Mechanisms of suppressed recall responses of CD8+T cells during malaria infection

FTY720抑制淋巴器官的淋巴细胞迁移，但不能对抗OVA疟疾感染过程中记忆OT-I细胞的扩张减少，提示疟疾感染过程中召回反应全身性降低。免疫组织化学研究表明，OVA疟疾感染过程中OT-I细胞和巨噬细胞在脾白髓中的积聚较少。这一结果提示抗原提呈的位置对细胞的扩张可能是重要的。在野生型疟疾和李斯特菌的感染过程中，OVA冲击的BMDC免疫并没有引起幼稚的OT-I细胞和记忆的OT-I细胞的比率的差异，这意味着降低的回忆反应可能依赖于抗原的提呈。

FTY720, which inhibits lymphocyte emigration from lymphoid organs, did not affect against the reduced expansion of memory OT-I cells compared with naive OT-I cells during OVA malaria infection, suggesting that the recall response was reduced systemically during malaria infection.Immunohistochemistory indicated that OT-I cells and macrophages did not accumulate in white pulp of spleen so much during OVA malaria infection. This result suggested that the location of antigen presentation may be important for cell expansion.Immunization of OVA-pulsed BMDC did not induced the difference in the ratio of naive OT-I cells and memory OT-I cells during the infections between wild type malaria and listeria, implying the possibility that the reduced recall response might be dependent on antigen presentation.