PDF(Pubmed)
Abstract：
The global burden of infections due to the pathogenic fungus Cryptococcus is substantial in persons with low CD4+ T-cell counts. Previously, we deleted three chitin deacetylase genes from Cryptococcus neoformans to create a chitosan-deficient, avirulent strain, designated as cda1∆2∆3∆, which, when used as a vaccine, protected mice from challenge with virulent C. neoformans strain KN99. Here, we explored the immunological basis for protection. Vaccine-mediated protection was maintained in mice lacking B cells or CD8+ T cells. In contrast, protection was lost in mice lacking α/β T cells or CD4+ T cells. Moreover, CD4+ T cells from vaccinated mice conferred protection upon adoptive transfer to naive mice. Importantly, while monoclonal antibody-mediated depletion of CD4+ T cells just prior to vaccination resulted in complete loss of protection, significant protection was retained in mice depleted of CD4+ T cells after vaccination but prior to challenge. Vaccine-mediated protection was lost in mice genetically deficient in interferon-γ (IFNγ), tumor necrosis factor alpha (TNFα), or interleukin (IL)-23p19. A robust influx of leukocytes and IFNγ- and TNFα-expressing CD4+ T cells was seen in the lungs of vaccinated and challenged mice. Finally, a higher level of IFNγ production by lung cells stimulated ex vivo correlated with lower fungal burden in the lungs. Thus, while B cells and CD8+ T cells are dispensable, IFNγ and CD4+ T cells have overlapping roles in generating protective immunity prior to cda1∆2∆3∆ vaccination. However, once vaccinated, protection becomes less dependent on CD4+ T cells, suggesting a strategy for vaccinating HIV+ persons prior to loss of CD4+ T cells.
OBJECTIVE: The fungus Cryptococcus neoformans is responsible for >100,000 deaths annually, mostly in persons with impaired CD4+ T-cell function such as AIDS. There are no approved human vaccines. We previously created a genetically engineered avirulent strain of C. neoformans, designated as cda1∆2∆3∆. When used as a vaccine, cda1∆2∆3∆ protects mice against a subsequent challenge with a virulent C. neoformans strain. Here, we defined components of the immune system responsible for vaccine-mediated protection. We found that while B cells and CD8+ T cells were dispensible, protection was lost in mice genetically deficient in CD4+ T cells and the cytokines IFNγ, TNFα, or IL-23. A robust influx of cytokine-producing CD4+ T cells was seen in the lungs of vaccinated mice following infection. Importantly, protection was retained in mice depleted of CD4+ T cells following vaccination, suggesting a strategy to protect persons who are at risk of future CD4+ T-cell dysfunction.
OBJECTIVE: The fungus Cryptococcus neoformans is responsible for >100,000 deaths annually, mostly in persons with impaired CD4+ T-cell function such as AIDS. There are no approved human vaccines. We previously created a genetically engineered avirulent strain of C. neoformans, designated as cda1∆2∆3∆. When used as a vaccine, cda1∆2∆3∆ protects mice against a subsequent challenge with a virulent C. neoformans strain. Here, we defined components of the immune system responsible for vaccine-mediated protection. We found that while B cells and CD8+ T cells were dispensible, protection was lost in mice genetically deficient in CD4+ T cells and the cytokines IFNγ, TNFα, or IL-23. A robust influx of cytokine-producing CD4+ T cells was seen in the lungs of vaccinated mice following infection. Importantly, protection was retained in mice depleted of CD4+ T cells following vaccination, suggesting a strategy to protect persons who are at risk of future CD4+ T-cell dysfunction.
摘要：
在CD4T细胞计数较低的人群中，致病性真菌隐球菌引起的全球感染负担很大。以前,我们从新生隐球菌中删除了三个几丁质脱乙酰酶基因，无毒毒株,指定为cda1Δ2Δ3Δ，which,当用作疫苗时，保护小鼠免受毒力C.neoformans菌株KN99的攻击。这里,我们探索了保护的免疫学基础。在缺乏B细胞或CD8+T细胞的小鼠中维持疫苗介导的保护。相比之下,缺乏α/βT细胞或CD4+T细胞的小鼠失去了保护作用。此外，来自接种疫苗的小鼠的CD4+T细胞在过继转移至幼稚小鼠时赋予保护。重要的是,而在疫苗接种前，单克隆抗体介导的CD4+T细胞耗竭导致保护完全丧失，在疫苗接种后但攻击前,CD4+T细胞耗竭的小鼠保留了显著的保护作用.在干扰素-γ（IFNγ）遗传缺陷的小鼠中，疫苗介导的保护作用丧失，肿瘤坏死因子α（TNFα），或白细胞介素（IL）-23p19。在接种和攻击的小鼠的肺中观察到白细胞和表达IFNγ和TNFα的CD4+T细胞的稳健流入。最后,离体刺激的肺细胞产生较高水平的IFNγ与肺中较低的真菌负荷相关。因此，而B细胞和CD8+T细胞是可有可无的，IFNγ和CD4+T细胞在cda1Δ2Δ3Δ疫苗接种前产生保护性免疫方面具有重叠作用。然而,一次，接种疫苗保护对CD4+T细胞的依赖性降低，建议在CD4+T细胞丢失之前接种HIV+人的策略。
目的：真菌新生隐球菌每年导致>100,000例死亡，主要是CD4+T细胞功能受损的人，如艾滋病。没有批准的人类疫苗。我们之前创造了一种基因工程的无毒菌株，指定为cda1Δ2Δ3Δ。当用作疫苗时，cda1Δ2Δ3Δ保护小鼠免受随后的毒性新衣原体毒株的攻击。这里,我们定义了负责疫苗介导保护的免疫系统组分.我们发现，虽然B细胞和CD8+T细胞是不可或缺的，在CD4+T细胞和细胞因子IFNγ遗传缺陷的小鼠中失去保护，TNFα,或IL-23。感染后，在接种疫苗的小鼠的肺中观察到产生细胞因子的CD4+T细胞的强劲流入。重要的是,疫苗接种后，CD4+T细胞耗尽的小鼠保留了保护作用，建议一种策略来保护未来有CD4+T细胞功能障碍风险的人。
目的：真菌新生隐球菌每年导致>100,000例死亡，主要是CD4+T细胞功能受损的人，如艾滋病。没有批准的人类疫苗。我们之前创造了一种基因工程的无毒菌株，指定为cda1Δ2Δ3Δ。当用作疫苗时，cda1Δ2Δ3Δ保护小鼠免受随后的毒性新衣原体毒株的攻击。这里,我们定义了负责疫苗介导保护的免疫系统组分.我们发现，虽然B细胞和CD8+T细胞是不可或缺的，在CD4+T细胞和细胞因子IFNγ遗传缺陷的小鼠中失去保护，TNFα,或IL-23。感染后，在接种疫苗的小鼠的肺中观察到产生细胞因子的CD4+T细胞的强劲流入。重要的是,疫苗接种后，CD4+T细胞耗尽的小鼠保留了保护作用，建议一种策略来保护未来有CD4+T细胞功能障碍风险的人。
