Adjuvantation of epidermal powder immunization

The skin is an immunologically active site and an attractive vaccination ro ute. All current vaccines, however, are administered either orally, intramu scularly, or subcutaneously. We previously reported that epidermal powder i mmunization (EPI) with an extremely small dose of powdered influenza vaccin e induces protective immunity in mice. In this study, we report that common ly used adjuvants can be used in EPI to further enhance the immune response s to an antigen. The IgG antibody response to diphtheria toroid (DT) following EPI was augme nted by 25- and 250-fold, when 1 mug DT was co-delivered with aluminum phos phate (alum) and a synthetic oligonucleotide containing CpG DNA motifs (CpG DNA), respectively. These antibodies had toxin-neutralization activity and were long lasting. Furthermore? EPI using an adjuvant selectively activate d different subsets of T helper cells and gave either a Th1 or a Th2 type o f immune response. Similar to needle injection into deeper tissues. EPI wit h alum adsorbed DT promoted a predominantly IgG1 subclass antibody response and elevated level of IL-4 secreting cells. These are indicative of Th2-ty pe immunity. In contrast: co-delivery of CpG DNA adjuvant via EPI led to Th -l type of response as characterized by the increased production of IgG2a a ntibodies and IFN-gamma secreting cells. This study indicated that EPI usin g appropriate adjuvants can produce an augmented antibody response and desi rable cellular immune responses. EPI is a promising immunization method tha t may be used to administer a broad range of vaccines including vaccines wi th adjuvants. (C) 2001 Elsevier Science Ltd. All rights reserved.