SslE (YghJ), a cell surface associated and secreted lipoprotein was identified as a potential vaccine candidate for extraintestinal pathogenic E. coli providing nearly complete protection from sepsis in a mouse model. We earlier found that SslE from neonatal septicemic E. coli could trigger the secretion of various proinflammatory cytokines in murine macrophages, the signaling pathway of which is still obscure. In this study, we showed that SslE specifically binds to TLR2/TLR1 heterodimer and recruits downstream adaptors MyD88, TIRAP and TRAF6. In addition, SslE stimulates nuclear translocation of NFkappaB as well as activates different MAP kinase signaling cascades specific to each cytokine secretion in murine macrophages which gets impaired in TLR2 siRNA transfected cells and in cells blocked with mAb against TLR2, suggesting the involvement of TLR2 in NFkappaB and MAPK activation and subsequent cytokine secretion. Furthermore, our study is the first to unveil that SslE can stimulate TLR2 dependent production of other proinflammatory hallmarks such as reactive nitrogen and oxygen species as well as type 1 chemokines which contribute to the anti-infection immune response of the host. Furthermore, the over-expression of MHC-II and other co-stimulatory molecules (CD80 and CD86) in macrophages essentially indicates that SslE promotes macrophage activation and M1 polarization, crucial in framing host's innate immune response to this protein and hence, SslE could be a potent immunotherapeutic target against E. coli sepsis.