Figure 6.

Reduction in parasite burden following virulent challenge in various groups. (A) Schematic diagram showing C57Bl/6 mice were injected intravenously with 10³ LdWT^LLO parasites. The mice were injected with 3 × 10⁶ LdCen^−/−2W parasites 21 days following the first low-dose infection. At 10 weeks postimmunization all the three groups were challenged with virulent L. donovani 10⁵ i.v. Eight weeks postchallenge parasite burden and immune response was measured. (B) Gating strategy showing the identification of multifunctional CD4 and CD8 T cells following in vitro stimulation with SLA. Splenocytes from the immunized challenged and control mice were stimulated with SLA. Live, activated CD4⁺ or CD8⁺ T cells with low CCR7 expression and producing IFN-γ, TNF and IL2 were identified as multifunctional T cells. (C) Multifunctional CD4⁺ and (D) CD8⁺ T cells from various groups are represented. (E) Splenic parasite burden of the LdWT parasites used in challenge experiment from various groups is expressed as log dilution end points. (F) Splenic parasite burden from the initial low-dose asymptomatic infection with LdWT^LLO parasites is shown as log dilution end points. Data from a representative experiment are shown with three to four mice per group.