Toxin Found In Bee Venom Kills HIV Virus

Wellness Update - - Health News -

ST. LOUIS, Mo. – Re­searchers at Washington Univer­sity School of Medicine in St. Louis have found that Nanopar­ti­cles car­ry­ing a toxin found in bee venom can de­stroy hu­man im­mun­od­e­fi­ciency virus (HIV) while leav­ing sur­round­ing cells un­harmed. The find­ing is an im­por­tant step to­ward de­vel­op­ing a vagi­nal gel that may pre­vent the spread of HIV, the virus that causes AIDS.

“Our hope is that in places where HIV is run­ning ram­pant, peo­ple could use this gel as a pre­ven­tive mea­sure to stop the ini­tial in­fec­tion,” says Joshua L. Hood, MD, PhD, a re­search in­struc­tor in medicine at Washington Univer­sity School of Medicine.

Bee venom con­tains a po­tent toxin called melit­tin that can poke holes in the pro­tec­tive en­ve­lope that sur­rounds HIV, and other viruses. Large amounts of free melit­tin can cause a lot of dam­age. In ad­di­tion to anti-vi­ral ther­apy, the re­searchers found melit­tin-loaded nanopar­ti­cles to be ef­fec­tive in killing tu­mor cells.

The new study shows melit­tin loaded onto th­ese nanopar­ti­cles does not harm nor­mal cells. That’s be­cause Hood added pro­tec­tive bumpers to the nanopar­ti­cle sur­face. When the nanopar­ti­cles come into con­tact with nor­mal cells, which are much larger in size, the par­ti­cles sim­ply bounce off. HIV, on the other hand, is even smaller than the nanopar­ti­cle, so HIV fits be­tween the bumpers and makes con­tact with the sur­face of the nanopar­ti­cle, where the bee toxin awaits.

“Melit­tin on the nanopar­ti­cles fuses with the vi­ral en­ve­lope,” Hood says. “The melit­tin forms lit­tle pore-like at­tack com­plexes and rup­tures the en­ve­lope, strip­ping it off the virus.”

Ac­cord­ing to Hood, an ad­van­tage of this ap­proach is that the nanopar­ti­cle at­tacks an es­sen­tial part of the virus’ struc­ture. In con­trast, most anti-HIV drugs in­hibit the virus’s abil­ity to repli­cate. But this anti-repli­ca­tion strat­egy does noth­ing to stop ini­tial in­fec­tion, and some strains of the virus have found ways around th­ese drugs and re­pro­duce any­way.

“We are at­tack­ing an in­her­ent phys­i­cal prop­erty of HIV,” Hood says. “The­o­ret­i­cally, there isn’t any way for the virus to adapt to that. The virus has to have a pro­tec­tive coat, a dou­ble-lay­ered mem­brane that cov­ers the virus.”

Be­yond preven­tion in the form of a vagi­nal gel, Hood also sees po­ten­tial for us­ing nanopar­ti­cles with melit­tin as ther­apy for ex­ist­ing HIV in­fec­tions, es­pe­cially those that are drug-re­sis­tant. The nanopar­ti­cles could be in­jected in­tra­venously and, in the­ory, would be able to clear HIV from the blood stream.

“The ba­sic par­ti­cle that we are us­ing in th­ese ex­per­i­ments was devel­oped many years ago as an ar­ti­fi­cial blood prod­uct,” Hood says. “It didn’t work very well for de­liv­er­ing oxy­gen, but it cir­cu­lates safely in the body and gives us a nice plat­form that we can adapt to fight dif­fer­ent kinds of in­fec­tions.”

Since melit­tin at­tacks dou­ble-lay­ered mem­branes in­dis­crim­i­nately, this con­cept is not lim­ited to HIV. Many viruses, in­clud­ing hep­ati­tis B and C, rely on the same kind of pro­tec­tive en­ve­lope and would be vul­ner­a­ble to melit­tin-loaded nanopar­ti­cles.

While this par­tic­u­lar pa­per does not ad­dress con­tra­cep­tion, Hood says the gel eas­ily could be adapted to tar­get sperm as well as HIV. But in some cases peo­ple may only want the HIV pro­tec­tion.

“We also are look­ing at this for cou­ples where only one of the part­ners has HIV, and they want to have a baby,” Hood says. “Th­ese par­ti­cles by them­selves are ac­tu­ally very safe for sperm, for the same rea­son they are safe for vagi­nal cells.”

While this work was done in cells in a lab­o­ra­tory en­vi­ron­ment, Hood and his col­leagues say the nanopar­ti­cles are easy to man­u­fac­ture in large enough quan­ti­ties to sup­ply them for fu­ture clin­i­cal tri­als.

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