Host and viral genetic factors which influence viral neurotropism

This chapter reviews host and viral genetic factors that influence viral neurotropism. It highlights a few recent insights that have been gained into the molecular and genetic basis for viral tropism, with specific emphasis on the factors that appear particularly relevant to understanding the basis for the tropism of viruses for the nervous system. The chapter discusses the way by which host genes, acting through a variety of mechanisms, can influence the susceptibility or resistance of animals to neurotropic viruses. It also reviews investigations concerning the role played by individual viral genes and the proteins they encode in determining specific pathways of viral spread to the central nervous system in the infected host. The chapter presents several examples illustrating the current state of knowledge concerning the nature of viral cell attachment proteins and host cell receptors for neurotropic viruses. It also presents examples of the way by which specific viral genetic elements such as enhancers can act to determine the cell-specificity of certain neurotropic viruses.