Widespread expression of the nonclassical class I Qa-2 antigens in hemopoietic and nonhemopoietic cells.

We reexamined expression patterns of one of the best characterized mouse class Ib MHC molecules, Qa-2. Transcripts encoding glycosylphosphatidylinositol-linked and soluble forms of Qa-2 are expressed in all organs except brain. The membrane-bound Qa-2 proteins are detectable, to varying degrees, in many cell types of immunological interest: on professional antigen-presenting cells capable of inducing anti-Qa-2 allogeneic responses, on thymic epithelial cells essential for T-cell positive selection, on mature as well as immature thymocytes, in immunologically privileged sites (testis/spermatazoa), and on cells implicated in mucosal immunity (lymphoid-derived and epithelial gut cells and hepatocytes).

Expression of a nonclassical MHC class Ib molecule in the eye.

Background: MHC class Ia molecules are absent, or expressed at low levels, on cells lining the anterior chamber of the eye, an immune-privileged site. Although the scarcity of class Ia MHC antigens may protect cells from T cell-mediated tissue injury, it may also render them vulnerable to natural killer cell-mediated cytolysis. There is growing evidence that MHC class Ib molecules share similar functions to class Ia.

Interaction of 2C T cells with a hybrid Ld molecule bearing an alpha 3 domain derived from the class IB molecule, Qa-2.

The CD8 co-receptor interacts with nonpolymorphic residues on class I molecules. LQ3, a laboratory engineered Ld molecule bearing an alpha 3 domain derived from Q7 (Qa-2), interacts poorly with anti-Ld CD8-dependent T cells. 2C TCR transgenic mice bear a receptor specific for the p2Ca peptide bound to Ld.

Relationships of serum opsonins and complement in human experimental gingivitis.

This study assessed the phagocytosis of polymorphonuclear neutrophils and the opsonic capacity of serum in experimental human gingivitis. Relationships were sought among these two measurements, clinical indices of gingivitis and complement-related opsonins. Measurements of chemiluminescence provided an index of phagocytosis and of opsonic capacity.