The skin, in contrast to the muscles, contains a rich network of antigen-presenting cells, which are immune signalling cells that are essential to initiating an immune response. The researchers found that microneedle skin immunization with inactivated influenza virus resulted in a local increase of cytokines important for recruitment of neutrophils, monocytes and dendritic cells at the site of immunization. All these cells play a role in activating a strong innate immune response against the virus.
Microneedle vaccination also may lead to prolonged depositing of antigen – the viral molecules that are the targets of antibody responses. Such a prolonged antigen release could allow more efficient uptake by antigen-presenting cells. In addition, activated and matured dendritic cells carrying influenza antigen were found to migrate from the skin– an important feature of activating the adaptive immune response.
The research was led by first author Doctor Maria del Pilar Martin and Doctor Richard W. Compans, Emory professor of microbiology and immunology. "Our research reveals new details of the complex but efficient immune response to influenza virus provided by microneedle skin patches," says Compans. "Despite the success of vaccination against influenza, the virus has many subtypes, mutates rapidly and continues to elude complete and long-term protection, and therefore requires annual vaccination with an updated vaccine each year.
"New vaccine formulations and delivery methods such as vaccine-coated microneedle patches could provide an improved protective response, which would be of particular benefit to those at high risk of related complications. Vaccine delivery to the skin by microneedles is painless, and offers other advantages such as eliminating potential risks due to use of hypodermic needles."
COMPAMED.de; Source: Emory University