[Is complete immunity against measles a realistic target for patients with rheumatic diseases and how can it possibly be achieved?] / Ist komplette Immunität gegen Masern bei Patienten mit rheumatischen Erkrankungen ein realistisches Ziel, und wie ist es möglicherweise zu erreichen?

Measles outbreaks occur rather frequently in Germany. Patients with chronic inflammatory diseases are often treated with immunosuppressants. A recent study showed that about 7% of such patients are not protected against measles according to the lack of documentation in the vaccination card or the absence of protective antibodies. The Standing Committee on Immunization (STIKO) recommends a first vaccination against measles as a measles-mumps-rubella combined vaccination (MMR) in children aged 11-14 months and a second vaccination at 14-23 months. For adults born after 1970, vaccination against measles is recommended if they have not yet been vaccinated against measles or have only been vaccinated once against measles or if their vaccination status is unclear. In April 2019, STIKO published instructions for vaccinations recommended for immunodeficiency. Since March 1, 2020, measles vaccination have been compulsory in Germany.

ELISpots for Detecting Antigen-Specific Memory B Cells in Infection or Autoimmunity.

Enzyme-Linked Immunosorbent Spot assay (ELISpot) is an immunoassay used to quantify individual protein-specific secreting cells. Proteins secreted by cells cultured in ELISpot plates (96- or 8-well format) bind to a specific antigen bound to a PVDF membrane at the bottom of the well. A detection antibody followed by an enzymatic reaction is used to identify secreted protein bound to the membrane coated antigen. This reaction results in distinct "spots" on the membrane corresponding to individual protein secreting cells. While the design is similar to an ELISA, ELISpots quantify the number and relative amount of secreted protein on a single cell level, as opposed to an ELISA that reveals the concentration of secreted proteins from a population of cells. The sensitivity, robustness, and diversity of different antigens used by ELISpots have led to an array of research applications such as measuring cytokines from cytotoxic T cells in cancer and quantifying antibody specificity from B cells following vaccinations. Improvements have been made to assays measuring cytokines and antibodies on a single cell basis, such as intracellular flow cytometry. Yet the ability of an ELISpot to evaluate the quantity and quality of protein secretion on an individual cell basis remains unmatched. Here, we describe the use of a modified ELISpot assay to detect antigen-specific memory B cells in the setting of a viral infection and autoimmunity.

Capture and display of antibodies secreted by hybridoma cells enables fluorescent on-cell screening.

Hybridoma methods for monoclonal antibody (mAb) cloning are a mainstay of biomedical research, but they are hindered by the need to maintain hybridomas in oligoclonal pools during antibody screening. Here, we describe a system in which hybridomas specifically capture and display the mAbs they secrete: On-Cell mAb Screening (OCMS™). In OCMS™, mAbs displayed on the cell surface can be rapidly assayed for expression level and binding specificity using fluorescent antigens with high-content (image-based) methods or flow cytometry. OCMS™ demonstrated specific mAb binding to poliovirus and rabies virus by forming a cell surface IgG "cap", as a universal assay for anti-viral mAbs. We produced and characterized OCMS™-enabled hybridomas secreting mAbs that neutralize poliovirus and used fluorescence microscopy to identify and clone a human mAb specific for the human N-methyl-D-aspartate receptor. Lastly, we used OCMS™ to assess expression and antigen binding of a recombinant mAb produced in 293T cells. As a novel method to physically associate mAbs with the hybridomas that secrete them, OCMS™ overcomes a central challenge to hybridoma mAb screening and offers new paradigms for mAb discovery and production.

Anti-Human Herpesvirus 8 antibodies affect both insulin and glucose uptake by virus-infected human endothelial cells.

INTRODUCTION: Human Herpesvirus 8 (HHV8) is known to be the cause of the malignant tumour named Kaposi's sarcoma. It is believed to induce an intense modification of cell metabolism in endothelial cells. In this work we analysed the role of anti-HHV8 antibodies in both the insulin and glucose uptake of HHV8-infected primary human endothelial cells (HUVEC). METHODOLOGY: Western blotting, immunofluorescence and radiolabelled glucose were employed to assess the pPI3K expression, insulin binding and glucose-uptake by HUVEC cells, respectively. RESULTS: We confirmed that HHV8-infection is able to enhance both insulin binding and glucose-uptake in HHV8-infected primary endothelial cells; in addition, we found that anti-HHV8 specific antibodies are able to further increase both insulin and glucose uptake during the late latent phase of HHV8-infection in vitro. CONCLUSIONS: These findings suggest that a specific immune response to HHV8-infection may cooperate in boosting the cell metabolism, further enhancing the already increased insulin binding and glucose-uptake in HHV8-infected cells, which is a peculiar property of several oncogenic viruses.

Oxidation-sensitive polymersomes as vaccine nanocarriers enhance humoral responses against Lassa virus envelope glycoprotein.

Lassa virus (LASV) causes severe hemorrhagic fever with high mortality, yet no vaccine currently exists. Antibodies targeting viral attachment proteins are crucial for protection against many viral infections. However, the envelope glycoprotein (GP)-1 of LASV elicits weak antibody responses due to extensive glycan shielding. Here, we explored a novel vaccine strategy to enhance humoral immunity against LASV GP1. Using structural information, we designed a recombinant GP1 immunogen, and then encapsulated it into oxidation-sensitive polymersomes (PS) as nanocarriers that promote intracellular MHCII loading. Mice immunized with adjuvanted PS (LASV GP1) showed superior humoral responses than free LASV GP1, including antibodies with higher binding affinity to virion GP1, increased levels of polyfunctional anti-viral CD4 T cells, and IgG-secreting B cells. PS (LASV GP1) elicited a more diverse epitope repertoire of anti-viral IgG. Together, these data demonstrate the potential of our nanocarrier vaccine platform for generating virus-specific antibodies against weakly immunogenic viral antigens.