RESUMO
Cultivation of pleomorphic Trypanosoma brucei strains was introduced in 1996 when matrix dependence of growth of natural isolates was recognized. Semisolid agarose or liquid methylcellulose are currently used and here we provide optimized protocols for these culture methods and for transfection of pleomorphic strains. Although more laborious than standard liquid culture, culture of native pleomorphic strains is important for a number of research questions including differentiation, virulence, tissue tropism, and regulated metabolism. Some subclones of pleomorphic strains have acquired matrix independence upon passage in culture but maintained a pleomorphic phenotype. It appears that matrix dependence and pleomorphism are not tightly linked traits, yet phenotypes have to be verified before choosing one of these subclones for given experiments. Based on direct comparisons, we give recommendations for pleomorphic strain selection and culture conditions that guarantee truly pleomorphic and differentiation competent Trypanosoma brucei.