Class II antigens on canine T lymphocytes

Area of Science:

• Immunology
• Cell Biology

Background:

• Major Histocompatibility Complex (MHC) class II antigens play crucial roles in immune responses.
• Understanding MHC class II expression on lymphocytes is vital for canine immunology.

Purpose of the Study:

• To investigate the expression of MHC class II antigens on canine T lymphocytes.
• To determine if MHC class II antigen expression is inducible or constitutive on canine T cells.

Main Methods:

• Utilized a panel of cross-reactive anti-MHC class II monoclonal antibodies (Mabs).
• Employed cytofluorometry to analyze antigen expression on T lymphocytes.
• Performed immunoprecipitation studies to confirm molecular identity.

Main Results:

• MHC class II antigens were detected on both activated and non-stimulated peripheral blood T lymphocytes.
• Some Mabs specifically recognized activated T lymphoblasts.
• Immunoprecipitation confirmed the Ia-like molecular nature of these antigens.
• Expression was observed on purified T lymphocytes from specific pathogen-free dogs, indicating constitutive presence.
• MHC class II antigen expression was also found in the neonatal thymus.
• Stimulated T lymphoblasts (lectin or allogeneic) exhibited enhanced MHC class II expression compared to non-stimulated cells.

Conclusions:

• Canine T lymphocytes constitutively express MHC class II antigens.
• MHC class II antigen expression is present from neonatal stages and in the thymus.
• While constitutive, expression levels can be upregulated upon T cell activation.