My main area of research is immune regulation, with two main focuses: 1) chronic immune system activation and 2) the ontogeny of the human immune system.
In the case of chronic activation, the delicate balance between immune effector responses and counter-activation is perturbed. My colleagues and I are pursuing studies of one of the principal mechanisms that modulate this balance, which is a subset of CD4+ T cells called regulatory T cells. We study the biology and function of these cells in the setting of acute and chronic immune activation (HIV infection, aging and fetal inflammation). In particular, my team and I were one of the first to show that the frequency of regulatory T cells increases during chronic HIV infection or aging, which prevents many aspects of harmful, unregulated inflammation. However, it acts as a double-edge sword, blunting other immune responses to other pathogens or vaccines.