Increasing evidence suggests that antibodies can have stimulatory effects on T-cell immunity. However, the contribution of circulating antigen-specific antibodies on MHC class I cross-priming in vivo has not been conclusively established. Here, we defined the role of circulating antibodies in cross-presentation of antigen to CD8 + T cells. Mice with hapten-specific circulating antibodies, but naϊve for the T-cell antigen, were infused with haptenated antigen and CD8 + T-cell induction was measured. Mice with circulating hapten-specific antibodies showed significantly enhanced cross-presentation of the injected antigen compared with mice that lacked these antibodies. The enhanced cross-presentation in mice with circulating antigen-specific antibodies was associated with improved antigen capture by APCs. Importantly, CD11c + APCs were responsible for the enhanced and sustained cross-presentation, although CD11c - APCs had initially captured a significant amount of the injected antigen. Thus, in vivo formation of antigen-antibody immune complexes improves MHC class I cross-presentation, and CD8 + T-cell activation, demonstrating that humoral immunity can aid the initiation of systemic cellular immunity. These findings have important implications for the understanding of the action of therapeutic antibodies against tumor-associated antigens intensively used in the clinic nowadays.

Antibodies, B cells, Cross-presentation, Dendritic cells, Tcells
dx.doi.org/10.1002/eji.201141613, hdl.handle.net/1765/67558
European Journal of Immunology
Department of Gastroenterology & Hepatology

van Montfoort, N, Mangsbo, S.M, Camps, M, van Maren, W.W.C, Verhaart, I.E.C, Waisman, A, … Ossendorp, F. (2012). Circulating specific antibodies enhance systemic cross-priming by delivery of complexed antigen to dendritic cells in vivo. European Journal of Immunology, 42(3), 598–606. doi:10.1002/eji.201141613