Serological relatedness of herpes simplex viruses. Type-specificity of antibody response.

The serological relatedness of forty-seven strains of type 1 and type 2 herpes simplex virus was investigated by reciprocal and non-reciprocal neutralization kinetics. Early rabbit antisera divided the virus strains into two distinct groups where confident indentification of virus type was possible. Hyperimmune mouse and rabbit antisera did not divide the two virus types into two distinct non-over-lapping groups. The extent of overlap varied with the particular attribute of the virus being studied. The virus types were best discriminated by their neutralizability by type 1 antisera and least well by their neutralizability by type 2 antisera. The results of reciprocal kinetic neutralization test with hyperimmune mouse antisera were analysed by multi-dimensional cluster analysis. Hyperimmune mouse or rabbit antisera could not be discriminated with respect to their immunogenic type by their absolute neutralization rate constants against either type 1 or type 2 virus, but could be distinguished on a group basis by their relative neutralizability against both virus types (antiserum specificity attribute); however, using this latter criterion, the type of immunogen could only be predicted in seven of the forty antisera under test. 'Early' mouse antisera could also be distinguished as groups by their absolute k-values against type 1 herpes virus. Thus, immunogenic identification, on other than a group basis, was unreliable. The specificity of a given serum was inversely related to its titre. There was a positive correlation between the specificity of a given virus strain and of its corresponding antiserum.