Morphine enhances complement receptor-mediated phagocytosis of Cryptococcus neoformans by human microglia

Myriam M. Lipovsky, Genya Gekker, Shuxian Hu, Andy I.M. Hoepelman, Phillip K. Peterson

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Recent studies have shown that opiates modulate the function of microglia, the resident macrophages of the brain. In this study, the effect of morphine on phagocytosis by human fetal microglial cells of the opportunistic fungus Cryptococcus neoformans was studied. Contrary to earlier findings with swine microglia, opsonization was required for the phagocytosis of C. neoformans by human microglia. Moreover, morphine (10-8 M) was shown to augment uptake of opsonized C. neoformans by over 50%. This contrasts with the earlier finding of morphine-induced inhibition of phagocytosis of nonopsonized cryptococci by swine microglia. The effect of morphine on cryptococcal phagocytosis by human microglia was reversed by treatment of microglial cells with μ opiate receptor antagonists as well as by addition of anti-complement receptor antibodies to the cell cultures, indicating that both the μ opiate receptor and the complement receptor are involved in morphine-enhanced phagocytosis. These findings support the concept of opiates as neuroimmunomodulatory agents and demonstrate that the effects of opiates on microglial cells may be influenced by the animal species from which the cells are derived.

Original languageEnglish (US)
Pages (from-to)163-167
Number of pages5
JournalClinical Immunology and Immunopathology
Issue number2
StatePublished - May 1998

Bibliographical note

Funding Information:
This study was supported, in part, by National Institutes of Health Grants DA-04381 and DA-09924. We thank Fred Kravitz for his invaluable assistance.


  • Complement receptor
  • Cryptococcus neoformans
  • Microgila
  • Opiates


Dive into the research topics of 'Morphine enhances complement receptor-mediated phagocytosis of Cryptococcus neoformans by human microglia'. Together they form a unique fingerprint.

Cite this