Restricted Genetic Diversity of Plasmodium Falciparum Major Merozoite Surface Protein 1 in Isolates From Colombia

Abstract

Abstract. The merozoite surface protein 1 (MSP-1) gene of Plasmodium falciparum encodes a major immune target under development as a malaria vaccine. In this study, we typed MSP-1 variable regions of parasites obtained from Buenaventura, Colombia. Four MSP-1 gene types were detected corresponding to prototype and recombinant K1 and MAD20 block 4 sequences. In contrast to variability within block 4, blocks 2, 6, and 16-17 corresponded exclusively to the MAD20 allelic type. Most (80%) blood samples contained multiple MSP-1 gene types. The presence of four MSP-1 variants within block 4 against a MAD20 background indicates that current P. falciparum populations in Buenaventura are derived from parasites expressing K1 and MAD20 alleles, some of which underwent two recombination events within or flanking block 4. Restricted MSP-1 diversity appears to be relatively stable in Buenaventura and suggests that selection has resulted in the dominance of the MAD20 type in most of the polymorphic blocks with the exception of block 4.

Genetic Diversity of Plasmodium falciparum Merozoite Surface Protein-1 Block 2 in Sites of Contrasting Altitudes and Malaria Endemicities in the Mount Cameroon Region

“…Other studies conducted in Colombia, southern Vietnam, the Brazilian Amazon, and some countries in Africa such as the Gambia, Nigeria, and Gabon reported the predominance of MAD20 and RO33 allelic variants. [36][37][38][39][40] These findings were attributed to a positive natural selection for these two allelic variants in P. falciparum. However, these results cannot explain the result obtained in this study with certainty because the high frequency of MAD 20 we observed is with respect to the frequency of K-1, which may be caused by poor annealing as explained.…”

“…Nevertheless, this finding corroborates findings of other studies. [36][37][38][39][40] The high frequency of the RO33 allelic variant in the region may be associated with reduced risk of clinical malaria. 41 Most patients who have this parasite allelic variant had high parasitemias ( 29,520 parasites/μL).…”

Genotipificación de Plasmodium falciparum por PCR múltiple por medio de los genes msp1, msp2 y glurp, en cuatro localidades de Colombia

“…En 1991, Snewin reportó la familia RO33 como el alelo predominante en msp1 (18). Sin embargo, todos los trabajos realizados posteriormente mostraron un predominio de la familia MAD20 con algunas diferencias muy sutiles en tamaño (12,(19)(20)(21), mientras que para msp2 se observó una frecuencia mayor de 90% para la familia del alelo IC con respecto a la FC (12,19). Son pocos los trabajos donde se evalúan simultáneamente los tres marcadores (msp1, msp2 y glurp); sin embargo, en ellos se ha podido mostrar el mayor aporte del gen glurp en cuanto a diversidad de los parásitos (22,23).…”

Longevity of Genotype-Specific Immune Responses to Plasmodium falciparum Merozoite Surface Protein 1 in Kenyan Children from Regions of Different Malaria Transmission Intensity

“…The block 16 section of the MSP1 gene, corresponding to T-cell epitopes in the MSP1 33 fragment, was then analyzed as previously described using allelerestricted polymerase chain reaction. 29 Details are provided in the Supplemental Information.…”