PMC

SHIV infection decreases the concentration of pDC and their ability to produce IFN-α in response to HSV-1 stimulation. (A) pDC concentration in peripheral blood from day of SHIV immunization to the day of SIV challenge. (B) The concentration of blood pDC that produce IFN-α in response to in vitro HSV-2 stimulation, from day of SHIV immunization to the day of SIV challenge. P values generated using Tukey's multiple comparison post hoc tests after a one-way ANOVA. Each animal is represented by a symbol.

The number of plasmacytoid dendritic cells in the endocervix of RM is highly variable and unrelated to SIV exposure/infection status. (A) CD123⁺ pDC in the endocervix of unimmunized monkey 28617 3 days after vaginal SIV challenge; (B) CD123⁺ pDC in the endocervix of SHIV-immunized monkey 32644 3 days after vaginal SIV challenge; (C) CD123⁺ pDC in the endocervix of unimmunized monkey 28257 3 days after vaginal SIV challenge; (D) CD123⁺ pDC in the endocervix of SHIV-immunized monkey 31298 3 days after vaginal SIV challenge; (E) CD123⁺ pDC in the endocervix of an age-matched, SIV-naïve, normal RM; (F) CD123⁺ pDC in the endocervix of a second age-matched, SIV-naïve, normal RM. All tissue sections were stained immunohistochemically using a horseradish peroxidase-DAB chromogen system so that CD123⁺ cells appear dark brown. Scale bars indicate 50 μm.

CD4⁺ FoxP3⁺ T cells rapidly increase in the vaginal mucosa of the immunized RM after SIV vaginal challenge. The mean number of CD4⁺/Foxp3⁺ T cells per mm² of tissue was assessed by immunohistochemistry on day 3 PC (SHIV-immunized RM, n = 3; SIV controls, n = 3) (A), on day 7 PC (SHIV, n = 6; SIV, n = 9) (B), and on day 14 PC (SHIV, n = 12; SIV, n = 9) (C). Five randomly chosen fields were counted for each individual animal. P values were generated using a two-sample t test.

The total numbers of CD4⁺ T cells and activated CD4⁺ T cells are increased in the genital tract of SHIV-immunized RM compared to those of normal RM. The mean number of CD4⁺ T cells and Ki67⁺/CD4⁺ T cells per mm² of tissue was assessed by immunohistochemistry 6 to 8 months after SHIV immunization (SHIV-immunized RM, n = 9 monkeys; normal controls, n = 6). (A) CD4⁺ T cells, endocervix; (B) Ki67⁺/CD4⁺ T cells, endocervix; (C) CD4⁺ T cells, ectocervix; (D) Ki67⁺/CD4⁺ T cells, ectocervix; (E) CD4⁺ T cells, vagina; (F) Ki67⁺/CD4⁺ T cells, vagina. Five randomly chosen fields were counted for each individual animal. P values were generated using a two-sample t test.

In vitro suppressive activity of CD4⁺ CD25⁺ T cells in spleen 14 days after vaginal SIV challenge. On the day of SIV challenge or on days 7 and 14 postchallenge, the suppressive capacity of CD25⁺ CD4⁺ splenic T cells was assessed by comparing the proliferative capacity of mitogen-stimulated cells with or without CD25⁺ T cell depletion. A suppression index was calculated as described in Materials and Methods. P values were generated using Tukey's multiple comparison post hoc tests after a one-way ANOVA.

Infection with attenuated SHIV89.6 induces transient T cell activation and a sustained increase in CD38⁻/HLA-DR⁺ CD8⁺ T cells. Flow cytometry was used to determine the percentage of activated T cell subsets in the blood of SHIV-immunized RM from the day of SHIV immunization to the day of SIV challenge. (A) Percent of CD3⁺ CD8⁺ T cells expressing CD38 but not HLA-DR; (B) percentage of CD3⁺ CD8⁺ T cells expressing HLA-DR but not CD38; (C) percentage of CD3⁺ CD8⁺ T cells expressing both CD38 and HLA-DR; (D) percentage of CD3⁺ CD4⁺ T cells expressing CD38 but not HLA-DR. P values were generated using Tukey's multiple comparison post hoc test after a one-way ANOVA. Each animal is represented by a symbol.

Infection with attenuated SHIV89.6 induces a transient increase in Tregs, while IDO⁺ cells in the vaginal mucosa are decreased. (A) Flow cytometry was used to determine the percentage of CD3⁺ CD4⁺ CD25⁺ HLA-DR⁺ T cells in blood of SHIV-immunized RM from the day of SHIV immunization to the day of SIV challenge. P values were generated using Tukey's multiple comparison post hoc test after a one-way ANOVA. In the tissues, the mean number of CD4⁺/Foxp3⁺ (B) and IDO⁺ (C) cells per mm² of tissue was analyzed using immunohistochemistry and quantified in normal monkeys (n = 6) and SHIV-immunized monkeys (n = 9) on the day of challenge. P values were generated using a two-sample t test.