Characterization of epitopes on a variant surface glycoprotein from Trypanosoma congolense by six monoclonal antibodies

Susceptibility and resistance to Trypanosoma congolense infections

We have put emphasis on recent findings in experimental Trypanosoma congolense infections in highly susceptible BALB/c and relatively resistant C57Bl/6 mice. Based on various analyses, it has been shown that a major difference in resistance to T. congolense infections is expressed early in infection at the macrophage level. A novel plastic-adherent Thy1.2(+) suppressor lymphocyte, which in absolute synergy with a Thy 1.2(-) cell exerts its suppression via interleukin-10 and interferon-gamma opens up an exciting new field of research.

Trypanosoma brucei contains two RNA polymerase II largest subunit genes with an altered C-terminal domain

We have identified and cloned four trypanosomal RNA polymerase largest subunit genes. Here, we present the molecular analysis of two genes, Trp4.8 and Trp5.9. The sequence of these genes shows that they are almost identical to each other and indicates that they encode the largest subunit of RNA polymerase II. Both genes contain a C-terminal extension that is clearly distinct from that of other eukaryotic RNA polymerase II genes, because it lacks the common tandemly repeated heptapeptide sequence and is rich in acidic amino acids. It shares many potential phosphorylation sites, however, with the C-terminal extension of other eukaryotic RNA polymerase II large subunits. The presence of two RNA polymerase II loci suggests that a fourth RNA polymerase could be formed. Interestingly, the fourth gene is only found in species exhibiting antigenic variation.

[African trypanosomes: parasites with protective mechanisms]

African trypanosomes have developed protective mechanisms in order to escape from their hosts' immune attack. New cell surface antigens become sequentially expressed during a chronic infection providing the parasites continuously with immunologically altered faces. The trypanosomal genome contains a considerable repertoire of different genes coding for the surface antigens; they become separately activated and expressed by a variety of novel molecular processes. In addition, the trypanosomal cell surface participates in the protection of the parasites against non-immune defense mechanisms of the host.