Abstract
The Centers for Disease Control and Prevention estimates that influenza virus infections kill tens of thousands of Americans each year. A major complication of influenza is the development of secondary bacterial infections that exacerbate the severity of the disease. In the current issue of Viral Immunology, Shepardson and colleagues describe a new mechanism by which influenza A viruses alter the host immune system and make them more or less susceptible to bacterial coinfection. The authors show that the nonstructural-1 protein (NS1) of the virus can regulate innate immunity and susceptibility to secondary bacterial infections. Deletion of a key section of the NS1 from the virus resulted in 100% survival and decreased bacterial burden in superinfected mice. These important findings suggest that NS1 regulates the time-dependent type I interferon response during influenza virus infection, which in turn determines susceptibility to secondary bacterial infections.
The current issue of Viral Immunology also includes two reviews on the host response to two important viral infections: hepatitis C virus (HCV) and dengue virus infections. Irshad et al. discuss current concepts regarding the mechanisms by which the host immune responses to HCV mediate liver cell injury. The authors conclude that the combined effect of different cell-mediated immune effector mechanisms ultimately dictate progression to either acute or chronic infection.
In a second review, Chen et al. note that dengue virus is a highly prevalent arbovirus disease in tropical and subtropical areas. They also note that some human leukocyte antigen (HLA) alleles may be either protective or risk factors for the disease. A meta-analysis identified specific HLA alleles that were either positively associated with severe dengue, compared with dengue fever, or were negatively associated with severe dengue when compared with normal controls. Altogether six alleles were shown to significantly affect dengue disease.
Two other articles in the current issue of Viral Immunology focus on other aspects of the immune response to viral infection. Righi et al. have investigated varicella zoster virus (VZV) vaccine responses in human immunodeficiency virus (HIV)-positive adults with end-stage renal disease or undergoing kidney transplantation. The authors show that VZV vaccination appeared safe and effective in HIV-positive kidney transplant patients. Guo and colleagues report on the construction of recombinant Lactococcus lactis strain expressing a variant porcine epidemic diarrhea virus S1 gene. Mouse vaccination studies with the recombinant bacterial strain elicited strong immunity to porcine epidemic diarrhea virus and represents a promising vaccine strategy against this important infection of pigs.
I thank all of the authors for their excellent contributions to the Journal and the reviewers who work to ensure the high quality of the accepted articles.