Obesity impairs cell-mediated immunity during the second trimester of pregnancy.

Objective: Obese pregnancy is associated with significantly higher rates of infection, which can harm both mother and fetus. The objective of this study was to determine the impact of obesity on maternal blood immune function.

Study Design: This was a cross-sectional, case control study of 15 obese (Ob) and 15 lean (Lc) subjects.

Inducible costimulator controls migration of T cells to the lungs via down-regulation of CCR7 and CD62L.

We and others reported that inducible costimulator-deficient (ICOS(-/-)) mice manifest a defect in Th2-mediated airway inflammation, which was attributed to reduced Th2 differentiation in the absence of ICOS signaling. Interestingly, the number of CD4 T cells present in the airways and lungs after sensitization and challenge is significantly reduced in ICOS(-/-) mice. We now show that this reduction is not attributable simply to a reduced proliferation of ICOS(-/-) cells, because significantly more ICOS(-/-) than wild-type activated CD4 T cells are present in the lymph nodes, suggesting that more ICOS(-/-) CD4 T cells than wild-type CD4 T cells migrated into the lymph nodes.