The expression of human leukocyte antigen-G on trophoblasts abolishes the growth-suppressing effect of interleukin-2 towards them

PROBLEM: We have shown the attenuated human leukocyte antigen (HLA)-G expre ssion on trophoblasts and an aberrant expression of interleukin (IL)-2, a c ytotoxic cytokine, in decidual tissue in preeclampsia, where deteriorated t rophoblastic invasion into decidual layers may constitute a crucial pathoge nesis. We hypothesized that the absence of HLA-G might make trophoblasts su sceptible to compromise by IL-2. METHOD OF STUDY: We analyzed the growth of HLA-G-negative and -positive cel l lines, all of which possessed IL-2 receptors, in the culture with or with out IL-2 supplementation. RESULTS: The proliferation of HLA-G-positive trophoblastic cell lines (BeWo and JEG-3) was not influenced by the addition of IL-2, whereas a HLA-G-neg ative trophoblastic eel line (JAR) exhibited significantly decreased prolif eration when cultured with IL-2. Interestingly, the transfection of JAR cel ls with HLA-G completely eliminates the growth-inhibitory effect of IL-2. CONCLUSION: The expression of HLA-G may commit trophoblasts to evade cell d amage by IL-2, which may be relevant to maternal tolerance of the fetus dur ing pregnancy and its derangement as exemplified by preeclampsia.