Role of basophils and histamine during the immune response

Our laboratory has been involved in histamine research and histamine-cytokine interactions during the immune response ever since we discovered that bone marrow cells generate important amounts of this mediator in response to a cytokine, which we identified as IL-3. Phenotypical characterization of this cell subset, which represents around 0.1 % of total bone marrow cells, led to the characterization of cells displaying ultrastructural features of immature basophils. Even though they did not express the FcRI on their membrane at this stage of maturation, they could be purified on the basis of their low density, low granular content, lack of mature lineage markers and high rhodamine-123 retention. Using in situ hybridization, we established that IL-3 induced increased histidine decarboxylase, both on transcriptional and protein levels, among this sorted population, together with IL-4, and IL-6, a cytokine profile that is typical for the basophil lineage. More recently, we have set up an in vitro culture method, performed with total bone marrow cells, which give rise to a highly enriched basophil population that can be purified completely by electronic sorting of FcRI+c-kit- cells and conserve the same functiona