Variola Virus and Immunity in Smallpox. H. Recovery of Variola-Specific Soluble Antigens from Infected Rhesus Monkey Kidney Cells

The multiplication of pox viruses in cell cultures is accompanied by the synthesis of a heterogeneous mixture of virus-specific soluble antigens. These antigens are presumed to be structural subunits of the virus, which were produced in excess, and virus-induced enzymes required for the synthesis of new viral material. Immunologic analyses of preparations of soluble antigen that are free of infectious virus have revealed the presence of 5-20 immunoprecipitinogens [1-7], two virus-specific hemagglutinins [8, 9], antigens with the capacity to fix complement in the presence of immune serum [10], and antigens capable of reacting with and eliciting the formation of virusneutralizing antibody [11-14]. Most of these studies were done with vaccinia or the viruses of cowpox and rabbitpox. Immunogenicity of the preparations of antigen was assayed with humoral antibody derived from hyperimmunized laboratory animals. The objective of the present investigation was recovery of virus-specific soluble antigens from cell cultures infected with variola virus. The role of various components in the production of variola-specific antibody was ascertained by determination of their immunogenicity in naturally occurring smallpox.