Dendritic cell vaccination in an allogeneic stem cell recipient receiving a transplant from a human cytomegalovirus (HCMV)-seronegative donor: induction of a HCMV-specific T(helper) cell response.

Background Aims: In the absence of a protective immune response, human cytomegalovirus (HCMV) infection remains a life-threatening complication after allogeneic stem cell transplantation (SCT), especially in recipients of grafts from HCMV-seronegative donors. After allogeneic SCT from a seronegative donor, prolonged and severe immune deficiency often leads to infectious complications. Vaccination with antigen-loaded dendritic cells (DC) has been shown to be a potent approach for the induction of antigen-specific cytotoxic T-cell responses in vivo.

Ex vivo detection of adenovirus specific CD4+ T-cell responses to HLA-DR-epitopes of the Hexon protein show a contracted specificity of T(HELPER) cells following stem cell transplantation.

Human adenovirus (HAdV) is a cause of significant morbidity and mortality in immunocompromised patients, especially after stem cell transplantation (SCT). Viral clearance has been attributed to CD4(+) T-cell responses against the Hexon-protein, but the frequency of specific T(HELPER) cells is extremely low or not detectable ex vivo and preference for different CD4(+) T-cell epitopes is variable among individuals. We therefore analyzed 44 healthy donors and 6 SCT-recipients for Hexon-specific CD4(+)-responses ex vivo, to identify epitopes which would be broadly applicable.