A Survey for a Trypanocidal Factor in Primate Sera

Abstract

The sera of 21 different species of primates were surveyed for the presence of a trypanocidal factor to a monomorphic human serum-sensitive clone of Trypanosoma brucei gambiense (T.b.g.); human, gorilla, baboon (2 species), and the mandrill were found to contain this factor. The factor in all the sera is in the high density lipoprotein (HDL) fraction, and has similar modes of biological action. It has been shown that the human and gorilla trypanocidal factor share cross-reactive antigenic epitopes, but do not share similar cross-reactive epitopes with the baboon and mandrill factor. There was no relationship between the presence or absence of this factor and the primate's position on the phylogenetic tree. In addition, there was also no obvious correlation between the animals' preferred diet, and the presence or absence of trypanocidal activity. The evidence to date suggests that only African ground-dwelling primates that live in tsetse endemic areas contain the trypanocidal factor. It is assumed that this factor is involved in resistance of these primates to T.b.b. We believe that the host has developed trypanocidal substances as a result of selective evolutionary pressure by the African trypanosomes.

The apolipoprotein L family of programmed cell death and immunity genes rapidly evolved in primates at discrete sites of host–pathogen interactions

“…We found intact APOL1 in only human and gorilla, which is consistent with the serum resistance of these species to trypanosomes (Seed et al 1990;Lugli et al 2004;Poelvoorde et al 2004). The only other primate species that have shown serum resistance are certain baboons, mangabeys, and mandrills.…”

“…By far, the best-studied family member is APOL1, which encodes a trypanolytic factor in humans and gorillas, lysing pathogenic Trypanosoma brucei subspecies during bloodstream infections (Vanhamme et al 2003). Most other primates lack APOL1 and do not have trypanolytic activity, except for certain species of baboons, mandrills, and mangabeys (Seed et al 1990;Lugli et al 2004). APOL1 is unique among APOL proteins because it can be secreted outside the cell, presumably due to its N-terminal signal peptide.…”

Blood incubation infectivity test (BIIT): usefulness as compared to the SRAPCR in the identification of <i>Trypanosoma brucei rhodesiense</i> in animal reservoirs

“…The original blood incubation infectivity test has been criticised for its level of inaccuracy for many years as there are clearly a number of factors in serum that can result in variations in the results of the BIIT (Seed et al, 1990). As such, the control serum to determine the survival of the parasite away from human serum was chosen as horse, as these animals are known to be particularly susceptible to T. brucei sl and it was assumed that their serum would have no or little adverse affects on the parasites (Kihurani et al, 1994).…”

In Vitro Generation of Human High-Density-Lipoprotein-Resistant Trypanosoma brucei brucei

“…This innate protection is provided by trypanolytic activity found in normal human blood and also in the blood of most apes and Old World monkeys (24,31,46,56). The trypanosome lytic factor (TLF) is a minor subfraction of heterogeneous human high-density lipoprotein (HDL) particles containing apoliprotein A-I (apoA-I), apoliprotein A-II (apoA-II), apolipoprotein L-I (apoL-I), and haptoglobin-related protein (Hpr) (23,29,38,45,48,49,50,51,52,57,59,60,64,65,69).…”

“…The mechanism of TLF killing of T. b. brucei has been controversial. Initially, Hpr was suggested to be the active component in TLF, based on the evolution of the Hpr gene during primate evolution, the correlation of the trypanolytic activity in primate sera, and the presence of the Hpr gene in T. b. brucei-resistant animals (33,56,59). More recently, highly purified, recombinant apoL-I has been shown to have trypanosome-killing activity (45,69).…”