OmpA targets dendritic cells, induces their maturation and delivers antigen into the MHC class I presentation pathway

We analyzed the interaction between a bacterial cell wall protein and dendr itic cells (DCs), Outer membrane protein A from Klebsiella pneumoniae (kpOm pA) specifically bound to professional antigen presenting cells and was end ocytosed by immature DCs via a receptor-dependent mechanism. kpOmpA signale d through Toll like receptor 2, induced DCs to produce interleukin 12 and i nduced maturation of DCs,Whole antigen that was coupled to kpOmpA and injec ted into mice was taken up by DCs and delivered to the conventional cytosol ic MHC class I presentation pathway. kpOmpA also primed antigen-specific CD 8(+) CTLs in the absence of CD4(+) T cell help or adjuvant and elicited the rapeutic immunity to antigen-expressing tumors. Thus, OmpA belongs to a cla ss of proteins that are able to elicit CTL responses to exogenous antigen.