Consider making poetic justice. Mosquitoes succumb to the parasite that causes malaria just as people do. But many are able to fight infection. the researchers now understand how the immune system of the insect parasite conquers the knowledge that could be used to fight against the spread of malaria in humans.
An insect immune system does not work like ours. It is not designed to suit specific threats over time, but it can still learn to fight infections. This is demonstrated by the fact that many mosquitoes are capable of fighting Plasmodium , the single-celled microbe that causes malaria. But researchers do not know exactly how the insects are.
To find out, vector biologist Janneth Rodrigues and colleagues at the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, fed two groups of mice crawling mosquitoes blood with Plasmodium . One group was infected, but the other placed in a room too hot for Plasmodium to grow-not. Seven days later, the researchers fed two groups again Plasmodium by mouse infected blood. The infected group was 10 times better kill Plasmodium .
The mosquito appears to have two weapons in its arsenal. One is granulocytes. The team found three times as many of these immune cells in the group they preinfected in the uninfected group. When granulocytes detect a foreign body in the blood of a mosquito, they can either kill themselves or report another cell to come to work.
But granulocytes do not show up to save the day without help, says Rodrigues. His team suspects that the bacteria are also involved in Plasmodium anti-because the parasite weakens the walls of the mosquito gut response and intestinal bacteria shed in the body parts they are not usually found. It probably triggers more "baby immune cells" to start turning into granulocytes, says vector biologist and co-author Carolina Barillas-Mury, priming the immune system to fight Plasmodium invaders.
to test if that were the case, the team repeated the experiment but gave mosquitoes antibiotics depleting their intestinal bacteria. This time the preinfected group did not increase its granulocyte count and like many of its members died as those in the control group. "Prevention of malaria is probably actually an indirect effect of the system preventing the bacteria being in the wrong place," said Barillas-Mury.
To see if they could create a kind of vaccine against malaria mosquitoes, the researchers injected some bugs with the serum of mosquitoes exposed to Plasmodium , but they removed the granulocyte serum. Mosquitoes that received saline were less intense Plasmodium infections and have 40% less often when they were fed malaria-infected mouse blood, the team reports in the 10 September issue of Science . This shows that there is a factor in the blood of mosquitoes exposed that ramps up production of granulocytes, said Barillas-Mury. If researchers could mimic this factor and place it in nets or spray on insects, they could immunize insects against infections and make poor vectors of malaria, she said.
Vector biologist Marcelo Jacobs-Lorena of Johns Hopkins University in Baltimore, Maryland, agrees that understanding the biology of mosquito resistance could have practical applications. "Since the mosquito is an essential link for transmission to occur, which is important if we want to eliminate malaria in the mosquito."
This article has been corrected to better reflect the nuanced differences between the insect and the human immune system. Furthermore, a sentence on mortality and reproduction of infected mosquitoes was deleted because the information came from other studies.
0 Komentar