Splenocytes and thymocytes migration patterns between lymphoid organs in pregnancy

Background Cell migration is essential for the immune system, and frequently is analyzing in adult non-pregnant animals, and poorly explored in pregnancy, however, a physiologic increase of size in the spleen and periaortic lymph nodes had been reported in pregnant mice. Methods Using a mouse model, we transferred PKH26-stained thymocytes and splenocytes from pregnant or non-pregnant animals to receptor mice in the presence or absence of pregnancy. Percentage and Mean Fluorescence Intensity were calculated by Flow cytometry in pregnant or non-pregnant mice. Non-parametric ANOVA analysis was performed. Results We detected that the percentage of PKH26+ thymocytes into the spleen, lymph nodes, and peripheral blood is higher in females than in males. Our results showed a similar frequency of thymocytes and splenocytes from pregnant and non-pregnant located into receptor lymphoid organs. Also, the location of marked cells was similar during the perinatal period. Conclusions The mobility of thymocytes and splenocytes in pregnant and non-pregnant mice is similar, therefore we suggest that the larger size of the spleen and periaortic lymph nodes noted previously in pregnant mice, could be the result of retention of leukocytes in the secondary lymphoid organs. ### Competing Interest Statement The authors have declared no competing interest. * SLO : Secondary Lymphoid Organs NP : Non-Pregnant P : Pregnant dpc : days post coitus MFI : Mean Fluorescence Intensity T : Thymus S : Spleen LN : Lymphnode PB : Peripheral Blood PP : PostPregnant