The present invention relates to trypanosomatid histones in substantially isolated form for use as a protective antigen against trypanosomatic infection. These histones may be either isolated from the corresponding parasite or be produced by means of recombinant DNA techniques. For the latter purpose the invention also provides genes encoding histones and derivatives of the genes like other nucleic acids and gene products like peptides and proteins. The invention further provides diagnostic tests, pharmaceutical compositions and vaccines comprising the usual excipients and/or adjuvants and at least one histone, a histone encoding gene or a derivative thereof.