Background: Chemokines and their receptors have been a research focus in transplantation immunology. Chemokines and their receptors play a role in lymphocyte recruitment and differentiation process. This study aimed to observe whether IL-4 and IL-10 may regulate the expression of chemokine receptors CCR3, CCR5 and CXCR3 on CD4(+) T cells in CBA/JxDBA/2 mouse model and to explore the role of CCR3, CCR5, CXCR3 in immune tolerance in pregnancy.
Methods: The mouse model of spontaneous abortion (CBA/JxDBA/2) and the normal pregnant mouse model (CBA/JxBALB/c) were used. CBA/JxDBA/2 mice were injected with IL-4 (CBA/JxDBA/2-IL-4), IL-4 and IL-10 (CBA/JxDBA/2-IL-4+IL-10), or normal saline (CBA/JxDBA/2-NS) as a control. The expression of CCR3, CCR5 and CXCR3 on CD4(+) T cells from mouse peripheral blood was measured by the double-labelled FCM method, and the embryo resorption rate was also examined.
Results: The embryo resorption rate in the CBA/JxDBA/2 group without any treatment was significantly higher than that in the CBA/JxBALB/c group (17.9% vs 3.7%, P < 0.01). The embryo resorption rate in the CBA/JxDBA/2 group immunized with IL-4 or IL-4 together with IL-10 was significantly decreased, compared with that in the control and NS groups respectively. CCR3 expression on CD4(+) T cells in the CBA/JxDBA/2 group without any treatment was significantly lower than that in the CBA/JxBALB/c group (0.3738 +/- 0.3575 vs 1.2190 +/- 0.2772, P < 0.01); both CCR5 (3.0900 +/- 1.5603 vs 1.2390 +/- 0.6361, P < 0.01) and CXCR3 (2.4715 +/- 0.9074 vs 0.9200 +/- 0.5585, P < 0.01) expressions on CD4(+) T cells of the CBA/JxDBA/2 group without any treatment were significantly higher than those of the CBA/JxBALB/c group. Significant up-regulation of CCR3 and down-regulation of CXCR3 were found in the CBA/JxDBA/2 group treated with IL-4 (CCR3: 2.0360 +/- 0.6944, CXCR3: 1.3510 +/- 0.5263, P < 0.01) or IL-4 and IL-10 (CCR3: 1.8160 +/- 1.0947, CXCR3:1.0940 +/- 0.7168, P < 0.01). Because of the CCR5, IL-4 and IL-10 (1.9400 +/- 0.8504 vs 3.0900 +/- 1.5603, P < 0.05), but IL-4 alone (2.5310 +/- 1.3595 vs 3.0900 +/- 1.5603, P > 0.05) treatment significantly decreased the expression of CCR5 in CBA/JxDBA/2.
Conclusions: The abnormal expression of CCR3, CCR5 and CXCR3 on CD4(+) T cells may play an important role in the pathogenesis of spontaneous abortion. The pregnancy immune tolerance may be induced through selective induction of CCR3, CCR5 and CXCR3 expressions by IL-4 together with IL-10.