Lymphocytes and Macrophages Are Infected by Theileria equi, but T Cells and B Cells Are Not Required to Establish Infection In Vivo
Figure 3
Immunophenotype of schizont-infected PBMC in vitro.
Flow cytometric (A) and IFA (B) analysis of schizont-infected cells in vitro. (A) Representative flow cytometric data for infect horse H2. Left column: percent of total PBMC dual labeled with leukocyte specific mAbs and T. equi specific mAb (anti-EMA 1/2). Right column: percent infected cells determined on IgM+ (B lymphocyte), CD3+ (T lymphocyte), or CD172a+ (macrophage) gated leukocytes. (B) IFA images of schizont-infected cells dual-labeled with one of the three leukocyte specific mAb and anti-EMA 1/2. The nuclei of all cells were stained blue with DAPI. The anti-EMA 1/2 mAb either formed diffuse signal throughout the cytoplasm of infected cells or discrete signal along the surface of intracytoplasmic macroschizonts. Rare cells had punctate foci of EMA 1/2+ immunoreactivity along their outer margin (top left panel; arrow). The space adjacent to cells multifocally contained scant, irregular to round, immunoreactive debris (left panels of second and third row; arrowhead). The anti-IgM, anti-CD3, and anti-CD172a mAb formed punctate to diffuse signal along the outer surface of infected cells. Labeling with an isotype control for the anti-EMA 1/2 mAb did not form any detectable signal (representative data shown in the bottom panels of B).