Abstract: The invention relates to a composition which contains at least one anti-slan antibody and to its diagnostic and therapeutic use. The composition according to the invention comprises: a) at least one anti-slan antibody, b) at least one binding unit which binds to a co-stimulus binding to a co-stimulus-specific receptor on dendritic cells, thereby bringing about the modulation, preferably the activation, of said dendritic cells, and c) at least one antigen. The invention furthermore comprises anti-slan antibodies which include CDRs with the following sequences: variable region of the heavy chain: CDR1 (SEQ ID No. 1), CDR2 (SEQ ID No. 2), where Xaa is selected from among M, L, F, or I, preferably from among M or I, CDR3 (SEQ ID No. 5) and variable region of the light chain: CDR1 (SEQ ID No. 6), where Xaa is selected from among S, T, N, Q, H, K or R, preferably from among S or N, CDR2 (SEQ ID No. 9) and CDR3 (SEQ ID No. 10).