Vaccination usually implies the use of an antigenic material to stimulate the immune system and develop adaptive immunity to a pathogen or infectious agents such as bacteria or viruses. The antigenic material or vaccine typically contains an agent made from a weakened or killed pathogen or some of its constituents and by-products such as surface proteins or toxins. Administering a vaccine results in immunization.
Cancer researchers have applied the concept of vaccination and immunization in cancer treatment. One of the most popular immunotherapies involves using anti-viral vaccines to prevent some types of cancer.
Examples include HPV vaccination administered to prevent cervical cancer and hepatitis B vaccination to prevent some liver cancers. Take note that these cancers result from viral infections. Immunization would help reduce or eliminate the risk. Recent developments in immunotherapy have opened the possibility for using non-virus vaccines to treat cancer. These are called therapeutic or treatment vaccines or cancer vaccines.
Compared with vaccination aimed at developing immunity or treating bacterial or viral infections, the concept behind cancer vaccines centers on stimulating the immune system and using it to attack cancer cells.
Using Immunotherapy in Cancer Treatment: Different Types of Cancer Vaccines
Of course, it is important to highlight the fact that the development of vaccines to fight cancer remains challenging due to the complexity of the immune system. But researchers are eager to develop these vaccines using knowledge gained from previous studies.
There are currently four new types of non-virus cancer vaccines that are under the process of further development. These are the following:
1. Tumor Cell Vaccines
These vaccines are made from the actual cancer cells that have been removed from a patient during surgery. The process involved in making these vaccines includes extracting the cancer cells and killing them before altering them in the laboratory.
This alteration is necessary to increase the response from the immune system. Once altered, these cells are injected into the patient. The goal is for the immune system to attack these altered cells and develop an immune response to attack living cancer cells within the body.
Most of these tumor cell vaccines are autologous. This means that a particular vaccine is only applicable to the same patient from which the extracted tumor cells came. There are allogeneic versions of tumor cell vaccines and these are easier to make than autologous vaccines. It is however unclear which between the two works better.
2. Antigen Vaccines
Rather than using an entire tumor cell, these vaccines only use antigens made from the proteins or peptides of cancer cells. The goal is to boost the immune system and trigger an immune response against cancer cells within the body.
Unlike autologous tumor cell vaccines, antigen vaccines are not made for a specific patient. However, they can be made for a specific type of cancer.
3. Dendritic Cell Vaccines:
Dendritic cells are immune cells that help the immune system recognize cancer cells. They function by breaking down cancer cells into smaller pieces and holding out the resulting antigens so other immune cells, particularly T cells, can start an immune response against any cells in the body that contain these antigens.
Noe that dendritic cell vaccines are autologous vaccines. They are made from the patient in whom they will be used. The process of making one is complex and expensive.
It involves removing some immune cells from the blood of the patient and turning them into dendritic cells in the laboratory by exposing them to cancer cells, cancer antigens, and other chemicals. The dendritic cells are then injected back into the patient, where they should cause an immune response to cancer cells in the body.
4. Vector-Based Vaccines
These are not a separate category of vaccines. Rather, these vaccines involve the use of special delivery systems or vectors such as altered viruses, bacteria yeast cells, or other structures as a medium for transporting the actual vaccine. Take note that there are antigen vaccines that use a vector for more effective delivery.
There are several advantages to using vector-based vaccines. The first is that a vector can deliver multiple cancer antigens at a time. This increases the likelihood of an effective immune response. Another advantage is that vectors such as viruses and bacteria might trigger a separate immune response that can make the overall immune system stronger.
Side Note on Immunotherapy: The Challenges of Using Cancer Vaccines
Researchers are currently exploring the applicability and effectiveness of these non-virus cancer vaccines. Some of the more common types of cancer in which these vaccines are now being studied include brain tumors, breast cancer, cervical cancer, colorectal cancer, kidney cancer, lung cancer, lymphoma, melanoma, pancreas cancer, and prostate cancer, among others.
However, there are pressing challenges in making these treatment vaccines effective and efficient. These include the tendency of cancer cells to suppress the immune system, inability of the immune system to readily recognize some cancerous cells, ineffectiveness in removing advanced tumors, and issues concerning people with compromised immune systems.