Polymorphism in the HASPB repeat region of East African Leishmania donovani strains.
OBJECTIVE
Visceral leishmaniasis (VL) caused by Leishmania donovani is a major health problem in Ethiopia. Parasites in disparate regions are transmitted by different vectors, and cluster in distinctive genotypes. Recently isolated strains from VL and HIV-VL co-infected patients in north and south Ethiopia were characterized as part of a longitudinal study on VL transmission.


RESULTS
Sixty-three L. donovani strains were examined by polymerase chain reaction (PCR) targeting three regions: internal transcribed spacer 1 (ITS1), cysteine protease B (cpb), and HASPB (k26). ITS1- and cpb--PCR identified these strains as L. donovani. Interestingly, the k26--PCR amplicon size varied depending on the patient's geographic origin. Most strains from northwestern Ethiopia (36/40) produced a 290 bp product with a minority (4/40) giving a 410 bp amplicon. All of the latter strains were isolated from patients with HIV-VL co-infections, while the former group contained both VL and HIV-VL co-infected patients. Almost all the strains (20/23) from southwestern Ethiopia produced a 450 bp amplicon with smaller products (290 or 360 bp) only observed for three strains. Sudanese strains produced amplicons identical (290 bp) to those found in northwestern Ethiopia; while Kenyan strains gave larger PCR products (500 and 650 bp). High-resolution melt (HRM) analysis distinguished the different PCR products. Sequence analysis showed that the k26 repeat region in L. donovani is comprised of polymorphic 13 and 14 amino acid motifs. The 13 amino acid peptide motifs, prevalent in L. donovani, are rare in L. infantum. The number and order of the repeats in L. donovani varies between geographic regions.


CONCLUSIONS
HASPB repeat region (k26) shows considerable polymorphism among L. donovani strains from different regions in East Africa. This should be taken into account when designing diagnostic assays and vaccines based on this antigen.
Department of Microbiology and Molecular Genetics, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Arie
A
Zackay
Abdelmajeed
A
Nasereddin
Yegnasew
Y
Takele
Dagimawie
D
Tadesse
Workagegnehu
W
Hailu
Zewdu
Z
Hurissa
Sisay
S
Yifru
Teklu
T
Weldegebreal
Ermias
E
Diro
Aysheshm
A
Kassahun
Asrat
A
Hailu
Charles L
CL
Jaffe
D000953:Antigens, Protozoan / Q000235:genetics*; D057056:Cysteine Proteases / Q000235:genetics; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005002:Ethiopia; D006801:Humans; D007893:Leishmania donovani / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA
D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D021903:DNA, Ribosomal Spacer; C401884:HASPB protein, Leishmania; D015800:Protozoan Proteins; D057056:Cysteine Proteases