Why is it necessary to fertilize an egg with 200 million sperm?

category:Hot
 Why is it necessary to fertilize an egg with 200 million sperm?


Womens innate immune system kills most sperm cells in semen, reducing hundreds of millions of sperm to hundreds of them entering the fallopian tube. When an egg is fertilized by more than one sperm and fails to develop, the defensive response eliminates excess sperm.

Because sperm is coated with sialic acid-rich polysaccharides and the innate immune system uses sialic acid to distinguish between human cells and invaders, researchers initially speculated that polysaccharides might interact with innate immune cells of neutrophils. But the neutrophils they tested did not seem to see any difference between sperm with and without sialic acid. Meanwhile, researchers observed sialic acid-binding receptors called Siglecs on endometrial cells. In solution, these endometrial receptors bind to the whole sperm. According to the researchers, this would help sperm suppress immune responses. Or it could be a way for uterine cells to remove defective sperm. In the immune system, this receptor class helps cells to recognize sialic acid molecules as egos, in which case the cells identified as egos will not be attacked. Source: Deep Science and Technology News Source: Three-inch Sun Responsible Editor: Luo Chongwei_NB12082

Because sperm is coated with sialic acid-rich polysaccharides and the innate immune system uses sialic acid to distinguish between human cells and invaders, researchers initially speculated that polysaccharides might interact with innate immune cells of neutrophils. But the neutrophils they tested did not seem to see any difference between sperm with and without sialic acid.