Increasing mechanical stimulus induces migration of Langerhans cells and impairs the immune response to intracutaneously delivered antigen.

Skin is subjected regularly to mechanical stimulus. Surprisingly, when studying the use of microneedle arrays to introduce antigen into skin, we observed that mechanical stimulus to skin achieved by application of the arrays or a flat metal plate resulted in temporary depletion of Langerhans cells, with the degree of depletion related to the applied stress, whereas no depletion was seen in the interspersed dendritic epidermal T cell population. Further, a significantly impaired immune response to intracutaneous antigen administration was observed in skin recently subjected to mechanical stimulus. This observation may have implications for selection of sites of skin immunisation and for immunogenicity of infections at skin sites routinely subjected to mechanical stimuli.

Nanopatch-targeted skin vaccination against West Nile Virus and Chikungunya virus in mice.

The 'Nanopatch' (NP) comprises arrays of densely packed projections with a defined geometry and distribution designed to physically target vaccines directly to thousands of epidermal and dermal antigen presenting cells (APCs). These miniaturized arrays are two orders of magnitude smaller than standard needles-which deliver most vaccines-and are also much smaller than current microneedle arrays. The NP is dry-coated with antigen, adjuvant, and/or DNA payloads. After the NP was pressed onto mouse skin, a protein payload co-localized with 91.4 + or - 4.1 APC mm(-2) (or 2925 in total) representing 52% of the delivery sites within the NP contact area, agreeing well with a probability-based model used to guide the device design; it then substantially increases as the antigen diffuses in the skin to many more cells. APC co-localizing with protein payloads rapidly disappears from the application area, suggesting APC migration. The NP also delivers DNA payloads leading to cutaneous expression of encoded proteins within 24 h. The efficiency of NP immunization is demonstrated using an inactivated whole chikungunya virus vaccine and a DNA-delivered attenuated West Nile virus vaccine. The NP thus offers a needle-free, versatile, highly effective vaccine delivery system that is potentially inexpensive and simple to use.

The performance of the HPV16 real-time PCR integration assay.

OBJECTIVES: Integration of high risk human papillomavirus (HPV) into the host genome leads to viral oncogene deregulation predisposing to neoplastic progression. Integration can be detected from pap smear or biopsy and use as marker of progressive disease. DESIGN AND METHODS: We have previously developed a highly sensitive real-time PCR method to determine HPV integration frequency and viral load of HPV16 in clinical samples. The test is accurate and sensitive detecting approx. 50 copies of integrated HPV in the sample. RESULTS: We found that a tenfold excess of episomal form to integrated form interferes with the test, regardless the amount of viral DNA. The same was true with background DNA more than 1500 ng in reaction. CONCLUSIONS: Overall, this method is reproducible and suitable for high-throughput screening of clinical samples, but excess episomal copies might mask the integrated form.