CD8A and chronic obstructive pulmonary disease: To test this hypothesis, CD8+ CD56- T cells isolated from lung tissue of COPD subjects were stimulated in vitro with plate-bound anti-CD3ε, plus each of the following TLR ligands: Pam3CSK4, heat-killed Listeria monocytogenes (HKLM), Poly(I:C), LPS, Flagellin, FSL-1, Imiquimod, ssRNA40, ODN 2006.