Christoph K?nigs from Universit?stsklinikum Frankfurt. different areas of application. assays to assess the immunogenic potential of biotherapeutics, but Imiquimod (Aldara) they are not used routinely during drug development. For several years, MAPPs (MHC associated peptide proteomics) has been applied on many different types of immunological questions (Table 1) and can be considered as the assay best characterized regarding its value for immunogenicity potential assessment. While the use of the MAPPs technology for the identification of immunogenic hotspots of biotherapeutics has been reviewed previously (1), this review is usually focusing on recent studies that have employed human HLA class II-MAPPs assays to rank biotherapeutic candidates, investigate clinical immunogenicity, and understand mechanistic root causes of immunogenicity. Table 1 Summary of studies that employed MAPPs for candidate ranking, investigative, and mechanistic purposes. into Imiquimod (Aldara) DCs, which are loaded with the BP of interest. After lysis, HLA class II molecules are isolated by immunocapture, and eluted peptides are analyzed via LC-MS with subsequent database search for peptide identification. MAPPs Assay Applications Due to the challenges with immunogenicity against biotherapeutics, methods that could potentially predict immunogenicity in human beings would be a game changer for drug development. One of the major caveats is the high variability of the published clinical immunogenicity data. Reported immunogenicity incidences are influenced by a multitude of aspects including patient-, treatment-, and sampling-related factors. Furthermore, they are Rabbit polyclonal to TOP2B impacted by the sensitivity, drug tolerance, and type of immunogenicity assay used to measure anti-drug Imiquimod (Aldara) antibody (ADA) responses in patients. A meaningful correlation between data and clinical immunogenicity of different marketed biotherapeutics would require the generation of clinical immunogenicity data with harmonized assays and sampling in clinical trials, which is usually practically utopian to achieve. The development of Imiquimod (Aldara) immunogenicity in an individual subject is dependent on multiple factors such as the presentation of BP-derived peptides via HLA class II molecules, the recognition of these peptides as well as co-stimulatory signals by T cells, the precursor frequency of responsive T cells, the recognition of the BP by B cells via the B cell receptor, the precursor frequency of such B cells, the efficiency of cell conversation in the lymph node and resulting affinity maturation, immune status, HLA haplotype, and the target biology of the BP, just to name a few. The MAPPs assay is usually covering one of the key contributing factors, the natural Imiquimod (Aldara) presentation of protein-derived peptides to T cells, which is the prerequisite for the development of a specific IgG-type immune response. The ability of the peptides to trigger T cell responses has to be resolved via subsequently applied T cell assays. Since the development of immunogenicity and the incidence of ADA in the patient population are depending on many more factors, the MAPPs assay data should never be considered as a direct prediction of immunogenicity incidence in human beings. Instead, MAPPs should be comprehended as a useful and relevant tool to: (1) rank comparable protein variants regarding their immunogenicity potential and support candidate selection, (2) identify root causes for clinical immunogenicity, (3) confirm the sequences predicted by algorithms to characterize and further improve them, and (4) improve the mechanistic understanding of principles of antigen presentation as well as factors that are contributing to the development of immunogenicity. Selection of Biotherapeutic Candidates by MAPPs Assay Ranking Due to the abovementioned caveats, absolute immunogenicity incidence rates between marketed BPs cannot be directly compared. Reported ADA incidences for a given BP can also vary significantly across studies depending on indication, co-medication, and assay format. Still, it becomes apparent that some BPs seem to have relatively low reported immunogenicity rates across many studies and indications, while other BPs seem to consistently show higher immunogenicity incidence rates. We have previously applied MAPPs and T cell activation assays on a panel of marketed monoclonal antibodies, secukinumab, adalimumab, ustekinumab,.