Control of toxoplasmosis by inducing Th1 helper cells

已知IL-12可增强NK活性、刺激CTL活性并诱导INF-γ产生，因此IL-12被认为是Th1辅助细胞源性免疫应答的关键细胞因子。克隆并表达了猫IL-12 p35和p40亚基的全长cDNA。重组猫IL-12具有诱导INF-γ和刺激ctl的活性。2)刚地弓形虫免疫优势抗原基因的克隆与表达以RH菌株cDNA为模板，对刚地弓形虫免疫优势抗原编码基因P22 （SAG2）、P30 （SAG1）、P54 （ROP2）和SRS1进行pcr扩增，并在大肠杆菌细胞中表达。用重组抗原免疫小鼠对弓形虫攻击感染产生部分保护性免疫。3)构建了表达刚地弓形虫抗原基因的重组猫疱疹病毒1型（FHV-1），构建了表达刚地弓形虫免疫原性抗原（P22、P30、P54、SRS1）的重组猫疱疹病毒1型（FHV-1），并证实重组抗原在结构和抗原性上与刚地弓形虫天然抗原相似。表达IL-12的FHV-1的构建正在进行中。4)表达弓形虫抗原的重组FHV-1对FHV-1/TgP22、FHV-1/TgP30、FHV-1/TgP54和FHV-1/SRS1免疫猫对弓形虫感染的保护作用分别产生部分保护性免疫。我们下一步将在猫身上进行免疫试验，以检查FHV-1/IL-12诱导对弓形虫病有效免疫的效力。

1) Cloning and expression of feline IL-12 geneIt is known that IL-12 enhances NK activity, stimulates CTL activity and induces INF-γ production, and therefore IL-12 is considered as a key cytokine in Th1 helper cell-derived immune responses. A full length cDNA of feline IL-12 p35 and p40 subunits was cloned, expressed and characterized. The recombinant feline IL-12 has both INF-γ -inducing activity and CTL-stimulating activity.2) Cloning and expression of the immunodominant antigen genes of T. gondiiThe genes encoding immunodominant antigens, P22 (SAG2), P30 (SAG1), P54 (ROP2), and SRS1 of T. gondii were PCR-amplified using cDNA from RH strain as templates, and expressed in E. coli cells. Mice immunized with recombinant antigens produced a partial protective immunity against T. gondii challenge infections.3) Construction of recombinant feline herpesviruses expressing the antigen genes of T. gondiiRecombinant feline herpesvirus type 1 (FHV-1) expressing immunogenic antigens (P22, P30, P54, SRS1) of T. gondii were constructed, and demonstrated that the recombinant antigens were similar to the native antigens from T. gondii in structure and antigenicity. Construction of FHV-1 expressing IL-12 is under way.4) Protective effects of recombinant FHV-1 expressing T. gondii antigens against challenge infection in catsCats immunized with FHV-1/TgP22, FHV-1/TgP30, FHV-1/TgP54, and FHV-1/SRS1 produced a partial protective immunity against T. gondii infections, respectively. Our next step will be immunization trials with cats to check the potency of the FHV-1/IL-12 to induce effective immunity against toxoplasmosis.