Fate of uptaken host proteins in Taenia solium and Taenia crassiceps cysticerci

Abstract

During the study of host-parasite relationships in taeniid parasite diseases, including cysticercosis and hydatidosis, reports have described the presence of host proteins in the cyst fluid and tissue of metacestodes. However, the fate or role of host elements inside the parasite remains barely explored. After the publication of genomes of four cestode species, it became clear that these organisms possess a limited biosynthetic capability. The initial goal of the present study was to determine if uptaken host proteins could be a source of essential amino acids for cysticerci. To track the utilization of uptaken proteins, we added metabolically labeled IgG-H and GFP-H to the culture medium of cysticerci. Incorporation of labeled amino acid was evaluated by fluorography in cysticerci extracts. Our results showed that the use of uptaken proteins by cysticerci as a source of amino acids appeared negligible. Exploring alternative fates for the host proteins, proteomic analysis of the protein matrix in calcareous corpuscles was carried out. Since does not contain calcareous corpuscles, proteomic analyses were performed in corpuscles of cysticerci. Our results demonstrated that host proteins represented approximately 70% of protein content in the calcareous corpuscles. The presence of the two major uptaken host proteins, namely albumin and IgG, was also demonstrated by Western blot in the matrix of corpuscles. Our findings strongly suggested that the uptake and disposal of host proteins involve calcareous corpuscles, expanding the physiological role of these mineral concretions to a far more important level than previously proposed.

Peripheral Taenia infection increases immunoglobulins in the central nervous system.

“…In our experiments, C57BL/6 mice were easily infected and mounted a significant humeral response to the parasite, as evidenced by the presence of T. crassiceps targeting antibodies in the serum. In addition, we were able to corroborate recent research, which has shown that the larvae themselves can take-up and release host protein, including IgG (Flores-Bautista et al, 2018). We found that even after 10 days in culture T. crassiceps larvae were still releasing host IgG and cytokines into the culture media.…”

“…To modulate the host immune response, Taenia larvae produce and excrete/secrete molecules which impair dendritic cell maturation and promote Th2-driving ability (Terrazas et al, 2010). Furthermore, the larvae can sequester and dispose of host immune proteins, including IgG (Flores-Bautista et al, 2018). The effect of these systemic parasite-induced host immune responses on the brain is still relatively uncertain.…”

Evolutionary Adaptations of Parasitic Flatworms to Different Oxygen Tensions

“…Some of the most abundant host proteins reported are serum albumin and immunoglobulins [ 87 , 190 ]. In the case of the former, the parasite can use it to maintain internal osmotic pressure, whereas the latter could help to prevent antigen exposure of the immune system [ 192 , 193 ]. Surprisingly, it has been reported that these organisms can incorporate various host antioxidant proteins to their antioxidant repertoire, such as the SOD, Prxs, and CAT isoforms [ 81 , 87 ].…”

Neuroimmunology of Common Parasitic Infections in Africa

“…The cysticerci can utilize several mechanisms to evade or downregulate both the humoral and cellular arms of the host immune response ( 180 ). Modulation of the humoral immune response occurs in several ways including by taking up host immunoglobulins (IgG, IgM, IgE and IgG) in the cyst tegument to mask parasite antigens ( 196 ) and by releasing molecules (such as taeniastatin), which inhibit the complement pathway ( 197 ). Taenia cysticerci also modulate cells of the immune system in multiple ways.…”