Staphylococcal enterotoxin B (SEB) is one of the many exotoxins produce by Staphylococcus aureus and is implicated in inducing diarrhea, vomiting, muscle numbness, possible involvement in autoimmune disorders and lethal shock [1]. The massive impact of T cell activation, proliferation, and cytokine production by CD4 + T cells via specific V b elements of T cell antigen receptor [2] has prompted a number of investigations to focus on the intricate signaling activities of SEB. Even though the molecular events of SEB-induced lethal shock in human peripheral blood mononuclear cell (PBMCs) are not very apparent, the actual response of lethal shock is expected to herald by changes in signaling pathways [3,4]. In mammalian cells, a variety of stimuli generate intracellular responses that converge on a limited number of components of multiple pathways [5]. Mitogen-activated protein kinase (MAPK) cascades together with arachidonic Staphylococcal enterotoxin B (SEB) has been the focus of a number of studies due to its ability to promote septic shock and a massive impact on the human immune system. Even though symptoms and pathology associated with SEB is well known, early molecular events that lead to lethality are still poorly understood. Our approach was to utilize SEB induced human peripheral blood mononuclear cells (PBMCs) as a prototype module to further investigate the complexity of signaling cascades that may ultimately lead to lethal shock. Our study revealed the activation of multiple divergent intracellular pathways within minutes of SEB induction including components that interconnect investigated pathways. A series of performed inhibi-tor studies identified a specific inhibitor of 5-LO (MK591), which has the ability to block JNK, MAPK, p38kinase and 5-LO signaling-cascades and drastically reducing the activity of pro-inflammatory cytokine TNF-a. Further evaluation of MK591 utilizing cell proliferation assays in PBMCs, human proximal tubule cells and in vivo studies (monkey) showed a decrease in cell proliferation. The inhibitory effect of MK591 was reconfirmed at a genetic level through the utilization of a set of SEB specific genes. Signaling activities, inhibitor studies, cellular analysis and gene expression analysis in unison illustrated the significance of pathway inter-connectors such as 5-LO as well as inhibiting such inter-connectors (using MK591) in SEB induced human PBMCs. Abbreviations 5-LO, 5-lipoxygenase; HIF, hypoxia-inducible factor; IL, interleukin; JNK, c-Jun N-terminal kinase; MAPK, mitogen-activated protein kinase; p38kinase, p38-mitogen activated protein kinase; PBMC, peripheral blood mononuclear cell; REPTC, renal epithelial proximal tubular cell; SEB, staphylococcal enterotoxin B; TNF, tumor necrosis factor.