MR:soluble antigen Exogenous soluble antigen MR/other probable receptors Exogenous soluble antigen targeted to more stable early endosome Authored: Garapati, P V, 2011-03-28 Edited: Garapati, P V, 2011-03-28 Pubmed15592474 Reactome Database ID Release 431236940 Reactome, http://www.reactome.org ReactomeREACT_111150 Reviewed: Desjardins, M, English, L, 2011-05-13 Within the endosome the receptor and cargo separate and the receptor recycles back to the cell surface. Soluble antigens are targeted into the stable early endosome lumen for efficient cross presentation. Early endosomes are mildly acidic and relatively poor in proteases.