"These findings and the related mechanism are very different from the current residing view of activation of specific T helper cell responses," said principal investigator Eyal Raz, MD, professor of medicine.
"The role of cAMP formation and action in dendritic cells in the induction of allergic response was really surprising," added co-author Paul Insel, MD, professor of pharmacology and medicine. "It suggested to us that this signaling pathway is involved in other immune-related functions."
The immune response of humans, mice and other vertebrates consists of two fundamental components. The first is the innate immune system, which recognizes and responds to pathogens in an immediate, but generalized, way and does not confer long-lasting immunity. The second is the adaptive immune system in which highly specialized T and B cells eliminate or prevent pathogen growth -- and create immunological memory in case of future encounters with the same pathogen.
Th2 immunity is one of two major aspects of adaptive immunity. Th1 responses target intracellular pathogens, such as viruses and bacteria that have invaded host cells. The Th2 response is more effective against extracellular pathogens (such as bacteria, parasites and toxins that operate outside of cells) and also plays a major role in allergic reactions and related diseases.
Allergic asthma is triggered by inhaled allergens, such as pet dander, pollen, mold and dust mites. It is characterized by inflammation and narrowing of the airways, resulting in wheezing, chest tightness, shortness of breath, coughing and other symptoms. The common form of allergic asthma is associated with an exaggerated Th2 immune response. Allergic asthma affects people of all ages, most often appearing in childhood. More than 25 million Americans suffer from the condition.
