Skin/immune system: Lasers as vaccine adjuvants

Influenza A (H1N1), a negative-sense RNA virus colloquially referred to as the “swine flu,” commonly causes fever, inflammation, and cough but can lead to more dangerous symptoms, such as respiratory compromise. To combat H1N1, scientists often look for adjuvant therapies that could increase the efficacy of vaccines that are already stockpiled, as opposed to creating new ones.

One potential adjuvant treatment is a technique used in cosmetic dermatology referred to as nonablative fractional laser (NAFL) treatment. Laser light is used to lightly damage skin, creating a microthermal zone (MTZ) of 200 by 300 micrometers. In dermatology practices, limiting the area of damage allows epithelial cells to quickly grow over the MTZ but provides the skin with a healthier appearance. Using NAFL at the site of injection could also potentially make vaccines more effective.

Figure 1 A diagram of NAFL treatment; prior to inoculation, the injection site is exposed to laser light for a short time.

To assess NAFL as an adjuvent, laboratory mice were divided into three groups: a control group, a group receiving a combination of the vaccine and NAFL, and a group receiving a combination of the vaccine and AddaVax, an oil-based adjuvant currently on the market. After a brief inoculation period, serum immunoglobulin G levels were measured for each group. This was followed by testing levels of interleukin 6, a cytokine involved in the mediation of fever and inflammation, as well as body temperature recordings made over a 10-hour time frame. Results are shown in Figures 2-4.

Figure 2 Immunoglobulin G levels of each group after inoculation.

Figure 3 Interleukin 6 levels of each group over a two-day period.

Figure 4 Average relative body temperature over 10 hours; all temperatures were normalized to mice receiving no treatment or intervention