CD14 expression on monocytes can be divided into two subsets. Whole blood was stained with anti-CD14 and one of the antibodies listed in Table 1. Based on CD14 expression and side-scatter log characteristics, monocytes can be divided into CD14^hi and CD14^lo subsets. Each of these gated populations was monitored for changes in expression of phenotypic markers (Table 1) throughout the course of the disease in 6 SIV-infected pigtailed macaques. Isotype controls from CD14^hi and CD14^lo subsets are shown.

Mean fluorescent intensity (MFI) of activation markers on CD14^hi cells during the course of infection in 6 pigtailed macaques infected with SIV/DeltaB670. Based on histological findings, macaques were retrospectively classified at post-mortem for presence of SIV encephalitis. For each phenotypic marker, macaques that developed SIVE (M157, M158, M159, and M161) are shown in the left graph, while macaques that did not develop SIVE (SIVnoE) (M156 and M160) are shown in the right graph. At indicated weeks post-infection (wpi), whole blood was stained with anti-CD14 and the panel of antibodies listed in Table 1. MFI of each phenotypic marker on CD14^hi cells was followed every 2 wpi: (a) CCR5, (b) CD69, (c) HLA-DR, (d) CD62L, (e) CD40, (f) CD64, (g) CD163, and (h) CD16. Note the difference in y-axes scales.

Proportion of CD14^hi cells that expressed phenotypic markers of activation during the course of infection in 6 pigtailed macaques infected with SIV/DeltaB670. Based on histological findings, macaques were retrospectively classified at post-mortem for the presence of SIV encephalitis (SIVE). For each phenotypic marker, macaques that developed SIVE (M157, M158, M159, and M161) are shown in the left graph, while macaques that did not develop SIVE (SIVnoE) (M156 and M160) are shown in the right graph. At indicated weeks post-infection (wpi), whole blood was stained with anti-CD14 and the panel of antibodies listed in Table 1. CD14^hi cells were gated as shown in Fig. 1. Shown here are longitudinal changes in percent expression of each phenotypic marker: (a) CCR5⁺/CD14^hi, (b) CD69⁺/CD14^hi, (c) HLA-DR⁺/CD14^hi, (d) CD62L⁺/CD14^hi, (e) CD40⁺/CD14^hi, (f) CD64⁺/CD14^hi, (g) CD163⁺/CD14^hi, and (h) CD16⁺/CD14^hi.

Proportion of CD14^lo cells that expressed phenotypic markers of activation during the course of infection in 6 pigtailed macaques infected with SIV/DeltaB670. Based on histological findings, macaques were retrospectively classified at post-mortem for the presence of SIV encephalitis. For each phenotypic marker, macaques that developed SIVE (M157, M158, M159, and M161) are shown in the left graph, while macaques that did not develop SIVE (SIVnoE) (M156 and M160) are shown in the right graph. At indicated weeks post-infection (wpi), whole blood was stained with anti-CD14 and the panel of antibodies listed in Table 1. CD14^lo cells were gated as shown in Fig. 1. Shown here are longitudinal changes in percent expression of each phenotypic marker: (a) CCR5⁺/CD14^lo, (b) CD69⁺/CD14^lo, (c) HLA-DR⁺/CD14^lo, (d) CD62L⁺/CD14^lo, (e) CD40⁺/CD14^lo, (f) CD64⁺/CD14^lo, (g) CD163⁺/CD14^lo, and (h) CD16⁺/CD14^lo.

The proportion of CD14^hi/CD16^lo cells increased while the percentage of CD14⁻/CD16^hi cells decreased during the course of infection in 6 pigtailed macaques infected with SIV/DeltaB670 regardless of development of encephalitis. At each week post-infection (wpi), whole blood was stained with anti-CD14 and anti-CD16 antibodies. (a) These representative pseudo-color plots (ungated) from M156 show the proportions of CD14^hi/CD16^lo and CD14^lo/CD16^hi cells increased during the course of infection. The baseline plot shows three CD16⁺ cell populations: A = CD14^hi/CD16^lo; B = CD14^lo/CD16^hi; and C = CD14⁻/CD16^hi. (b–d) Macaques that developed SIVE (M157, M158, M159, and M161) are shown in red, while macaques that did not develop SIVE (M156 and M160) are shown in blue. The A, B, and C subsets cells were gated as shown in (a). Insets show changes in the mean percentage of each subset as a function of duration of infection (wpi). (b) A subset. The proportion of CD14^hi/CD16^lo cells increased during the course of infection, r² = 0.55, m = 0.05 ± 0.01 and P = 0.006. (c) B subset. The proportion of CD14^lo/CD16^hi cells was variable during the course of infection. Most macaques showed increased proportions at 1 wpi. However, there was no estimated change in mean percentage during the course of infection, r² = 0.006, m = 0.004 ± 0.01 and P = 0.774. (d) C subset. The proportion of CD14⁻/CD16^hi cells decreased during the course of infection, r² = 0.51, m = −0.18 ± 0.05 and P = 0.001. r² = measure of goodness of fit. m = slope of line. Since only one animal survived after 26 wpi, the insets show data from 0 to 26 wpi to avoid inaccuracies in statistical analyses presented. Note the difference in y-axes scales for (b–d).