Bergtold Amy, Desai Dharmesh D, Gavhane Anamika, Clynes Raphael
Integrated Program in Cellular, Molecular, and Biophysical Studies, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
Immunity. 2005 Nov;23(5):503-14. doi: 10.1016/j.immuni.2005.09.013.
Dendritic cells process internalized antigens to present degradative products on MHC for TCR recognition. Because antigen-exposed DCs also induce humoral immunity, DCs must also retain antigen in its native state for the engagement of BCR on B cells. Here, we demonstrate that antigen endocytosed by the inhibitory Fc receptor, FcgammaRIIB, accesses a non-degradative intracellular vesicular compartment that recycles to the cell surface, enabling interaction of native antigen with BCR on B cells. Immunization with IgG-opsonized, T independent antigens leads to enhanced humoral responses in a FcgammaRIIB and complement dependent manner. IC-loaded DCs trafficking to the splenic marginal zone can prime a T independent response in an FcgammaRIIB-dependent manner. Thus dendritic cells are equipped with both non-degradative and degradative antigen uptake pathways to facilitate antigen presentation to both B and T cells.
树突状细胞处理内化的抗原，以在主要组织相容性复合体（MHC）上呈递降解产物供T细胞受体（TCR）识别。由于暴露于抗原的树突状细胞也能诱导体液免疫，因此树突状细胞还必须将抗原保持在其天然状态，以便与B细胞上的B细胞受体（BCR）结合。在此，我们证明，被抑制性Fc受体FcγRIIB内吞的抗原进入一个非降解性的细胞内囊泡区室，该区域循环至细胞表面，使天然抗原能够与B细胞上的BCR相互作用。用IgG调理的、非T细胞依赖性抗原进行免疫，以FcγRIIB和补体依赖性方式增强体液反应。携带免疫复合物（IC）的树突状细胞向脾边缘区的迁移能够以FcγRIIB依赖性方式引发非T细胞依赖性反应。因此，树突状细胞具备非降解性和降解性抗原摄取途径，以促进向B细胞和T细胞呈递抗原。
