Immunotherapy Explained: Types, Mechanisms and What to Expect
What if your own immune system could tackle cancer without the devastating side effects of chemotherapy? For a growing number of patients, immunotherapy is making this possible by unlocking the body’s natural defences rather than poisoning tumours with toxic drugs. This article explains how immunotherapy works, which medicines are used, and where natural imunomodulators, such as BioBran fit into the picture, all grounded in published clinical evidence.
What Is Immunotherapy?
Immunotherapy is a type of medical treatment that uses the body’s immune system to recognise and destroy cancer cells. Every day, the immune system patrols the body for abnormal cells. Specialised white blood cells, namely T-cells and natural killer (NK) cells, are designed to detect and destroy threats, including cancer.
The problem is that tumours have evolved ways to hide. They produce surface proteins that switch off immune cells, effectively telling them: “Move along, nothing to see here.”
Immunotherapy reverses that deception. Instead of directly killing cancer cells the way chemotherapy does, it removes the molecular disguises that tumours use, allowing immune cells to recognise and attack the disease. This fundamental difference is why immunotherapy can produce long-lasting remissions. Once the immune system learns to identify a tumour, it can keep hunting it for years (1).
The approach gained serious momentum in the 1990s, when researchers identified so-called “immune checkpoints”, proteins such as PD-1 and CTLA-4 that normally prevent excessive immune reactions. Cancer hijacks these checkpoints to shut down the very cells that should be destroying it.
Drugs that block these checkpoints have since been approved for more than 20 types of cancer, and in 2018, James Allison and Tasuku Honjo received the Nobel Prize in Physiology or Medicine for their pioneering work on checkpoint inhibition (2).
Will immunotherapy cure cancer? Far from it. Only 20 to 40 percent of patients with advanced-stage cancers respond to current treatments, and the likelihood of success depends heavily on specific tumour characteristics (3).
How Does Immunotherapy Work?
Immunotherapy helps the body’s own immune system do a better job of finding and killing cancer cells. Let’s take a closer look at the core mechanisms behind what does immunotherapy do to your immune system (4,5,6,7).
1. Helping the immune system “see” cancer
Cancer cells often look only slightly different from normal cells, so they can go unnoticed. Immunotherapy can:
- make cancer cells show clearer “flags” (antigens) on their surface
- help immune cells, especially T cells, better recognise these flags
2. Taking the “brakes” off immune cells
The immune system has built‑in brakes (called checkpoints) to stop it from attacking healthy tissue. Cancer cells can exploit these control mechanisms to shut down T cells. Some immunotherapies:
- block the signals that act as checkpoints
- “release” T cells so they can stay active and keep attacking the tumour
3. Sending in more and stronger fighter cells
Sometimes there are too few effective T cells, or they are too weak or exhausted. Immunotherapy can:
- increase the number of cancer-fighting cells
- make them more aggressive and longer-lasting
- support them with helpful immune messengers (cytokines)
4. Changing the tumour’s “neighbourhood”
The area around a tumour (the tumour microenvironment) is often hostile to immune cells. It can contain substances and cells that suppress immunity and protect the cancer. Immunotherapy can:
- reduce suppressive signals and cells
- make the environment more welcoming to T cells
- help immune cells enter and stay inside the tumour
5. Building long-term immune memory
A major goal is to create immune memory so the body remembers the cancer and can respond quickly if it comes back. Some immunotherapies train the immune system much like a vaccine, so it can react faster and stronger in the future.
What are the three types of immunotherapy?
Checkpoint inhibitors, adoptive cell transfer, and therapeutic vaccines are three smart ways doctors now fight cancer by supercharging the immune system. Each type works differently, but all aim to strengthen the immune system’s ability to target tumour cells more effectively.
1. Checkpoint inhibitors – releasing the brakes
The immune system has natural “brakes” to protect healthy tissue. Cancer exploits these regulatory pathways to hide from immune attack and avoid being destroyed.
Checkpoint inhibitors are medicines that block these signals, allowing immune cells to work faster and attack cancer cells (8,9).
Drugs like pembrolizumab (Keytruda), nivolumab (Opdivo), and ipilimumab (Yervoy) release those brakes so immune cells attack. Many patients experience significantly longer survival. However, the trade-off involves immune-related toxicity, and approximately 30% develop severe inflammation of the gut or liver.
2. Adoptive cell transfer – training special forces
Adoptive cell transfer is a cancer treatment where doctors take immune cells called T-cells from a patient’s body, train or change them in the lab to recognise cancer cells better, and then put them back into the patient to fight the cancer (10,11,12).
This approach is like giving the immune system specially trained soldiers that can find and attack cancer more precisely. Scientists are working to make this treatment safer and more widely available for different types of cancer.
The most well-known type of this treatment is called CAR-T therapy, which targets a protein called CD19 found on some blood cancers like certain lymphomas and leukaemias. This therapy has helped many patients, with about 50 to 80% seeing their cancer completely disappear. However, it can cause a serious side effect called cytokine release syndrome, which is a strong immune reaction that needs careful management.
3. Therapeutic vaccines – issuing a wanted poster
Unlike preventive vaccines (such as those against HPV), therapeutic cancer vaccines are given after a diagnosis. They teach the immune system how to recognise and attack cancer cells by showing it specific “faces” or markers unique to the tumour. This helps the immune system spot cancer cells quickly and target them more effectively, much like how a wanted poster helps police identify a suspect (13).
Therapeutic RNA-based cancer vaccines are the newest frontier. Early results from combining these vaccines with other immunotherapies have shown promising reductions in cancer recurrence, especially in melanoma. More than 120 clinical trials are currently under way, and the first commercial approvals are anticipated by the end of this decade (14).
Category | How it works | Key medicines | Main indications | Approximate response | Notable risks |
Checkpoint inhibitors | Release immune brakes | Pembrolizumab, nivolumab, ipilimumab | Melanoma, lung, kidney, head and neck | 20-50% | Colitis, pneumonitis, hepatitis |
Adoptive cell transfer | Lab-trained immune cells reinfused | Yescarta, Kymriah (CAR-T) | B-cell lymphomas, leukaemias | 50-80% | Cytokine release syndrome |
Therapeutic vaccines | Teach immunity to spot tumour markers | mRNA vaccines (trials) | Melanoma, pancreatic, lung (trials) | 44% recurrence reduction (early data) | Injection-site reactions, fatigue |
BioBran: Complementary Immune Support
Natural immunomodulators are increasingly studied as supportive tools alongside modern cancer immunotherapies. While checkpoint inhibitors, CAR-T therapy, and therapeutic vaccines aim to activate specific immune pathways, natural compounds can influence multiple parts of the immune system at once.
BioBran, also called MGN-3, is one such natural immunomodulator. It is made from rice bran and has been studied as a complementary approach in cancer care. It does not replace immunotherapy drugs. Instead, it supports baseline immune function and may help strengthen the body’s overall immune response during conventional cancer treatment (18,19).
Immunomodulator vs immunotherapy – what is the difference? Immunotherapy is a targeted medical treatment that activates the immune system to attack cancer directly. An immunomodulator, by contrast, regulates or balances overall immune activity and may be used as supportive therapy. To explore this distinction in more detail, see Immunomodulators: Natural Allies of Our Immune System and Natural Immunomodulators: How Plant Compounds Support Immunity.
How does Biobran work and how can it support immune function?
BioBran works by activating important immune cells, especially natural killer cells, macrophages, and dendritic cells (20). These cells play a central role in identifying and attacking abnormal or cancerous cells. Research suggests that BioBran can:
- increase natural killer cell activity (21)
- support signals that promote cancer cell death, known as apoptosis (22,23)
- reduce inflammation that may support tumour growth (24)
- help protect the liver and immune system during chemotherapy (25)
- slow tumour growth in animal and human studies (26)
- improve survival trends (27)
- reduce side effects when used alongside chemotherapy or radiotherapy and improve quality of life in patients receiving conventional cancer treatment (28)
Important limitations of BioBran: Most studies are small or pilot trials, often involving fewer than 100 participants. Large-scale randomised controlled trials comparing BioBran directly with modern immunotherapy drugs have not yet been conducted. BioBran is currently classified as a food supplement, not a medicine, and it does not replace prescribed cancer treatment. Its role is supportive, and any use alongside chemotherapy, radiotherapy, or immunotherapy should be discussed with an oncologist.
The Future of Immunotherapy
Immunotherapy is expanding rapidly, but significant challenges remain. Between 50 and 70 percent of patients do not respond to current checkpoint inhibitors.
Newer approaches aim to address these gaps. What does this mean for patients today? Immunotherapy is not a universal cure, but for the right patient it offers the possibility of long-term disease control that was unimaginable two decades ago.
Complementary approaches such as BioBran may support overall immune health during and between treatment cycle. The most important step is an informed conversation with a specialist who can assess individual circumstances.
Frequently Asked Questions
What is meant by immunotherapy?
Immunotherapy is a treatment that uses the body’s own immune system to fight diseases such as cancer. Instead of directly destroying tumour cells, it helps immune cells recognise and attack harmful cells more effectively. It can involve antibodies, vaccines, or modified immune cells that strengthen the immune response.
What is life expectancy after immunotherapy?
Life expectancy after immunotherapy depends on the type and stage of cancer. In advanced lung cancer, median survival after treatment with immune checkpoint inhibitors is often around 12 months or longer, and some patients live several years. However, these treatments can trigger immune-related adverse events affecting organs such as the lungs or liver, which require careful monitoring.
What is the purpose of immunotherapy?
The purpose of immunotherapy is to help the immune system recognise and destroy diseases, especially cancer. It activates or strengthens specific immune cells so they can target harmful cells more precisely, rather than attacking all rapidly dividing cells as chemotherapy does. By training the immune system to recognise tumour markers, immunotherapy can provide longer-lasting control of disease and, in some patients, improved survival and quality of life.
What can immunotherapy be used for?
Immunotherapy is mainly used to treat cancer. It is often used when standard treatments are not effective or in combination with chemotherapy or radiotherapy. In some patients, it can lead to sustained remission. Research is also exploring its role in autoimmune diseases and infections, but cancer remains its primary use today.
What are the names of immunotherapy drugs?
Common immunotherapy drugs include checkpoint inhibitors such as ipilimumab, nivolumab, and pembrolizumab. CAR-T therapies like Yescarta and Kymriah use modified immune cells to fight certain blood cancers. Other types include cancer vaccines and bi-specific antibodies. Newer drugs target additional immune pathways to improve treatment response.
Will immunotherapy cure cancer?
Immunotherapy can cure some patients with certain cancers, but it does not work for everyone. Only a minority achieve complete remission, and many patients do not respond or later relapse. Researchers are developing better combinations to improve results. Complementary options such as BioBran may support immune function during treatment, but they are not a cure and do not replace medical therapy.
About the author
Maria Piknova, PhD, is a biochemist and science blogger specialising in microbiology and molecular biology. She is passionate about translating complex science into clear, evidence-based insights. [ORCID / LinkedIn]