Decreased human IL-2 receptor expression due to a protozoan pathogen.

A number of parasites suppress immune responses during - and in some cases after - their establishment in their hosts. Many instances of altered levels of immunocompetence have been documented, but the early events and mechanisms leading to such impairment have not been elucidated. Here, Felipe Kierszenbaum and colleagues discuss the ability of the pathogenic protozoan Trypanosoma cruzi to suppress the expression of interleukin 2 receptors by human lymphocytes. Absence or reduced levels of this receptor would prevent lymphocytes from receiving the very important growth factor signal that allows them to continue their division cycle and to proliferate after activation.