Injection instead of castration

Ivan Sychev, Geektimes based on Science News: DNA ‘vaccine' sterilizes mice, could lead to one-shot birth control 

In 2014, 2.7 million cats and dogs were euthanized in US kennels. To control reproduction, ovaries or testicles are usually removed – these operations are expensive, they require anesthesia and veterinarian time, which is why there are so many stray animals in cities.

Biologists from the California Institute of Technology in Pasadena are working on a cheap and fast method of sterilization. They tested a DNA vaccine on mice that causes the animal's muscle tissues to produce antibodies to block gonadotropins, whose function is to regulate the work of the sex glands.

A separate type of reproduction control involves the use of the animal's own immune system. The introduction of exogenous reproductive proteins causes the body to produce antibodies against its own sex hormones and proteins. For immunocontraceptives, such targets are used as the shiny zone of the egg – the coating of the egg with which sperm binds during fertilization, and the reproductive hormones testosterone and estrogen through the suppression of the hormone that secretes gonadotropin. Such vaccines need to be repeated every few years.

Bruce Hay's team is working on a vaccine that affects animal DNA and causes muscle tissue to produce antibodies for a long time – up to ten years. Muscles begin to produce gonadotropin, that is, they use one of the two classical approaches to controlling reproduction using the immune system. Scientists injected mice of both sexes with a vaccine packed in an inactive virus, and two months later they reported the results. All the mice turned out to be completely infertile. The team of scientists suggests that the same method can be used to produce antibodies against the shiny zone of the egg. In this case, the spermatozoa cannot fertilize the egg, because they do not reach it.

"It took a two-month break to allow the muscles to start producing enough antibodies. In the future, we will try to use other systems to avoid such a delay," explains Bruce Hay.

Scientists claim that the effect of their vaccine on hormones does not change the behavior of the animal. If the DNA vaccine works on cats and dogs in the same way as on mice, then in the future developments can be used to create long-acting contraceptives for humans.

Article by Li et al. Vectored antibody gene delivery mediates long-term contraception published in open access in the journal Current Biology – VM.Portal "Eternal youth" http://vechnayamolodost.ru

06.10.2015