ENHANCEMENT OF IMMUNOHISTOCHEMICAL DETECTION OF HIV-1 P24 ANTIGEN IN BRAIN BY TYRAMIDE SIGNAL AMPLIFICATION

Human immunodeficiency virus type 1 (HIV-1) infection of the brain has been demonstrated in formalin fixed, paraffin embedded post-mortem br ain tissue (PM) by chromogenic immunohistochemistry for the HIV p24 an tigen. The sensitivity of antigen detection is increased significantly by tyramide signal amplification (TSA) compared to the conventional p eroxidase labelled Avidin-Biotin complex (ABC) technique. The TSA meth od also permitted the use of a lower concentration of primary antibody than is conventionally used. Sensitivity was enhanced further by micr owave irradiation of the paraffin embedded tissues in citrate buffer. HIV-1 p24 antigen was also detected in PM brain tissue by TSA enhanced immunofluorescence and demonstrated increased sensitivity compared to the conventional immunofluorescence technique with a greatly reduced autofluorescence background. (C) 1997 Elsevier Science B.V.