[Effectiveness of anti-CD47 antibody and Ara-C combination targeting therapy NOD/SCID mouse of myeloid leukemia].

OBJECTIVE: To study the prognostic significance of CD47 in a NOD/SCID mouse model of acute myeloid leukemia (AML) and the best strategy for targeted therapy for this disease. METHODS: CD34(+)CD38(-) leukemia stem cells (LSCs) were separated and transplanted into NOD/SCID mice to establish a mouse model of acute monocytic leukemia (AMoL). Anti-human CD47 antibody, alone or combined with cytosine arabinoside (Ara-C), was used to treat the mice with AMoL for 7-14 days, and therapeutic efficacy was assessed. LSCs were cultured together with mouse macrophages in culture medium containing anti-CD47 or anti-CD45 monoclonal antibody for 2 hours, to observe the phagocytic ability of macrophages to LSCs. RESULTS: CD34(+)CD38(-) LSCs existed among THP-1 cells, with a content of about (0.12 ± 0.06)%, and a mouse model of AML was successfully established after the purified CD34(+)CD38(-) LSCs (97.0% ± 1.7%) were transplanted into NOD/SCID mice. The in vivo experiment showed that mice with AMoL had the most significant decrease in CD33(+)CD45(+) leukemia cells in peripheral blood and bone marrow and survived the longest after being treated with Ara-C (7 days) plus anti-CD47 monoclonal antibody (14 days) (P < 0.01). After 2 hours of in vitro culture, the phagocytic index in the culture medium containing anti-CD47 monoclonal antibody was significantly higher than in the culture medium containing anti-CD45 monoclonal antibody (76.9% ± 12.2% vs 7.60% ± 2.4%; P < 0.05). CONCLUSIONS: High expression of CD47 is an adverse prognostic factor in AML. Combination therapy with anti-CD47 monoclonal antibody and Ara-C can effectively eliminate leukemia cells and LSCs, demonstrating great clinical significance in curing AML.

[Efficacy of immunosuppressive therapy for children with aplastic anemia].

OBJECTIVE: To study the effectiveness and safety of immunosuppressive therapy (IST) in the treatment of childhood aplastic anemia (AA) and to study the main factors influencing the effectiveness. METHODS: The clinical data of 55 children with severe aplastic anemia (SAA) and 51 children with chronic aplastic anemia (CAA) were retrospectively analyzed. All patients received IST from January 2007 to December 2010. RESULTS: In children with CAA, the effective rate of antithymocyte globulin (ATG) plus cyclosporine A(CsA) combination therapy was significantly higher than that of CsA alone (80% vs 44%; P<0.05); in children with SAA, the effective rate of ATG plus CsA combination therapy was also significantly higher than that of CsA alone (75% vs 40%; P<0.05). No patients developed clonal disease such as myelodysplastic syndrome, paroxysmal nocturn hemoglobinuria or acute myelocytic leukemia. In patients treated with the ATG plus CsA combination therapy, the response rate was relatively high for children whose disease course was less than six months, bone marrow hematopoietic area was more than 40%, had no severe infections, and experienced granulocyte colony stimulating factor (G-CSF) reaction during the early treatment; however, it was not related to AA subtypes and age. CONCLUSIONS: ATG plus CsA combination therapy is effective and safe in the treatment of childhood AA. The disease course, bone marrow hematopoietic area, severe infections and G-CSF reaction to early treatment are the main factors influencing the therapeutic effects.

[Cloning, expression and preparation of polyclonal antibody for IBDV non-structure protein gene].

Infectious bursal disease virus (IBDV) VP5 gene was amplified and cloned into an N-terminal GST-Tag fusion expression vector, pGEX-4T-2, which was controlled by T7 promoter. The sequencing result showed that the VP5 gene was composed of 438 base pairs, and coded 145 amino acids. High VP5 product was expressed in E. coli BL21 induced by IPTG, and the GST-VP5 fusion protein existed in inclusion. High titer anti-VP5 serum was also prepared in New Zealand rabbit immunized with purified fusion protein inclusion. These results gave a basis for further research for VP5 function in IBDV replication and pathogenicity, which also paved the way for developing VP5 gene deleted IBDV live vaccine.

Development of an overlapping PCR method to clone the full genome of infectious hypodermal and hematopoietic necrosis virus (IHHNV).

Decapod Penstyldensovirus 1, previously named as infectious hypodermal and hematopoietic necrosis virus (IHHNV), is an economically important pathogen that causes shrimp diseases worldwide. However, a rapid method for cloning full-length IHHNV genome sequences is still lacking, which makes it difficult to study the genomics and molecular epidemiology of IHHNV. Here, a novel and rapid PCR technique was developed to determine the complete genomic sequences of IHHNV. The IHHNV genome was amplified in two overlapping fragments which each yielded a 2kb PCR product covering the first half or the second half of IHHNV genome, respectively. Using this method, six complete genomic sequences of IHHNV, which were collected from different regions of Zhejiang province in China, were cloned and sequenced successfully. The new cloning method will greatly facilitate the study on the genomics and molecular epidemiology of IHHNV.