Impaired immune responses toward alloantigens and tumor cells but normal thymic selection in mice deficient in the beta2 integrin leukocyte function-associated antigen-1.

We have generated mice deficient in the beta2 integrin LFA-1 by targeted disruption of the CD11a gene in embryonic stem cells. In vitro LFA-1 -/- cells exhibit a delayed proliferative response toward alloantigens in the MLR. In vivo the host-vs-graft reaction toward injected allogeneic cells is also reduced.

Transgenic mice expressing the human high-affinity immunoglobulin (Ig) E receptor alpha chain respond to human IgE in mast cell degranulation and in allergic reactions.

The high-affinity receptor for immunoglobulin (Ig) E (Fc epsilon RI) on mast cells and basophils plays a key role in IgE-mediated allergies. Fc epsilon RI is composed of one alpha, one beta, and two gamma chains, which are all required for cell surface expression of Fc epsilon RI, but only the alpha chain is involved in the binding to IgE. Fc epsilon RI-IgE interaction is highly species specific, and rodent Fc epsilon RI does not bind human IgE.

Tepoxalin, a novel immunomodulatory compound, synergizes with CsA in suppression of graft-versus-host reaction and allogeneic skin graft rejection.

Tepoxalin, a dual 5-lipoxygenase and cyclooxygenase inhibitor with nonsteroidal antiinflammatory effects, has recently been shown to suppress NF kappa B transactivation and inhibit T cell proliferation via a mechanism very different from cyclosporine (CsA). In this report, we demonstrate that this novel immunosuppressive effect of tepoxalin is manifested in in vivo transplantation models. Tepoxalin suppressed murine spleen cell proliferation in a mixed lymphocyte reaction (MLR) with an IC50 of 1.

Reduced thymic maturation but normal effector function of CD8+ T cells in CD8 beta gene-targeted mice.

CD8 is a cell surface glycoprotein on major histocompatibility complex class I-restricted T cells. Thymocytes and most peripheral T cells express CD8 as heterodimers of CD8 alpha and CD8 beta. The intestinal intraepithelial lymphocytes (IEL), which have been suggested to be generated extrathymically, express CD8 predominantly as homodimers of CD8 alpha.