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Objective To analyze the status of Leishmania infantum asymptomatic infection in human population of a Kala-azar endemic area in Wenxian County,Gansu Province,and to evaluate the tests used.Methods Blood samples were tested by PCR using two pairs of primers,RV1-RV2 and K13A-K13B,for detecting Leishmania-specific DNA.ELISA and rK39-dipstick were used to detect Leishmania-specific antibodies.Results The positive rate of PCR,ELISA and rK39-dipstick was 30.9%(83/269),24.2%(65/269) and 0(0/269) respectively.Conclusion The prevalence of asymptomatic infection of L.infantum in humans is high in the area.PCR test based on RV1-RV2 and K13A-K13B primer pairs is a sensitive and specific method for detecting the asymptomatic infection.
RESUMO
Objective To prepare monoclonal antibodies specific to lactate dehydrogenase of Plasmodiun falciparum. Methods The Plasmodium falciparum lactate dehydrogenase (pLDH) gene was amplified from whole blood of malaria patients by PCR and cloned into expression vector pGEX-3X. Recombinant pLDH protein was expressed and purified, and used for immunizing mice to prepare monoclonal antibodies (McAbs). The McAbs were characterized by Western blotting analysis. Results The Plasmodium falciparum lactate dehydrogenase gene was amplified and cloned into expression vector pGEX-3X. The recombinant pLDH plasmid was expressed in E.coli) BL-21 cells. 15 cell lines of McAbs with high titer against pLDH were obtained using the recombinant pLDH as immunogen. Western blotting analysis showed that these McAbs recognized a Mr 33 000 of native Plasmodiun falciparum protein without cross-reaction with constituents of red blood cell of febrile patients from endemic area of malaria. Conclusion Fifteen hybridoma cell lines secreting high titer of McAb specific to Plasmodium falciparum LDH were established based on the recombinant pLDH.