%0 Journal Article
%T Ultrapotent Broadly Neutralizing Human-llama Bispecific Antibodies against HIV-1.
%A Xu J
%A Zhou T
%A McKee K
%A Zhang B
%A Liu C
%A Nazzari AF
%A Pegu A
%A Shen CH
%A Becker JE
%A Bender MF
%A Chan P
%A Changela A
%A Chaudhary R
%A Chen X
%A Einav T
%A Kwon YD
%A Lin BC
%A Louder MK
%A Merriam JS
%A Morano NC
%A O'Dell S
%A Olia AS
%A Rawi R
%A Roark RS
%A Stephens T
%A Teng IT
%A Tourtellott-Fogt E
%A Wang S
%A Yang ES
%A Shapiro L
%A Tsybovsky Y
%A Doria-Rose NA
%A Casellas R
%A Kwong PD
%J Adv Sci (Weinh)
%V 11
%N 26
%D 2024 Jul 5
%M 38704686
%F 17.521
%R 10.1002/advs.202309268
%X Broadly neutralizing antibodies are proposed as therapeutic and prophylactic agents against HIV-1, but their potency and breadth are less than optimal. This study describes the immunization of a llama with the prefusion-stabilized HIV-1 envelope (Env) trimer, BG505 DS-SOSIP, and the identification and improvement of potent neutralizing nanobodies recognizing the CD4-binding site (CD4bs) of vulnerability. Two of the vaccine-elicited CD4bs-targeting nanobodies, G36 and R27, when engineered into a triple tandem format with llama IgG2a-hinge region and human IgG1-constant region (G36×3-IgG2a and R27×3-IgG2a), neutralized 96% of a multiclade 208-strain panel at geometric mean IC80s of 0.314 and 0.033 µg mL-1, respectively. Cryo-EM structures of these nanobodies in complex with Env trimer revealed the two nanobodies to neutralize HIV-1 by mimicking the recognition of the CD4 receptor. To enhance their neutralizing potency and breadth, nanobodies are linked to the light chain of the V2-apex-targeting broadly neutralizing antibody, CAP256V2LS. The resultant human-llama bispecific antibody CAP256L-R27×3LS exhibited ultrapotent neutralization and breadth exceeding other published HIV-1 broadly neutralizing antibodies, with pharmacokinetics determined in FcRn-Fc mice similar to the parent CAP256V2LS. Vaccine-elicited llama nanobodies, when combined with V2-apex broadly neutralizing antibodies, may therefore be able to fulfill anti-HIV-1 therapeutic and prophylactic clinical goals.