Effect of immunization on herpes simplex virus type 1 latent infection in the trigeminal ganglion

Treg depletion attenuates the severity of skin disease from ganglionic spread after HSV-2 flank infection

Regulatory T cells (Tregs) attenuate lesion severity and disease after HSV ocular or genital infection, but their role in cutaneous infection remains unclear. Treg depletion (anti-CD25 mAb in C57BL/6 mice or diphtheria toxin (DT) in DEREG mice) prior to tk-deficient HSV-2 flank infection significantly decreased skin lesion severity, granulocyte receptor-1(Gr-1(+)) cell number, and chemokine (KC) expression in the secondary skin, but significantly increased immune effectors and chemokine expression (MCP-1, KC, VEGF-A) in the draining LN, and activated, interferon-γ producing CD8(+)T cells in the ganglia. Treg depletion also significantly reduced HSV-2 DNA in the ganglia. Thus, Tregs increase the severity of recurrent skin lesions, and differentially alter chemokine expression and immune effector homing in the skin and LN after cutaneous infection, and limit CD8(+) T cell responses in the ganglia. Our data suggests that effects of Treg manipulation on recurrent herpes lesions should be considered when developing Treg mediated therapeutics.

DNA vaccine delivery by densely-packed and short microprojection arrays to skin protects against vaginal HSV-2 challenge

There is an unmet medical need for a prophylactic vaccine against herpes simplex virus (HSV). DNA vaccines and cutaneous vaccination have been tried for many applications, but few reports combine this vaccine composition and administration route. We compared DNA administration using the Nanopatch™, a solid microprojection device coated with vaccine comprised of thousands of short (110 μm) densly-packed projections (70 μm spacing), to standard intramuscular DNA vaccination in a mouse model of vaginal HSV-2 infection. A dose-response relationship was established for immunogenicity and survival in both vaccination routes. Appropriate doses administered by Nanopatch™ were highly immunogenic and enabled mouse survival. Vaginal HSV-2 DNA copy number day 1 post challenge correlated with survival, indicating that vaccine-elicited acquired immune responses can act quickly and locally. Solid, short, densely-packed arrays of microprojections applied to the skin are thus a promising route of administration for DNA vaccines.