[Purification and isolation of different stages of Plasmodium vivax, P. falciparum and P. berghei].

The present paper reported the results of purification and isolation of different stages of P. vivax, P. falciparum and P. berghei by Percoll gradient centrifugation after removal of leukocytes (WBCs) by passing the blood suspension through CF-11 cellulose columns. 94.7% and 75.4% of WBCs from the patients' blood of vivax malaria and the mice blood infected with P. berghei respectively were removed with no alteration of the parasite density and the malaria stage ratio after the cellulose filtration. The densities of the uninfected and the infected erythrocytes with different stages of 3 species of malaria parasites were determined by isopycnic centrifugation on multi continuous gradients of Percoll. The mean densities (kg/L) of schizonts, trophozoites, ring form and uninfected cells were approximately 1.059, 1.072, 1.096 and 1.099 in P. vivax; 1.070, 1.079, 1.10 and 1.10, gametocytes 1.085 in P. falciparum; 1.059, 1.062, 1.103 and 1.104 in P. berghei, respectively. Based on these values, 3 different density gradients of Percoll were devised to separate erythrocytes infected with the more mature stages (trophozoites and schizonts) from ring forms and uninfected cells. By these method, it is possible to obtain high purified parasites of 93.5% from blood with starting parasitaemias of 0.8% in P. vivax, 100% from 2.3% in P. falciparum and 93.0% from 30.6% in P. berghei, being raised by 113.8, 43.4 and 2.0 times respectively.