Robert W. McCollum

Australia (Hepatitis-Associated) Antigen: Physicochemical And Immunological Characteristics*

Publisher Summary This chapter discusses the discovery, characterization, immunology, and etiological significance of “Australia antigen (Au),” a new antigenic specificity appearing in the serum of patients with serum hepatitis, and carried on characteristic lipoprotein particles. In addition to its original name, given before its relationship to viral hepatitis became known, the antigen has also been given the designations, including Au(1) , SH antigen, Au/SH antigen, hepatitis antigen, and hepatitis-associated antigen (HAA). The synthesis of Au antigen, and its appearance in the serum, is specifically associated with infection by the causal agent of the SH type of viral hepatitis. The chapter discusses properties of the antigen, and of the particles which carry the Au specificity. It also discusses various serological techniques for Au antigen, such as two-dimensional double immunodiffusion (ID), complement fixation (CF), immunofluorescence (IF), reversed passive hemagglutination (RPHA) of antibody-coated red cells, immune electron microscopy (IEM), immunoelectroosmophoresis (IEOP), and radioimmunoassay (RIA).

Epidemiologic patterns of viral hepatitis

Abstract Because of the marked variation in host response, which may occur as a result of infection with the virus of infectious hepatitis, our knowledge of its epidemiologic patterns is still incomplete and is likely to remain so until methods are available for relatively precise identification of anicteric and asymptomatic infections and an evaluation of their roles in direct and indirect transmission of the virus. If the history of hepatitis is viewed in perspective, a picture emerges which in many respects is similar to that which has been observed for poliomyelitis. Under environmental conditions which support widespread dissemination by the intestinal-oral route the virus is maintained in an endemic state and infection may be extremely common at an early age when symptoms and signs related to hepatitis involvement are rare. As the complex of socioeconomic changes and associated sanitary reforms takes place, an increasing proportion of the population reaches an older age without protective immunity gained as a result of asymptomatic infection in childhood. With appropriate exposure to infection at these later ages the likelihood of recognizable, or even severe, hepatic involvement is increased and hepatitis eventually emerges as an epidemic disease of major clinical and public health importance. During the past decade the United States and several other countries appear to have reached this stage in the epidemiologie evolution of hepatitis.

The Size of Serum Hepatitis Virus.

Summary 1. Known icterogenic (SH) serum (J.W. strain), undiluted and diluted 10% in normal saline, was filtered through gradocol membranes of various average pore diameters down to 52 mμ, and tested in human volunteers. 2. Evidence has been presented that the strain of serum hepatitis virus used is small enough to pass through a 52 mμ A.P.D. membrane, thus indicating a size of 26 mμ or less. The limitations of the application of this method for determining the size of this virus are mentioned. The author is indebted to Dr. John R. Paul for valuable advice and criticism.

THE INCIDENCE OF INFECTION AMONG CONTACTS OF POLIOMYELITIS CASES

One of the epidemiological features which puzzled early students of poliomyelitis was the apparently erratic spread of the disease with rarely more than one case in a family. Subsequently, it became apparent that unlike measles among the common virus diseases, the majority of infections with poliomyelitis virus were either mild or inapparent and, therefore, went undetected. A number of epidemiological survey studies carried out during the past two decades indicated that actually a high infection rate was common among family contacts of poliomyelitis cases even though only one individual in the family became sick. Until recently, however, the laboratory methods available for studying the problem were largely limited to the isolation of virus by monkey inoculation, and the exact rates or degree of spread of this infection through families remained unknown. With the introduction of tissue culture methods into poliomyelitis research, it has been possible to carry out more extensive virological studies, and to relate virus isolation-or its absence-to the immune or antibody status of the individuals tested. The present study is concerned with poliomyelitis infection rates among close contacts of cases and indicates actually how high they may be. Tissue culture methods, which have been brought to bear on the problem, have been responsible for these results.

Poliomyelitis Virus in Human Blood During the “Minor Illness” and the Asymptomatic Infection.∗

Summary Poliomyelitis virus has been isolated from the blood of 4 children in one family during a poliomyelitis epidemic in Ohio in 1952. Three of the children had characteristic clinical pictures of the minor illness or abortive poliomyelitis, and one was asymptomatic. All were found to have virus in the throut and rectal swabs as well as in the blood. None went on the develop signs or symptoms of the major illness, either paralytic or nonparalytic.

Japanese B Encephalitis Virus in Tissue Culture.

Summary Two strains of Japanese B encephalitis virus have been serially propagated in tissue cultures of chick embryo fibroblasts (both plasma-clot explants and trypsinized cells), monkey kidney epithelium. HeLa cells, and Detroit-6 cells. Cytopathogenicity, which was consistent and reproducible, was observed only with the Detroit-6 cells. Maximal virus growth and release was observed 2 days before CPE became pronounced. This effect was readily neutralized by JBE immune serum. A similar CPE has been observed in Detroit-6 cells infected with the Egypt 101 strain of West Nile virus.

DENGUE VIRUS PLAQUE FORMATION IN RHESUS MONKEY KIDNEY CULTURES.

Summary Plaques were produced by mouse-adapted strains of the 6 recognized Dengue serotypes using a modified overlay of cultures of rhesus monkey kidney cells. Overlay modifications included changes in the magnesium and calcium ion concentration and addition of Larginine and oxalacetic acid. Plaques 1-3 mm in diameter appeared 5-11 days after inoculation of cultures. Endpoints were generally higher in rhesus kidney cultures during parallel titrations of the virus in tissue culture and mice.