Oncology & Cancer

Tumors disrupt the immune system throughout the body

Cancer treatment has advanced with the advent of immunotherapies that, in some cancers, can overcome tumors' ability to evade the immune system by suppressing local immune responses. But a new study in mice by UC San Francisco ...

Medical research

Platform precisely quantifies antigens presented on cell surfaces

Normally, the immune system is able to differentiate between healthy and abnormal cells. Peptides, fragments created by the synthesis and breakdown of proteins inside each cell, are presented on the surface as antigens and ...

Oncology & Cancer

Infection risk up in month after CAR T-cell immunotherapy

(HealthDay)—For children and young adults receiving CD19 chimeric antigen receptor (CAR) T-cell infusion (CTI), infection rates increase in the first month after treatment and then decrease, according to a study published ...

Diseases, Conditions, Syndromes

New coronavirus test is imperfect step toward mass screening

A new type of coronavirus test offers a cheaper, quicker way to screen for infections, moving the U.S. toward the kind of mass screening that experts say is essential to returning millions of Americans to school and work.

Oncology & Cancer

Mathematical model predicts patient outcomes to adaptive therapy

Prostate cancer is the most common malignancy among men in the United States. It is also the second most common cause of cancer-related deaths. Despite improved treatments for prostate cancer, many patients with advanced ...

Oncology & Cancer

CAR macrophages go beyond T cells to fight solid tumors

Chimeric antigen receptor (CAR) T cell therapy has been a game-changer for blood cancers but has faced challenges in targeting solid tumors. Now researchers from the Perelman School of Medicine at the University of Pennsylvania ...

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Antigen

An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as pollen or cells such as bacteria. The term originally came from antibody generator and was a molecule that binds specifically to an antibody, but the term now also refers to any molecule or molecular fragment that can be bound by a major histocompatibility complex (MHC) and presented to a T-cell receptor. "Self" antigens are usually tolerated by the immune system; whereas "Non-self" antigens are identified as invaders and attacked by the immune system. self antigens.

An immunogen is a specific type of antigen. An immunogen is a substance that is able to provoke an adaptive immune response if injected on its own. An immunogen is able to induce an immune response, whereas an antigen is able to combine with the products of an immune response once they are made. The overlapping concepts of immunogenicity and antigenicity are, therefore, subtly different. According to a current textbook:

Immunogenicity is the ability to induce a humoral and/or cell-mediated immune response

Antigenicity is the ability to combine specifically with the final products of the immune response (i.e. secreted antibodies and/or surface receptors on T-cells). Although all molecules that have the property of immunogenicity also have the property of antigenicity, the reverse is not true."

At the molecular level, an antigen is characterized by its ability to be "bound" at the antigen-binding site of an antibody. Note also that antibodies tend to discriminate between the specific molecular structures presented on the surface of the antigen (as illustrated in the Figure). Antigens are usually proteins or polysaccharides. This includes parts (coats, capsules, cell walls, flagella, fimbrae, and toxins) of bacteria, viruses, and other microorganisms. Lipids and nucleic acids are antigenic only when combined with proteins and polysaccharides. Non-microbial exogenous (non-self) antigens can include pollen, egg white, and proteins from transplanted tissues and organs or on the surface of transfused blood cells. Vaccines are examples of immunogenic antigens intentionally administered to induce acquired immunity in the recipient.

Cells present their immunogenic-antigens to the immune system via a histocompatibility molecule. Depending on the antigen presented and the type of the histocompatibility molecule, several types of immune cells can become activated.

This text uses material from Wikipedia, licensed under CC BY-SA