Antibody VRC01 is a human immunoglobulin that neutralizes about 90% of HIV-1 isolates. To understand how such broadly neutralizing antibodies develop, we used x-ray crystallography and 454 pyrosequencing to characterize additional VRC01-like antibodies from HIV-1–infected individuals. Crystal structures revealed a convergent mode of binding for diverse antibodies to the same CD4-binding-site epitope. A functional genomics analysis of expressed heavy and light chains revealed common pathways of antibody-heavy chain maturation, confined to the IGHV1-2*02 lineage, involving dozens of somatic changes, and capable of pairing with different light chains. Broadly neutralizing HIV-1 immunity associated with VRC01-like antibodies thus involves the evolution of antibodies to a highly affinity-matured state required to recognize an invariant viral structure, with lineages defined from thousands of sequences providing a genetic roadmap of their development.

Chikungunya virus (CHIKV) has infected millions of people in Africa, Europe, and Asia1,2 since its re-emergence in Kenya in 2004. The severity of disease and spread of this epidemic virus present a serious public health threat in the absence of vaccines or anti-viral therapies. Here, we describe a novel vaccine that protects against emerging CHIKV infection of non-human primates (NHP). We show that selective expression of viral structural proteins gives rise to virus-like particles (VLPs) in vitro that resemble replication-competent alphaviruses. Immunization with these VLPs elicited neutralizing antibodies against envelope proteins from different CHIKV strains. Monkeys immunized with VLPs produced high titer neutralizing antibodies that protected against viremia after high dose challenge. We transferred these antibodies into immunodeficient mice, where they protected against subsequent lethal CHIKV challenge, establishing a humoral mechanism of protection. Immunization with alphavirus VLP vaccines represents a strategy to contain the spread of CHIKV and related pathogenic viruses in humans.

Containment of highly lethal Ebola virus outbreaks poses a serious public health challenge. Although an experimental vaccine has successfully protected non-human primates against disease, more than six months was required to complete the immunizations, making it impractical to limit an acute epidemic. Here, we report the development of accelerated vaccination against Ebola virus in non-human primates. The antibody response to immunization with an adenoviral (ADV) vector encoding the Ebola glycoprotein (GP) was induced more rapidly than with DNA priming and ADV boosting, but it was of lower magnitude. To determine whether this earlier immune response could nonetheless protect against disease, cynomolgus macaques were challenged with Ebola virus after vaccination with ADV-GP and nucleoprotein (NP) vectors. Protection was highly effective and correlated with the generation of Ebola-specific CD8(+) T-cell and antibody responses. Even when animals were immunized once with ADV-GP/NP and challenged 28 days later, they remained resistant to challenge with either low or high doses of virus. This accelerated vaccine provides an intervention that may help to limit the epidemic spread of Ebola, and is applicable to other viruses.