CD20 is expressed strictly by B-cells and is ubiquitously expressed at high 
surface densities of malignant human B-cells. This suggests that CD20 may be a 
tumor target for immunotherapy of B-cell lymphomas. Rituximab, a chimeric 
monoclonal antibody directed against CD20, has been demonstrated to be an 
effective treatment for non-Hodgkin's lymphoma (NHL) and some autoimmune 
diseases. In the current study, we used the phage display technique to generate 
mimotopes that complemented the screening Ab Rituximab. A total of seven 
candidate mimotopes were isolated from a 12-mer peptide library from which one 
mimotope was conjugated to keyhole limpet hemocyanin (KLH) or tetanus toxoid 
(TT). The immunogenicity of the two vaccines generated was examined in BALB/c 
mice. Sera from the vaccinated mice demonstrated high-titer specific antibodies 
to the mimotope conjugates. Antibody binding to native CD20 and Ab-mediated 
cytotoxicity (CDC, complement-dependent cytotoxicity) were also analyzed. Our 
data suggest that a Rituximab mimotope may be a useful tool for the construction 
of a functional vaccine to treat B-cell malignancy as well as some CD20 related 
autoimmune disorders.