Mouse Thy-1.1, also known as CD90.1, is a glycosylphosphatidylinositol (GPI)-anchored cell-surface glycoprotein belonging to the Thy-1 (CD90) family. Thy-1.1 is an allelic form of the Thy-1 antigen expressed in certain mouse strains and is widely used as a genetic and immunological marker in experimental mouse models.

Thy-1.1 is expressed primarily on T lymphocytes and may also be detected on other cell types, including subsets of hematopoietic and stromal cells, depending on the tissue and experimental context. It has been implicated in the regulation of cell adhesion, signal transduction, immune-cell interactions, and cellular differentiation.

Anti-mouse Thy-1.1 antibodies specifically recognize the Thy-1.1 (CD90.1) antigen and are valuable tools for the identification, tracking, and characterization of Thy-1.1-expressing cells. These antibodies are widely used in immunophenotyping, flow cytometry, cell depletion, adoptive cell-transfer studies, and other immunological applications. In particular, the Thy-1.1/Thy-1.2 system is commonly used to distinguish donor and recipient lymphocytes or to track specific cell populations in mouse transplantation and immune-reconstitution models.