Antibodies as contraceptives: an experimental method in which sperm “is the virus” and which promises fewer side effects than hormonal ones
While the controversial race to find the male “birth control pill” continues, about female birth control methods is not all written, especially when those based on hormonal control can cause a series of notable side effects. In this sense, there is the study path of antibody-based contraceptive methods for women, a term that today may sound like something to us.
With the pandemic and the different methods of diagnosis and treatment, we may have become a little more familiar with the terminology related to our defenses (or we have remembered the biology classes at the institute). Antibodies are proteins that are made by certain cells of the body and that specifically mark what is considered foreign for elimination, and in this case the idea is that “the enemy” is the sperm.
An idea that is not new, but that required technological advance to develop
Hormones are substances that generally act as activators and / or inhibitors, so that very varied functions and aspects can be regulated, such as the storage of calcium in the bones, blood sugar and many more, also covering the sexual and reproductive sphere. But normaly a hormone does not have a unique effect, but they end up affecting several cycles or functions and increasing / decreasing the concentration of one of them is usually associated with more effects beyond what we are looking for, as can happen with the supply of exogenous testosterone seeking to increase muscle mass.
Hence, female contraceptives based on hormonal control may have associated side effects, unlike others like the condom. In addition, they are either invasive and even require interventions to place them (such as the IUD) or they depend on the memory of the user, such as the (daily) pill to work.
Looking for an alternative that does not lower the efficacy and that may have fewer side effects than hormonal control, research began on creating antibodies against sperm. In this sense, in two recent investigations they claim to have achieved encouraging results.
These are the works published in Science Translational Medicine and EBioMedicine, based on the action of an IgG on sperm (immunoglobulin G, a type of antibody). What they saw is that these antibodies recognized male sex cells joining them and coalescing, a common defense strategy in certain cases that in this case serves to immobilize the sperm.
In this way, by remaining immobile at some point in the female reproductive tract, male cells end up dying due to the inhospitable environment (very acidic), so that they are unable to fertilize the ovum. In work on MTS, the efficacy of antibodies when it came to finding human spermatozoa reached 99.9% according to what they show, yes, tested in sheep.
The other work has reached phase 1 of the tests, so it has already been tested in women. Nine women applied a vaginal film with antibodies for a week, noting that there were no changes in this acidic pH or infections and that the protection lasted about 24 hours.
The next step would be to test it on sexually active women and see if the film remains active (and for longer). Also exists the possibility of testing an antibody-based method applied to men in the form of gel for the penis, although they have not started working on it yet (at least this team).
The idea is that it is a topical method like a patch or gel or that it can be inserted into something like a vaginal ring and that it can even be bought without a prescription, according to Deborah J. Anderson (from the study published in EBioMEdicine a Wired). It is still early to ensure its effectiveness and safety and much remains to be tested, but it is an interesting way of study that with current technology could reach production and would not be expensive, according to the researchers.
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