Resiquimod is a drug that acts as an immune response modifier, and has antiviral

Antiviral drug

Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics for bacteria, specific antivirals are used for specific viruses...

 and antitumour activity. It is used as a topical

Topical

In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...

 cream in the treatment of skin lesions such as those caused by herpes simplex virus

Herpes simplex virus

Herpes simplex virus 1 and 2 , also known as Human herpes virus 1 and 2 , are two members of the herpes virus family, Herpesviridae, that infect humans. Both HSV-1 and HSV-2 are ubiquitous and contagious...

, and as an adjuvant to increase the effectiveness of 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...

s. It has several mechanisms of action, being both an agonist

Agonist

An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...

 for toll-like receptor 7

TLR 7

Toll-like receptor 7, also known as TLR7, is protein that in humans is encoded by the TLR7 gene. Orthologs are found in mammals and birds.- Function :...

 and 8, and an upregulator of the opioid growth factor receptor.