Table 3.

Kinetics and stoichiometry of Fab binding to SOSIP trimers and SOSIP-I53-50NPs

Langmuir modeling of Fabs binding
Fab	Envelope protein	n	kon (Ms−1)	koff (s−1)	KD (nM)	Sm/NP	Sm/trimer
PGT145	BG505 SOSIP	3	2.4 × 105 ± 5.9 × 104	3.5 ×  10−4 ± 3.3 × 10−6	1.8 ± 0.62	–	0.94 ± 1.9 × 10−2
	BG505 SOSIP-I53-50NP	2	2.1 × 105 ± 1.6 × 105	3.1 × 10−4 ± 1.2 × 10−4	4.8 ± 4.2	18 ± 0.64	0.88 ± 3.2 × 10−2
	ConM SOSIP	4	1.6 × 105 ± 1.1 × 104	3.8 × 10−4 ± 9.5 × 10−6	2.5 ± 0.15	–	0.79 ± 5.2 × 10−2
	ConM SOSIP-I53-50NP	3	1.5 × 105 ± 9.5 × 103	4.2 × 10−4 ± 3.8 × 10−5	2.8 ± 0.26	20 ± 2.5	0.94 ± 9.9 × 10−2
3BNC117	BG505 SOSIP	3	3.5 × 104 ± 1.2 × 103	9.0 × 10−5 ± 1.3 × 10−5	2.6 ± 0.33	–	2.9 ± 0.18
	BG505 SOSIP-I53-50NP	2	2.0 × 104 ± 5.0 × 102	4.0 × 10−5 ± 3.5 × 10−6	2.1 ± 0.15	55 ± 0.89	2.8 ± 4.5 × 10−2
	ConM SOSIP	2	2.7 × 104 ± 5.0 × 102	2.6 × 10−4 ± 5.0 × 10−6	9.6 ± 0	–	2.8 ± 0
	ConM SOSIP-I53-50NP	2	1.4 × 104 ± 5.0 × 102	7.6 × 10−5 ± 2.4 × 10−5	5.8 ± 1.8	50 ± 0.39	2.5 ± 1.9 × 10−2
PGT122	BG505 SOSIP	3	1.3 × 104 ± 6.7 × 102	1.6 × 10−4 ± 3.1 × 10−5	13 ± 2.7	–	1.3 ± 1.1 × 10−2
	BG505 SOSIP-I53-50NP	3	6.6 × 103 ± 2.0 × 102	2.4 × 10−4 ± 8.4 × 10−5	36 ± 13	25 ± 1.2	1.3 ± 6.2 × 10−2
	ConM SOSIP	5	4.2 × 104 ± 1.4 × 103	4.2 × 10−5 ± 6.3 × 10−6	0.99 ± 0.14	–	2.8 ± 4.7 × 10−2
	ConM SOSIP-I53-50NP	6	3.5 × 104 ± 8.8 × 102	1.0 × 10−4 ± 1.7 × 10−5	2.9 ± 0.49	51 ± 0.82	2.5 ± 4.1 × 10−2
35O22	BG505 SOSIP	3	1.2 × 104 ± 3.3 × 102	2.6 × 10−4 ± 2.7 × 10−5	22 ± 2.3	–	1.5 ± 5.5 × 10−2
	BG505 SOSIP-I53-50NP	2	4.6 × 103 ± 5.0 × 102	2.4 × 10−4 ± 1.5 × 10−5	51 ± 9.0	25 ± 1.9	1.2 ± 0.10
	ConM SOSIP	2	2.3 × 104 ± 5.0 × 102	8.0 × 10−5 ± 1.9 × 10−5	3.5 ± 0.90	–	1.1 ± 4.8 × 10−2
	ConM SOSIP-I53-50NP	2	5.5 × 104 ± 5.0 × 102	1.0 × 10−4 ± 1.1 × 10−5	1.9 ± 0.25	28 ± 1.3	1.4 ± 6.5 × 10−2
3BNC315	BG505 SOSIP	3	5.5 × 103 ± 2.7 × 102	4.1 × 10−5 ± 2.3 × 10−5	8.8 ± 4.9	–	1.7 ± 4.5 × 10−2
	BG505 SOSIP-I53-50NP	2	4.1 × 103 ± 0	<10−5	<3	22 ± 0.52	1.1 ± 2.6 × 10−2
	ConM SOSIP	2	3.6 × 104 ± 4.5 × 103	1.8 × 10−4 ± 2.0 × 10−5	5.1 ± 0.15	–	2.2 ± 0.19
	ConM SOSIP-I53-50NP	2	1.5 × 104 ± 1.0 × 103	6.0 × 10−5 ± 2.4 × 10−5	4.2 ± 2.0	33 ± 1.7	1.6 ± 8.3 × 10−2

Conformational-change modeling of PGT151 Fab binding
Fab	Envelope protein	n	kon (Ms−1)	koff (s−1)	kf (s−1)	kb (s−1)	KD (nM)
PGT151	BG505 SOSIP	2	9.8 × 104 ± 5.0 × 102	1.4 × 10−3 ± 8.6 × 10−4	6.2 × 10−3 ± 1.1 × 10−3	1.3 × 10−3 ± 3.7 × 10−4	15 ± 5.8
	BG505 SOSIP-I53-50NP	2	5.4 × 104 ± 1.0 × 103	2.8 × 10−4 ± 5.0 × 10−6	8.6 × 10−5 ± 8.4 × 10−5	9.1 × 10−4 ± 8.9 × 10−4	5.1 ± 0.19
	ConM SOSIP	3	9.3 × 104 ± 1.5 × 103	6.2 × 10−3 ± 3.1 × 10−4	5.7 × 10−3 ± 2.7 × 10−4	3.3 × 10−4 ± 5.4 × 10−5	67 ± 2.3
	ConM SOSIP-I53-50NP	2	4.7 × 104 ± 1.0 × 103	1.2 × 10−2 ± 5.0 × 10−4	1.2 × 10−2 ± 0	2.1 × 10−4 ± 2.5 × 10−5	250 ± 5.4

Fab	Envelope protein	n	K F	KD(conf) (nM)	Sm/NP	Sm/trimer
PGT151	BG505 SOSIP	2	5.2 ± 2.2	2.3 ± 0.11	–	1.8 ± 5.6 × 10−3
	BG505 SOSIP-I53-50NP	2	0.17 ± 7.4 × 10−2	4.4 ± 0.19	29 ± 0.17	1.5 ± 8.4 × 10−3
	ConM SOSIP	3	18 ± 4.0	3.7 ± 0.56	–	1.8 ± 0.12
	ConM SOSIP-I53-50NP	2	59 ± 7.2	3.8 ± 0.36	37 ± 0.55	1.9 ± 2.8 × 10−2

Shown are average kinetics (k_on = the on-rate constant, k_on = the off-rate constant, K_D = disassociation constant) and stoichiometry values (S_m = stoichiometry) of replicate (n) SPR experiments with standard error of the mean. Since a Langmuir model did not fit well for PGT151 Fab binding to ConM SOSIP a conformational-change model was used for this particular Fab. Average kinetics and stoichiometry values are shown in addition to conversion constants k_f and k_b and the forward-conversion-equilibrium constant K_F. See also Supplementary Fig. 4 and Supplementary Methods for further analysis and explanation