This is an interesting review to remind us of the flexibility of the immune response! It is widely accepted that secondary lymphoid tissues, such as spleen and lymph nodes, provide the basis for cooperative interactions between antigen-presenting cells, T and B cells. Although the widely held belief that adaptive immunity in general requires the structural support of secondary lymphoid tissues, there is ample evidence to indicate that only B cells, but not T cells are dependent on secondary lymphoid tissues. Indeed besides bone marrow and lung, the liver is one organ that can potentially serve as surrogate lymphoid organs.
T cells do not need secondary lymphoid organs to mount efficient cell-mediated immune responses.