Control of toxoplasmosis by inducing Th1 helper cells

1)猫IL-12基因的克隆和表达已知IL-12可增强NK细胞活性，刺激CTL活性，并诱导干扰素-γ的产生，因此IL-12被认为是Th1型辅助性细胞免疫应答中的关键细胞因子。克隆、表达和鉴定了猫科动物IL-12p35和p40亚基的全长基因。2)弓形虫免疫优势抗原基因的克隆与表达以RH株γ为模板，扩增弓形虫免疫优势抗原P22(SAG2)、P30(SAG1)、P54(ROP2)和SRS1基因，并在大肠杆菌中表达。3)构建了表达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)，证明重组抗原在结构和抗原性上与弓形虫天然抗原相似。4)表达弓形虫抗原的重组FHV-1对猫攻击感染的保护作用FHV-1/TgP22、FHV-1/TgP30、FHV-1/TgP54和FHV-1/SRS1免疫的猫分别对弓形虫感染产生部分保护性免疫。我们的下一步将是对猫进行免疫试验，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.