Immunotherapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies, while immunotherapies that reduce or suppress are classified as suppression immunotherapies.
The diagram above represents the process of chimeric antigen receptor T-cell therapy (CAR), this is a method of immunotherapy, which is a growing practice in the treatment of cancer. The final result should be a production of equipped T-cells that can recognize and fight the infected cancer cells in the body.
T-cells (represented by objects labeled as ’t’) are removed from the patient's blood.
Then in a lab setting the gene that encodes for the specific antigen receptors are incorporated into the T-cells.
Thus producing the CAR receptors (labeled as c) on the surface of the cells.
The newly modified T-cells are then further harvested and grown in the lab.
After a certain time period, the engineered T-cells are infused back into the patient.
In recent years, immunotherapy has become of great interest to researchers, clinicians and pharmaceutical companies, particularly in its promise to treat various forms of cancer.
Immunomodulatory regimens often have fewer side effects than existing drugs, including less potential for creating resistance when treating microbial disease.
Cancer immunotherapy attempts to stimulate the immune system to destroy tumors. A variety of strategies are in use or are undergoing research and testing. Randomized controlled studies in different cancers resulting in significant increase in survival and disease free period have been reported and its efficacy is enhanced by 20–30% when cell-based immunotherapy is combined with conventional treatment methods.
One of the oldest forms of cancer immunotherapy is the use of BCG vaccine, which was originally to vaccinate against tuberculosis and later was found to be useful in the treatment of bladder cancer.
The extraction of G-CSFlymphocytes from the blood and expanding in vitro against a tumour antigen before reinjecting the cells with appropriate stimulatory cytokines. The cells then destroy the tumor cells that express the antigen.
Alternatively, Genetically engineered T cells are created by harvesting T cells and then infecting the T cells with a retrovirus that contains a copy of a T cell receptor (TCR) gene that is specialised to recognise tumour antigens. The virus integrates the receptor into the T cells' genome. The cells are expanded non-specifically and/or stimulated. The cells are then reinfused and produce an immune response against the tumour cells. The technique has been tested on refractory stage IV metastatic melanomas and advanced skin cancer
Whether T cells are genetically engineered or not, before reinfusion, lymphodepletion of the recipient is required to eliminate regulatory T cells as well as unmodified, endogenous lymphocytes that compete with the transferred cells for homeostatic cytokines. Lymphodepletion may be achieved by myeloablative chemotherapy, to which total body irradiation may be added for greater effect. Transferred cells multiplied in vivo and persisted in peripheral blood in many people, sometimes representing levels of 75% of all CD8+ T cells at 6–12 months after infusion. As of 2012, clinical trials for metastatic melanoma were ongoing at multiple sites. Clinical responses to adoptive transfer of T cells were observed in patients with metastatic melanoma resistant to multiple immunotherapies.
The body naturally does not launch an immune system attack on its own tissues. Immune tolerance therapies seek to reset the immune system so that the body stops mistakenly attacking its own organs or cells in autoimmune disease or accepts foreign tissue in organ transplantation. Creating immunity reduces or eliminates the need for lifelong immunosuppression and attendant side effects. It has been tested on transplantations, and type 1 diabetes or other autoimmune disorders.
Immunotherapy may produce long-term benefits. Immunotherapy is partly effective in some people and ineffective in others, but it offers allergy sufferers a chance to reduce or stop their symptoms.
The therapy is indicated for people who are extremely allergic or who cannot avoid specific allergens. Immunotherapy is generally not indicated for food or medicinal allergies. This therapy is particularly useful for people with allergic rhinitis or asthma.
The first dose contain tiny amounts of the allergen or antigen. Dosages increase over time, as the person becomes desensitized. This technique has been tested on infants to prevent peanut allergies.
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