Abstract: Objective:To investigate the effects of maternal staphylococcal enterotoxin B(SEB) administration on proliferation of splenic lymphocytes of the newborn offspring rats in vitro.Methods:Pregnant rats on gestational day 16 were injected i.v.15 μg SEB,and the control group was injected using the same volume of PBS.The spleens of newborn offspring rats on the third day after delivery were acquired,and the splenic lymphocytes were separated.The splenic lymphocytes were co-cultured with ConA or SEB for 3 days in vitro.The subpopulation of splenic lymphocytes and its proliferation were detected using the flow cytometry and liquid scintillation analyzer,respectively.Results:After co-cultured with ConA or SEB in vitro,the percentage of CD4⁺T cells of splenic lymphocytes in SEB group significantly increased compared with the PBS group(P<0.05 to P<0.01).The percentages of CD4⁺TCR Vβ8.2⁺ T cells on the first day of culture,and CD8⁺TCR Vβ8.2⁺ T cells on the three day of culture in SEB group significantly increased compared with the contrd group(P<0.05 to P<0.01).Compared with PBS group,the stimulation of ConA or SEB significantly increased the proliferation ability of splenic lymphocytes in SEB group on the first day of culture,and significantly decreased on the second and third day of culture(P<0.05 to P<0.01).Conclusions:Maternal SEB administration during pregnancy can affect the proliferation of splenic lymphocytes in the newborn offspring rats in vitro.