KA1 and SH25 strains demonstrated the highest parasite burdens, while DE5 strain showed intermediate and DA39 strain displayed the lowest load of the viable parasites in the LN cells culture with statistically significant differences compared with the mice infected with the other strains.
Data were also in agreement with the results obtained in our previous study, suggesting the induction of the lowest and the highest load of the parasite by DA39 and SH25 strains in draining LN of BALB/c mice, respectively, 8 weeks post-infection [14]. Gamma interferon is the key feature of Th1 response and mediates macrophage learn more activation against L. major. Induction of this cytokine mRNA expression describes the direction of a protective immune response. These data show that all four strains elicited a distinct pattern of Ifng mRNA expression and among them DA39 strain induced augmented levels of the transcript expression at 16 h, rising to a peak of 127 FI at 40 h post-infection. Although the expression of Ifng transcript in draining LN cells at the late period showed rather lower rate at W1 and W5, the increase in this cytokine transcript in LN of mice injected with DA39 and SH25 strains at W3, drug discovery and all four strains at W8 displayed a tendency towards a Th1 immune response. Interestingly, DA39 strain
which induced the lowest load of parasites eight weeks post-infection had an ability to elicit higher expressions of Ifng mRNA than other strains at 40 h, W3 and somehow W8 post-infection. These results show consistency with results acetylcholine of Kabaier et al.
who observed higher production of IL-4 and lower generation of IFN-γ by isolates with higher virulence [11]. Moreover, a burst of Il2 transcript expression was documented in the early phase of the infection which peaked to 113 FI at 40 h post-infection in draining LN cells of the mice inoculated with DA39 strain. These data showed consistency with the increase of Ifng mRNA expression at early phase of the infection, particularly with the results observed at 40 h post-infection (Fig. 2a). Likewise, the results obtained were in agreement with reports of Gumy et al., suggesting an early production of Il2 transcript in BALB/c mice [24]. Indeed, there is a bulk of evidence suggesting that IL-2 might be one of the cytokines of Th1 response [6]. However, a controversy exist which correlates the effect of IL-2 on induction of Th1 or Th2 responses in the literature, and recent studies have documented the important role of IL-2 along with IL-4 in mediating Th2 responses [24]. Meanwhile, our results showed disagreement with the suggestion of Gumy et al. about the preceding of Il2 mRNA expression to Il4 transcript expression at early stages of the infection [24].