Anti-apoptotic Serine Protease Inhibitors contribute towards the survival of allergenic Th2 cells

Publication date: Available online 26 October 2017
Source:Journal of Allergy and Clinical Immunology
Author(s): Mohamed H. Shamji, Jeff N. Temblay, Wei Cheng, Susan M. Byrne, Ellen Macfarlane, Amy R. Switzer, Natalia D.C. Francisco, Fedina Olexandra, Fabian Jacubczik, Stephen R. Durham, Philip G. Ashton-Rickardt
BackgroundThe mechanisms regulating the maintenance of persistent Th2 cells that potentiate allergic inflammation are not well understood.ObjectiveThe function of Serine Protease Inhibitor 2A (Spi2A) was studied in mouse Th2 cells and Serine Protease Inhibitor (SERPIN) B3 and B4 genes were studied in Th2 cells from grass pollen allergic individuals.MethodsSpi2A deficient Th2 cells were studied in vitro culture or in vivo after challenge of Spi2A Knock-Out (KO) mice with ovalbumin in alum. The expression of SERPIN B3 and B4 mRNA was measured in vitro cultured Th2 cell and in ex vivo CD27^-CD4⁺ and ICL2 cells from grass pollen allergic individuals using quantitative PCR. SERPIN B3 and B4 mRNA levels were knocked down in cultured CD27^-CD4⁺ cells with shRNA.ResultsThere were lower levels of in vitro polarized Th2 cells from Spi2A KO mice (P<0.005) and in vivo after OVA challenge (P<0.05), higher levels of apoptosis (annexin V positivity P<0.005) and less lung allergic inflammation (number of lung eosinophils P<0.005). In vitro polarized Th2 cells from grass pollen allergic individuals expressed higher levels of both SERPIN B3 and B4 (both P<0.05) mRNA compared to un- polarized CD4 T cells. CD27^-CD4⁺ from grass pollen allergic individuals expressed higher levels of both SERPIN B3 and B4 (both P<0.0005) mRNA compared to CD27⁺CD4⁺ cells. ICL2 cells expressed higher levels of both SERPIN B3 and B4 (both P<0.0005) mRNA compared to ICL1 cells. Knock-down of either SERPIN B3 or B4 (both P <0.005) mRNA levels resulted in decreased viability of CD27^-CD4⁺ compared to control transduced cells.ConclusionThe serpins Spi2A in mice and Serpin B3 and B4 in allergic individuals, control viability of Th2 cells. This provides proof-of-principle for a therapeutic approach for allergic disease through the ablation of allergic memory Th2 cells through mRNA SERPIN B3 and B4 down-regulation.



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