An adjuvant is a pharmacological

Pharmacology

Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...

 or immunological

Immunology

Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders ; the...

 agent that modifies the effect of other agents, such as a drug

Drug

A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

 or vaccine

Vaccine

A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

, while having few if any direct effects when given by itself. They are often included in vaccines to enhance the recipient's immune response to a supplied antigen

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...

, while keeping the injected foreign material to a minimum.

Immunologic adjuvants

Immunologic adjuvants are added to vaccines to stimulate the immune system

Immune system

An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

's response to the target antigen

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...

, but do not in themselves confer immunity

Immunity (medical)

Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...

. Adjuvants can act in various ways in presenting an antigen to the immune system. Adjuvants can act as a depot for the antigen, presenting the antigen over a long period of time, thus maximizing the immune response before the body clears the antigen. Examples of depot type adjuvants are oil emulsion

Emulsion

An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

s. Adjuvants can also act as an irritant which causes the body to recruit and amplify its immune response. A tetanus

Tetanus

Tetanus is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, rod-shaped, obligate anaerobic bacterium Clostridium tetani...

, diphtheria

Diphtheria

Diphtheria is an upper respiratory tract illness caused by Corynebacterium diphtheriae, a facultative anaerobic, Gram-positive bacterium. It is characterized by sore throat, low fever, and an adherent membrane on the tonsils, pharynx, and/or nasal cavity...

, and pertussis

Pertussis

Pertussis, also known as whooping cough , is a highly contagious bacterial disease caused by Bordetella pertussis. Symptoms are initially mild, and then develop into severe coughing fits, which produce the namesake high-pitched "whoop" sound in infected babies and children when they inhale air...

 vaccine, for example, contains minute quantities of toxin

Toxin

A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...

s produced by each of the target bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, but also contains some aluminum hydroxide. Such aluminum salts are common adjuvants in vaccines sold in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and have been used in vaccines for over 70 years. The body's immune system develops an antitoxin

Antitoxin

An antitoxin is an antibody with the ability to neutralize a specific toxin. Antitoxins are produced by certain animals, plants, and bacteria. Although they are most effective in neutralizing toxins, they can kill bacteria and other microorganisms. Antitoxins are made within organisms, but can be...

 to the bacteria's toxins, not to the aluminum, but would not respond enough without the help of the aluminum adjuvant.

Adjuvants as stabilizing agents

Although immunological adjuvants have traditionally been viewed as substances that aid the immune response to antigen, adjuvants have also evolved as substances that can aid in stabilizing formulations of antigens, especially for vaccines administered for animal health.

See also

• Adjuvant care
• Agricultural spray adjuvant
  Agricultural spray adjuvant
  In agriculture, an adjuvant is broadly defined as any substance added to the spray tank, that will improve the performance of the pesticides, herbicides, feeding stimulants etc. The water molecule has a high surface tension and this leads to formation of water droplets when sprayed on a waxy surface...
  
  
• Combination therapy
  Combination therapy
  Combination therapy or polytherapy is the use of more than one medication or other therapy. In contrast, monotherapy is any therapy which is taken by itself....
  
  
• Freund's adjuvant
  Freund's adjuvant
  Freund's adjuvant is a solution of antigen emulsified in mineral oil and used as an immunopotentiator . The complete form, Freund's Complete Adjuvant, is composed of inactivated and dried mycobacteria , whereas the incomplete form lacks the mycobacterial components...
  
  
• Immunologic adjuvant
  Immunologic adjuvant
  In immunology, an adjuvant is an agent that may stimulate the immune system and increase the response to a vaccine, without having any specific antigenic effect in itself. The word “adjuvant” comes from the Latin word adiuvare, meaning to help or aid...
  
  
• Inactivated vaccine
  Inactivated vaccine
  An inactivated vaccine consists of virus particles which are grown in culture and then killed using a method such as heat or formaldehyde.-Examples:Types include:* viral: polio vaccine and influenza vaccine...
  
  
• Pharmaceutic adjuvant
  Pharmaceutic adjuvant
  In pharmacology, adjuvants are drugs that have few or no pharmacological effects by themselves, but may increase the efficacy or potency of other drugs when given at the same time....