#Dm mage drops code#

MAGE-3 codes for a protein of 315 amino acids, and it is very likely that many other peptides derived from MAGE-3 bind to various HLA molecules and hence could be additional target antigens for an antitumor CTL response. Others were identified by “reverse immunology” approaches, based on the knowledge of gene sequences and in vitro stimulation of lymphocytes of noncancerous individuals with candidate peptides considered likely to bind to a given HLA. Some of these epitopes were identified as targets of CTL clones obtained by stimulation of T lymphocytes with autologous tumor cells. They are presented to CTLs by HLA-A1, -A2 (two epitopes), -A24, and -B44 ( 12– 17).

Five antigenic peptides presented by class I molecules have been identified in the MAGE-3 protein. For instance, it is expressed in 76% of metastatic melanomas ( 12).

As a result, there is now a large supply of sequences potentially coding for tumor-specific shared antigens.Īmong the MAGE genes, MAGE-3 is one of the most frequently expressed in tumors. In addition to the genes identified with the approach involving antitumor CTLs, several other MAGE-type genes, i.e., genes expressed only in tumors and in male germline cells, have been identified by purely genetic approaches or by the use of antibodies present in the sera of cancer patients ( 9– 11). Other families of genes with the same pattern of expression have been identified ( 7, 8). They are silent in normal cells, except in testicular germ cells, which do not express MHC class I molecules and are therefore incapable of presenting antigens to CTLs ( 5, 6). MAGE genes are activated in tumors of many different histological types. The MAGE antigens are of particular interest for cancer immunotherapy because of their strict tumoral specificity and because they are shared by many tumors.

#Dm mage drops code#

These CTLs have been used as tools to isolate genes that code for tumor antigens, such as those of the MAGE gene family ( 3, 4). The use of antigenic peptides presented by class II in addition to peptides presented by class I may also improve the efficacy of therapeutic antitumor vaccination.įrom cultures of blood lymphocytes or tumor-infiltrating lymphocytes of cancer patients stimulated with autologous tumor cells, it is possible to isolate CTLs that show specificity for tumor cells ( 1, 2). The knowledge of such antigens will be useful for evaluation of the immune response of cancer patients immunized with proteins or with recombinant viruses carrying entire genes coding for tumor antigens.

Our procedure should be applicable to other proteins for the identification of new tumor-specific antigens presented by HLA class II molecules. The second epitope is also encoded by MAGE-1, -2, and - 6. We isolated CD4 + T cell clones that recognized two different MAGE-3 epitopes, MAGE-3 114–127 and MAGE-3 121–134, both presented by the HLA-DR13 molecule, which is expressed in 20% of Caucasians.

Monocyte-derived dendritic cells were loaded with a MAGE-3 recombinant protein and used to stimulate autologous CD4 + T cells. We describe here the identification of the first MAGE-encoded epitopes presented by histocompatibility leukocyte antigen (HLA) class II molecules to CD4 + T lymphocytes. Therefore, the antigens encoded by MAGE-type genes are strictly tumor specific and common to many tumors. MAGE-type genes are expressed by many tumors of different histological types and not by normal cells, except for male germline cells, which do not express major histocompatibility complex (MHC) molecules.