Sedimentary cycles in the Pennsylvanian strata; a reply

Abstract

<h3>Abstract</h3> <h3>Background</h3> The variant surface glycoprotein (VSG) of the African trypanosomes is the major membrane protein of the plasma membrane of the bloodstream stage of the parasite. African trypanosomiasis (sleeping sickness in humans and nagana in animals) is caused by the systemic infection of the host by several sub-species of the extracellular haemoflagellate protozoa under genus Trypanosoma. As a defense barrier against the host immune response, the entire surface of the bloodstream form of trypanosome is covered with densely packed molecules of VSG that determines the antigenic phenotype of the parasite. Variant surface glycoprotein has a C-terminal domain that is highly conserved in various species of trypanosomes. <h3>Methods</h3> The membrane bound VSG (VSGm) protein was prepared without denaturing the homologous region and by including numerous variable antigen types from <i>Trypanosoma brucei brucei</i> parasites. The purified VSGm native trypanosome protein was used to produce anti-VSGm immune sera in rabbits. The indirect immunofluorescence assay (IFA) was used to detect trypanosomes from mice blood, artificial culture media and cattle histological sections. <h3>Results</h3> The resultant immune sera were able to detect different strains and species of African trypanosomes from <i>in vivo</i> and <i>in situ</i> sources after immunostaining. Anti-VSGm antibodies also demonstrated a unique property to locate trypanosomes within the histological tissues even after the trypanosome’s morphology had been distorted. <h3>Conclusion</h3> The produced immune sera can be utilized for immunohistochemistry to detect <i>Trypanosoma species</i> in various fluids and tissues. <h3>Author summary</h3>