Table 1.
Groups of virulence factors from T. brucei, T. cruzi and Leishmania spp., with different functions on vertebrate and invertebrate hosts.
| Virulence factor | Host | Function | Reference |
|---|---|---|---|
| T. brucei | |||
| Variant surface glycoprotein (VSG) | Vertebrate | Adaptive immune response evasion | (Horn, 2014; Pays et al., 2014) |
| Insect | Reduce the peritrophic matrix barrier function and help the parasite establish infection of the gut | (Aksoy et al., 2016) | |
| Procyclin | Vertebrate | Not present | |
| Insect | Protection of the parasite surface against digestive enzymes and metacyclicogenesis | (Acosta-Serrano et al., 2001b; McConville et al., 2002) | |
| T. cruzi | |||
| Glycoinositolphospholipids (GIPLs) | Vertebrate | Downregulation of immunomodulatory components on macrophages and dendritic cells | (Brodskyn et al., 2002) |
| Insect | Adhesion to the insect’s gut | (Garcia et al., 2007; Nogueira et al., 2007) | |
| Glycoprotein gp63 | Vertebrate | No clear function detected on vertebrate host cell stages (trypomastigote and amastigote) | (Cuevas et al., 2003) |
| Insect | Metalloprotease activity in the insect stage | (Cuevas et al., 2003) | |
| Adhesion to the insect’s gut | (Rebello et al., 2019) | ||
| Cruzipain | Vertebrate | Cell invasion and immune evasion | (McKerrow et al., 2006) |
| Insect | Adhesion to the insect’s gut | (Uehara et al., 2012) | |
| Trans-sialidases (TS) | Vertebrate | Transfer of sialic acid residues | (Schenkman et al., 1994) |
| Host cell adhesion and evasion | |||
| Insect | Protection from the gut glycolytic enzymes | (Schenkman et al., 1994) | |
| Adhesion to the insect’s gut | |||
| Mucins | Vertebrate | Cell adhesion | (Almeida et al., 1999; Acosta-Serrano et al., 2001a) |
| Immunomodulation of host defense | |||
| Complement system evasion | |||
| Insect | TcSMUG S | (Mortara et al., 1992; Herreros-Cabello et al., 2020) | |
| Protection against proteases in the insect’s intestines | |||
| TcSMUG L Adhesion to the insect’s gut | (Gonzalez et al., 2013) | ||
| Leishmania spp. | |||
| Lipophosphoglycans (LPG) | Vertebrate | Complement system evasion | (Forestier et al., 2015) |
| Adhesion to macrophages | (Cunningham, 2002) | ||
| Impairment of phagosome maturation and acidification | (Lodge et al., 2006; Borges et al., 2021) | ||
| Insect | Protection from insect’s digestive enzymes | (Schlein et al., 1990) | |
| Adhesion to the insect’s gut | (Sacks et al., 2000; Ilg, 2001) | ||
| Proteophosphoglycans (PPG) | Vertebrate | Adhesion to macrophages | (Piani et al., 1999) |
| Modulation of macrophages at the early stage of infection | |||
| Insect | Protection from insect’s digestive enzymes | (Schlein et al., 1990) | |
| Involved with the production of the Promastigote Secretory Gel (PSG), that may be responsible for the regurgitation of the parasites by the sand flies during the blood feeding | (Franco et al., 2012; Giraud et al., 2019) | ||
| Glycoprotein gp63 | Vertebrate | Complement system evasion | (Isnard et al., 2012; Shao et al., 2019) |
| Macrophage binding and entry | (Olivier et al., 2012) | ||
| Downregulation of cellular compounds aimed to parasite elimination | (Podinovskaia and Descoteaux, 2015) | ||
| Insect | Adhesion to the insect’s gut | (D’Avila-Levy et al., 2006a; Pereira et al., 2009; Soares et al., 2017) | |
| Parasite protection against the insect’s defense mechanisms | (D’Avila-Levy et al., 2014) |