Behavior of Chemokine Receptor 6 (CXCR6) in Complex with CXCL16 Soluble form Chemokine by Molecular Dynamic Simulations: General Protein‒Ligand Interaction Model and 3D-QSAR Studies of Synthetic Antagonists

Validation of the DLQI questionnaire in assessing the disease burden and principal aspects related to life quality of vitiligo patients

According to many studies, vitiligo has a negative psychological influence on the patient's life. Multiple factors contribute to the severity of the vitiligo disease burden, among which the most important are self-esteem, stress, and stigma. We aimed to measure the importance of health-related life quality in assessing disease burden in patients with vitiligo. We formulated an HA, which is the principal hypothesis, claiming a single fundamental factor that characterizes the life quality of patients with vitiligo. We also formulated 10 important research questions related to the quality of life that can be generally formulated for patients with dermatological illnesses but particularly suited for vitiligo patients. These research questions capture fundamental aspects of the health-related quality of life of vitiligo patients influenced by symptoms and feelings, daily activities, leisure, job and education, personal relationships, and treatment. These also cover specific aspects related to the quality of life, such as skin-caused sexual difficulties, difficulties in social relationships, and difficulties in performing sports, among others. The Dermatology Life Quality Index (DLQI) questionnaire measures the health-related quality of life of persons suffering from skin diseases. We applied this generic questionnaire to patients with vitiligo. Following a set of inclusion and exclusion criteria, we obtained 114 carefully selected patients who responded to all the questions. This study also validated the DLQI questionnaire on persons who suffer from vitiligo. We investigated whether DLQI has acceptable internal consistency by applying Cronbach's alpha internal consistency indicator (Cα). The obtained Cα = 0.914 indicates excellent internal consistency. We also examined whether all the questions in the questionnaire were mathematically consistent, which we finally proved. It was not necessary to remove any of the questionnaire questions. To prove our HA, a Principal Axis Factoring (PAF) was applied, verifying the assumptions regarding the Average Variance Extracted (AVE) and Convergent Validity (CV). HA proved that applying PAF on DLQI resulted in extracting a single general vitiligo latent factor of life quality, with an initial eigenvalue = 5.671, SS loadings = 5.2, and 52 % of the total cumulative variance explained. Diverse statistical analyses were applied to analyze the 10 formulated research questions. The results of the analysis of the research questions are presented and discussed in the manuscript. One of the conclusions related to the analysis of a research question was that sex had the lowest correlation with the latent life quality factor identified for vitiligo patients.

Establishment of a Novel Anti-Human CCR6 Monoclonal Antibody C6Mab-19 with the High Binding Affinity in Flow Cytometry

CC chemokine receptor 6 (CCR6) is a member of the G-protein-coupled receptor family that is highly expressed in B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. CCR6 has been revealed to have important functions in many pathological conditions, such as cancer, intestinal bowel disease, psoriasis, and autoimmune diseases. The only CCR6 chemokine ligand, CC motif chemokine ligand 20 (CCL20), is also involved in pathogenesis by interacting with CCR6. The CCL20/CCR6 axis is drawing attention as an attractive therapeutic target for various diseases. In this study, we developed novel monoclonal antibodies (mAbs) against human CCR6 (hCCR6) using the peptide immunization method, which are applicable to flow cytometry and immunohistochemistry. The established anti-hCCR6 mAb, clone C6Mab-19 (mouse IgG1, kappa), reacted with hCCR6-overexpressed Chinese hamster ovary-K1 (CHO/hCCR6), human liver carcinoma (HepG2), and human differentiated hepatoma (HuH-7) cells in flow cytometry. The dissociation constant (KD) of C6Mab-19 was determined as 3.0 × 10-10 M for CHO/hCCR6, 6.9 × 10-10 M for HepG2, and 1.8 × 10-10 M for HuH-7. Thus, C6Mab-19 could bind to exogenously and endogenously expressed hCCR6 with extremely high affinity. Furthermore, C6Mab-19 could stain formalin-fixed paraffin-embedded lymph node tissues from a patient with non-Hodgkin lymphoma by immunohistochemistry. Therefore, C6Mab-19 is suitable for detecting hCCR6-expressing cells and tissues and could be useful for pathological analysis and diagnosis.

Identification of the Binding Epitope of an Anti-Mouse CCR6 Monoclonal Antibody (C6Mab-13) Using 1× Alanine Scanning

CC chemokine receptor 6 (CCR6) is one of the members of the G-protein-coupled receptor (GPCR) family that is upregulated in many immune-related cells, such as B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. The coordination between CCR6 and its ligand CC motif chemokine ligand 20 (CCL20) is deeply involved in the pathogenesis of various diseases, such as cancer, psoriasis, and autoimmune diseases. Thus, CCR6 is an attractive target for therapy and is being investigated as a diagnostic marker for various diseases. In a previous study, we developed an anti-mouse CCR6 (mCCR6) monoclonal antibody (mAb), C₆Mab-13 (rat IgG₁, kappa), that was applicable for flow cytometry by immunizing a rat with the N-terminal peptide of mCCR6. In this study, we investigated the binding epitope of C₆Mab-13 using an enzyme-linked immunosorbent assay (ELISA) and the surface plasmon resonance (SPR) method, which were conducted with respect to the synthesized point-mutated-peptides within the 1-20 amino acid region of mCCR6. In the ELISA results, C₆Mab-13 lost its ability to react to the alanine-substituted peptide of mCCR6 at Asp11, thereby identifying Asp11 as the epitope of C₆Mab-13. In our SPR analysis, the dissociation constants (K_D) could not be calculated for the G9A and D11A mutants due to the lack of binding. The SPR analysis demonstrated that the C₆Mab-13 epitope comprises Gly9 and Asp11. Taken together, the key binding epitope of C₆Mab-13 was determined to be located around Asp11 on mCCR6. Based on the epitope information, C₆Mab-13 could be useful for further functional analysis of mCCR6 in future studies.