CHARACTERIZATION OF MONOCLONAL-ANTIBODIES RECOGNIZING AMINO-TERMINAL AND CARBOXY-TERMINAL EPITOPES OF THE HERPES-SIMPLEX VIRUS UL42 PROTEIN

A panel of monoclonal antibodies (MAbs) directed against the herpes si mplex virus type 1 (HSV-1) DNA polymerase (Pol) accessory protein, UL4 2, was developed and characterized. Thirteen different MAbs were isola ted which exhibited varied affinities for the protein. All MAbs reacte d with UL42 in ELISA, Western blot and immunoprecipitation analyses, C ompetitive ELISA was used to show that 6 different epitopes within UL4 2 were recognized by the MAbs. Immunoprecipitation of amino- and carbo xy-terminal truncations of UL42 mapped the epitopes to regions contain ing amino acids 1-10, 10-108, 338-402, 402-460, and 460-477. All but o ne of these epitopes were outside the minimal active portion of the pr otein previously mapped to amino acids 20-315. None of these MAbs, alo ne or in combination, specifically neutralized the ability of UL42 to stimulate Pol activity in vitro. These results are consistent with str ucture-function studies that showed that Nand C-terminal regions of th e UL42 protein, those recognized by the MAbs, are not involved in UL42 function in vitro.