Intracellular antigens (microtubule-associated protein copurified with glycosomal enzymes)--possible vaccines against trypanosomiasis.

African trypanosomes are motile unicellular eukaryotes that can cause diseases such as sleeping sickness in humans and nagana in animals, debilitating millions of people and livestock. All members of the Trypanosomatidae family contain subpellicular microtubules cross-linked to each other and to the plasma membrane by unique trypanosomal microtubule-associated proteins (MAPs). These MAPs may serve as specific intracellular target sites for therapeutic attack against trypanosomiasis. A trypanosomal MAP (p52) copurifies with two glycosomal enzymes (aldolase and GAPDH) on phosphocellulose columns. Rats and mice vaccinated with antigen preparation p52 containing the glycosomal enzymes were protected against a potentially fatal Trypanosoma brucei infection. Sera of protected animals caused in vitro aggregation of trypanosomes, and immunoelectron microscopy of these aggregates located antibodies in the cytoplasm of the trypanosomes.