111Indium-labeled human alveolar macrophages and monocytes: function and ultrastructure

Area of Science:

• Immunology
• Radiochemistry
• Cell Biology

Background:

• Cellular labeling is crucial for tracking immune cell function and migration in vivo.
• Indium-111 (111In) is a radioisotope with potential applications in cell labeling.

Purpose of the Study:

• To evaluate the efficiency and functional impact of labeling human alveolar macrophages and peripheral blood mononuclear cells with indium-111 (111In)-oxine.
• To assess cell viability and functional integrity post-labeling.

Main Methods:

• Human alveolar macrophages and peripheral blood mononuclear cells were labeled with 111In-oxine.
• Labeling efficiency was determined.
• Functional assays including phagocytosis, colony stimulating factor (CSF) release, and chemotaxis (using C5-derived chemotactic factor and f-MLP) were performed on labeled and unlabeled cells.

Main Results:

• High labeling efficiencies were achieved: 84% for macrophages and 74% for mononuclear cells.
• Labeled cells exhibited phagocytic, secretory (CSF release), and migratory (chemotaxis) functions comparable to unlabeled control cells.
• Microscopic examination and radioautography confirmed cell integrity and distribution of 111In within the cells, with a notable concentration over nuclei.

Conclusions:

• Indium-111 (111In)-oxine is an effective agent for labeling human immune cells.
• Cellular functions remain intact after labeling with 111In, supporting its utility in immunological and cell tracking research.
• The findings contribute to the validation of 111In as a reliable radiolabel for functional cell studies.