The key issue in asthma research is allergen capture and presentation. An increase in understanding in this area may result in the development of new types of therapeutic drugs, although at present there remain a number of points to be elucidated. In this paper, we review recent research in this field. Allergens are small air-conducted soluble antigens which are capable of inducing a specific immune response characterized by a significant synthesis of IgE. The allergen passes through the bronchial epithelium and specialized antigen presenting cells (APC) capture and present the antigen to T-cells, causing their activation via an interaction with class II MHC molecules on the APC. Allergens are also capable of activating other cell types and the subsequent release of inflammatory mediators, chemoattractants and cytokines may result in bronchial inflammation which is one of the cardinal signs of asthma.