Rapid typing of herpes simplex virus based on immunological specificity of viral thymidine kinase and typing according to sensitivity to iododeoxyuridine.

We describe two methods for typing of herpes simplex virus (HSV). One procedure is based on the finding that the multiplication of HSV type 1 strains in primary rabbit kidney cells is inhibited by 2 x 10(-5) M iododeoxyuridine, whereas growth of HSV type 2 strains is considerably less affected. Forty-nine different HSV isolates were typed according to this method. For all isolates except two the results were found to be in agreement with results obtained by another typing procedure, the counterimmunoelectroosmophoretic method (S. Jeansson, Appl. Microbiol. 24:96-100, 1972). One HSV type 1 isolate behaved as a type 2 strain and was found to be a deoxythymidine kinase-negative mutant strain. The other deviant strain exhibited an intermediate iododeoxyuridine sensitivity, thus being impossible to type with this method. Another, faster typing procedure which is based on the immunological difference between HSV type 1 and 2 deoxythymidine kinase is also presented. This assay, in combination with the conventional methods for isolation, enables the detection of deoxythymidine kinase-negative therapy-resistant HSV strains. Finally, we report the detection and typing of HSV deoxythymidine kinase present in vesicle fluids.