Tumor vaccines can be divided into two broad categories– peptide-based vaccines and cell-based vaccines – as determined by the immunogen used in the vaccine (peptide vs cells).
Peptide vaccines prime an antigen-specific immune response through their interactions with antigen-presenting cells (APCs) and subsequently cytotoxic T lymphocytes (CTLs), which ultimately kill antigen-expressing leukemia targets. These interactions, which require functional APCs that can provide adequate costimulation to T cells, in addition to antigen presentation, are complex and are the subject of a large body of investigations.
Peptide vaccines are HLA restricted and therefore are applicable to distinct patient populations expressing the HLA type, require prior knowledge and characterization of the antigenic epitope of the target protein, and elicit a narrow immune response against a single antigen. Peptide vaccines primarily focus on enhancing the CTL immune response, although a few peptide vaccines have elicited immune responses by helper CD4+ T cells.
 Alatrash, G. and J. J. Molldrem (2011). "Vaccines as consolidation therapy for myeloid leukemia." Expert Rev Hematol 4(1): 37-50.