The histidine-rich protein is the major component of the knob-like
protrusions detected on the membrane of both human and monkey erythrocytes
infected with Plasmodium falciparum (SA Luse & LH Miller 1971, M
Hommel et al. 1982, F Ardeshir et al. 1987. The knobs on the red blood cell
surface are generally associated with strain pathogenicity and virulence.
Isolates collected from naturally infected patients are consistently of
knobby phenotype (Hommel et al.) and knobless lines were reported to be
less virulent in monkey models (S Langreth & E Peterson 1985, T Fandeur et