Generation of avirulent Leishmania parasites and induction of nitric oxide production in macrophages by using polyacrylic acid

Exp Parasitol. 2013 Mar;133(3):237-42. doi: 10.1016/j.exppara.2012.11.014. Epub 2012 Dec 10.


Polyacrylic acid (PAA) is one of the anionic synthetic polyelectrolytes and is used in various immunological and pharmaceutical applications. PAA has been used as adjuvant in veterinary vaccines, in particular. However, to our knowledge, there are no studies that document immunostimulant properties of PAA in Leishmania infection. The main aim of this study was to investigate the interaction of Leishmania parasites with PAA: the possible effects on the infectivity of Leishmania promastigotes; and, induction of nitric oxide (NO) production in macrophages in vitro. The cytotoxicity of PAA on both macrophages and Leishmania infantum promastigotes were determined by MTT assay. NO production in the macrophage culture supernatant was measured by the Griess method. A significant, dose-dependent and time-dependent decrease in the infection index was observed after PAA exposure. The value of this decrease was found to be between 93% and 100% for all concentration and time points. PAA (molecular weight (MW) 30, 100 kDa at 1mg/1h)-exposed parasites stimulate NO production significantly at 48 h post-infection (PI), when compared to the control. This study demonstrates that Leishmania parasites lost their virulence upon interaction with PAA, and this interaction induced NO production in infected macrophages. These results may have important implications in the development of anti-leishmanial vaccines and amelioration of immune response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylic Resins / pharmacology*
  • Adjuvants, Immunologic / pharmacology*
  • Animals
  • Cell Line
  • Dose-Response Relationship, Immunologic
  • Inhibitory Concentration 50
  • Leishmania infantum / drug effects*
  • Leishmania infantum / immunology
  • Leishmania infantum / metabolism
  • Leishmania infantum / pathogenicity
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Macrophages / parasitology*
  • Mice
  • Nitric Oxide / metabolism*
  • Time Factors
  • Virulence / drug effects


  • Acrylic Resins
  • Adjuvants, Immunologic
  • Nitric Oxide
  • carbopol 940