Table 1.
List of protozoans and the associated diseases for which in vitro models are published.
Table 2.
Recent advances in the field of in vitro culture systems for Cryptosporidium parvum.
Fig 1.
Schematic illustration of organoids using parasite surface antigen SAG1.
Schematic illustration showing immunofluorescent staining of bovine (a–c) and porcine (d–f) intestinal organoids using parasite surface antigen SAG1 (Alexa Fluor 488—green), F-actin (rhodamine—red), and nuclei (DAPI—blue). Organoids were incubated with 106 T. gondii RH strain tachyzoites for 1 hour at 37°C, embedded in Matrigel and incubated for a further 24 hours at 37°C. SAG1 in green shows intraluminal parasites (a, d, a’, and d’), parasite rosettes indicating replication (b, e, b’, and e’), and white arrows point to intracellular parasites (c, c’, c”, f, f’, and f”). Scale bars represent 20 μm in panels a, b, d, and e and 30 μm in panels c and f. 400x magnification. Open-access image reused from [48].
Fig 2.
In vitro hepatic spheroid formation.
Schematic diagram showing hepatic spheroid formation in the 3D Cellulosponge in vitro system for P. cynomolgi parasites. (A) Spheroids of uninfected hepatocytes. (B) Spheroids of hepatocytes pre-infected using sporozoites. (C) Successful reinfection and completion of life cycle in erythrocytes. (D) Potential models for drug evaluation in liver stages are shown. Open-access image reused from [52]. RBC, red blood cell.
Fig 3.
Illustration showing variations of a 3D liver infection model of E. histolytica infection in vitro.
Hepatic cells (red), amoebae (green), and COL-I (collagen-I, blue) are shown. (A) Virulent trophozoites added to the medium adhere to the LSEC in the 3D liver model but not in the setup without LSECs (No LSEC) seen in transversal view of reconstructed 3D images. (B) Incubation of liver model with trophozoites for 1.5 and 3 hours. (C) Incubation of the distinct setups with trophozoites for 3 hours. (B–E) Percentage of amoeba crossing the LSEC layer or COL-I matrix. Infection of the liver model (D) with various E. histolytica strains in the presence of glucose/galactose for 1.5 hours and similarly, infection of the setup without LSEC (F) for 3 hours. (F) Parasite invasion rate at 3 hours for the model and the no LSEC setup showing 0% invasion at the LSEC and 100% at the hepatocyte layer z-position, respectively. Red bars indicate mean values. (G–I) Parasite interaction with the LSEC layer of the 3D liver model at 3 hours. In panels (G) and (H), the arrows point to LSEC detaching in the presence of trophozoites. In panel (I), the asterisks point out vesicular structures localized inside the trophozoites labeled with hepatic cell staining. Open-access image reused from [77]. LSEC, liver sinusoidal endothelial cell.