RESUMO
Objective: To compare limiting dilution assay and real-time PCR methods in Leishmania tropica parasite load measurement in vaccinated mice.Methods: BALB/c mice were vaccinated by Leishmania tropica soluble Leishmania antigen or recombinant Leishmania tropica stress-inducible protein-1 with/without adjuvant. After three vaccinations, mice were challenged by Leishmania tropica promastigotes. Two months after challenge, the draining lymph nodes of mice footpad were removed and parasite load was assayed by limiting dilution assay and real-time PCR methods. Limiting dilution assay was done by diluting tissue samples to extinction in a biphasic medium. For real-time PCR, DNA of the lymph nodes was extracted, equal dilutions of each sample were prepared and hot-start real-time PCR was done using appropriate primers. The data of the two methods were compared by appropriate statistical methods. Results: Both methods were able to measure different levels of parasite load in vaccinated/unvaccinated mice. In addition, wherever parasite load of a group was estimated high (or low) by one method, the estimated parasite load by another method was the same, although statistically significant differences were found between some groups. Conclusions: Both methods lead to approximately similar results in terms of differentiating parasite load of the experimental groups. However, due to the lower errors and faster process, the real-time PCR method is preferred.
RESUMO
Objective: To compare limiting dilution assay and real-time PCR methods in Leishmania tropica parasite load measurement in vaccinated mice. Methods: BALB/c mice were vaccinated by Leishmania tropica soluble Leishmania antigen or recombinant Leishmania tropica stress-inducibleprotein-1 with/without adjuvant. After three vaccinations, mice were challenged by Leishmania tropica promastigotes. Two months after challenge, the draining lymph nodes of mice footpad were removed and parasite load was assayed by limiting dilution assay and real-time PCR methods. Limiting dilution assay was done by diluting tissue samples to extinction in a biphasic medium. For real-time PCR, DNA of the lymph nodes was extracted, equal dilutions of each sample were prepared and hot-start real-time PCR was done using appropriate primers. The data of the two methods were compared by appropriate statistical methods. Results: Both methods were able to measure different levels of parasite load in vaccinated/unvaccinated mice. In addition, wherever parasite load of a group was estimated high (or low) by one method, the estimated parasite load by another method was the same, although statistically significant differences were found between some groups. Conclusions: Both methods lead to approximately similar results in terms of differentiating parasite load of the experimental groups. However, due to the lower errors and faster process, the real-time PCR method is preferred.
RESUMO
Limiting dilution assay and ~(51)Cr-release assay were used to quantitate the pre-cursors of MAF-secreting T cells in lymph nodes or lymphoblast population of themice infected with Leishmania major(Lm).At lst and 4th week after infectionwith live Lm,the numbers of MAF-P in lymph nodes of resistant mice(CBA/T6)and susceptible mice(BALB/C)showed no significant difference but resistantmice had much more MAF-P than susceptible mice at 8th week.The effect ofantigen,interleukin-2 and irradiated syngeneic spleen cells on the detection of MAF-P were investigated、It was found that syngeneic spleen cells were an impor-tant factors for the assay of MAF-P of lymphoblasts but lymph nodes cells,and that the addition of both antigen and interleukin-2 can significantly increasethe number of MAF-P than antigen or interleukin-2 alone when the cells oflymph nodes were examined.