ACAID requires early replication of HSV-1 in the injected eye

Ocular immune privilege: a review

The definition of the term 'immune privilege' has evolved over the last century. Current usage refers to a state within a particular organ or tissue in which elements of normal immunity are absent. The fact that this deficiency is thought to be generally beneficial has compelled others to go a step further and venture that immune privilege acts to minimize expression of immunopathology. The purpose of this article is to review which parts of the eye hold immune privileged status, what mechanisms contribute to it, and what clinical benefits may have driven the development of these unique immune environments. The article ends with an examination of recent studies which have sought to use components of ocular immune privilege to prevent systemic autoimmune disease.

Fate of orthotopic corneal allografts in C57BL/6 mice

Our aim was to determine whether corneal allografts placed in normal eyes of C57BL/6 mice enjoy immune privilege, and whether recipients of long-standing grafts acquire donor-specific ACAID. C57BL/6 mice received corneal grafts from BALB/c, C57BL/6, C3H, B10.D2 or BALB.B mice; for comparison, BALB/c mice received C3H or C57BL/6 corneal allografts. Delayed hypersensitivity and anterior chamber associated immune deviation (ACAID) induction were assessed in recipient mice at four and eight weeks after grafting. It was found that C57BL/6 mice resemble BALB/c mice in mounting more vigorous rejection reactions against minor H, rather than MHC, alloantigenic corneas, and in the acquisition of donor-specific DH within four weeks of engraftment. In addition, C57BL/6 mice with long-standing, healthy allografts display donor-specific ACAID. However, C57BL/6 mice differ from BALB/c mice in that (1) fewer allodisparate corneal grafts were accepted indefinitely; and (2) rejection in these eyes correlated with sustained donor-specific DH. It was concluded that immune privilege is less secure in the eyes of C57BL/6 mice, compared to BALB/c mice. This conclusion is discussed in terms of known polymorphic differences between these mouse strains at genetic loci governing (a) immune responsiveness, (b) alloform of Fas ligand, and (c) bias of immune response toward Th1 or Th2 phenotypes.

Induction of bilateral retinal necrosis in mice by unilateral intracameral inoculation of a glycoprotein-C deficient clinical isolate of herpes simplex virus type 1

Herpes simplex virus can cause acute retinal necrosis, a blinding retinal disease in man. A unilateral intracameral inoculation of herpes simplex virus type 1 (HSV-1) in mice induces retinal necrosis primarily in the contralateral eye and provides an experimental model for the disease. Previous studies suggested that a major envelope glycoprotein of HSV-1, glycoprotein C (gC), is required for retinal necrosis. We studied HSV-1 strain TN-1, a gC-deficient clinical isolated from a lesion of herpetic keratitis, for its pathogenicity in mice with an intracameral inoculation of the virus and found that TN-1 could induce severe necrotizing retinitis in both inoculated and uninoculated eyes of BALB/c mice. Inoculation with a lower dose of TN-1 resulted in a unilateral necrotizing retinitis in the uninoculated eyes. Tissue virus titration of infected mice killed at various times after inoculation detected an infectious virus in various organs including the eyeballs, trigeminal ganglia, brain and adrenal glands. Anterior chamber-associated immune deviation (ACAID) was observed in TN-1-inoculated mice as well as in mice inoculated with gC-positive laboratory strain KOS 7 days postinoculation. Our findings suggested that gC of HSV-1 is not necessary for either the induction of retinal necrosis, neural spread of the virus, or ACAID.