Increased immunofluorescent staining of rabies-infected, formalin-fixed brain tissue after pepsin and trypsin digestion

This study was undertaken to evaluate the sensitivity of the direct immunofluorescence test on Formalin-fixed, trypsin-digested, rabies-infected brain tissue. Our results suggest that the optimal unmasking of rabies antigenic sites is obtained by using a double enzyme digestion with pepsin and trypsin in lieu of only trypsin.