Lymphocyte locomotion and attachment on two-dimensional surfaces and in three-dimensional matrices

Area of Science:

• Cell Biology
• Immunology
• Biophysics

Background:

• Lymphocyte adhesion and migration are crucial for immune responses.
• Understanding lymphocyte behavior in different microenvironments is key.

Purpose of the Study:

• To compare lymphocyte adhesion and locomotion on 2-D protein-coated substrata versus 3-D matrices.
• To elucidate the mechanism of lymphocyte migration in 3-D environments.

Main Methods:

• Comparing lymphocyte behavior on 2-D surfaces (serum/fibronectin-coated glass) and 3-D matrices (collagen lattices).
• Utilizing hydrated and dehydrated collagen matrices.
• Employing serum-coated micropore filters with varying pore sizes (3, 8, 0.22, 0.45 µm).
• Conducting cinematographic studies of lymphocyte locomotion in collagen gels.

Main Results:

• Lymphocytes failed to adhere or migrate on 2-D substrata.
• Lymphocytes attached to and migrated within hydrated 3-D collagen lattices.
• Dehydration of collagen reduced lymphocyte attachment.
• Lymphocyte migration in 3-D matrices involved pseudopod extension into matrix gaps, acting as anchorage points.
• Lymphocyte attachment and migration occurred in filters with large pores (3, 8 µm) but not small pores (0.22, 0.45 µm).
• Cinematography revealed variable lymphocyte morphology with pseudopodia extending into matrix gaps.

Conclusions:

• Lymphocytes, being poorly adhesive, utilize a non-classical mechanism for migration in 3-D matrices.
• Pseudopod extension and anchoring within matrix gaps facilitate lymphocyte locomotion in 3-D environments.
• The 3-D matrix structure, rather than direct cell-matrix adhesion, is critical for lymphocyte migration.