Biology subjects

Ullrich, L.

Publications and source records attributed to Ullrich, L..

5 recordsLinked to original sources

bioRxiv2026

B cell response to HCMV gH/UL116 elicits neutralizing and FcγR-activating antibodies

Humoral immune mechanisms that can contribute to limiting HCMV disease include neutralizing antibodies that block viral entry and Fc-mediated effector functions that promote elimination of infected cells. Here, we identify the gH/UL116 envelope complex as a naturally immunogenic target that elicits antibodies capable of mediating both of these immune mechanisms. Using single-cell sorting of antigen-specific memory B cells, we isolated gH/UL116-reactive monoclonal antibodies from HCMV-seropositive donors. Epitope mapping showed that gH binding was required for virus neutralization, whereas UL116 targeting was associated with potent and broad Fc{gamma} receptor (Fc{gamma}R) activation. Furthermore, cryo-electron microscopy provided high-resolution structures revealing how UL116-specific antibodies bind gH/UL116. In mice, gH/UL116 immunization elicited serum IgG responses whose binding titers strongly correlated with both neutralization and mouse Fc{gamma}R activation. Together, these findings provide an epitope-level map linking antibody specificity to neutralization and Fc{gamma}R activation across HCMV gH-associated complexes and position gH/UL116 as a promising HCMV vaccine candidate.

immunology↗

bioRxiv2026

Identification of a pan-orthoebolavirus-reactive antibody from an rVSV-EBOV vaccinated individual

Orthoebolaviruses such as Ebola virus (EBOV), Sudan virus (SUDV) and Bundibugyo virus (BDBV) can cause severe disease with high case-fatality rates. While licensed EBOV vaccines and therapeutic antibodies protect against EBOV infection, no single monoclonal antibody currently provides broad protection across multiple orthoebolaviruses. Here, we analyzed the humoral immune response of an rVSV-EBOV vaccinee to identify pan-orthoebolavirus-neutralizing antibodies. Using BDBV- and SUDV-glycoproteins for single B cell-sorting, we identified B10, which neutralized authentic EBOV and SUDV, with potent activity against SUDV compared with established cross-reactive antibodies. Structural analysis mapped antibody B10 binding to the pan-orthoebolavirus conserved GP2-stalk/HR2 region, associated with asymmetric trimer destabilization and spike opening. In vivo, B10 showed significant prophylactic efficacy in an EBOV mouse model and partial protection with antiviral activity in a SUDV mouse model. Together, these findings demonstrate that rVSV-EBOV vaccination induced the development of a broadly orthoebolavirus-neutralizing antibody that holds exeptional therapeutic potential.

immunology↗

bioRxiv2026

Next-generation all-in-one CRISPR/Cas9 multiply-edited CD30CAR-T cells:Potency despite risk of translocations

BackgroundChimeric antigen receptor (CAR)-T cells are therapeutic breakthroughs against advanced non-Hodgkin lymphomas and myelomas. On the other hand, no CAR-T cell product has been so far clinically approved for therapy of Hodgkin Lymphoma (HL), T cell lymphoma (TCL), or Epstein-Barr-Virus (EBV)-associated lymphoproliferative diseases (EBV-LPDs). CD30 (TNFRSF8) is commonly expressed on HL and on subsets of TCL and EBV-LPDs. CD30CAR-T cells generated via transduction with viral vectors have been tested in clinical trials, showing overall good responses against HL. CAR-T cells produced entirely with locus-specific gene editing methods are emerging as attractive next-generation engineered cell products for ease of multiple seamless cell modifications. MethodsUsing CRISPR/Cas9-mediated techniques, we optimized homology-directed repair templates (HDRTs) and performed all-in-one multiplex editing to knock-in (KI) CD30CAR within the TCR constant (TRAC) locus and to simultaneously knock-out (KO) PD-1 or/and {beta}2M. CD30CAR-T cells were tested in CD30+ cell models of HL, TCL, and EBV-LPDs. ResultsWe compared mouse versus human anti-CD30 scFv designs in HDRTs incorporating TRAC homology arms, FcIg spacer/detection domain, and CD28 / CD3{zeta} signaling domains. We obtained an average of 30% TRACKICD30CAR-T cells and efficient in vitro cytotoxicity with CD30+ cell targets. CARs incorporating the high-affinity humanized 5F11 scFv showed the highest CAR expression, and the editing templates were further modified to incorporate a truncated CD34 (tCD34) spacer/detection domain. 5F11-CD30CAR-tCD34-T cells showed high CAR-KI rates (approx. 50-80% 12-14 days after editing) and potency in vitro and in vivo. Subsequently, we tested all-in-one CAR KI with additional KOs by co-electroporation of guide RNAs (gRNAs) targeting the genes encoding PD-1 or /and {beta}2M to improve function and allow for improved cell persistence in allogeneic recipients, respectively. Compared with CD30CAR-T cells, CD30CAR-{beta}2MKO-T cells were similarly viable and functional and showed low risk of translocations. PD1KO enabled CD30CAR-T cells to produce higher levels of cytotoxic features upon exposure to targets. However, simultaneous {beta}2MKO and PD-1KO compromised the expansion capacity of CD30CAR-T cells and resulted in detectable translocations. ConclusionsNon-virally engineered 5F11-CD30CAR-T cells represent a novel cell therapy modality against CD30+ lymphomas. Multiplex editing remains to be optimized to avoid unwanted genomic alterations and chromosomal translocations.

cancer biology↗

bioRxiv2026

Development of a multi-species luciferase-based double antigen ELISA for the detection of antibodies against Influenza A virus H5 clade 2.3.4.4b

The highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 represent a major threat to animal and public health. The current panzootic with H5 clade 2.3.4.4b has caused numerous, widespread outbreaks in various domestic and wild avian species with high mortalities, massive losses and a high frequency of spillover events to unexpected novel mammalian hosts such as dairy cows. The global H5N1 situation raises serious concerns about zoonotic risks due to effective mammal-to-mammal transmission. Therefore, it is critical to increase surveillance intensity of a broadened species range, particularly at the human-animal interface. For this purpose, reliable and cost-effective serological tools that are easy to perform and suitable for high-throughput screenings are critically needed. The newly developed double antigen ELISA format employing a luminescence-based detection technology has demonstrated to comply with such prerequisites. The assay allowed the detection of H5-specific antibodies even early after infection or vaccination in a wide range of birds and mammals including humans. It further demonstrated superior analytical sensitivity and high specificity for antibodies directed against H5 hemagglutinin of clade 2.3.4.4b as no cross-reactivity with other hemagglutinin subtypes was observed. Thus, the assay represents a valuable contribution to existing serological diagnostic tests for a clade-optimized detection of influenza A virus antibodies in a broad range of species. ImportanceThe ongoing HPAIV H5N1 panzootic has caused numerous outbreaks in domestic and wild animals with frequent spillover events to unexpected host species, which underscores the importance of an intensified surveillance. However, sensitive and specific multi-species serological assays represent a major gap. For this purpose, we developed a novel double antigen ELISA which employs an innovative luminescence-based read-out strategy. The test allowed a highly sensitive and specific detection of H5-specific antibodies even early after infection or vaccination in a wide range of avian and mammalian species including humans. It therefore represents a significant contribution to improving species-independent serological diagnostic tools for the detection of influenza A virus antibodies.

microbiology↗

bioRxiv2025

Detection of low pre-existing humoral immunity against influenza virus H5N1 clade 2.3.4.4b in unexposed individuals

The spill-over of Influenza A virus H5N1 clade 2.3.4.4b from cattle to humans highlights the risk of a human H5N1 pandemic. Given the impact of pre-existing immunity on the course and severity of viral infections, we comprehensively assessed the humoral immunity against the H5N1 A/Texas/37/2024 isolate in H5N1-naive individuals. To this end, we performed complementary binding and neutralization assays on 66 subjects and ranked activities among a panel of 76 influenza A virus isolates. We detected low but distinct cross-neutralizing titers against A/Texas/37/2024 with a 3.9 to 15.6-fold reduction compared to selected H1N1 or H3N2 strains. By cloning and evaluating 136 monoclonal antibodies from memory B cells, we identified potent A/Texas/37/2024-neutralizing monoclonal antibodies in five out of six investigated individuals. These antibodies cross-neutralize H1, compete with antibodies targeting the HA stem, and protect mice from lethal H5N1 challenge. Our findings demonstrate partial pre-existing humoral immunity to A/Texas/37/2024 in H5N1-naive individuals.

immunology↗