Andrew W. Taylor, PhD, FARVO

Biography

A large part of our research effort has been to characterize the immunosuppressive and immunoregulating factors within the immune privileged eye. Through immunochemical and biological analysis of aqueous humor, the fluid filling the anterior chamber of the eye, and the soluble factors produced by retinal pigment epithelial cells. We have identified several potent immunoregulating and immunosuppressing neuropeptides that:
1. Suppress macrophage-mediated inflammation.
2. Induce activation of myeloid suppressor cells
3. Alter phagocytic pathways within potential Antigen Presenting Cells.
4. Suppress the activation of effector T cells
5. Mediate the induction of antigen-specific regulatory T cells.

Our research has found constitutively present neuropeptides in the immune-privileged eye, alpha-melanocyte stimulating hormone (a-MSH), vasoactive intestinal peptide, calcitonin gene related peptide, and somatostatin. Collectively, the neuropeptides in aqueous humor suppress activation of delayed-type hypersensitivity of adaptive immunity and endotoxin activation of macrophages in innate immunity. Individually, the neuropeptides target different cells at different stages in the induction of immune responses within the immune-privileged eye.

We are finding that the activation of macrophages to pathogens within the ocular microenvironment does not promote inflammation but promotes suppressor functionality in the macrophages. These macrophages respond to pathogens without mediating inflammation or activating T cells. Moreover, the macrophages produce anti-inflammatory cytokines, suppress activation of effector T cells while promoting Treg cell activity.

As we continue to examine the mechanisms of ocular immune privilege, we further promote the importance of the interactions between the nervous and the immune systems and how we can use these interactions therapeutically to manipulate immunity to suppress autoimmune disease.