In silico Epitope Mapping of Glucose-6-Phosphate Isomerase: A Rheumatoid Arthritis Autoantigen

Rheumatoid arthritis-like symptoms can be initiated experimentally in naive K/BxN mice by simultaneously administering the two monoclonal antibodies 11H3 and 46H9. Both antibodies specifically recognize Glucose-6-Phosphate Isomerase (GPI), a known auto antigen in RA patients. Amino acid sequences of the Fv parts of the antibodies were determined by translating the respective hybridoma DNA sequences and served for threedimensional structure modeling of the paratope regions. In silico docking of both Fv antibody structure models to the X-ray structures of the homodimeric murine GPI as well as to the homodimeric human GPI predicted the murine epitope of the 11H3 antibodies to comprise partial amino acid sequences QRVRSGDWKGYTGKS (aa134-148) and AAKDPSAVAK (aa232-241), generating an assembled (conformational) epitope. The 11H3 epitope on human GPI encompasses the matching partial amino acid sequences QRVRSGDWKGYTGKT (aa134-148) and AAKDPSAVAK (aa232-241). The epitope of the 46H9 antibody was determined to consist of the partial murine GPI amino acid sequence RKELQAAGKSPEDLEK (aa446-461) and the human GPI amino acid sequence RKELQAAGKSPEDLER (aa446-461), respectively, resembling consecutive (linear) epitopes. The predicted epitopes were verified by mass spectrometric epitope mapping using synthetic epitope peptides. Peptide QRVRSGDWKGYTGKS[GSMSGS] AAKDPSAAK included a small spacer sequence in between the epitope sequences, mimicking the assembled epitope for the 11H3 antibody. The peptide RKELQAAGKSPEDLEK represented the consecutive epitope for the 46H9 antibody. The determined B-cell epitopes of GPI and their interactions with the monoclonal antibodies provide a detailed structural understanding of immunological disease onset mechanisms in a mouse model of rheumatoid arthritis

Patients’ and Relatives’ Preferences for Outpatient and Day Care Services Within End-of-Life Care in Germany – A Discrete Choice Experiment

Beate Apolinarski,1,* Lea de Jong,2,* Franziska A Herbst,1 Carolin Huperz,1,3 Hanna AA Röwer,1 Nils Schneider,1 Kathrin Damm,2,* Stephanie Stiel1,* 1Institute for General Practice and Palliative Care, Hannover Medical School, Hannover, Germany; 2Center for Health Economics Research Hannover (CHERH), Leibniz University Hannover, Hannover, Germany; 3Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, Germany*These authors contributed equally to this workCorrespondence: Franziska A Herbst, Hannover Medical School, Institute for General Practice and Palliative Care, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany, Fax +49 511 532 4176, Email [email protected]: In Germany, patients with incurable chronic diseases living at home increasingly have the option of using outpatient and day care hospice and specialized palliative care services. The present study examined and compared patients’ and their relatives’ preferences for end-of-life outpatient and day care services.Patients and Methods: The study used a questionnaire integrating a discrete choice experiment. For six scenarios, participants chose between two hypothetical end-of-life care offers, described by seven attributes. The model compared place of care, frequency and duration of care and support, specialized medical palliative care, accompanied activities, and relieving patient counselling. The model also included optional overnight care and willingness to pay. Patients and the relatives of patients suffering from incurable, chronic diseases who were not yet receiving palliative care were recruited via hospitals and self-help groups (06/2021– 07/2022).Results: The results were based on data from 436 questionnaires (patients: n=263, relatives: n=173). All attributes had a statistically significant impact on choice decisions, with place of care showing the greatest importance. All respondents highly preferred care in the patient’s home over out-of-home care. Patients stressed the importance of special medical (palliative) care and valued accompanied activities, often facilitated by hospice volunteers. Relatives, but not patients, considered the frequency and duration of care highly relevant.Conclusion: The results suggest a higher demand for care in the patient’s home than for out-of-home care. Patients’ and relatives’ high preference for special medical care and the relief of family caregiver burden should be considered in the design of day care services.Keywords: palliative care, hospice care, preferences, discrete choice experiment, medical day care, ambulatory car

Mass spectrometric characterization of limited proteolysis activity in human plasma samples under mild acidic conditions.

We developed a limited proteolysis assay for estimating dynamics in plasma-borne protease activities using MALDI ToF MS analysis as readout. A highly specific limited proteolysis activity was elicited in human plasma by shifting the pH to 6. Mass spectrometry showed that two singly charged ion signals at m/z 2753.44 and m/z 2937.56 significantly increased in abundance under mild acidic conditions as a function of incubation time. For proving that a provoked proteolytic activity in mild acidic solution caused the appearance of the observed peptides, control measurements were performed (i) with pepstatin as protease inhibitor, (ii) with heat-denatured samples, (iii) at pH 1.7, and (iv) at pH 7.5. Mass spectrometric fragmentation analysis showed that the observed peptides encompass the amino acid sequences 1-24 and 1-26 from the N-terminus of human serum albumin. Investigations on peptidase specificities suggest that the two best candidates for the observed serum albumin cleavages are cathepsin D and E. Reproducibility, robustness, and sensitivity prove the potential of the developed limited proteolysis assay to become of clinical importance for estimating dynamics of plasma-borne proteases with respect to associated pathophysiological tissue conditions