Antigen-specific peripheral immune responses are unaltered during normal pregnancy in sheep

Area of Science:

• Reproductive Immunology
• Immunology
• Comparative Immunology

Background:

• A shift in T(Helper) (T(H))1/T(H)2 cytokine balance is a known feature of successful mammalian pregnancy.
• This phenomenon is well-documented in species with invasive placentation but less studied in those with non-invasive placentation, like sheep.

Purpose of the Study:

• To investigate the T(H)1/T(H)2 cytokine profile in pregnant versus non-pregnant sheep.
• To determine if a shift in cytokine balance occurs in species with synepitheliochorial placentation.

Main Methods:

• Sixteen sheep were immunized with chicken egg albumin (Ova).
• Peripheral blood mononuclear cells (PBMC) were isolated from pregnant and non-pregnant sheep.
• PBMCs were restimulated in vitro with Ova or concanavalin A (ConA) to measure proliferation and cytokine production (IFN-gamma, IL-4, IL-10).

Main Results:

• No significant differences in antigen-driven PBMC proliferation or cytokine production (IFN-gamma, IL-4, IL-10) were observed between pregnant and non-pregnant sheep.
• No significant differences in ConA-induced cytokine production were found between the groups.

Conclusions:

• A shift in T(H)1/T(H)2 cytokine production does not appear to occur in pregnant sheep.
• Further comparative studies in species with non-invasive placentation are needed to understand materno-fetal immune interactions.