Intramuscular immunization of mice with irradiated Plasmodium berghei sporozoites. Enhancement of protection with albumin
Kramer, L.D.; Vanderberg, J.P.
American Journal of Tropical Medicine and Hygiene 24(6 Pt 1): 913-916
1975
ISSN/ISBN: 0002-9637 PMID: 1106231 Document Number: 84813
Mice were immunized with 100,000 Plasmodium berghei sporozoites irradiated with 15,000 rad followed by 4 boosters at weekly intervals of 10,000 irradiated sporozoites each, by the intravenous, subcutaneous or intramuscular routes. 6 to 9 days after the final booster, the mice were challenged with 10,000 non-irradiated sporozoites. With intramuscular immunization the plain inoculum protected 4 of 38 mice; but if the inoculum contained 3.0% bovine serum albumin it protected 10 of 24, thus showing that albumin enhances the protective effect of irradiated sporozoites when injected intramuscularly. All mice immunized intravenously were completely protected. All mice immunized subcutaneously became infected after challenge. Albumin may induce motility in the immunizing sporozoites, thus permitting them to enter blood vessels more readily.