Overcoming resistance with designer immunotoxins

Area of Science:

• Parasitology
• Immunology
• Drug Discovery

Background:

• Normal human serum contains apolipoprotein L-I (apoL-I), crucial for lysing African trypanosomes.
• Human African Trypanosomiasis is caused by resistant trypanosome forms expressing apoL-I-neutralizing proteins.
• Current treatments for human African trypanosomiasis face challenges due to parasite resistance.

Purpose of the Study:

• To develop a novel immunotoxin targeting human serum-resistant trypanosomes.
• To engineer a mutant apoL-I conjugated to a nanobody for enhanced trypanosome targeting.
• To evaluate the therapeutic efficacy of the engineered immunotoxin in a mouse model.

Main Methods:

• Construction of a mutant apolipoprotein L-I (apoL-I).
• Conjugation of the mutant apoL-I to a nanobody targeting the trypanosome variant surface glycoprotein.
• Treatment of mice infected with both serum-resistant and serum-sensitive trypanosome strains.

Main Results:

• The engineered immunotoxin demonstrated both alleviating and curative effects in mice.
• Successful treatment of both chronic and acute infections was observed.
• The therapy was effective against both normal human serum-resistant and -sensitive trypanosome strains.

Conclusions:

• The engineered apoL-I-nanobody immunotoxin is a promising therapeutic strategy against human African trypanosomiasis.
• This approach overcomes parasite resistance mechanisms mediated by serum resistance-associated protein.
• Further development could lead to effective treatments for this neglected tropical disease.