The use of combined in situ hybridization and immunocytochemistry to identify HIV-infected cells in brain tissue.

It is frequently important to identify the types of cells that are infected with human immunodeficiency virus type-1 (HIV-1) in sections of formalin-fixed paraffin-embedded (FFPE) brain tissue. Currently, both immunocytochemical and in situ hybridization methods are used for this purpose. Combined in situ hybridization and immunocytochemistry results in simultaneous detection of HIV-1 nucleic acids and proteins and allow comparison of transcriptional and translational events of cells infected with HIV-1 in the same section. In addition, this technique allows morphologic and immunologic identification of the cells within which in situ hybridization occurs and confirmation of the identity of the cells that are not hybridized. Procedures are described for use with FFPE brain tissue.