Figure 1. Detection of HIV-1/HIV-2 cross-reactive antibodies in sera from 11 primate species by using a line immunoassay (INNO-LIA HIV Confirmation, Innogenetics, Ghent, Belgium). Varying patterns of reactivity to HIV peptides and proteins (HIV-1 gp120, gp41, p31, p24, and p17; HIV-2 gp130, and gp36) are shown. Samples from which Simian immunodeficiency virus (SIV) sequences were subsequently amplified by polymerase chain reaction are color-coded as in Figure 2. Plasma samples from HIV-1/HIV-2-negative and -positive persons are shown as controls on the left. The 3+, 1+ and +/- bands at the top of all test strips control for sample addition (presence of plasma immunoglobulin) and test performance (binding of secondary antibody).