Figure 2.

Monoclonal antibodies (mAbs) to the M antigen can modify the pathogenesis of experimental histoplasmosis. The generation of the mAbs is described in Guimaraes et al. (2008). The mAbs produced are mAb 7C7 (IgM isotype), mAb 6F12 (IgG2a), and mAb 8H2 (IgG2a). Using methods described in Guimaraes et al. (2011b), the phagocytosis rates (A), and killing capacity (B) of J774.16 macrophage-like cells reveal that the mAbs significantly enhanced the uptake of yeast cells by the phagocytes (p < 0.05 vs. controls) and that two of the three mAbs enabled the killing of yeast cells by the J774.16 cells (p < 0.05 for mAbs 8H2 and 7C7 vs. controls). (C) C57Bl/6 mice infected with 1.25 × 10⁷ opsonized yeast cells had a 100% survival whereas control infected mice died within 1 month after infection (p < 0.001 for mAbs 8H2, 6F12, and 7C7 vs. controls).