Detection of HIV-1 p24-positive cells and cytokine mRNA expressing cells by combined immunocytochemistry and in situ hybridization. (A) Negative control (LPS-stimulated, uninfected MAC hybridized with IL-8 sense oligonucleotides). (B) Simultaneous detection of HIV-1 p24 (red staining) with immunocytochemistry and IL-8 mRNA in LPS-stimulated MAC with in situ hybridization (dark granules) at day 22 after start of culture. Cell no. 1, HIV p24-negative and IL-8–negative; cell no. 2, HIV p24-negative and IL-8–positive; cell no. 3, HIV p24-positive and IL-8–positive (×1,500).