Effect on rosette formation of antibodies to duffy binding-like 1 alpha domain of Plasmodium Falciparum erythrocyte membrane protein 1
Saiwaew S., Moll K., Leitgeb AM., Piaraksa N., Sila P., Patthanacharoern N., Phetsouvanh R., Charunwatthana P., Uthaisin C., Dondorp AM., Wahlgren M., Chotivanich K.
© 2016, SEAMEO TROPMED Network. All rights reserved. The highly conserved Duffy binding-like domain 1 a (DBL1α) of Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP1) is central to cytoadherence properties of infected erythrocytes. Antibodies against DBL1α in plasma from African children in high malaria transmission settings disrupt rosettes (clumping of infected to uninfected erythrocytes) and may possibly protect against severe malaria. This phenomenon has not been established in low transmission settings in Asia. Using ELISA reactivity towards a recombinant DBL1α was examined in 53 plasma samples from patients with uncomplicated falciparum malaria in Thailand compared to 13 negative plasma controls and related to disruption of rosette formation. Plasma reactivity to DBL1α was stronger in patient samples compared to non-immune controls (p < 0.0001). Overall, antibody concentrations against DBL1α did not correlate with rosette disruption of P. falciparum strain FCR3S1.2 (r = -0.06; p = 0.72), but plasma containing antibodies to DBL1α did disrupt rosette formation by > 15% in 52% and ≥ 50% in 10% of samples. There was no correlation between presence of antibodies and patient’s age. In conclusion, patients with uncomplicated falciparum malaria produce antibodies against DBL1α domain of PfEMP1, resulting in partial disruption of rosette formation, similar to the results obtained in African children. This might have a protective effect on disease severity.