NOVEL DELIVERY SYSTEM FOR A HERPESVIRUS DNA VACCINE

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Most adults harbor herpes simplex virus type I(HSV-1) but only some suffer periodic episodes of painful fever blisters. T cells limit viral pathogenesis by inducing a nonpermissive state in ganglion cells, where the virus lies latent. Cytotoxic T lymphocytes (CTL), especially CD4+ CTL, are critical in resistance against recurrent herpes lesions. Viral glycoproteins (gP), expressed early in HSV infection are CTL targets and have been used as therapeutic vaccines with some success. Although living vaccines are usually needed to stimulate effective CTL responses, naked DNA vaccines encoding HSV gP stimulate CTL and antibody responses experimentally. The hypothesis of this study is that a DNA vaccine encoding HSV-1 glycoprotin D (gD), protected from nuclease activity and targeted to cells bearing receptors for asialoorosomucoid (ASOR), can stimulate specific cellular immunity to herpes simplex virus in mice. The novelty of this strategy is that ligands, such as poly-L-lysine-ASOR (ASOR-L), protect the DNA from nucleases while directing it to cells bearing receptors for the ligand, features lacking in naked HSV gP DNA vaccines. To test the hypothesis, gD DNA either complexed to ASOR-L or naked will be injected into BALB/c and C3H mice by 4 different routes [intravenous (iv), intraperitoneal (ip), intramuscular (im), and oral (po)]. At 2 weeks after injection of 10 mug doses of DNA, splenic T cells will be examined for CTL activity against histocompatible target cells expressing gD. Since hepatocytes, macrophages and enterocytes bear receptors for ASOR, higher levels of gD-specific CTL activity will more likely develop in mice receiving gD-ASOR by iv, ip and po routes. Conditions for stimulating optimal HSV CTL responses will be defined by this study. The practical application of this novel approach is a therapy for alleviating recurrences of painful herpes lesions in humans.