Treatment with Cancer Vaccines
Therapeutic vaccines use cancer cells that have been attenuated (weakened) or tumor antigens (sometimes with adjuvants). This type of treatment is called active specific immunotherapy.
Another type of cancer treatment immunotherapy has already show very strong results. The first monoclonal antibodies were approved for treatment of cancer in 1986, and many new varieties are under development. Although they are not vaccines, monoclonal antibodies do use the immune system to fight cancer cells in a similar manner: In a cancer vaccine, an antigen is injected that stimulates the B cells to produce antibodies against the tumor cells, but in monoclonal antibody therapy, the antibodies that would be produced by B cells are injected directly into the patient. The same or similar antibodies reach the tumor cell, but they are produced outside the patient’s body rather than by the patient’s own cells. Cancer is essentially a genetic disease, in that all cancer cells have some alteration of gene expression.
The antibodies are instead produced in cell cultures of B cells that have
been stimulated by the tumor antigen. The antigen is first injected into
a human or some other vertebrate several times, and the B cells that make
antibodies against it are removed. The antibody producing B cells are then
fused with cancerous B cells (because the cancerous cells can divide indefinitely
due to the telomerase discussed earlier) that have lost the ability to produce
antibodies. The result is multiple lines of cells that produce mass quantities
of antibodies against the antigen of interest. The various cell lines are
tested, and the one that produces the antibody that binds to the antigen
best is used to produce the antibodies that are ultimately injected as monoclonal