vaccination and before the mRNA-1273 booster, anti-RBD were significantly higher at all time points in subjects with documented SARS-CoV-2 infection before the first study time point (previously infected subjects; n = 50) compared to naïve subjects (n = 208; p < 0.05). During a 16-month follow up period following the mRNA-1273 booster, anti-RBD were lower at all time points in previously infected subjects (n = 21) compared to naïve subjects (n = 109), although the differences were non-significant. Breakthrough SARS-CoV-2 infections increased over time in both groups, particularly after the mRNA-1273 booster. Most participants had a persistent SARS-CoV-2 specific T cell response regardless of prior infection. Conclusions: These findings suggest a modulating effect of previous SARS-CoV-2 infection on the humoral immune response to mRNA vaccination, a non-durable hybrid immunity following mRNA vaccination in previously infected subjects, and attenuation of the humoral immune response (immune damping) after repeated exposure to SARS-CoV-2 antigens through mRNA vaccination and/or infection. Full article

Interferon-γ (IFN-γ), a member of the Type II IFN family, is a crucial cytokine in the immune system and serves as an important indicator of immune response. Intracellular cytokine staining (ICS) is a technique used to analyze the production of cytokines within individual cells, and it has a wide range of applications in the fields of immunological monitoring, vaccine trials, and the study of infectious diseases. This study aimed to prepare monoclonal antibodies against duck IFN-γ protein and to establish an ICS protocol for detecting the duck IFN-γ protein. The duIFN-γ-His or duIFN-γ-Fc gene was cloned into the pEE12.4 expression vector and expressed as a recombinant protein of size 20.2 KDa or 54.9 KDa in 293F cells. The purified recombinant proteins were inoculated into BALB/c mice to generate splenic lymphocytes capable of secreting anti-duIFN-γ antibodies, and hybridoma cells were obtained after fusion with SP2/0 cells. A new hybridoma cell line named 24H4, which stably secreted IgG3 κ subtype antibody against duck IFN-γ, was established. This monoclonal antibody (mAb) was identified by Western blot to recognize duck IFN-γ antibodies, and the indirect ELISA results showed that its ability to recognize IFN-γ protein reached 0.001 μg/mL. The established ICS method was used to stain PBMCs after Concanavalin A (ConA) stimulation, and duck IFN-γ protein was successfully detected by flow cytometry, indicating that the ICS method was successful. In this study, we provide a crucial tool for subsequent research on duck cellular immune responses by using the monoclonal antibody 24H4. Full article

In celiac disease (CeD), interleukin 15 (IL-15) affects the epithelial barrier by acting on intraepithelial lymphocytes, promoting interferon γ (IFN-γ) production and inducing strong cytotoxic activity as well as eliciting apoptotic death of enterocytes by the Fas/Fas ligand system. This study investigates the effects of a monoclonal antibody neutralizing the effects of IL-15 (aIL-15) on tissue-damaging immune response in untreated CeD patients by using an organ culture system. Jejunal biopsies from 10 untreated CeD patients were cultured ex vivo with or without aIL-15. Epithelial expressions of CD95/Fas, HLA-E and perforin were analyzed by immunohistochemistry. Apoptosis was detected in the epithelium by using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Additionally, the surface epithelium compartment of ex vivo cultured biopsy samples was isolated by laser capture microdissection (LCM). RNA from each LCM sample was extracted and the relative expression of IFN-γ was evaluated by quantitative reverse transcriptase-PCR (qRT-PCR). Biopsies cultured with the aIL-15 antibody showed a reduction in Fas, HLA-E and perforin epithelial expression, as well as a decrease in epithelial TUNEL+ cells compared to biopsies cultured without the aIL-15 antibody. Moreover, downregulation of epithelial IFN-γ expression was recorded in biopsies incubated with aIL-15, compared to those cultured without aIL-15. Our findings suggest that neutralizing the effects of IL-15 in ex vivo cultured untreated CeD intestinal mucosa could block apoptosis by downregulating Fas and HLA-E expression and the release of cytotoxic proteins, such as perforin. Furthermore, it can dampen the hyperactive immune response by reducing IFN-γ expression. More generally, our study provides new evidence for the effects of anti-IL-15 neutralizing monoclonal antibodies in preventing or repairing epithelial damage and further supports the concept that IL-15 is a meaningful therapeutic target in CeD, or inflammatory diseases associated with the upregulation of IL-15. Full article

Background/Objectives: The impact of vaccines against SARS-CoV-2 on the immunity of patients with multiple sclerosis (PwMS) is still not fully known. Further clarification could help address medical concerns related to the use of immunosuppressive and immunomodulatory medications, known as disease-modifying therapies (DMTs), in PwMS, as well as ensure adequate protection against severe outcomes of COVID-19. Therefore, the aim of our study was to evaluate the humoral and cellular immune response in PwMS treated with DMTs. Methods: The concentrations of IgG Spike (S) anti-SARS-CoV-2 antibodies and IgG Nucleocapsid (N) anti-SARS-CoV-2 antibodies, as well as interferon-gamma (IFN-γ) titers were analyzed in PwMS groups treated with dimethyl fumarate (DMF), interferon beta (IFN), and healthy control group. Results: Almost 100% of PwMS experienced seroconversion, which resulted from either vaccination and/or prior infection. Additionally, there were no significant differences between the study and control groups in terms of IgG (S) and (N) anti-SARS-CoV-2 antibody levels. However, interferon-gamma titers were lower in both PwMS groups, which may indicate adequate humoral and decreased cellular response to the examined PwMS. Additionally, after the division of the whole study group into two subgroups according to the time since the last vaccination, IgG (S) anti-SARS-CoV-2 and IFN-γ concentrations were significantly lower in the case of patients who were immunized more than 200 days before sample collection. No differences were observed in the case of subgroups in which sample collection was less than 200 days after vaccination when compared to the control group. Conclusions: This could indicate a time-related decrease in immunity in PwMS treated with DMTs. Full article

Natural killer (NK) and CD8⁺ T cell function is compromised in human immunodeficiency virus type 1 (HIV-1) infection by increased expression of inhibitory receptors such as TIGIT (T cell immunoreceptor with Ig and ITIM domains). Blocking inhibitory receptors or their ligands with monoclonal antibodies (mAb) has potential to improve antiviral immunity in general and facilitate HIV eradication strategies. We assessed the impact of TIGIT engagement and blockade on cytotoxicity, degranulation, and interferon-gamma (IFN-γ) production by CD8⁺ T cells from persons living with HIV (PLWH). The effect of TIGIT engagement on non-specific anti-CD3-redirected cytotoxicity was assessed in redirected cytotoxicity assays, and the effect of TIGIT blockade on HIV-specific CD8⁺ T cell responses was assessed by flow cytometry. In 14/19 cases where peripheral blood mononuclear cells (PBMC) mediated >10% redirected cytotoxicity, TIGIT engagement reduced the level of cytotoxicity to <90% of control values. We selected PLWH with >1000 HIV Gag or Nef-specific IFN-γ spot forming cells per million PBMC to quantify the effects of TIGIT blockade on HIV-specific CD8⁺ T cell responses by flow cytometry. Cell surface TIGIT expression decreased on CD8⁺ T cells from 23/40 PLWH following TIGIT blockade and this loss was associated with increased anti-TIGIT mAb fluorescence on monocytes. In total, 6 of these 23 PLWH had enhanced HIV-specific CD8⁺ T cell degranulation and IFN-γ production with TIGIT blockade, compared to 0/17 with no decrease in cell surface TIGIT expression. Reduced CD8⁺ T cell TIGIT expression with TIGIT blockade involved trogocytosis by circulating monocytes, suggesting that an effector monocyte population and intact fragment crystallizable (Fc) functions are required for mAb-based TIGIT blockade to effectively enhance HIV-specific CD8⁺ T cell responses. Full article

Background/Objectives: The efficacy of monovalent BNT162b2 Omicron XBB.1.5 booster vaccination in liver transplant recipients (LTRs) has yet to be described, particularly regarding the immune response to emerging variants like JN.1. Methods: This study evaluated humoral and cellular immune responses in 34 liver transplant recipients (LTRs) with varying SARS-CoV-2 immune histories before and after receiving a BNT162b2 Omicron XBB.1.5 booster vaccination. The assessment involved variant-specific serology, pseudovirus neutralization tests, and Interferon-γ release assays. Results: Participants had a median of four prior vaccinations, with 91.2% having a history of infection. Post-vaccination, significant increases in both Wuhan anti-S and Omicron-specific IgG antibodies and improved neutralization of B.1, XBB.1.5, and JN.1 pseudovirus particles were observed. Also, T-cell responses significantly increased post-vaccination. However, 17.6% of LTRs had no neutralizing antibodies against XBB.1.5 and JN.1, while 100% of healthy controls did. Shortly after vaccination, 18% of patients developed mild COVID-19. These LTRs had particularly low immune responses at baseline. Conclusions: The monovalent XBB.1.5 booster improved overall SARS-CoV-2-specific immunity. However, some LTRs still showed low or undetectable immune responses, indicating that ongoing monitoring and further booster doses are necessary in this high-risk group. Full article

Background/Objectives: The emergence of the Omicron variant has complicated COVID-19 control and prompted vaccine updates. Recent studies have shown that a fourth dose significantly protects against infection and severe disease, though long-term immunity data remain limited. This study aimed to assess Anti-S-RBD antibodies and interferon-γ levels in healthcare workers 12 months after receiving bivalent Original/Omicron BA.4-5 fourth SARS-CoV-2 vaccine. Methods: In this prospective cohort study, 549 healthcare workers were categorized by the initial vaccination schedule, with 229 individuals having received the fourth SARS-CoV-2 vaccine dose. Blood samples were collected from all participants 12 months post-vaccination. Results: Significant differences in Anti-S-RBD antibody levels were observed between those receiving a fourth dose and those who did not, while no differences were seen in interferon-γ levels. After 12 months, there were no significant differences in humoral and cellular immunity response between volunteers primoinfected or reinfected across different periods by the Omicron variant. A multivariable analysis revealed an association between high antibody levels (>6000 U/mL) and interferon-γ levels (OR: 3.13; 95% CI: 1.3–7.7; p < 0.05). Regarding primary vaccine schedules, participants vaccinated with ChAdOx1 (a single or double dose) had notably lower antibody levels compared to those who received mRNA-based vaccines. Additionally, the study shows a higher frequency of multiple infections among those with a single-dose ChAdOx1 primary schedule (OR: 6.24; 95% CI: 1.25–31.15; p < 0.01). Conclusions: Overall, mRNA-based vaccines exhibited stronger long-term immunogenicity. Repeated exposure to the Omicron variant seems to mitigate immune imprinting from the wild-type SARS-CoV-2. An association was observed between high antibody levels and a strong cellular response, although the correlation was not linear. Full article

Background: Immune cells from rheumatoid arthritis (RA) patients display a reduced in vitro response to Porphyromonas gingivalis (P. gingivalis), which may have functional immune consequences. The aim of this study was to characterize, by flow cytometry, the frequency/activity of monocytes and naturally occurring myeloid dendritic cells (mDCs) in peripheral blood samples from patients with periodontitis and patients with periodontitis and RA. Methods: The relative frequency of monocytes and mDCs in the whole blood, the frequency of these cells producing TNFα or IL-6 and the protein expression levels for each cytokine, before and after stimulation with lipopolysaccharide (LPS) from Escherichia coli plus interferon-γ (IFN-γ), were assessed by flow cytometry, in peripheral blood samples from 10 healthy individuals (HEALTHY), 10 patients with periodontitis (PERIO) and 17 patients with periodontitis and RA (PERIO+RA). Results: The frequency of monocytes and mDCs producing IL-6 or TNF-α and the expression of IL-6 and TNF-α in the PERIO group were generally higher. Within the PERIO+RA group, P. gingivalis and related antibodies were negatively correlated with the monocyte and mDC expression of IL-6. A subgroup of the PERIO+RA patients that displayed statistically significantly lower frequencies of monocytes producing IL-6 after activation presented statistically significantly higher peptidylarginine deiminase (PAD)2/4 activity, anti-arg-gingipain (RgpB) IgG levels, mean probing depth (PD), periodontal inflamed surface area (PISA) and bleeding on probing (BoP). Conclusions: In the patients with PERIO+RA, innate immune cells seemed to produce lower amounts of pro-inflammatory cytokines, which are correlated with worse periodontitis-related clinical and microbiological parameters. Full article