CD40LG and neoplasm: B cells can function as antigen-presenting cells by presenting antigen in MHC class II after B-cell-receptor-antigen internalization and processing (Figure 2).43, 44, 45 Vaccination of mice with melanoma or lymphoma with antigen-loaded, CD40-ligand-activated B cells led to tumour-specific T-cell responses and a significant delay in tumour growth.46