Active immunotherapy is a type of

immunotherapy Immunotherapy or biological therapy 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 immunotherap ...

that aims to stimulate the host's

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as Tumor immunology, cancer cells and objects such ...

or a specific

immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...

to a disease or

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...

and is most commonly used in

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bl ...

treatments. Active immunotherapy is also used for treatment of

neurodegenerative disorders A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic ...

, such as Alzheimer's disease,

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

prion disease Prions are misfolded proteins that have the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals. It ...

, and multiple sclerosis. Active immunotherapies induce an immune response through direct immune system stimulation, while immunotherapies that administer antibodies directly to the system are classified as passive immunotherapies. Active immunotherapies can elicit generic and specific immune responses depending on the goal of the treatment. The categories of active immunotherapy divide into: * Non-specific active immunotherapy: generating a general immune system response using

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in a ...

s and other

cell signaling In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

molecules. * Specific active immunotherapy: the generation of cell-mediated and antibody immune responses focused on specific antigens expressed by the cancer cells, typically using a

vaccine platform A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifie ...

. Active immunotherapies fall under the category of activation immunotherapies, which is a subset of immunotherapies that activate the immune system as opposed immunotherapies that suppress the immune system.

Non-specific active immunotherapy

Non-specific active immunotherapy is administered with the overall goal of generally eliminating malignant pathogens or cells from the host system. This treatment stimulates the immune system in a general sense, rather than specifically targeting a cell type e.g. cancer cells. Non-specific approaches aim to create a robust immune response that would lead to the eventual killing of malignant cells through

immunomodulators Immunotherapy or biological therapy 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 immunother ...

such as cytokines.

Cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in a ...
s

Immunomodulating agents regulate the immune system's response and are produced by various immune cells. These agents include the following agents and markers:

BCG Vaccine Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis (TB). It is named after its inventors Albert Calmette and Camille Guérin. In countries where tuberculosis or leprosy is common, one dose is recommende ...

The

BCG vaccine Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis (TB). It is named after its inventors Albert Calmette and Camille Guérin. In countries where tuberculosis or leprosy is common, one dose is recommende ...

has been used against tuberculosis, mycobacteria, and various cancers in the form of vaccination as an initial immune system stimulant. In cancer, the anti-tumor immunological effects are elicited by the host's immune response and the BCG infection against the tumor cells, most commonly in bladder cancer. The immune activation allows for further recognition and elimination of malignant tumor cells.

Specific active immunotherapy

Specific active immunotherapy administers a specific antigen as the therapy. The therapy allows the host to create an antigen-specific response with the development of antibodies, proliferation of

cytotoxic T lymphocyte A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected by intracellular pa ...

responses, or both, directed at the desired pathogen or malignant tumor cell in the case of cancer therapy.

Vaccine Therapies

Vaccine therapies are a type of specific active immunotherapy. Vaccine therapies deliver various agents that will lead to a specific immune response e.g. antibody development or CTL response.

Tumor antigen Tumor antigen is an antigenic substance produced in tumor cells, i.e., it triggers an immune response in the host. Tumor antigens are useful tumor markers in identifying tumor cells with diagnostic tests and are potential candidates for use in c ...

s have been a main target in specific active immunotherapy by way of vaccination. Tumor antigens are antigens produced by tumor cells and can be common among patients with the same cancer-type, or unique to a particular patient. Their specificity to malignant tumor cells makes tumor antigens ideal candidates for vaccination.

References

{{reflist Immunotherapy