RESUMEN
Broadly neutralizing monoclonal antibodies protect against infection with HIV-1 in animal models, suggesting that a vaccine that elicits these antibodies would be protective in humans. However, it has not yet been possible to induce adequate serological responses by vaccination. Here, to activate B cells that express precursors of broadly neutralizing antibodies within polyclonal repertoires, we developed an immunogen, RC1, that facilitates the recognition of the variable loop 3 (V3)-glycan patch on the envelope protein of HIV-1. RC1 conceals non-conserved immunodominant regions by the addition of glycans and/or multimerization on virus-like particles. Immunization of mice, rabbits and rhesus macaques with RC1 elicited serological responses that targeted the V3-glycan patch. Antibody cloning and cryo-electron microscopy structures of antibody-envelope complexes confirmed that immunization with RC1 expands clones of B cells that carry the anti-V3-glycan patch antibodies, which resemble precursors of human broadly neutralizing antibodies. Thus, RC1 may be a suitable priming immunogen for sequential vaccination strategies in the context of polyclonal repertoires.
Asunto(s)
Vacunas contra el SIDA/inmunología , Linfocitos B/inmunología , Células Clonales/inmunología , VIH-1/química , VIH-1/inmunología , Macaca mulatta/inmunología , Vacunación , Secuencia de Aminoácidos , Animales , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/genética , Anticuerpos Neutralizantes/inmunología , Anticuerpos Neutralizantes/ultraestructura , Afinidad de Anticuerpos , Especificidad de Anticuerpos/inmunología , Complejo Antígeno-Anticuerpo/inmunología , Linfocitos B/citología , Proliferación Celular , Células Clonales/citología , Clonación Molecular , Reactividad Cruzada/inmunología , Microscopía por Crioelectrón , Femenino , Anticuerpos Anti-VIH/química , Anticuerpos Anti-VIH/genética , Anticuerpos Anti-VIH/inmunología , Anticuerpos Anti-VIH/ultraestructura , Epítopos Inmunodominantes/química , Epítopos Inmunodominantes/inmunología , Epítopos Inmunodominantes/ultraestructura , Activación de Linfocitos , Masculino , Ratones , Modelos Moleculares , Polisacáridos/inmunología , Conejos , Hipermutación Somática de InmunoglobulinaRESUMEN
A small number of HIV-1-infected individuals develop broadly neutralizing antibodies to the virus (bNAbs). These antibodies are protective against infection in animal models. However, they only emerge 1-3 yr after infection, and show a number of highly unusual features including exceedingly high levels of somatic mutations. It is therefore not surprising that elicitation of protective immunity to HIV-1 has not yet been possible. Here we show that mature, primary mouse and human B cells can be edited in vitro using CRISPR/Cas9 to express mature bNAbs from the endogenous Igh locus. Moreover, edited B cells retain the ability to participate in humoral immune responses. Immunization with cognate antigen in wild-type mouse recipients of edited B cells elicits bNAb titers that neutralize HIV-1 at levels associated with protection against infection. This approach enables humoral immune responses that may be difficult to elicit by traditional immunization.