IL10 and infection: This observation isconsistent with results of a study showing a role for IL-10 in the suppressionof host immunity upon vaccination; the blockade of IL-10 allowed an ineffectivetherapeutic DNA vaccine to stimulate even stronger immunity and enhance clearanceof persistent viral replication [52].(iii) Similar to cancer and infection, systemic immunization is able to induceantigen-specific T cells in the peripheral system, but cannot overcome theimmunosuppressive microenvironment within local immune response sites.