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Reduced IgG Fc-receptor-mediated phagocytosis in human monocytes isolated from alcoholics
H Mørland1, J Johnsen, A Bjørneboe
1National Institute of Forensic Toxicology, Oslo, Norway.
Abstract:
Blood monocytes (MC) were isolated from alcoholics and from age-matched controls. Phagocytosis mediated by the IgG Fc-receptor (Fc-R) was assessed in the MC immediately after isolation by using IgG-opsonized sheep erythrocytes as test particles. Experiments were also performed after preincubating the MC in medium containing 10% autologous serum with or without ethanol (80 mM) in vitro at 37 degrees C for 15 min, and with or without ethanol (80 mM) present during the internalization assay in vitro (37 degrees C for 60 min). MC from alcoholics exhibited lower phagocytic capacity via the Fc-R than MC from healthy controls, approximately 50% versus 70% phagocytosing cells. Preincubation of the MC in medium containing 10% autologous serum with 80 mM ethanol, reduced the percentage of phagocytosing MC from controls to 55%, whereas no further reduction occurred in cells from alcoholics. When present during the assays of Fc-R function, ethanol decreased MC phagocytosis of IgG-coated particles significantly in both test groups, to about 30% phagocytosing cells. Blood samples disclosed increased serum levels of markers of liver dysfunction, immunoglobulins, increased sedimentation rate, and white blood cell counts among the alcoholics, while their serum levels of 1,25-dihydroxyvitamin D3 were reduced.
Insights
Alcohol consumption impairs immune cell function. Blood monocytes from alcoholics show reduced phagocytosis via Fc-receptors, an effect exacerbated by ethanol exposure.
Area of Science:
- Immunology
- Toxicology
- Cell Biology
Background:
- Alcohol abuse is linked to immune dysfunction.
- Monocytes play a critical role in innate immunity, including phagocytosis.
- Fc-receptor (Fc-R)-mediated phagocytosis is a key function of monocytes.
Purpose of the Study:
- To investigate the phagocytic capacity of blood monocytes from alcoholic individuals.
- To assess the impact of ethanol on monocyte Fc-R-mediated phagocytosis.
- To compare immune cell function between alcoholics and healthy controls.
Main Methods:
- Isolated blood monocytes (MC) from alcoholics and age-matched controls.
- Assessed IgG Fc-receptor (Fc-R)-mediated phagocytosis using IgG-opsonized sheep erythrocytes.
- Exposed monocytes to ethanol in vitro during preincubation and/or internalization assays.
Main Results:
- Monocytes from alcoholics demonstrated significantly lower phagocytic capacity (50%) compared to controls (70%).
- In vitro ethanol exposure reduced phagocytosis in control monocytes to 55% after preincubation and to 30% during assays.
- Alcoholics showed no further reduction in phagocytosis after ethanol preincubation, suggesting pre-existing impairment.
Conclusions:
- Alcoholism impairs monocyte Fc-R-mediated phagocytosis.
- Ethanol directly inhibits Fc-R function in monocytes.
- Alcoholics exhibit compromised immune surveillance due to reduced monocyte phagocytic function.