Expression of affordable microbicides to combat the spread of HIV pandemic

Abstract

HIV prevalence is over 33 million worldwide with 68% of AIDS sufferers residing in sub-Saharan Africa (1). Currently the available HIV prevention tools are feasible but women cannot insist on these preventive measures due to social, cultural and economic issues. Therefore, there is a strong need to find appropriate HIV prevention measure that women can initiate, and microbicides are one such measure. Microbicides are products that are applied topically inside the vagina or rectum to prevent the transmission of HIV and other sexually transmitted diseases (2). Previous microbicide candidates have failed due to lack of safety and efficacy, new candidates will need to be appropriate for use (3). Some human chemokines, including RANTES (regulated upon activation, normal T expressed and secreted) show anti-HIV activity through their ability to block the HIV coreceptor CCR5 (Figure 1), and a number of N-terminally modified analogues of these proteins with much higher antiviral potency have been developed to generate potentially new low-cost preventatives or medicines (Figures 2 and 3) (3). These molecules have strong potential for use as microbicides, and it is imperative that they be produced in a cost effective manner. Plants offer an alternative method of cost effective production of protein therapeutics, and in this work, we test their effectiveness in expressing two RANTES analogues, 5P12 and 6P4 RANTES.