The immune system intercepts any invading pathogens or abnormal cells within the body, including cancer cells. It has evolved numerous mechanisms to recognize such threats, all the while limiting the risk of autoimmunity or attack on normal cells and tissues. However, many cancer cells aren’t recognized as dangerous by our immune system, so bypass the body’s natural defense system, proliferate destructively, and eventually challenge the body’s ability to function. In many cancers, malignant progression is accompanied by profound immunosuppression that interferes with effective antitumor response and tumor elimination. 


Physicians and researchers in both human and veterinary medicine have developed ways to reverse this immunosuppression, or otherwise make the immune system recognize and attack the previously undetected cells. These treatments—immunotherapy and immuno-oncology—offer new ways of treating certain cancers.


  • What treatment opportunities are available?

    During development, the developing immune system is educated to distinguish between cells that belong to that organism versus those that are “foreign” or do not belong to that particular organism. As such, the immune system is programmed to attack “non-self” agents and cells which include infectious organisms such as bacteria and viruses, as well tissues from other organisms, including organs that might be needed for transplant. Therefore, because transplant organs come from other individuals they are considered to be “foreign” by the immune system and will be rejected by the patient’s immune

  • Can immunotherapies be used with other cancer treatments?

    Since the patient’s immune system is responsible for rejecting foreign tissues and organs, the mainstay of treatment to prevent organ rejection is immune suppression. Immune suppression is usually achieved by using drugs such as prednisone and cyclosporine.

  • What side effects might occur with treatment?

    Current immune suppressive drugs used to prevent immune rejection of organ transplants cause widespread immune suppression which makes the patient susceptible to systemic infections, and can increase the incidence of cancer. In addition, immune suppressive drugs such as prednisone have additional side effects including increasing thirst, appetite, muscle weakness, and weight gain.

  • What makes immuno-oncology therapies different?

    Cellular therapies that induce immune “tolerance” to the transplanted organ or graft are being actively investigated. These may include the use of the patient’s own immune cells known as regulatory T cells (that regulate the immune response) as well as cells from a healthy donor known as invariant NKT cells (iNKT cells) that can mediate their own immune tolerance as well as provide tolerance to a transferred graft.