Biology subjects

Momburg, F.

Publications and source records attributed to Momburg, F..

6 recordsLinked to original sources

bioRxiv2025

FcεR1γ-based Activating Chimeric Antigen Receptors enhanced Natural Killer cell function against HLA-E+ cells

Fc{varepsilon}R1{gamma} is a transmembrane adaptor protein regulating NKp30, NKp46, and CD16 expression and function in human NK cells. HLA-E expression by cancer cells suppresses NK cell function through interaction with NKG2A. Here, we engineered human NK cells to express a modified Fc{varepsilon}R1{gamma} with a 4-1BB co-stimulatory motif. Fc{varepsilon}R1{gamma}41BB expression led to upregulation of NKp30, NKp46, and CD16 expression and enhanced NKp30 and CD16-mediated target cell lysis. Against cells expressing HLA-E, Fc{varepsilon}R1{gamma}41BB improved NK cell lytic function relative to Fc{varepsilon}R1{gamma}. We then generated an CD19ScFv-CD8hinge-Fc{varepsilon}R1{gamma}41BB(TM-IC) CAR (FCRG10). Engineering human NK cells to express FCRG10 led to upregulation of NKp30 and CD16, and improved NK cell-mediated cytotoxicity against cells co-expressing B7H6, CD19, and HLA-E relative to NK cells expressing the conventional CD19CAR41BB-CD3{zeta} with a CD8 transmembrane domain. Our results indicate that modification of Fc{varepsilon}R1{gamma} enhanced NK cell lytic function mediated by several activating receptors and improved CAR NK cell response in conditions favoring NK cell suppression by HLA-E. Our work may contribute to NK cell-based cancer immunotherapy mediated by co-recognition of stress-induced ligands, antibody-coated cells, and tumor-associated antigens.

immunology↗

bioRxiv2023

Hepatitis B virus neutralization with DNA origami nanoshells

We demonstrate the use of DNA origami to create virus-trapping nanoshells that efficiently neutralize hepatitis B virus (HBV) in cell culture. By modifying the shells with a synthetic monoclonal antibody that binds to the HBV envelope, the effective neutralization potency per antibody is increased by approximately 100 times compared to using free antibodies. The improvements in neutralizing the virus are attributed to two factors: first, the shells act as a physical barrier that block the virus from interacting with host cells; second, the multivalent binding of the antibodies inside the shells lead to stronger attachment to the trapped virus, a phenomenon known as avidity. Pre-incubation of shells with HBV and simultaneous addition of both components separately to cells lead to comparable levels of neutralization, indicating rapid trapping of the virions by the shells. Our study highlights the potential of the DNA shell system to rationally create novel antivirals using components that, when used individually, show little to no antiviral effectiveness.

biophysics↗

bioRxiv2023

optiPRM: A targeted immunopeptidomics LC-MS workflow with ultra-high sensitivity for the detection of mutation-derived tumor neoepitopes from limited input material

Personalized cancer immunotherapies such as vaccines and T cell receptor (TCR)-transgenic T cells rely on the presentation of tumor-specific peptides by human leukocyte antigen (HLA) class I molecules to cytotoxic T cells. Such neoepitopes can for example arise from somatic mutations and their identification is crucial for the rational design of new therapeutic interventions. For their detection by liquid chromatography mass spectrometry (LC-MS), we have developed a parameter optimization workflow to tune targeted assays for maximum detection sensitivity on a per peptide basis, termed optiPRM. Optimization of collision energy using optiPRM allows for improved detection of low abundant peptides that are very hard to detect using standard parameters. Applying this to immunopeptidomics, we detected a neoepitope in a patient-derived xenograft (PDX) from as little as 2.5x106 cells input. Application of the workflow on small patient tumor samples allowed for the detection of five mutation-derived neoepitopes in three patients. One neoepitope was confirmed to be recognized by patient T cells. In conclusion, we here present optiPRM, a targeted MS workflow reaching ultra-high sensitivity by per peptide parameter optimization, which allowed for the identification of actionable neoepitopes from sample sizes usually available in the clinic.

immunology↗

bioRxiv2023

Multimodal HLA-I genotype regulation by human cytomegalovirus US10 and resulting surface patterning

To control human cytomegalovirus (HCMV) infection, NK cells and CD8+ T-cells are crucial. HLA class I (HLA-I) molecules play a central role for both NK and T-cell responses and are targets of multifaceted HCMV-encoded immunoevasins. A so far insufficiently studied HLA-I immunoevasin is the glycoprotein US10. It was shown that US10 targets HLA-G, but it is unknown whether US10 contributes also to escape from classical HLA-I antigen presentation. Our biochemical analysis revealed that early during maturation, all investigated HLA-I (HLA-A/B/C/E/G) heavy chains are recognized and bound by US10. Remarkably, the consequences of this initial binding strongly depended on both the HLA-I geno- and allotypes: i) HLA-A molecules escaped down-regulation by US10, ii) tapasin-dependent HLA-B molecules exhibited impaired recruitment to the peptide loading complex and maturation, iii) HLA-C and HLA-G, but not HLA-A/B/E, strongly bound US10 also in their {beta}2m-assembled form. Thus, US10 senses geno- and allotypic differences in a so far unparalleled and multimodal manner, suggestive of adaptation to HLA-I genotype differences. At a further level of complexity, in HCMV-infected fibroblasts inhibition of overlapping US10 and US11 transcription revealed an additional HLA-I specificity, suggesting targeting of HLA-I in a synergistically arranged manner. Our study unveils the exceptional HLA-I selectivity of HCMV-encoded US10 and underlines its contribution to immune escape.

microbiology↗

bioRxiv2020

Hepatitis B virus envelope proteins can serve as therapeutic targets embedded in the host cell plasma membrane

Hepatitis B virus (HBV) infection is a major health threat causing 880,000 deaths each year. Available therapies control viral replication, but do not cure HBV leaving patients at risk to develop hepatocellular carcinoma. Here we show that HBV envelope proteins (HBs) - besides their integration into endosomal membranes - become embedded in the plasma membrane where they can be targeted by redirected T-cells. HBs was detected on the surface of HBV-infected cells, in livers of mice replicating HBV and in HBV-induced hepatocellular carcinoma. Staining with HBs-specific recombinant antibody MoMab recognizing a confirmational epitope indicated that membrane-associated HBs remains correctly folded in HBV-replicating cells in cell culture and in livers of HBV-transgenic mice in vivo. MoMab coated onto superparamagnetic iron oxide nanoparticles allowed to detect membrane-associated HBs after HBV infection by electron microscopy in distinct stretched of the hepatocyte plasma membrane. Last not least we demonstrate that HBs located to the cell surface allows therapeutic targeting of HBV-positive cells by T-cells either engrafted with a chimeric antigen receptor or redirected by bispecific, T-cell engager antibodies.

microbiology↗

bioRxiv2020

Activating NK- receptors, homing selectins and inhibitory Siglecs recognize EBOLA-GP and HPV-L1NK

The Ebola virus glycoprotein (EBOV)-GP is extensively glycosylated. Its expression induces a physical alteration of surface adhesion molecules, which causes cell rounding and detachment of the infected cells. This phenomenon likely plays a crucial role in viral pathogenicity. In this study, we show that such morphological changes are cell line-dependent as well as dependent on the surface proteins that interact with EBOV-GP in cis and trans. We have generated data showing that natural killer (NK) cell receptors (NCRs: NKp44 and NKp46), selectins (CD62E/P/L) and inhibitory Siglecs function as receptors for Ebola-GP and human papilloma virus (HPV-L1). We used HEK293 cells transfected with Ebola-GP and recombinant fusion proteins containing the extracellular domain of each of these receptors linked to the Fc of human IgG1, which showed significant differences in their virus-binding behavior compared to HEK293 cells transfected with empty vector. Further, to demonstrate that EBOV-GP is a ligand for NKp44 and other NK-receptors, and to investigate their role in immune escape, we also used human HEK-293, HeLa- and hamster CHO-GP-transfectants. Our data show that the NK receptors NKp44 and NKp46 play a key role in recognizing EBOV (Ebolavirus) and strongly suggest that other inhibitory (Siglec-7, Siglec-5) and non-inhibitory homing receptors (P-Selectin, L-Selectin, E-Selectin, and DC-SIGNR/DC-SIGN) take part in the interaction with virus particles. In addition, we show that NKp44, and NKp46, Siglec-7, and -5, and P-, L-, E-selectins as well as of and DC-SIGNR/DC-SIGN bind to the artificial viral envelope of a lentiviral vector that contains EBOV-GP. Altogether we prove that NCRs and a range of other inhibitory and activating receptors can interact with viral envelope/capsid proteins and that such interaction could play an important role in the elimination of virus infected cells. Our findings could be used to develop new strategies for prevention and treatment of infections by these viruses. Author summaryThe innate immune system is able to recognize specifically certain virus components. Here we show that activating NK-cell receptors (NKp44, and NKp46) are involved in such interaction by using HEK293 and CHOK1 cells transfected with the Ebola virus glycoprotein (EBOV-GP) and by binding studies with purified EBOV-GP. In detail, we have found moderate to strong affinity of Siglecs (Siglec-7, and -5), selectins (P-, L-, E-Selectin) and DC-SIGNR/DC-SIGN to purified EBOV-GP, and to cells transfected with EBOV-GP as well as to the envelope of a lentiviral vector carrying the EBOV-GP. Our findings show that NKp44, and NKp46, Siglec-7, and -5, as well as P-and L-selectins have a strong affinity to EBOV-G.

immunology↗