Trypanosoma rhodesiense: protection in mice by inoculations of homologous parasite products.

DUXBURY, RALPH E., SADUN, ELVIO H., SCHOENBECHLER, MAURICE J., AND STROUPE, DAVID A. 1974. Tryparwsomu rhodesiense: Protection in mice by inoculations of homologous parasite products. Experimental Parasitology 36, 70-76. Mice were immunized against Trypanosoma rhodesiense (Wellcome strain) with whole lyuphilized trypanosomes, with antigens produced by disrupting lyophilized trypanosomes under pressure, and with excretions and s#ecretions of the living parasites. The survival rate in groups of 40 mice inoculated with ‘disrupted trypansomes and challenged with the homologous strain was 48% with a soluble fraction, and 70% with a particulate fraction of the parasites. There was 95% survival after challenge in a group immunized with lyophilized trypanosomes; none of the controls survived. Results were essentially the same whether or not an aluminum hydroxide adjuvant was used. In subsequent experiments, complete promotion was obtained with either crude excretion-secretion (ES) antigens or the particulate fraction of the ES antigen, while 40% of the mice survived challenge after inoculations of ES supernatant fluid. Mice immunized with crude ES antigen failed to survive challenge with a heterologous strain, although their mean survival time was prolonged several days beyond that of the controls. INDEX DESCRIPTORS: Trypanosomu ddesiense; Immunization; Antigens, excretion and secretion; Lyophilization; Pressure cell fractionation; Mice.