Antibiotics build malaria immunity in mice

Anopheles albimanus mosquito
Credit: James Gathany
Provider: CDC

Prophylactic use of clindamycin or azithromycin in mice was found to protect against malaria infection, as well as provide long-term immunity against the disease.

Malaria sporozoites were injected into the blood of the mice.  The antibiotics did not slow the maturation of the parasites to merozoites in liver cells, but they did prevent the infection of red corpuscles in the blood.

However, the accumulation of parasites prompted the immune system to develop long-term immunity. The mice were not only injected with malaria during the 3-day administration of antibiotics, but 40 days, 4 months, and 6 months later.  All the animals were completely protected without any additional antibiotics.

The team of researchers, led by Steffen Borrmann, MD, from Heidelberg University Hospital in Germany, and Kai Matuschewski, PhD, from the Max Planck Institute for Infection Biology in Berlin, believe antibiotics could be used as safe and affordable vaccinations in areas with high malaria infection rates.

The researchers don’t know if the results will be the same in humans. Mosquito bites provide frequent but low doses of parasites. When this high-frequency, low-dose mode of infection was tested in mice, 30% were still protected.

For 85% that were still infected, the disease did not affect the brain, which usually indicates a favorable prognosis.

Clindamycin and azithromycin target the apicoplast of the parasites, which is required to penetrate other cells. Targeting the apicoplast still allows sporozoites to reproduce and the host to build immunity.

“Even if our results cannot be confirmed in a field trial, the apicoplast is a promising target for future medication,” said Dr Johannes Friesen, also of the Max Planck Institute for Infection Biology.

Their findings were published July 14 in Translational Medicine.