LS-engineered human IgG1 broadly neutralizing monoclonal antibody targeting the HIV-1 Env gp120 CD4-binding site; neutralizes free virions and blocks Env–CD4/coreceptor-mediated entry. The Fc domain can recruit effector functions (e.g., ADCC/ADCP) against Env-expressing infected cells, and LS mutations enhance FcRn binding to extend serum half-life.