Evasion of Immunologic Defenses and Emerging Viral Threats

Abstract

New viruses and virus strains appear at irregular but frequent intervals in the human population. Those that represent a widespread serious threat to human populations have evolved mechanisms for either short-term or longer-term evasion of immunologic recognition and neutralization. These mechanisms include (1) antigenic shift, (2) intracellular transport, (3) intracellular latency, (4) direct infection and destruction of cells of the immune system, (5) infection in utero or early infancy so the developing immune system regards it as part of the host repertoire of antigens, and probably (6) nonantigenicity. In this article, I discuss these mechanisms and their relationship to the threat constituted by emerging viral agents.

Human herpes virus 6 and human herpes virus 8 DNA sequences in brains of multiple sclerosis patients, normal adults and children

“…In the NMO case, we may also argue that the dramatic impairment of the immunocompetent system may have reactivated a latent infection of the virus in the CNS with the well-known effect, in common with all the other human herpesviruses [8]. Moreover, very recently HHV-6 has been recognized as being implicated in the etiology of myelopathy, still now considered to be of unknown origin [18].…”

“…Autoradiography of HHV-6 positive PCR (lanes 1,2,6,7) and negative PCR (lanes3,4,5,8) in normal brains obtained from immunocompetent adults. The positive and negative controls are represented by the HHV-6 infected (HSB-2) and uninfected (NC) cells DNA, respectively.…”