Iranian journal of immunology
Volume:20 Issue: 3, Summer 2023

Two central questions in COVID-19 treatment which should be considered are: “How does the imbalance of the complement system affect the therapeutic approaches?” and “Do we consider complement inhibitors in therapeutic protocols?”. The complement system is a double-edged sword since it may either promote immune responses against COVID-19 or contribute to destructive inflammation in the host. Therefore, it is crucial to regulate this system with complement inhibitors. In this manuscript, we discuss the molecular mechanisms of complement and complement inhibitors in COVID-19 patients. We searched the terms “COVID-19”, “Complement”, “Complement inhibitor”, “SARS-CoV-2”, and all complement fragments and inhibitors from 2000 to 2022 in PubMed and google scholar and checked the pathways in “KEGG pathway database”. Complement is not well-appreciated in the treatment protocols despite its multiple roles in the disease, and most of the preventive anti-inflammatory therapeutic approaches did not include a complement inhibitor in COVID-19 therapeutic protocols. In this review article, we discussed the most recent studies regarding complement components mediated interventions and the mechanism of these interventions in COVID-19 patients. Since the control of the complement system overactivation is associated with a better prognosis in the initial stages of COVID-19, heparin, anti-thrombin, C1-inhibitor, montelukast, and hydralazine can be effective in the initial stages of this viral infection. Recombinant complement activation (RCA) proteins are more effective in regulating complement compared to terminal pathway therapeutic approaches such as the C3a and C5a inhibitors.

Buerger’s disease, also known as Thromboangiitis Obliterans (TAO), is a progressive, inflammatory vascular disease with unknown etiology. To address the degree of T cell immunosenescence in this inflammatory disease, the frequency of senescent T cells expressing CD57 and/or CD153 (CD30L) in patients with TAO. In this study, nine male cigarette smoker patients with TAO, nine male healthy cigarette smokers, and nine male healthy non-smoker blood donors were enrolled. PBMCs were extracted from the blood of all participants and stored in liquid nitrogen before use. The percentages of senescent T cells were detected by flow cytometry. The results were analyzed using non-parametric statistical tests. The frequencies of senescent CD3+CD4+CD57+CD153+ and CD3+CD4+CD57-CD153+ T cells significantly increased in patients compared with the non-smoker controls (p=0.01 and p=0.04, respectively). The frequency of senescent CD3+CD4-CD57-CD153+ T cells was higher in patients compared with the smoker controls (p=0.02). In patients with TAO, CD57+CD153- cells were more frequent in CD3hiCD4- and CD3hiCD4+ T cells compared with the CD3loCD4- and CD3loCD4+ T cells (p=0.008 and p=0.0002, respectively). Conversely, the frequency of CD57-CD153+ T cells was significantly higher in CD3loCD4- T cells compared with the CD3hiCD4- T cells (p=0.004). The percentage of CD3+CD4+CD57+CD153- T cells correlated negatively with smoking level in smoker controls (p=0.02, Spearman r=-0.80). Elevated frequencies of senescent CD4+CD57+CD153+ and CD4+CD57-CD153+ T cells in patients compared with non-smoker and smoker controls suggest the contribution of immunosenescence in TAO.

CD39 is an inhibitory checkpoint exerting rate-limiting effects on the ATP-adenosine pathway. It can be targeted to block adenosine-mediated immunosuppression. To analyze the relationship between the CD39 expression and clinicopathological characteristics including FIGO stage, lymph node and distant metastasis, and to further explore its potential role in cervical cancer. Peripheral blood was collected from 59 healthy people and 43 patients with cervical cancer. The percentage and absolute counts of CD3-positive, CD4-positive and CD8-positive T lymphocytes, CD4/CD8 ratio and the percentage of the CD39+ T cells in T lymphocytes were assessed by flow cytometry, and their correlations with clinical parameters were analyzed. Absolute numbers of CD8+ T lymphocytes, CD4/CD8 ratios, and the percentage of the CD39+ T cells were linked with FIGO stage, lymph node metastasis, and distant metastasis. The total numbers of CD8+ T lymphocytes were significantly higher in the peripheral blood of patients with cervical cancer in the early and middle stages than in the advanced stage. In addition, patients with early and middle-stage cervical cancer had considerably lower percentage of CD4+ CD39 + and CD8 + CD39 + T lymphocytes than those with advanced cervical cancer. These results suggest that the absolute counts of CD8+ T lymphocytes may be associated with the patient’s prognosis and that the CD39 molecule, expressed on the surface of CD8+ T cells, is also related to FIGO stage, lymph node metastasis, and distant metastasis. CD39 expression on CD8-positive T cells exhibits a negative correlation with the number of CD8-positive T lymphocytes.

Type 2 innate lymphoid cells (ILC2s) and NLRP3 inflammasome are related to allergic and inflammatory responses. NLRP3 inflammasome inhibitor MCC950 was demonstrated to ameliorate allergic rhinitis (AR) in animal models. To elucidate the effect of MCC950 on ILC2 responses in AR. NLRP3 inflammasome, ILC2s, IL-5+ILC2s, IL-13+ILC2s, and Th2-related factors were examined in 30 AR patients. ILC2s were identified as Lin-CRTH2+CD127+lymphocytes. ILC2s isolated from PBMCs were stimulated with LPS plus ATP. The effect of MCC950, IL-1β, and IL-18 on ILC2 responses was detected by flow cytometry. AR models were established in 60 BALB/c mice. Nasal symptoms and ILC2 responses in the AR models after MCC950 treatment were detected. Human nasal epithelial cells were stimulated with IL-13 (10 ng/mL) and treated with MCC950 (10 μM). AR patients showed activated NLRP3 inflammasome and increased ILC2 responses compared to controls. NLRP3 inflammasome levels in the AR patients were positively related to the proportion of ILC2s, IL-5+ILC2s, and IL-13+ILC2s in total PBMCs. MCC950 treatment or IL-1β/IL-18 suppression inhibited ILC2 proliferation and Th2-related factors (GATA3, RORα, IL-5, and IL-13). MCC950 administration alleviated frequencies of nasal rubbing and sneezes in the AR models. ILC2s, IL-5+ILC2s, and IL-13+ILC2s in mice were reduced by MCC950. MCC950 inhibited NLRP3 inflammasome in the in vitro models of AR. MCC950 inhibited ILC2 responses in AR and mice models, suggesting that blocking NLRP3 inflammasome may be a promising target for AR clinical treatment.

Trastuzumab is a humanized monoclonal antibody that targets site-specifically human epidermal growth factor-2 receptor (HER2) cell surface antigen overexpressed in approximately 20% of human breast carcinomas. Despite its positive therapeutic outcomes, a large proportion of individuals are unresponsive to the treatment with trastuzumab or develop resistance to it. To evaluate a chemically synthesized trastuzumab-based antibody-drug conjugate (ADC) to improve the trastuzumab therapeutic index. The current study explored the physiochemical characteristics of the trastuzumab conjugated to a cytotoxic chemotherapy agent DM1 via Succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, created in our earlier study, using SDS-PAGE, UV/VIS, and RP-HPLC analyses. The antitumor effects of the ADCs were analyzed using MDA-MB-231 (HER2-negative) and SK-BR-3 (HER2-positive) cell lines utilizing in vitro cytotoxicity, viability, and binding assays. Three different formats of a HER2-targeting agent: trastuzumab, synthesized trastuzumab-MCC-DM1, and commercially available drug T-DM1 (Kadcyla®) were compared. UV-VIS spectroscopic analysis showed that the trastuzumab-MCC-DM1 conjugates, on average, entailed 2.9 DM1 payloads per trastuzumab. A free drug level of 2.5% was determined by RP-HPLC. The conjugate appeared as two bands on a reducing SDS-PAGE gel. MTT viability assay showed that conjugating trastuzumab with DM1 significantly improved the antiproliferative effects of this antibody in vitro. Importantly, the evaluations using LDH release and cell apoptosis assays confirmed that trastuzumab maintains its ability to induce cell death response while conjugating with the DM1. The binding efficiency of trastuzumab-MCC-DM1 was comparable to that of the naked trastuzumab. Trastuzumab-MCC-DM1 was found effective against HER2+ tumors. The potency of this synthesized conjugate brings it closer to the commercially available T-DM1.

Lupus nephritis (LN) refers to the injury caused by systemic lupus erythematosus (SLE) involving the kidneys. A previous study identified angiopoietin-like protein 4 (ANGPTL4) as a novel urinary biomarker for tracking disease activity in LN. To investigate the detailed role and regulatory mechanism of ANGPTL4 in experimental models of LN. MRL/lpr mice 11-week-old were injected with adeno-associated virus (AAV)-mediated ANGPTL4 short hairpin RNA (shRNA). At 16 and 20 weeks of age, 24-h urine samples were harvested to measure proteinuria levels. After the mice were sacrificed, blood and kidney tissues were harvested to examine serum creatinine (cr) and blood urea nitrogen (BUN) levels, kidney histological changes, and pro-inflammatory cytokine production. Additionally, the levels of NLRP3 inflammasome-associated molecules in mouse renal tissues were detected to clarify the underlying mechanism. The AAV-sh-ANGPTL4 injection significantly reduced the proteinuria, cr, and BUN levels in MRL/lpr mice. ANGPTL4 silencing ameliorated glomerular, tubular, and interstitial damage in mice, mitigating the pathological alternations of LN. In addition, ANGPTL4 knockdown repressed pro-inflammatory cytokine production in the kidneys. Mechanically, ANGPTL4 suppression inhibited NLRP3 inflammasome expression in renal tissues of mice. ANGPTL4 silencing inhibits the NLRP3 inflammasome-mediated inflammatory response, thereby ameliorating LN in MRL/lpr mice.

Kawasaki disease (KD) is a vasculitis associated with vascular injury and autoimmune response. Inflammatory factors stimulate neutrophils to produce web-like structures called neutrophil extracellular traps (NETs). Citrullinated histone 3 (H3Cit) is one of the main protein components of neutrophil extracellular traps involved in the process of NETosis. The levels of NETs and H3Cit in the KD are not known. To determine the changes in the levels of NETs and H3Cit in KD. Children with KD were recruited and divided into the acute KD and the sub-acute KD group according to the disease phase and whether intravenous immunoglobulin (IVIG) was used or not. Peripheral venous blood was taken before and after the IVIG administration and sent for the examination of NETs by flow cytometry. The level of H3Cit was measured by enzyme-linked immunosorbent assay (ELISA). The counts of NETs in the acute KD group significantly increased compared with the healthy controls (p<0.01). The level of H3Cit was significantly higher in the acute KD group than in the healthy control subjects. Of note, both the counts of NETs and the level of H3Cit decreased in the KD patients treated with IVIG compared with the acute KD group (p<0.01). Acute KD is characterized by an increased formation of NETs and high levels of H3Cit. IVIG significantly inhibited NETs formation and also reduced the level of plasma H3Cit in children with KD.

Spi-B transcription factor (SPIB) is an E-twenty-six (ETS) transcription factor associated with tumor immunity. To investigate the functions and mechanisms of SPIB in ovarian cancer (OC) cells. Cell proliferation, apoptosis, migration, and invasion were determined using colony formation, EdU, flow cytometry, and transwell assays, respectively. The binding sites of programmed death-ligand 1 (PD-L1) and SPIB were predicted using the JASPAR database and verified using the ChIP and luciferase reporter assays. SPIB knockdown inhibited OC cell proliferation, migration, and invasion, and significantly boosted apoptosis (p<0.05). SPIB directly enhanced PD-L1 transcription in OVCAR-3 and SKOV3 cells (p<0.05). Importantly, the JAK/STAT pathway was markedly inactivated in OC cells upon SPIB knockdown. SPIB knockdown markedly decreased JAK2 and STAT1 phosphorylation in OVCAR-3 and SKOV3 cells (p<0.05). These data indicate that SPIB knockdown inhibits OC cell progression by downregulating PD-L1 and inactivating the JAK/STAT pathway.

Different subtypes of dendritic cells (DCs) can induce different types of immune responses. Our previous study found that Echinococcus granulosus (E. granulosus) antigens (Eg.ferritin, Eg.mMDH and Eg.10) stimulated DC differentiation to different subtypes and produced different immune responses. To further understand whether Eg.ferritin, Eg.mMDH and Eg.10 affect the DC-mediated immune response by promoting the differentiation of monocytes to DCs. Bone marrow-derived monocytes were exposed to three antigens of E. granulosus on days 0, 3, 5, and 7. The percentage of monocyte-derived DCs (moDCs), DCs subsets, and the expression of surface molecules of DCs at different time points in different groups were assessed by flow cytometry. The levels of cytokines of IL-1β, IL-4, IL-6, IL-10, IL-13, IFN-γ, TNF-α, IL-12p70, IL-18, IL-23, and IL-27 in the cell culture supernatant were detected by multi-factorial detection technology. The percentage of moDCs revealed that none of the three antigens blocked monocyte differentiation to DCs. The monocytes of 7-day-old cultures showed increased sensitivity to these antigens. The Eg.ferritin induced more mature DCs, which expressed high levels of MHC II and costimulatory molecules, and secreted Th1 cytokines. Eg10 and Eg.mMDH induced lower degrees of DC maturation, however differentiated DCs were in a semi-mature state due to low expression of MHC II and costimulatory molecules and secretion of higher Th2 and lower Th1 cytokines. Eg.ferritin promotes full maturation of DCs and induces Th1 immune response, whereas Eg.10 and Eg.mMDH induce semi-mature DCs producing higher levels of Th2 cytokines.

The initial inflammatory reaction starts following occlusion in ischemic stroke (IS). Interleukin-1β (IL-1β) is a pro-inflammatory cytokine with a crucial role in the pathogenesis of neurodegenerative disorders.

To investigate the levels of IL-1β and vitamin D (VitD) in patients with IS compared with controls and their correlation.

The serum level of 25-OH VitD and IL-1β was assessed in 102 IS patients (0-24 h after stroke) and 102 controls with an enzyme-linked immunosorbent assay (ELISA) kit.

We found a significant increase in IL-1β (80.14±6.8 vs. 60.32±4.1 pg/ml, p<0.05) and a decrease in VitD level (24.3±1.4 vs. 29.9±1.5 ng/ml, p<0.01) in the IS patients compared with the controls. There was a significantly positive correlation between the National Institutes of Health Stroke Scale (NIHSS) and IL-1β according to both the Spearman correlation (r=0.35, p=0.0003) and the linear regression (beta=0.255, p=0.014). Also, a significant negative association between VitD and NIHSS was detected by the Spearman correlation (r=-0.41, p<0.0001) and the linear regression (beta=-0.381, p=0.000). Moreover, we found a significant negative correlation (r=-0.26, p=0.006) between the serum levels of VitD and IL-1β in the patient group.

Ischemic stroke correlates positively with IL-1β and negatively with VitD levels. The speculated role of VitD deficiency in the evolution and severity of stroke may be justified by its role in the modification of inflammation.

Heat shock proteins (HSPs) are involved in innate and adaptive immune responses, especially inflammatory responses due to immune cell activation. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was one of the most important causes of death in the recent pandemic. Increased cellular stress and excessive inflammation are common in coronavirus disease-19 (COVID-19), although the underlying mechanisms are still poorlyunderstood.

To evaluate the relationship between HSP and the pathological effects of COVID-19.

A group of 107 patients was categorized to two populations (mild and severe) based on their chest high-resolution computed tomography (HRCT) results. The HSP70, HSP90 alpha, and serum levels of C-reactive protein (CRP) were measured by enzyme-linked immunosorbent assay (ELISA). Lactate dehydrogenase (LDH), and creatine phosphokinase (CPK) were measured by the automated analyzer.

Our data showed increased levels of HSP70 and HSP90 in patients with COVID-19. The HSPs levels were elevated in the severe group compared to the mild group. This study demonstrated a positive correlation between both elevated levels of HSP70, HSP90, and HRCT grade and also a positive correlation with CRP and CPK in the severe group.

HSP90 and HSP70 contribute to excessive immune responses and cytokine storms. They may serve as prognostic serum markers for COVID-19 lung injury. Additionally, they arecandidates for anti-inflammatory therapy.

The coronavirus disease 2019 (COVID-19) was first reported in December 2019 in Wuhan, Hubei Province of China. As long as the 27th of December 2021, approximately 280 million people have been infected with coronavirus, resulting in more than 5,418,421 deaths worldwide. Since the beginning of the COVID-19 pandemic, different methods were introduced for diagnosing coronavirus-infected patients and evaluating the immune response, following the vaccination.

The current study aimed to compare the level of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) specific IgG in a group of patients who recovered from COVID-19, measured by three different enzyme-linked immunosorbent assay (ELISA) kits.

This cross-sectional study was conducted on sera from patients who recovered from a real-time reverse transcriptase-polymerase chain reaction (RT-PCR)-confirmed COVID-19 in Birjand, South Khorasan, Iran. SARS-CoV-2 anti-nucleocapsid (N) and spike (S) protein IgG levels were measured using commercial ELISA kits. Comparison between groups was made using one-way ANOVA and Tukey post hoc tests.

The mean titer of anti-N IgG was significantly higher for the PishtazTeb Diagnostics kit than the Ideal Tashkhis Atieh kit (p<0.05). There was no correlation between the titer of anti-N IgG (PishtazTeb Diagnostics and Ideal Tashkhis Atieh) and anti-S IgG (Chemobind Company) antibodies.

This study indicates that the domestic ELISA kits have variable but acceptable sensitivity for detecting SARS-CoV-2 specific IgG antibodies.