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Identifying polymorphic regions of the p190 protein from different Plasmodium falciparum strains by using specific T
1Department of Biology, F. Hoffmann-La Roche Ltd., Basle, Switzerland.
Abstract:
The p190 protein (also called MSA1 or MSP1) of the asexual blood stage forms of Plasmodium falciparum, a human malaria vaccine candidate, shows polymorphism between different isolates. Mice were immunized with p190-3, a recombinant protein which contains mostly conserved sequences derived from the p190 protein of the K1 parasite isolate. Proliferative T-cell responses of lymph node cells from immunized mice were assessed by stimulation in vitro with p190-3 or preparations of parasitized red blood cells (PRBC) containing the native protein. The p190-3-specific T cells from C57BL/6 mice consistently responded to some P. falciparum isolates, representing either the K1 or MAD20 serotype of p190, but not to other P. falciparum strains or to rodent malaria parasite-infected red blood cells. p190-3-specific T-cell responses from other mouse strains (BALB/c, C3H/He) did not distinguish between P. falciparum isolates. The polymorphic epitopes which were preferentially recognized by T cells from C57BL/6 mice were identified.
Insights
The Plasmodium falciparum p190 protein shows variations, impacting malaria vaccine development. T-cell responses in mice varied, identifying specific polymorphic epitopes for potential vaccine targets.
Area of Science:
- Immunology
- Parasitology
- Vaccine Development
Background:
- The p190 protein (also known as MSA1 or MSP1) from Plasmodium falciparum, a candidate for a human malaria vaccine, exhibits polymorphism across different parasite isolates.
- Understanding this protein's variability is crucial for designing effective malaria vaccines.
Purpose of the Study:
- To investigate the T-cell responses in mice immunized with a conserved region of the p190 protein.
- To identify specific polymorphic epitopes recognized by T cells from different mouse strains.
Main Methods:
- Mice were immunized with p190-3, a recombinant protein containing conserved sequences of P. falciparum p190.
- Proliferative T-cell responses were assessed in vitro using p190-3 and parasitized red blood cells (PRBC).
Main Results:
- T cells from C57BL/6 mice immunized with p190-3 responded to specific P. falciparum isolates (K1 or MAD20 serotypes) but not others.
- T-cell responses from BALB/c and C3H/He mice did not differentiate between P. falciparum isolates.
- Polymorphic epitopes preferentially recognized by C57BL/6 mouse T cells were identified.
Conclusions:
- The study identified specific polymorphic epitopes on the P. falciparum p190 protein that elicit differential T-cell responses in mice.
- These findings contribute to understanding immune responses against Plasmodium falciparum and inform the design of malaria vaccines targeting polymorphic antigens.