CD4 and infection: These recent studies, coupled with our increasing appreciation of the multiplicity of functions that CD4 T cells carry out in the lung (42, 57) and the distinctive antigen bearing cells within the lung after infection (22, 58–60), raised the possibility that the CD4 T cell immunodominance hierarchy established in the dLN after infection might be remodeled as CD4 T cells are selected for lung homing during priming or alternatively, after establishment of residency in the lung tissue.