The potential of plant systems to break the HIV-TB link

Abstract

Tuberculosis (TB) and human immunodeficiency virus (HIV) can place a major burden on healthcare systems and constitute the main challenges of diagnostic and therapeutic programmes. Infection with HIV is the most common cause of Mycobacterium tuberculosis (Mtb), which can accelerate the risk of latent TB reactivation by 20-fold. Similarly, TB is considered the most relevant factor predisposing individuals to HIV infection. Thus, both pathogens can augment one another in a synergetic manner, accelerating the failure of immunological functions and resulting in subsequent death in the absence of treatment. Synergistic approaches involving the treatment of HIV as a tool to combat TB and vice versa are thus required in regions with a high burden of HIV and TB infection. In this context, plant systems are considered a promising approach for combatting HIV and TB in a resource-limited setting because plant-made drugs can be produced efficiently and inexpensively in developing countries and could be shared by the available agricultural infrastructure without the expensive requirement needed for cold chain storage and transportation. Moreover, the use of natural products from medicinal plants can eliminate the concerns associated with antiretroviral therapy (ART) and anti-TB therapy (ATT), including drug interactions, drug-related toxicity and multidrug resistance. In this review, we highlight the potential of plant system as a promising approach for the production of relevant pharmaceuticals for HIV and TB treatment. However, in the cases of HIV and TB, none of the plant-made pharmaceuticals have been approved for clinical use. Limitations in reaching these goals are discussed.

Keywords: global health; infectious diseases; medicinal plants; molecular pharming; pharmaceuticals.

Figure 1

schematic presentation of HIV life cycle. (a) HIV attachment to CD4 antigen and a specific chemokine receptor. (b) Virus fusion with the cell membrane and entry of the virion core into the cell. (c) Release of viral RNA and core proteins and their transport into the nucleus. (d) Formation of double‐stranded DNA by reverse transcriptase. (e) Transport of double‐stranded viral DNA into the cell nucleus. (f) Integration of viral DNA into cellular DNA. (g) Synthesis of viral RNA by RNA polymerase II and production of RNA transcripts with shorter spliced RNA (h) and full‐length genomic RNA (j). (h) Transport of shorter spliced RNAs to the cytoplasm and the production of several viral proteins that are then modified in the Golgi apparatus of the cell (i). (j) Transport of full‐length genomic RNAs into the cytoplasm (k). (l) Assembly, budding and maturation of new virions. (m) Release of mature virus.