Adenoviral transgene ubiquitination enhances mouse immunization and class I presentation by human dendritic cells

International audienceTherapeutic vaccination aims at a strong stimulation of antigen-specific CD8(+) T-cells, so that they differentiate into effectors active in vivo against antigenic targets. Two adenovirus vectors ( Ad) encoding two HLA-A*0201-restricted HIV epitope sequences (pol 476 and pol 589) were constructed. The Ad differ by the presence or absence of a ubiquitin monomer sequence (AdUb(+) and AdUb(-)). The effect of transgene product ubiquitination was analyzed on (1) in vivo, the immunization of Ad vaccinated HLA-A* 0201 humanized HHD mice and ( 2) in vitro, the presentation of the transgene encoded peptides by transduced human dendritic cells ( DC). In vivo, we found that immunization of humanized HHD mice with AdUb(+) elicited a transgene product-specific ;interferon (INF)-gamma CD8(+) T-cell response detectable by enzyme-linked immunospot (ELISPOT), whereas the AdUb(-) construction did not. Antigen-specific cytotoxic T lymphocytes (CTL) were also generated in HHD mice immunized with AdUb(+) and not with AdUb(-). In vitro, using human AdUb(+)-transduced DC, a sizeable expansion of pol 476 and pol 589 tetramer positive CD8(+) T cells as well as CD8(+) CTL were obtained in healthy donors. Compared to AdUb(-)-transduced DC, AdUb(+)-transduced DC triggered a higher number of pol 476-specific IFN-gamma-secreting CD8(+) T cells. In agreement, AdUb(+) transduced DC, used as target in a Cr-51-release assay, were more efficiently lysed by peptide-specific CTL than AdUb(-)-transduced DC. In conclusion, the addition of an ubiquitin sequence to the adenoviral transgene, used as an antigen source, resulted in both in vivo enhanced CD8(+) T-cell immunogenicity in HHD mice and in vitro increased HLA class I-restricted presentation of encoded peptides by human DC

Human health risk assessment for aluminium, aluminium oxide, and aluminium hydroxide.

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