Novel NKG2D-directed bispecific antibodies enhance antibody-mediated killing of malignant B cells by NK cells and T cells.

The activating receptor natural killer group 2, member D (NKG2D) represents an attractive target for immunotherapy as it exerts a crucial role in cancer immunosurveillance by regulating the activity of cytotoxic lymphocytes. In this study, a panel of novel NKG2D-specific single-chain fragments variable (scFv) were isolated from naïve human antibody gene libraries and fused to the fragment antigen binding (Fab) of rituximab to obtain [CD20×NKG2D] bibodies with the aim to recruit cytotoxic lymphocytes to lymphoma cells. All bispecific antibodies bound both antigens simultaneously. Two bibody constructs, [CD20×NKG2D#3] and [CD20×NKG2D#32], efficiently activated natural killer (NK) cells in co-cultures with CD20+ lymphoma cells. Both bibodies triggered NK cell-mediated lysis of lymphoma cells and especially enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) by CD38 or CD19 specific monoclonal antibodies suggesting a synergistic effect between NKG2D and FcγRIIIA signaling pathways in NK cell activation. The [CD20×NKG2D] bibodies were not effective in redirecting CD8+ T cells as single agents, but enhanced cytotoxicity when combined with a bispecific [CD19×CD3] T cell engager, indicating that NKG2D signaling also supports CD3-mediated T cell activation. In conclusion, engagement of NKG2D with bispecific antibodies is attractive to directly activate cytotoxic lymphocytes or to support their activation by monoclonal antibodies or bispecific T cell engagers. As a perspective, co-targeting of two tumor antigens may allow fine-tuning of antibody cancer therapies. Our proposed combinatorial approach is potentially applicable for many existing immunotherapies but further testing in different preclinical models is necessary to explore the full potential.

Differential Upregulation and Functional Activity of S1PR1 in Human Peripheral Blood Basophils of Atopic Patients.

Basophils are key effector cells in atopic diseases, and the signaling sphingolipid Sphigosine-1-phosphate (S1P) is emerging as an important mediator in these conditions. The possible interaction of S1P and basophils and the resulting biological effects have not yet been studied. We hypothesize that S1P influences the function of basophils in atopy and aim to elucidate the modes of interaction. S1P receptor (S1PR) expression in human peripheral blood basophils from atopic and non-atopic patients was assessed through qRT-PCR and flow cytometry analysis. Functional effects of S1P were assessed through a basophil activation test (BAT), calcium flux, apoptosis, and chemotaxis assays. Immunofluorescence staining was performed to visualize intracellular S1P. Human basophils express S1PR1, S1PR2, S1PR3, and S1PR4 on the mRNA level. 0.1 µM S1P have anti-apoptotic, while 10 µM exhibits apoptotic effects on basophils. Basophils from atopic patients show less chemotactic activity in response to S1P than those from healthy donors. Protein expression of S1PR1 is downregulated in atopic patients, and basophils in lesional AD skin possess intracellular S1P. These findings suggest that the interaction of S1P and basophils might be an important factor in the pathophysiology of atopy.

Antibody bivalency improves antiviral efficacy by inhibiting virion release independently of Fc gamma receptors.

Across the animal kingdom, multivalency discriminates antibodies from all other immunoglobulin superfamily members. The evolutionary forces conserving multivalency above other structural hallmarks of antibodies remain, however, incompletely defined. Here, we engineer monovalent either Fc-competent or -deficient antibody formats to investigate mechanisms of protection of neutralizing antibodies (nAbs) and non-neutralizing antibodies (nnAbs) in virus-infected mice. Antibody bivalency enables the tethering of virions to the infected cell surface, inhibits the release of virions in cell culture, and suppresses viral loads in vivo independently of Fc gamma receptor (FcγR) interactions. In return, monovalent antibody formats either do not inhibit virion release and fail to protect in vivo or their protective efficacy is largely FcγR dependent. Protection in mice correlates with virus-release-inhibiting activity of nAb and nnAb rather than with their neutralizing capacity. These observations provide mechanistic insights into the evolutionary conservation of antibody bivalency and help refining correlates of nnAb protection for vaccine development.

Anticoagulation Prior to COVID-19 Infection Has No Impact on 6 Months Mortality: A Propensity Score-Matched Cohort Study.

The coronavirus disease 2019 (COVID-19) shows high incidence of thromboembolic events in humans. In the present study, we aimed to evaluate if anticoagulation prior to COVID-19 infection may impact clinical profile, as well as mortality rate among patients hospitalized with COVID-19. The study was based on retrospective analysis of medical records of patients with laboratory confirmed SARS-CoV-2 infection. After propensity score matching (PSM), a group of 236 patients receiving any anticoagulant treatment prior to COVID-19 infection (AT group) was compared to 236 patients without previous anticoagulation (no AT group). In 180 days, the observation we noted comparable mortality rate in AT and no AT groups (38.5% vs. 41.1%, p = 0.51). Similarly, we did not observe any statistically significant differences in admission in the intensive care unit (14.1% vs. 9.6%, p = 0.20), intubation and mechanical ventilation (15.0% vs. 11.6%, p = 0.38), catecholamines usage (14.3% vs. 13.8%, p = 0.86), and bleeding rate (6.3% vs. 8.9%, p = 0.37) in both groups. Our results suggest that antithrombotic treatment prior to COVID-19 infection is unlikely to be protective for morbidity and mortality in patients hospitalized with COVID-19.

Human carotid bodies as a therapeutic target: new insights from a clinician's perspective.

From the physiological point of view, carotid bodies are mainly responsible for the ventilatory response to hypoxia; however, they also take part in the regulation of sympathetic tone. According to preclinical data, these structures likely contribute to the development and progression of sympathetically mediated diseases. Moreover, carotid body deactivation in animal models improved blood pressure control in hypertension and reduced mortality in heart failure, along with reducing sympathetic activity. On this basis, two first-in-man studies have been recently performed to investigate the safety and feasibility of such an approach in humans. In this review we summarise the current knowledge regarding the function of carotid bodies, the prevalence of their abnormalities, and the consequences of their excision in human hypertension and heart failure.

Patients with acute myocardial infarction and severe target lesion calcifications undergoing percutaneous coronary intervention have poor long-term prognosis.

BACKGROUND: To assess the influence of severe target lesion calcification (TLC) on the outcomes of patients undergoing percutaneous coronary interventions (PCI) due to acute myocardial infarction (AMI). AIM: Contemporary data concerning coronary artery calcifications (CAC) are based on pooled analyses from randomised trials with short follow-up. We still lack the knowledge on how CAC in target lesions affect long-term prognosis of patients with AMI in everyday practice. METHODS: We evaluated clinical and laboratory data of 206 consecutive patients who underwent coronary angiography and PCI due to AMI. Primary endpoints were all-cause death and recurrent hospitalisations due to acute coronary syndrome (ACS). RESULTS: Severe TLC lesions were present in 17% of patients. These patients were older (71 vs. 65 years, p = 0.02) and more often diagnosed with non-ST segment elevation myocardial infarction (77% vs. 58%, p = 0.03). Patients with severe TLC had lower rates of PCI success (80% vs. 97%, p < 0.0001) and less often achieved full revascularisation during index procedure (14% vs. 41%, p = 0.003). During 30 months follow-up patients with severe TLC more often suffered from another ACS (37% vs. 13%, p = 0.0005) and had higher all-cause mortality (31% vs. 16%, p = 0.04). Multivariate Cox regression model showed severe TLC to be an independent predictor of another ACS (HR 2.8; 95% CI 1.4-5.6; p = 0.004). CONCLUSIONS: Severe TLC are not uncommon in patients with ACS. The presence of severe TLC is a prognostic factor of another ACS in AMI patients undergoing PCI.

Impact of pre-hospital electrocardiogram teletransmission on time delays in ST segment elevation myocardial infarction patients: a single-centre experience.

INTRODUCTION: Delay in diagnosis and treatment has a great influence on morbidity and mortality of ST-segment elevation myocardial infarction (STEMI) patients. Every 30 min of delay in reperfusion is associated with an 8% increase in mortality. ECG teletransmission was proved to effectively shorten time delays in STEMI treatment. In 2012 an ECG teletransmission program was introduced in the Lower Silesia region. AIM: To assess the frequency of ECG teletransmission in STEMI patients and its influence on time delays. MATERIAL AND METHODS: We conducted a retrospective analysis of all patients admitted to our hospital with STEMI in 2013. Time delays, treatment and clinical characteristics of patients with and without teletransmission performed were compared. RESULTS: The study included 137 patients, of whom 49 (36%) had teletransmission performed. Direct transport to a percutaneous coronary intervention (PCI)-capable hospital was more frequent in patients with ECG teletransmission performed (88% vs. 63%, p = 0.002). In patients with teletransmission pain-emergency room time and total ischemic time were shorter (respectively 125 (91-184) min vs. 201 (113-339) min, p = 0.001 and 159 (136-244) min vs. 259 (170-389) min, p < 0.001). There were no differences in in-hospital delay, patients' characteristics, or applied therapy. CONCLUSIONS: The percentage of STEMI patients who had ECG teletransmission performed was low. Patients with ECG teletransmission had a shorter total ischemic time and lower percentage of indirect transport to a PCI-capable hospital.