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Basic surface properties of mononuclear cells from Didelphis marsupialis
V P Nacife1, M de N de Meirelles, F C Silva Filho
1Laboratório de Ultra-estrutura Celular, Instituto Oswaldo Cruz, Rio de Janeiro, Brasil. vnacife@gene.dbbm.fiocruz.br
Memorias Do Instituto Oswaldo Cruz
|January 28, 1999
Summary
Mononuclear cells from marsupials (Didelphis marsupialis) exhibit anionic surface charges, with adult cells showing a more negative charge. Cell surface hydrophilicity is primarily due to sialic acid-containing glycoproteins.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- Mononuclear cells play crucial roles in immune responses.
- Understanding marsupial cell surface properties is vital for comparative immunology.
- Electrostatic charge and surface tension influence cell behavior and interactions.
Purpose of the Study:
- To investigate the electrostatic surface charge and surface tension of mononuclear cells from young and adult marsupials (Didelphis marsupialis).
- To identify the components responsible for the observed cell surface properties.
- To compare cell surface characteristics between young and adult marsupials.
Main Methods:
- Cationized ferritin and colloidal iron hydroxide labeling for anionic sites.
- Whole cell electrophoresis to determine surface charge.
- Contact angle measurements to assess surface hydrophilicity/hydrophobicity.
- Enzymatic treatments (trypsin, neuraminidase, phospholipase C) to probe surface components.
Main Results:
- Anionic sites were uniformly distributed across marsupial mononuclear cell surfaces.
- Cells from young animals had a charge of -18.8 mV, while adult cells had -29.3 mV.
- Enzymatic treatments reduced negative charge and increased hydrophobicity, particularly with trypsin and neuraminidase.
- Marsupial mononuclear cells exhibited high hydrophilicity (contact angles ~40-42 degrees).
Conclusions:
- Marsupial mononuclear cells possess significant anionic surface charges.
- Sialic acid-containing glycoproteins are the primary contributors to the hydrophilicity of these cell surfaces.
- Age influences the net negative charge of marsupial mononuclear cells.