Qa alloantigen expression on functional T lymphocytes from spleen and thymus.

Area of Science:

• Immunology
• Cell Biology
• T cell immunology

Background:

• The Qa-2 molecule is a class I alloantigen expressed on the cell surface.
• Its role in T cell maturation and function is not fully understood.

Purpose of the Study:

• To analyze the cell-surface expression of Qa-2 on resting and activated spleen and thymus cells.
• To determine if Qa-2 can serve as a marker for functionally mature T cells.

Main Methods:

• Cytotoxic elimination assays
• Immunofluorescence
• Flow cytometry
• Monoclonal antibody (mAb) treatment

Main Results:

• Activated spleen cells were uniformly Qa-2 positive, but expressed less Qa-2 than nonstimulated cells.
• Qa-2 was enriched in cortisone-resistant thymocytes, a population containing mature thymocytes.
• Treatment with Qa-2-specific mAb abrogated cytotoxic T lymphocyte (CTL) activity, indicating Qa-2's role in T cell function.

Conclusions:

• The Qa-2 molecule is a marker for resting and activated peripheral T cells.
• Qa-2 serves as a unique marker for functionally mature T cells within the thymus.