Researchers have shown that antibodies to a molecule secreted by Propionibacterium acnes can reduce inflammation in human acne lesions, a finding that may be an early step in the development of an acne vaccine.
Once validated by a large-scale clinical trial, the findings could be valuable to patients with acne vulgaris, lead investigator Chun-Ming Huang, PhD, said in a press release on Aug. 29. Dr. Huang is from the department of dermatology, University of California, San Diego in La Jolla, Calif., and the department of biomedical sciences and engineering, National Central University, in Jhongli, Taiwan. “Current treatment options are often not effective or tolerable for many of the 85 per cent of adolescents and more than 40 million adults in the United States who suffer from this multi-factorial cutaneous inflammatory condition. New, safe, and efficient therapies are sorely needed.”
Published in Journal of Investigative Dermatology online ahead of print, the research showed that a secretory Christie-Atkins-Munch-Petersen (CAMP) factor of P. acnes is up-regulated in anaerobic cultures. As well, mutation of the CAMP factor significantly diminishes P. acnes colonization and inflammation in mice, which the authors say demonstrates that CAMP factor plays an important role in the cytotoxicity of the bacteria.
When investigators vaccinated mice with CAMP factor, they found the vaccination considerably reduced the growth of P. acnes and production of an inflammatory cytokine known as MIP-2, which is similar to the human interleukin (IL)-8.
Investigators also collected acne lesions from human patients in order to establish an ex vivo acne model for validation of the efficacy of the CAMP factor antibodies in counteracting acne inflammation. They found that P. acnes CAMP factor and two proinflammatory cytokines (IL-8 and IL-1β) were expressed at higher levels in acne lesions than those in non-lesional skin. When researchers incubated acne lesions taken from human subjects with monoclonal antibodies to CAMP factor, there was a marked reduction in the amounts of IL-8 and IL-1β measured.
This is the first attempt to develop an acne vaccine that is intended to target bacteria already present in human skin, rather than invading pathogens, according to the release.