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Fig. 6 | Arthritis Research & Therapy

Fig. 6

From: Longitudinal assessment of reactivity and affinity profile of anti-Jo1 autoantibodies to distinct HisRS domains and a splice variant in a cohort of patients with myositis and anti-synthetase syndrome

Fig. 6

Affinity binding profiles against HisRS-FL for IgG purified from sera at first available sample close to diagnosis measured by SPR in single cycle kinetics mode. Sensorgrams showing the obtained signal in response units (RU, y-axis) over time (seconds, s, x-axis) from four representative patients (P1, P5, P9, and P17). A Three patients did not show any binding in SPR, as indicated by a flat line (same observation for P4 and P13, data not shown). B P9 is an example of a patient having a biphasic off-rate (Avekd). This sort of heterogeneity was also observed for 6 other patients (P3, P7, P11, P12, P16, and P18). C, D A slower and more homogenous off-rate (Avekd < 0.0005 s-1) was observed for P5 and P17 (as well as P2, P8, P14, P15, P19), representing the other group (n=7) of patients. The biphasic binding profiles observed in approximately half the patients (n=7) could be explained by an avidity effect caused by the dimeric form of the antigen but can also be the result of the polyclonal nature of the patient sample and, thus, containing antibodies of different off-rates. Red lines represent the measured data values and dashed black lines represent the fit of the curve using the 1:1 Langmuir binding model. To distinguish the average values reported herein from traditionally reported affinity (KD) and dissociation rate constants (kd), we use the nomenclature AveKD and Avekd. For control samples, see Supplementary material

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Arthritis Research & Therapy

ISSN: 1478-6362

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