Although systemic viral infection gives rise to robust responses from both
CD8(+) and CD4(+) T cells, there are striking differences as well as simila
rities in the way the two classes of lymphocyte cells react. Insights into
the patterns of response by each type of T cell could lead to the developme
nt of new therapeutics that enhance or suppress factors governing CD8(+) an
d CD4+ T-cell immunity.