The humoral response of the immune system to a foreign antigen usually requires the recognition of two antigenic determinants. The one, called the carrier, is recognized by T-Iymphocytes, the other, called the hapten, by B-Iympho- cytes. As a consequence, T - and B-Iymphocytes proliferate, B-Iymphocytes produce hapten-specific antibodies, and the system develops memory to the antigens. It was long thought that antigens would form a bridge to mediate the cooperation of T - and B-Iymphocytes. However, it now appears that antigens are broken down to fragments which then act as carrier...

Although retroviruses have long been associated with a variety of animal diseases, active research in the field of human retroviruses dates from the discovery of human immunodefici- ency virus (HIV) in association with acquired immunodefici- ency syndrome (AIDS). The enormous research efforts in this field have been directed toward understanding the nature of the virus and toward its elimination through preventive vaccin- ation and the cure of the disease. Human T-cell leukemia virus (HTLV-l) was the first member of the human retrovirus family to be discovered. It was implicated as the cause...

Lyssaviruses are the etiological agents of rabies, one of the oldest documented and feared maladies in medical history. The last century has been particularly fruitful in regard to progress in Iyssavirus phylogenetic affinities, diagnostics, pathogenesis, molecular virology and epidemiology, pro- phylaxis and control. Yet, despite these academic and practical advances in research, the age-old horror evoked by rabies is still very real, with only four documented human recoveries once symptoms are realized. After decades of intense scrutiny and four recent books describing rabies and its viral...

Genetic / DNA immunization represents a novel approach to vaccine and immune therapeutic development. The direct injec- tion of nucleic acid expression cassettes into a living host results in a limited number of its cells becoming factories for production of the introduced gene products. This host-inappropriate gene expression has important immunological consequences, resulting in the specific immune activation of the host against the gene- delivered antigen. The recent demonstration by a number of laboratories that the induced immune responses are functional in experimental models against...

Borna disease was first described over 200 years ago, in what is now Southeastern Germany, as a fatal neurologic affliction of horses and was considered a curiosity for many decades. The causative agent was unknown, and the animal species infected in nature were limited to horses and sheep. Today, as described in this volume, the host range has extended to all warm-blooded animals, the genes and proteins of the virus have been identified, and many of the mechanisms responsible for behavioral disturbances are understood. Serologic studies suggest that BDV or related agents are likely to play a...