Bovine afferent lymph veiled cells differ from blood monocytes in phenotype and accessory function

Area of Science:

• Immunology
• Veterinary Science
• Cell Biology

Background:

• Veiled cells (VC) are antigen-presenting cells found in afferent lymph.
• Understanding their phenotype and function is crucial for immune response studies.
• Comparison with blood monocytes provides insights into immune cell differentiation and localization.

Purpose of the Study:

• To characterize the surface phenotype of bovine afferent lymph veiled cells (ALVC).
• To compare the immune accessory function of ALVC with bovine blood monocytes.
• To identify specific ALVC subpopulations responsible for antigen presentation.

Main Methods:

• Preparation of veiled cells from bovine afferent lymph.
• Surface phenotyping using monoclonal antibodies (mAb) against bovine leukocyte antigens.
• Functional assays including mixed leukocyte cultures and soluble antigen presentation to T cells.

Main Results:

• ALVC express CD1c and bovine CD45R, while monocytes express CD11b.
• Both cell types share CD11a, CD11c, and p110/75 expression, with some restricted to ALVC subpopulations.
• ALVC demonstrate superior stimulatory capacity in mixed leukocyte cultures and antigen presentation to T cells, linked to enhanced lymphocyte clustering.

Conclusions:

• Bovine ALVC possess a distinct surface phenotype compared to blood monocytes.
• ALVC exhibit significantly enhanced antigen-presenting capabilities, particularly in activating T cells.
• The p110/75+ CD11a- subpopulation of ALVC is primarily responsible for presenting soluble antigens to T cell clones.