Monoclonal antibodies to the human immunodeficiency virus p18 protein cross-react with normal human tissues

The immunohistochemical reactivity of four monoclonal antibodies (MAbs): CVK, 49-5, 49-6 and 63-FH2, raised against the p18 protein of HIV-1 was assessed in tissues obtained from HIV-infected and uninfected individuals. As already reported, all the MAbs specifically labelled follicular dendritic cells (FDC) in lymph nodes from HIV-infected patients with lymphadenopathy, and cells of microglial nodules in the brain from patients with AIDS-related encephalopathy. However, cross-reactivity with normal uninfected tissues was also observed: epithelial cells of the skin, the thymus and tonsils with CVK, and astrocytes in the brain of 49-6 and 63-FH2. Such cross-reactivities suggest that 'molecular mimicry' could exist between p18 of HIV and normal constituents of human cells. This phenomenon could be relevant for the diagnostic use of anti-p18 MAbs on pathological specimens, and it could be of importance in the pathophysiology of HIV infection.