METHODS: Peripheral blood mononuclear cells (PBMC) (1×106/mL) from adult healthy subjects were infected or mock-infected for 1h +/- C. pneumoniae TW-183 at a multiplicity of infection (MOI) =1.0, 0.1 or 0.01 and cultured for 24-48 hrs. Distributions of lymphocytes (CD4+, CD8+) and TEM cells (CD4+CD45 RA+, CD4+CD45 RO+, CD4+CCR7+/-; CD8+CD45RA+, CD8+45RO+, CD8+CCR7+/-) were determined. Levels of intracellular Interleukin (IL)-2, IL-4, and Interferon (IFN)-gamma were measured (flow microfluorimetry).
RESULTS: C. pneumoniae infection (48 hr) led to an increase (~90%, 43%, respectively) in numbers of TEMS (CD4+IL-2+, CD4+ IL-4+) (CD8+IL-2+, CD8+ IL-4+); however, numbers of TEMS (CD4+ IFN-gamma+, CD8+IFN-gamma+) did not change significantly (P<0.05).
CONCLUSIONS: C. pneumoniae infection can enhance CD4+ IL-2+, CD4+IL-4+, CD8+IL-2+ and CD8+IL-4+ TEM responses in healthy subjects. These findings are important in understanding the persistence of C. pneumoniae infection and may allow development of diagnostic tests.