The development of proliferative responses of ovine peripheral blood mononuclear cells to Chlamydia psittaci during pregnancy.

In vitro lymphoproliferative responses to Chlamydia psittaci elementary bodies were detected in the peripheral blood mononuclear cells of pregnant sheep infected with C. psittaci. These responses were suppressed in cells collected in the immediate peri-parturient period, but returned to levels significantly above background within 14 days. Infection also suppressed the lymphoproliferative response to the T-cell mitogen Con A until abortion or lambing, but did not affect the proliferative response to the B-cell mitogen LPS.