Enhancement of host resistance to viral and tumor challenge by treatment with methionine-enkephalin

Ann N Y Acad Sci. 1987:496:137-45. doi: 10.1111/j.1749-6632.1987.tb35756.x.


Host resistance to disease is dependent upon a number of factors. Recent evidence indicates that natural killer (NK) cells play an important role in resistance to both neoplastic and virally induced disease. Treatment of C57Bl/6 mice with methionine-enkephalin (1, 3, 10, or 30 mg/kg body weight) results in significant increases in NK activity of splenic lymphocytes 20 hours after injection of the enkephalin. Enkephalin treatment also enhances host resistance. The short-term survival of A/J female mice after HSV-2 infection was significantly increased by daily subcutaneous injections (3 mg/kg body weight) of methionine-enkephalin. Similarly, daily doses of 50 micrograms of methionine-enkephalin for 7 to 14 days inhibit the local subcutaneous tumor growth of B15 melanoma in C57Bl/6 mice.

MeSH terms

  • Adjuvants, Immunologic
  • Animals
  • Enkephalin, Methionine / immunology
  • Enkephalin, Methionine / pharmacology*
  • Female
  • Herpes Simplex / immunology*
  • Herpes Simplex / mortality
  • Immunity, Innate / drug effects*
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / immunology*
  • Melanoma, Experimental / immunology*
  • Melanoma, Experimental / pathology
  • Mice
  • Mice, Inbred A
  • Mice, Inbred C57BL
  • Naloxone / pharmacology


  • Adjuvants, Immunologic
  • Naloxone
  • Enkephalin, Methionine