Newswise — A potent new inhibitor of HIV, derived from bananas, may open the door to new treatments to prevent sexual
transmission of HIV, according to a University of Michigan Medical
School study published this week.
Scientists have an emerging interest in lectins, naturally occurring chemicals in plants, because of
their ability to halt the chain of reaction that leads to a variety of
In laboratory tests, BanLec, the lectin found in bananas, was as potent as two current anti-HIV drugs. Based on the
findings published March 19 in the Journal of Biological Chemistry,
BanLec may become a less expensive new component of applied vaginal
microbicides, researchers say.
New ways of stopping the spread of the HIV are vitally needed. The rate of new infections of HIV is
outpacing the rate of new individuals getting anti-retroviral drugs by
2.5 to1, and at present it appears an effective vaccine is years away.
“HIV is still rampant in the U.S. and the explosion in poorer countries
continues to be a bad problem because of tremendous human suffering and
the cost of treating it,” says study senior author David Marvovitz,
M.D., professor of internal medicine at the U-M Medical School.
Although condom use is quite effective, condoms are most successful in
preventing infection if used consistently and correctly, which is often
not the case.
“That’s particularly true in developing countries where women have little control over sexual encounters so development of
a long-lasting, self-applied microbicide is very attractive,” Markovitz
Some of the most promising compounds for inhibiting vaginal and rectal HIV transmission are agents that block the virus prior to integration into its target cell.
The new study describes the complex actions of lectins and their ability to outsmart
the HIV virus. Lectins are sugar-binding proteins. They can identify
foreign invaders, like a virus, in the body, and attach themselves to
The U-M team discovered Ban Lec, the lectin in bananas, can inhibit HIV infection by binding to the sugar-rich HIV-1 envelope protein, gp120, and block its entry to the body.
Co-authors Erwin J. Goldstein, Ph.D., professor emeritus of biological chemistry
at U-M and Harry C. Winter, Ph.D., research assistant professor in
biological chemistry at U-M, developed the biopurification method to
isolate BanLec from bananas. Following their work, the U-M team
discovered BanLec is an effective anti-HIV lectin and is similar in
potency to T-20 and maraviroc, two anti-HIV drugs currently in clinical
Yet therapies using BanLec could be cheaper to create than current anti-retroviral medications which use synthetically produced
components, plus BanLec may provide a wider range of protection,
“The problem with some HIV drugs is that the virus can mutate and become resistant, but that’s much harder to do in
the presence of lectins,” says lead author Michael D. Swanson, a
doctoral student in the graduate program in immunology at the University
of Michigan Medical School.
“Lectins can bind to the sugars found on different spots of the HIV-1 envelope, and presumably it will take multiple mutations for the virus to get around them,” he says.
Swanson is developing a process to molecularly alter BanLec to enhance its
potential clinical utility. Clinical use is considered years away but
researchers believe it could be used alone or with other anti-HIV drugs.
Authors say even modest success could save millions of lives. Other
investigators have estimated that 20 percent coverage with a microbicide
that is only 60 percent effective against HIV may prevent up to 2.5
million HIV infections in three years.
Authors: Michael D. Swanson, Harry C. Winter, Irwin J. Goldstein and David M. Markovitz, all of U-M.
Reference: The Journal of Biological Chemistry, Vol. 285, Issue 12
Funding: National Institutes of Health, Burroughs Wellcome Fund
AIDS Info U.S. Department of Health and Human Services
U-M Medical School
U-M Department of Biological Chemistry