TABLE 2.

Kinetic and affinity constants of C1q binding to different purified recombinant IgMs expressed in mammalian expression systems. Values are obtained after global fitting of the binding signals (Figure 5) and averaging from replicates (2–4). Affinity constants (K_D1 and K_D2) are obtained from the ratio between kinetics parameters (k_d1/k_a1 and k_d2/k_a2). Standard errors are obtained as standard deviation between replicates.

IgM	Source	Construct	ka1	kd1	KD1	ka2	kd2	KD2
			105/Ms	10−4/s	10−9 M	107/Ms	10−1/s	10−9 M
Total IgM	Plasma		3.04 ± 0.47	7.02 ± 1.63	2.31 ± 0.09	2.00 ± 0.90	1.30 ± 0.60	6.52 ± 1.34
IgM617	CHO DG44	HLJ	0.78 ± 0.17	6.20 ± 1.02	8.00 ± 0.31	0.57 ± 0.44	0.74 ± 0.08	12.30 ± 3.87
	HEK293E	HLJ	0.92 ± 0.16	6.26 ± 1.77	6.82 ± 0.11	0.86 ± 0.49	0.59 ± 0.33	6.90 ± 1.13
	HEK293F	HLJ	1.59 ± 0.76	11.30 ± 3.04	7.10 ± 1.06	0.44 ± 0.05	1.15 ± 0.53	26.4 ± 2.89
	HEK293F	HL	1.66 ± 0.50	9.25 ± 4.84	5.59 ± 1.02	0.96 ± 0.38	0.96 ± 0.47	9.97 ± 2.00
IgM012	CHO DG44	HLJ	2.22 ± 0.08	2.57 ± 0.37	1.16 ± 0.01	2.04 ± 0.31	1.34 ± 0.13	6.54 ± 0.11
	HEK293E	HLJ	1.64 ± 0.35	3.57 ± 0.33	2.18 ± 0.06	1.84 ± 0.40	1.57 ± 0.15	8.51 ± 0.24
	HEK293F	HLJ	2.22 ± 0.33	6.18 ± 0.08	2.79 ± 0.03	1.41 ± 0.34	1.34 ± 0.28	9.50 ± 0.48
	HEK293F	HL	4.65 ± 2.54	5.81 ± 2.61	1.25 ± 0.31	1.79 ± 0.51	0.73 ± 0.04	4.09 ± 0.17