further examination of the biochemical proper-
ties and specificities of the naïve Abs. Twenty-
three HMP Fabs bound to N332-GT1 and/or
N332-GT2 by SPR and did not bind detect-
ably to the MD39 native-like trimer, demon-
strating proper N332 glycan supersite epitope
specificity (Fig. 3, E and F). These SPR-
validated epitope-specific clones were highly
enriched for VL3-25, VL3-1, or the closely related
VL3-10 (Fig. 3E). Thus, the protein design
strategy resulted in Envtrimersthatcould
successfully bind human naïve B cells with
BG18-like LCs.
All N332-supersite bnAbs identified to date
require a long HCDR3 [≥20 amino acids (aa)],
Steichenet al.,Science 366 , eaax4380 (2019) 6 December 2019 5of13
45
N332-GT2 AF647
N332-GT2 AF488
N332-KO AF568
N332-GT2 A488
0.059
12.4
79.0
95.8
B220+ GT2++
BG18gH
WT
Non-immunized
VH
genes
VL
genes IGKV6-32*01
IGKV4-80*01
IGKV4-79*01
IGKV4-69*01
IGKV4-68*01
IGKV4-55*01
IGKV3-4*01
IGKV3-10*01
IGKV4-61*01
IGKV3-5*01
IGKV3-1*01
IGKV12-41*01
IGKV4-57-1*01
IGKV10-96*01
IGKV12-46*01
IGKV10-94*01
IGKV12-44*01
48
48
20.8%
20.9%
12.5%
10.
5%
Frequency of B cells (%)
GT2++KO-
Day8
post-immunization
Day42
post-immunization
VH
genes
VL
genes Tree scale: 0.01
GT2 MD39
0.0
12.5
25.0
GT2 MD39
0.00
0.63
1.25
*
**
CD45.2 GT2++KO- CD45.1 GT2++KO-
Frequency of B cells [%] Frequency of B cells [%]
GC formation CD45.2
IgG ED
50
Immunogen:
GT2
GT2KOGT2KOGT2KOGT2KO
1×10-1
1×10^0
1×10^1
1×10^2
1×10^3
1×10^4
1×10^5
***
Immunogen:
MD39
0
5
10
15
BG18gH
WT
134
134
Day8
post-immunization
Day42
post-immunization
GT2-AF488 GT2-AF488
GT2-AF647 GT2-AF647
ELISA
GT2 MD39
0.00
0.40
0.80
*
**
GT2 MD39
0.00
0.06
0.12
*
ns
IGKV12-41*01
IGKV4-57-1*01
IGKV12-46*01
IGKV12-44*01
IGHV4-4*02
IGHV4-4*02
45
BC
F
A
HI
D E
G
J K
IC50
(μg/mL)
<0.01
0.01 - 0.1
0.1 - 1
1 - 50
>50
BG505_V1
mod
SF162P3_V
1 mod
AC10_V
1 mod
AD8_V1
mod
BG505_7mutBG505_MD39N332-GT2_KO
1×10^1
1×10^2
1×10^3
1×10^4
1×10^5
KD
(nM) d42_iGL
d42
naive
7m
ut
BG505_MD39N332-GT2_KO
d42_iGL
d42
naive
KD
(nM)
Ab BG505 T332N BG505-V1mod
d42.4 >50 3.3
d42.8 >50 0.06
d42.13 >50 1.61
d42.11 >50 0.45
d42.12 >50 0.1
d42.10 >50 ND
d42.iGL1 >50 >50
d42.iGL2 >50 >50
d42.iGL3 >50 >50
d42.iGL4 >50 >50
d42.iGL5 >50 >50
naive1 >50 >50
naive2 >50 >50
naive3 >50 >50
naive4 >50 >50
naive5 >50 >50
BG18 0.005 0.006
RESEARCH | RESEARCH ARTICLE
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