Earlier studies have primarily looked at the role of defensin in bacterial diseases. The new analysis examines their role as natural antiviral substances.

Theresa Chang and colleagues at Mount Sinai School of Medicine showed how alpha-defensin-1 inhibits HIV infection in white blood cells (CD4+ T cells). The innate immune system has been shown to have anti-HIV activity with which the body attempts to protect itself from HIV infection.

"Understanding the mechanism by which natural host defensins work against viruses such as HIV will give us insight into understanding the host virus relationship,” says Theresa Chang, PhD and Assistant Professor of Medicine. "This study suggests defensins may be quite important not only to HIV but to other viral infections.”

The researchers show that alpha-defensin-1 fights HIV in two different ways. With a low watery portion of blood that remains when blood cells are removed, alpha-defensin-1 directly inactivates HIV virus. When serum is present, alpha-defensin-1 acts on vulnerable cells to block HIV infection. The authors also show that the way alpha-defensin-1 blocks HIV infection in cells is by inhibiting a CD4+ cell-signalling molecule called PKC.

The findings offer insight into the function of alpha-defensin-1 the virus and the cell and the innate immunity against HIV. In addition, this study provides a basis to develop defensin-like drugs for prevention of HIV and for therapeutic use in patients who are already infected.

MEDICA.de; Source: Mount Sinai School of Medicine