Activation of the cytokine network and unfavorable outcome in patients with yellow fever.

To study the contribution of inflammatory mediators to the pathogenesis of yellow fever (YF), the serum levels of several cytokines and chemokines were measured in 7 patients with fatal YF (f-YF), 11 patients with nonfatal hemorrhagic YF (nf/h-YF), and 18 patients with nonfatal nonhemorrhagic YF (nf/nh-YF). The levels of interleukin (IL)-6, monocyte chemoattractant protein-1, interferon-inducible protein (IP)-10, tumor necrosis factor- alpha , and IL-1 receptor antagonist (IL-1RA) were all statistically significantly higher in the patients with f-YF than in those with nf/nh-YF. In patients with nf/h-YF, only levels of IP-10 and IL-1RA were significantly elevated.

Old and New World arenaviruses share a highly conserved epitope in the fusion domain of the glycoprotein 2, which is recognized by Lassa virus-specific human CD4+ T-cell clones.

Data from human studies and animal experiments indicate a dominant role of T-cells over antibodies in controlling acute Lassa virus infection and providing immunity to reinfection. Knowledge of the epitopes recognized by T-cells may therefore be crucial to the development of a recombinant Lassa virus vaccine. In order to study human T-cell reactivity to the most conserved structural protein of Lassa virus, the glycoprotein 2 (GP2), seven GP2-specific CD4+ T-cell clones (TCCs) were generated from the lymphocytes of a Lassa antibody positive individual.