Figure 6.

CD4⁺ T-cell depletion and KEX1-antibody responses in KEX1-immunized animals and mock-immunized animals with rapid progression of disease. A, Comparable rapid decreases in CD4⁺ T-cell counts occurred in animals 17911 (KEX1 immunized) and 19111 (mock immunized). B–D, However, plasma anti-KEX1 immunoglobulin G (IgG; B) and bronchoalveolar lavage (BAL) fluid IgG (C) and immunoglobulin A (IgA; D) responses were notably greater in animal 17911, compared with animal 19111. These data suggest that immune responses to KEX1 immunization prior to simian/human immunodeficiency virus (SHIV) infection can be maintained at comparably high levels despite severe CD4⁺ T-cell depression. Dashed line indicates KEX1-specific IgG titer correlate of protection [22].