Induction of protection in mice against a respiratory challenge by a vaccine formulated with exosomes isolated from infected cells.

The goal of this study was to determine if exosomes, isolated from infected HeLa cells (-exosomes), induce protective immune responses in mice following vaccination using CpG plus Montanide as adjuvants. Exosomes, collected from uninfected HeLa cells and PBS, formulated with the same adjuvants, were used as negative controls. Mass spectrometry analyses identified 113 proteins in the -exosome preparation including the major outer membrane protein and the polymorphic membrane proteins. Vaccination with -exosomes elicited robust humoral and cell-mediated immune responses to elementary bodies. Following vaccination, mice were challenged intranasally with . Compared to the negative controls, mice immunized with -exosomes were significantly protected as measured by changes in body weight, lungs' weight, and number of inclusion forming units recovered from lungs. This is the first report, of a vaccine formulated with exosomes, shown to elicit protection against a challenge.