(int‵ĕr-fēr'on‵ )

ABBR: IFN

Any of a group of glycoproteins with antiviral activity. The antiviral type I interferons (alpha and beta interferons) are produced by leukocytes and fibroblasts in response to invasion by a pathogen, esp. a virus. Type I interferons enable invaded cells to produce class I major histocompatibility complex surface antigens, increasing their ability to be recognized and killed by T lymphocytes. They also inhibit virus production within infected cells. Type I alpha interferon is used to treat condyloma acuminatum, chronic hepatitis B and C, and Kaposi sarcoma. Type I beta interferon is used to treat multiple sclerosis.

Type II gamma interferon is distinctly different from and less antiviral than the other interferons. It is a lymphokine, excreted primarily by CD8+ T cells and the helper T subset of CD4+ cells that stimulates several types of antigen-presenting cells, esp. macrophages, to release class II MHC antigens that enhance CD4+ activity. It is used to treat chronic granulomatous disease.

SEE: antigen-presenting cell; macrophage.