A pilot surveillance report of SARS-CoV-2 rapid antigen test results among volunteers in Germany, 1st week of July 2022.

PURPOSE: We hypothesized that SARS-CoV-2 infection numbers reported by governmental institutions are underestimated due to high dark figures as only results from polymerase chain reaction (PCR) tests are incorporated in governmental statistics and testing capacities were further restricted as of July, 2022. METHODS: A point prevalence investigation was piloted by rapid antigen testing (RAT) among participants of the VACCELERATE volunteer registry. 2400 volunteers were contacted, of which 500 received a RAT including instructions for self-testing in the first week of July, 2022. Results were self-reported via e-mail. RESULTS: 419 valid RAT results were collected until July 7th, 2022. Between July-1 and July-7, 2022, 7/419 (1.67%) tests were positive. Compared to reports of the German Federal Government, our results suggest a more than twofold higher prevalence. Three out of seven positive individuals did not have a PCR test and are therefore likely not to be displayed in governmental statistics. CONCLUSION: Our findings imply that the actual prevalence of SARS-CoV-2 may be higher than detected by current surveillance systems, so that current pandemic surveillance and testing strategies may be adapted.

The macrophage-TCRαß is a cholesterol-responsive combinatorial immune receptor and implicated in atherosclerosis.

Recent evidence indicates constitutive expression of a recombinatorial TCRαß immune receptor in mammalian monocytes and macrophages. Here, we demonstrate in vitro that macrophage-TCRß repertoires are modulated by atherogenic low density cholesterol (LDL) and high-density cholesterol (HDL). In vivo, analysis of freshly obtained artery specimens from patients with severe carotid atherosclerosis reveals massive abundance of TCRαß(+) macrophages within the atherosclerotic lesions. Experimental atherosclerosis in mouse carotids induces accumulation of TCR bearing macrophages in the vascular wall and TCR deficient rag(-/-) mice have an altered macrophage-dependent inflammatory response. We find that the majority of TCRαß bearing macrophages are localized in the hot spot regions of the atherosclerotic lesions. Advanced carotid artery lesions express highly restricted TCRαß repertoires that are characterized by a striking usage of the Vß22 and Vß16 chains. This together with a significant degree of interindividual lesion repertoire sharing suggests the existence of atherosclerosis-associated TCRαß signatures. Our results implicate the macrophage-TCRαß combinatorial immunoreceptor in atherosclerosis and thus identify an as yet unknown adaptive component in the innate response-to-injury process that underlies this macrophage-driven disease.

A second combinatorial immune receptor in monocytes/macrophages is based on the TCRγδ.

Recent evidence indicates that monocytes and macrophages express T cell receptor (TCR)αß-like combinatorial immune receptors. Here, we demonstrate the presence of a second recombinatorial immunoreceptor, which is structurally based on the TCR γ- and δ-chains, in human and murine monocytes and differentially activated macrophages (referred to here as TCRL(m)γδ). In vitro, infection of macrophages with mycobacteria and gram positive or gram negative bacteria induced expression of donor-specific and differential TCRL(m)Vδ repertoires indicating that the novel immunoreceptor represents a dynamic flexible host defense system that responds to bacterial challenge. In vivo, we find that TCRL(m)γδ bearing macrophages, which express highly restricted repertoires of the antigen-binding Vδ chain, accumulate in the cerebrospinal fluid in acute bacterial meningitis and in advanced lesions of atherosclerosis. These results identify an as yet unrecognized monocyte/macrophage subpopulation that bears combinatorial TCRL(m)γδ immune receptors, and is associated with both acute and chronic inflammatory diseases. Moreover, they indicate that the monocytic lineage uses the same bipartite system of TCRαß/TCRγδ-based combinatorial immune receptors that is present in T cells. Our findings suggest specific roles of monocytes/macrophages in various inflammatory conditions and lend further evidence that flexible immune recognition in higher vertebrates operates on a broader cellular basis than previously thought.

Identification of a new prostate-specific cyclic peptide with the bacterial FliTrx system.

UNLABELLED: Peptides are useful tools for directing radioisotopes into tumors. We evaluated the ability of a bacterial peptide display system to isolate new prostate tumor-specific peptides. METHODS: We used the bacterial FliTrx system to identify a new cyclic peptide that binds to prostate carcinoma. Serum stability and binding affinities of the (125)I-labeled peptide were tested. Furthermore, the (131)I-labeled peptide was used to evaluate its biodistribution. RESULTS: Several peptides showing a potential consensus motif were identified. The new peptide MM-2 is stable in serum for up to 24 h. It binds to PC-3 cells, and this binding can be inhibited more than 70% with the unlabeled peptide. Binding to human umbilical vein endothelial cells (HUVECs) and PNT-2 cells is weaker, and competition (27%) in HUVECs is less efficient. The biodistribution showed moderate accumulation in tumor. CONCLUSION: Bacterial peptide display, an alternative to phage peptide display, can allow the identification of specific binding and stable peptides.