Human gamma delta T cells amplify IgE production by Epstein-Barr virus-activated B cells.

In summary, these data document that gamma delta T cells regulate B cell differentiation, antibody synthesis, and IgE secretion in EBV-activated B cells. The classical "helper" subset of CD4+ alpha beta T cells, although potent inducers of other Ig isotypes, are not as efficient in augmenting IgE synthesis. However, interactions between alpha beta and gamma delta cells enhance the IgE response further. The precise mechanism by which gamma delta T cells function to augment IgE secretion is under study. It will be important, for example, to determine whether gamma delta T cells, or products of these cells, directly regulate class switching or mediate the clonal expansion of IgE-expressing B cells. In this regard, we ruled out the possibility that IL-4 release alone could replace gamma delta cells in increasing IgE secretion. Finally, we think it is of potential interest that gamma delta cells migrate to skin epithelia as well as gastrointestinal and pulmonary mucosa, sites of invasion by parasitic organisms and contact with allergens. If gamma delta T cells were specifically activated, either directly or indirectly, by these foreign pathogens, then the data presented here might elucidate the cellular basis for the events leading to IgE secretion, a critical step in the immune response to both parasites and allergens.