Fig. 5: Epitope mapping of IgG for α-melanocyte-stimulating hormone (α-MSH) in patients and controls.
From: Immunoglobulin G modulation of the melanocortin 4 receptor signaling in obesity and eating disorders
a Ten tetrapeptide fragments (black lines) overlapping the α-MSH sequence were used for adsorption of total IgG from eating disorder and obese (OB) patients and controls before detection of their immune complex binding by enzyme-linked immunosorbent assay on the entire α-MSH molecule. Adsorption levels of plasma IgG for each fragment was expressed in percentage from non-absorbed total binding to α-MSH (100%). Adsorption levels were compared among the groups for individual tetrapeptides as shown here for: b α-MSH7–10, the central part which includes 3 amino acids of α-MSH pharmacophore (red box in a); c the C-terminal (Ct, gray box in a), as mean levels of α-MSH9–12 and α-MSH10–13; d the pharmacophore sequence as mean levels of α-MSH5–8 and α-MSH6–9; and e the N-terminal (Nt, blue box in a) as mean levels of α-MSH1–4 and α-MSH2–5. f Schematic illustration of α-MSH-binding epitopes in IgG of patients and controls (see also Fig. 6 legend); the degree of adsorption of IgG binding to α-MSH by specific tetrapeptides is shown here by the width of traits toward corresponding parts of the α-MSH sequence. Data are means ± s.e.m. Kruskal–Wallis test, Dunns’ post-test, **p < 0.01; *p < 0.05. Mann–Whitney test, $$p < 0.01, $p < 0.05, #p < 0.10. Ctrl (n = 9), OB (n = 10), anorexia nervosa (n = 9), bulimia nervosa (n = 7), binge eating disorder (n = 6)
