STUDIES ON THE SUSCEPTIBILITY OF DIFFERENT INBRED STRAINS OF MICE TO PLASMODIUM YOELII / 第二军医大学学报

ABSTRACT

Albino mice are animals commonly used for experimental studies on malaria. It is very necessary to find a strain of mice most susceptible to the P. yoelii-A. stephensi system. Thus, experimental studies were carried out on 9 inbred strains of mice (SMMC/A, SMMC/B, SMMC/C, SMMC/D, C57BL, C3H, 615, SMMC/C?615, Jin-bai N0.1)and one outbred strain (Kuming strain) by means of both sporozoite-and blood-induced infections. The results obtained are summarized as follows.(1) Although all of the 10 strains became patent after blood inoculation, producing an infection rate of 100%, yet there exists a very significant difference in susceptibility to sporozoite-induced infection between different strains of the test mice. Six strains of them including SMMC/C were found most susceptible to infection, reaching 100% patency. (2) As compared with others, the SMMC/C strain had the shortest prepatent period (4.22?0.43 days) with the least difference in the time of first appearance of the parasites in the circulating blood amongst individuals of this strain. (3) When the anopheline mosquitoes fed on each of the 10 strains, SMMC/C strain was found most infective to the vector with the gland infection rate of 73.20?5.9%. From all the results obtained, with A. stephensi as its transmitter, out of the 10 strains the SMMC/C is considered the most susceptible and suitable animal model for experimental studies on rodent malariaThe observations made on the SMMC/C mice showed the following results. (1) Five thousand sporozoites per mouse intraporitoneally inoculated were required to ensure an infection rate of 100%. (2) More than 90% of the mice became infected following intraporitoneal inoculation of the sporozoites which were preserved in the glucose normal saline mixed with albino rat serum (11 in ratio) either at 3-5? or at 23-25? up to 24 hrs after dissection from the mosquitose. (3) Ambient temperature of 18-20℃ was most favourable to development of the parasite in the mice. (4) Young mice were most susceptible to the sporozoite-induced infection, the adult being second to them.All the experimental results obtained are discussed.