ABSTRACT
Although the human malaria parasite Plasmodium vivax is closely related to Asian Old World monkey malaria parasites, there are no reports of P. vivax infections in macaques. In this study, we compared the infectivity of P. vivax and Plasmodium cynomolgi in Japanese macaques (Macaca fuscata) and in cynomolgus macaques (Macaca fascicularis). The Japanese macaques were highly susceptible to P. cynomolgi but not to P. vivax, whereas cynomolgus macaques showed mild/limited P. cynomolgi infection and were, also, not susceptible to P. vivax. Serotyping and amino acid sequence comparison of erythrocyte surface Duffy antigen/receptor for chemokines (DARC) indicate that the Japanese macaque DARC sequence is nearly identical to that of rhesus (Macaca mulatta) and cynomolgus macaques. This suggests that the macaques share a common mechanism for preventing P. vivax infection. Comparison of amino acid sequences of the Duffy-binding-like (DBL) domain from several different Plasmodium species suggests that P. vivax DBLs will not bind to macaque DARCs, which can explain the lack of P. vivax infectivity. The DBL sequence analyses also suggest that P. cynomolgi DBLs may target Japanese macaque erythrocytes through a DARC-independent interaction.
Subject(s)
Antigens, Protozoan/genetics , Macaca/parasitology , Malaria, Vivax/veterinary , Malaria/veterinary , Monkey Diseases/parasitology , Plasmodium cynomolgi/pathogenicity , Plasmodium vivax/pathogenicity , Protozoan Proteins/genetics , Receptors, Cell Surface/genetics , Amino Acid Sequence , Animals , Antigens, Protozoan/chemistry , Disease Susceptibility , Humans , Macaca/blood , Macaca/genetics , Macaca/immunology , Macaca fascicularis/blood , Macaca fascicularis/genetics , Macaca fascicularis/immunology , Macaca mulatta/blood , Macaca mulatta/genetics , Macaca mulatta/immunology , Malaria/parasitology , Malaria, Vivax/parasitology , Molecular Sequence Data , Plasmodium cynomolgi/genetics , Plasmodium vivax/genetics , Protozoan Proteins/chemistry , Receptors, Cell Surface/chemistry , Serotyping , Species SpecificityABSTRACT
BACKGROUND: Differential agglutination procedures and flow cytometric analysis have been used for detecting and quantitating mixed cell populations. For more than 20 years in our laboratory, a differential agglutination method using the coil planet centrifuge and polyclonal anti-A or anti-B has been used. However, it is now difficult to obtain polyclonal antisera, and it is unknown whether MoAbs can take the place of polyclonal antisera in the coil planet centrifuge method. STUDY DESIGN AND METHODS: Polyclonal antisera and MoAbs were filled into a coil first and then unsensitized packed RBCs from ABO variants, and from chimeras and patients after ABO-incompatible HPC trans- plantation (HPCT) were loaded. After centrifugation, agglutinated and nonagglutinated RBCs were collected, hemolyzed, and subjected to colorimetric analysis for quantitation. RESULTS: ABO chimerism was quantitatively estimated with detection as low as 0.1 percent. ABO variants showed different patterns of agglutination and nonagglutination. The reconstitution status of the erythroid lineage after ABO-mismatched HPCT was also quantitatively evaluated. CONCLUSION: A modified coil planet centrifuge method is established by which ABO chimerism could quantitatively be analyzed and ABO variants identified to the same degree of accuracy as the other differential methods and flow cytometry. The monitoring of ABO chimerism might also help the diagnosis of early relapse or rejection after ABO incompatible HPCT.
