Neuroblastoma (NB) is the most common paediatric extracranial solid malignancy. We analysed the role of the epitope detection in monocytes (EDIM) technique for liquid biopsy in NB patients.
Tumour epitopes transketolase-like 1 (TKTL1), Apo10 (DNaseX) and GD2 were assessed: expression levels in seven NB tumour samples and five NB cell lines were analysed using RT-PCR and flow cytometry. LAN-1 cells were co-cultured with blood and assessed using EDIM. Peripheral blood macrophages of patients with neuroblastoma (n = 38) and healthy individuals (control group, n = 37) were labelled (CD14+/CD16+) and assessed for TKTL1, Apo10 and GD2 using the EDIM technology.
mRNA expression of TKTL1 and DNaseX/Apo10 was elevated in 6/7 NB samples. Spike experiments showed upregulation of TKTL1, Apo10 and GD2 in LAN-1 cells following co-culturing with blood. TKTL1 and Apo10 were present in macrophages of 36/38 patients, and GD2 in 15/19 patients. The 37 control samples were all negative. EDIM expression scores of the three epitopes allowed differentiation between NB patients and healthy individuals.
The EDIM test might serve as a non-invasive tool for liquid biopsy in children suffering from NB. Future studies are necessary for assessing risk stratification, tumour biology, treatment monitoring, and early detection of tumour relapses.
© 2022. The Author(s).

After successful cardiopulmonary resuscitation (CPR), many patients show signs of an overactive immune activation. Monocytes are a heterogeneous cell population that can be distinguished into 3 subsets by flow cytometry (classical monocytes [CM: CD14++ CD16- ], intermediate monocytes [IM: CD14++ CD16+ CCR2+ ] and non-classical monocytes [NCM: CD14+ CD16++ CCR2- ]). Fifty-three patients admitted to the medical intensive care unit (ICU) after cardiac arrest were included. Blood was taken on admission and after 72 h. The primary endpoint of this study was survival at 6 months and the secondary endpoint was neurological outcome as determined by cerebral performance category (CPC)-score at 6 months. Median age was 64.5 (49.8-74.3) years and 75.5% were male. Six-month mortality was 50.9% and survival with good neurological outcome was 37.7%. Monocyte subset distribution upon admission to the ICU did not differ according to survival. Seventy-two hours after admission, patients who died within 6 months showed a higher percentage of the pro-inflammatory subset of IM (8.3% [3.8-14.6]% vs. 4.1% [1.5-8.2]%; P = 0.025), and a lower percentage of CM (87.5% [79.9-89.0]% vs. 90.8% [85.9-92.7]%; P = 0.036) as compared to survivors. In addition, IM were predictive of outcome independent of time to ROSC and witnessed cardiac arrest, and correlated with CPC-score at 6 months (R = 0.32; P = 0.043). These findings suggest a possible role of the innate immune system in the pathophysiology of post cardiac arrest syndrome.
© 2020 The Authors. Journal of Leukocyte Biology published by Wiley Periodicals LLC on behalf of Society for Leukocyte Biology.

Local T-cell immunity is recognized for its contribution to the evolution and therapy response of various carcinomas. Here, we investigated characteristics of tumor-infiltrating lymphocytes (TILs), as well as T-cell evasive mechanisms in different soft tissue sarcoma (STS) subtypes.
Liposarcoma, gastrointestinal stromal tumor (GIST), leiomyosarcoma, myxofibrosarcoma and pleomorphic sarcomas were assessed for T-cell numbers and phenotypes using flow cytometry. Next-generation sequencing was used to analyze T-cell receptor repertoire, mutational load, immune cell frequencies, and expression of immune-related genes.
GIST, myxofibrosarcoma and pleomorphic sarcoma showed high numbers of CD8+ TILs, with GIST having the lowest fraction of effector memory T cells. These TILs coexpress the immune checkpoints PD1, TIM3, and LAG3 in myxofibrosarcoma and pleomorphic sarcoma, yet TILs coexpressing these checkpoints were near negligible in GIST. Fractions of dominant T-cell clones among STS subtypes were lowest in GIST and liposarcoma, whereas mutational load was relatively low in all STS subtypes. Furthermore, myeloid-derived cells and expression of the costimulatory ligands CD86, ICOS-L and 41BB-L were lowest in GIST when compared with other STS subtypes.
STS subtypes differ with respect to number and phenotypical signs of antitumor responsiveness of CD8+ TILs. Notably, GIST, myxofibrosarcoma and pleomorphic sarcoma harbor high numbers of CD8+ T cells, yet in the GIST microenvironment, these T cells are less differentiated and non-exhausted, which is accompanied with a relatively low expression of costimulatory ligands.
© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Regulatory T cells (Treg) have a central role in controlling the activation of self-reactive T cells and maintaining peripheral tolerance in our body. Many effector mechanisms for Treg function have been described including a role for the protein CTLA-4 which is constitutively expressed by these cells. Despite its importance, there is currently little consensus in the methods and protocols for studying CTLA-4 function, which is partially due to debate over CTLA-4 function itself. In this chapter, we outline protocols used in our lab to study CTLA-4 function, which have been generated based on the observation that CTLA-4 acts to physically remove and degrade its ligands expressed by antigen presenting cells. Accordingly, we provide protocols for isolation of human monocytes and their differentiation into dendritic cells (DC), purification of conventional and regulatory T-cell populations, and the assembly of CTLA-4-dependent Treg suppression assays. We hope that this will offer a reliable platform for dissecting the biology of CTLA-4 on Treg and for testing reagents aimed at modulating CTLA-4 function. Such assays are increasingly vital for the study of immune function in both healthy individuals and patients with a variety of autoimmune and immune dysregulation syndromes.

While five arenaviruses cause human hemorrhagic fevers in the Western Hemisphere, only Junin virus (JUNV) has a vaccine. The GP1 subunit of their envelope glycoprotein binds transferrin receptor 1 (TfR1) using a surface that substantially varies in sequence among the viruses. As such, receptor-mimicking antibodies described to date are type-specific and lack the usual breadth associated with this mode of neutralization. Here we isolate, from the blood of a recipient of the live attenuated JUNV vaccine, two antibodies that cross-neutralize Machupo virus with varying efficiency. Structures of GP1-Fab complexes explain the basis for efficient cross-neutralization, which involves avoiding receptor mimicry and targeting a conserved epitope within the receptor-binding site (RBS). The viral RBS, despite its extensive sequence diversity, is therefore a target for cross-reactive antibodies with activity against New World arenaviruses of public health concern.