Diversity and expression of Plasmodium falciparum var gene in severe and mild malaria cases from Central India

Genotyping var Gene DBL1α Domain of Severe and Non-severe Plasmodium falciparum Patients

This study analysed the genetic diversity of DBL1α domain of Plasmodium falciparum var gene in severe and non-severe malaria patients from Delhi and Mewat in Northern India. After confirming P. falciparum infection, samples were cloned and the var gene DBL1α domain was sequenced. Out of 377 cloned DBL sequences, 194 were from severe samples and 183 from non-severe samples. Proportion of DBL1α sequences belonging to groups 1, 4 and 5 were significantly higher in severe isolates as compared to non-severe isolates-group 1 (4.1% vs 1.09%, P = 0.0333), group 4 (69.58% vs 74.31%, P < 0.0001), and group 5 (19.58% vs 10.38%, P < 0.0001). Conversely, higher proportion of group 2 was observed in non-severe isolates (0% vs 3.82%, P = 0.0350). Highest diversity was seen in PoLV4 motif of severe and non-severe isolates and like other DBL1α sequences reported from several geographical areas (Africa, Americas, Asia, and Oceania). A total of 247 DBL1α domain haplotypes were found in this study where 139 (56.27%) haplotypes are novel and not reported from India till date. These findings could aid in developing effective malaria interventions, including vaccine and drug targets, by understanding the existing antigenic diversity and vulnerabilities in the parasite's genetic makeup.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01200-1.

The malarial blood transcriptome: translational applications

The blood transcriptome of malaria patients has been used extensively to elucidate the pathophysiological mechanisms and host immune responses to disease, identify candidate diagnostic and prognostic biomarkers, and reveal new therapeutic targets for drug discovery. This review gives a high-level overview of the three main translational applications of these studies (diagnostics, prognostics, and therapeutics) by summarising recent literature and outlining the main limitations and future directions of each application. It highlights the need for consistent and accurate definitions of disease states and subject groups and discusses how prognostic studies must distinguish clearly between analyses that attempt to predict future disease states and those which attempt to discriminate between current disease states (classification). Lastly it examines how many promising therapeutics fail due to the choice of imperfect animal models for pre-clinical testing and lack of appropriate validation studies in humans, and how future transcriptional studies may be utilised to overcome some of these limitations.

PfEMP1 and var genes - Still of key importance in Plasmodium falciparum malaria pathogenesis and immunity

The most severe form of malaria, caused by infection with Plasmodium falciparum parasites, continues to be an important cause of human suffering and poverty. The P. falciparum erythrocyte membrane protein 1 (PfEMP1) family of clonally variant antigens, which mediates the adhesion of infected erythrocytes to the vascular endothelium in various tissues and organs, is a central component of the pathogenesis of the disease and a key target of the acquired immune response to malaria. Much new knowledge has accumulated since we published a systematic overview of the PfEMP1 family almost ten years ago. In this chapter, we therefore aim to summarize research progress since 2015 on the structure, function, regulation etc. of this key protein family of arguably the most important human parasite. Recent insights regarding PfEMP1-specific immune responses and PfEMP1-specific vaccination against malaria, as well as an outlook for the coming years are also covered.

A systematic review on genetic diversity of var gene DBL1α domain from different geographical regions in Plasmodium falciparum isolates

Background The major variant surface antigen (VSA) in Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) encoded by var gene family has an important role in cytoadhesion/sequestration and rosetting by adhesion of uninfected erythrocytes to infected erythrocytes leading to disease severity. DBL1α domain in the PfEMP-1, protein is crucial in the cytoadhesion phenomena in P. falciparum infections and this review aims to analyse the genetic diversity of DBL1α domain sequences in PfEMP-1 from different geographical regions globally. Methods All available DBL1α sequence data was reviewed by using the electronic database PubMed, ResearchGate, Google, Google scholar, MEDLINE with the following Keywords-Plasmodium falciparum", "var gene", "DBL1α", "field isolate", "diversity", "polymorphism", "Africa", "America", "Asia" and "Caribbean" from different geographical regions across the world. Results A total of 240 studies were identified initially but only 20 studies qualified for this systematic review. The overall ratio of distinct sequences DBL1α domain was 24.62/1167 the highest in African region (33.59/766 isolates) and lowest in South America (5.6/215 isolates). In the 18 included studies, the presence of distinct DBL1α sequences was the highest in Oceania 55.32% (1186/2144) followed by Africa (38.43%), Asia (22.45%) and South America (16.48%), though the sample size in Oceania was comparatively smaller to that of Africa and South America. Conclusion This review highlights the ratio and percentage of distinct sequences of DBL1α domain of var gene in different geographical regions giving an idea of the existing diversity prevalent in this potential vaccine target gene which may contribute to designing the preventive measures towards disease severity.