Enhancement of Antibody Response by Mouse Dendritic Cells Pulsed with Tobacco Mosaic Virus or with Rabbit Antiidiotypic Antibodies Raised against a Private Rabbit Idiotype

The role of splenic lymphoid dendritic cells (DC) and macrophages (Mφ ) from mice in induction of immune responses in vivo has been investigated. Varying numbers of purified DC and Mφ pulsed in vitro with tobacco mosaic virus (TMV) or with rabbit antiidiotypic antibodies (Ab2) directed against a private rabbit anti-TMV idiotype were injected back into syngeneic mice. In both systems, DC appeared to strongly enhance the primary and secondary responses to the virus. Optimal responses were obtained with 5 × 10⁴ purified DC carrying TMV or rabbit Ab2. In contrast, Mφ were less efficient by a factor of at least 100. These results show the potency of lymphoid DC as inducing cells in T-dependent antibody responses in vivo.