CD4+ T cells are permissive to respiratory syncytial virus infection

PANDOLFI, JULIETA; RAIDEN, SILVINA; REMES LENICOV, FEDERICO; SANANEZ, INÉS; ERNST, GLENDA; JANCIC, CAROLINA; CEBALLOS, ANA; GEFFNER, JORGE; ARRUVITO, LOURDES

Buenos Aires

Congreso; 63 Reunión Anual de la Sociedad Argentina de Inmunología. 2da FAIC; 2015

Sociedad Argentina de Inmunología - LASID

Background: Respiratory Syncytial virus (RSV) is the leadingcause of severe bronchiolitis in young infants. We have recently reported thatRSV infection induces a dramatic reduction in the frequency of peripheral bloodTregs in children. Although human airway epithelial cells are the main targetof RSV, it has been shown that the virus can also infect immune cells as DCs.However, no studies have evaluated whether CD4+T cells are permissive to RSVinfection. Aims: 1) to test the invitro susceptibility of cord blood CD4+T cells to RSV infection; 2) todetermine if RSV infection modulates the function of CD4+T cells; 3) toinvestigate whether RSV proteins are detected in peripheral blood CD4+T cellsof infected infants. Results: Wefound that cord blood CD4+T cells exposed to RSV or co-cultured with infectedbronchial epithelial cells were effectively infected by RSV, as indicated bythe expression of viral proteins and mRNA. RSV infection of CD4+T cellsinhibits IL-2 production and cell proliferation induced by different stimuli (p<0.01). We detected RSV proteins inCD4+T cells from severe infected children by flow cytometry (n=12). Moreover,we found that the percentage of RSV+CD4+T cells negatively correlated (r=-0.72, p<0.01) with CD4+T cellfrequency in peripheral blood. Conclusions:We show that CD4+T cells from cord blood are permissive to RSV infection, andalso that it modulates cell function. Moreover, we found that CD4+T cells fromsevere infected infants express viral antigens. Our finding could partiallyexplain why RSV infection fails to induce long lasting immunity.