Duffy Blood Group System and the malaria adaptation process in humans
Relationship between genotypes of the Duffy blood groups and malarial infection in Keywords: Duffy blood-group system, ethnic groups, malaria, Plasmodium . by the Ethics Committee of the Medical Research Institute, School of Medicine. (1)Department of Hematology and Transfusion Medicine, Santa Casa Medical The Duffy blood group antigen serves not only as blood group antigen, but also. Interest in the global prevalence of the Duffy blood group variants is the transmission patterns of the neglected P. vivax malaria parasite.
In this same period, there was a considerable change in the transmission dynamics of malaria with concentrations of cases in specific municipalities.
Duffy blood group and malaria.
The number of municipalities at high risk, i. Sporadic autochthonic cases occurred in restricted focal areas. Often, infant mortality and morbidity are related to delay in establishing the correct diagnosis because of few clinical features.
This promotes the fertilization process producing zygotes that become invasive and grow and divide thus producing thousands of invasive sporozoites.
These migrate through the body and invade the salivary glands of female mosquitoes. Females, when they feed again, inoculate sporozoites in the blood of man, which rapidly migrate into hepatocytes and transform into trophozoites in the liver where they mature and divide to form thousands of merozoites.
The liver cells rupture releasing merozoites into the circulation, thereby initiating the blood cycle.
- Blood Groups and Red Cell Antigens [Internet].
- Navigation menu
In this phase, symptoms do not appear in the host. In the blood cycle, the merozoites develop into trophozoites forming schizonts. This stage of the cycle is associated with clinical symptoms.
After a period of asexual replication, some merozoites differentiate into gametocytes and become infective to mosquitoes. This distribution of Fy alleles suggests a selective advantage against P. This suggests that the relative frequencies of Fya and Fyb alleles in these populations may affect DBP vaccine efficacy.
Alternatively, DBP might remain the critical invasion ligand using alternate receptors for invasion. This novel ligand is anticipated to be involved in an alternate invasion pathway to DBP. Several in vitro assays have been used to study the interaction between the ligand domains of P. The region between cysteines 4 and 7 constitutes the major determinants for receptor recognition.
This mechanism of interaction suggests that dimerization is critical for, and driven by DARC binding, leading to the formation of a stable high-affinity complex composed of two DBP and two DARC molecules. Unlike the parasite ligands, ECD1 alone is not sufficient for chemokine binding.
Duffy antigen system - Wikipedia
A schematic for the stepwise assembly is shown at the bottom. Red blood cell invasion by Plasmodium vivax: Current opinion and future therapeutic prospects Chemokines and their receptors play a major role in facilitating the entry and transmission of intracellular pathogens, typical examples being in HIV and P. As such, they represent attractive targets for novel therapeutics. Methods that can prevent receptor—ligand interaction such as interfering with signaling pathways that are induced upon receptor activation and modification of receptor trafficking pathways can be explored to develop therapeutics.
This is mainly based on the evidence that some individuals are able to develop long-lasting and strain-transcending inhibitory antibodies against DBPII.
Notwithstanding, strategies targeting the other counterpart of this host—parasite interaction in the blood stream, that is DARC, have not been intensively explored.Malaria - causes, symptoms, diagnosis, treatment, pathology
To date, it is mostly established that P. Inhibition of this key interaction provides an excellent opportunity for parasite inhibition. This shows the importance of the DARC binding pocket and dimer formation for parasite survival. These molecules if targeted to the dimer interface and receptor-binding pocket, they could prevent dimer formation and consequently merozoite invasion.
Vaccines as a therapeutic tool Vaccines are considered the best means of control of infectious diseases. Over 70 different vaccines against P. The most promising vaccine against P. Unfortunately, the same advances have not been seen for vaccines against P. A series of P. These include the apical membrane antigen AMA-198 DBP, 99reticulocyte binding proteins,and merozoite surface proteins. Population genetics[ edit ] Differences in the racial distribution of the Duffy antigens were discovered inwhen it was found that the overwhelming majority of blacks had the erythrocyte phenotype Fy a-b-: Because the Duffy antigen is uncommon in those of Black African descent, the presence of this antigen has been used to detect genetic admixture.
Duffy antigen system
However, the study's authors point out that the Brazilian population has arisen from intermarriage between Portuguese, Black Africans, and Indians, which accounts for the presence of this mutation in a few members of Brazil's non-Caucasian groups.
Two of the three Afro-Brazilian test subjects that were found to have the mutation out of a total of 25 Afro-Brazilians tested were also related to one another, as one was a mother and the other her daughter.
Several of these have gone extinct. One surviving tribe—the Jarawas —live in three jungle areas of South Andaman and one jungle area in Middle Andaman. The area is endemic for malaria.
The causative species is Plasmodium falciparum: Blood grouping revealed an absence of both Fy a and Fy b antigens in two areas and a low prevalence in two others. The incidence of Fya among Ashkenazi Jews is 0. The incidence of Fyb is higher in both groups with frequencies of 0.