Globally, efforts to advance malaria control and prevention have focused on two main areas of research: (1) Finding vaccine candidates to immunize populations and prevent posterior infections, (2) Finding novel and unknown molecules and fields where remain interesting questions unsolved. The intracellular malaria parasite Plasmodium falciparum organization, particular organelles as endoplasmic reticulum and domains of the infected erythrocytes affected by changes and modifications to evading the immune response, are important basic studies. P. falciparum export virulent proteins and built a complex cell modified to transport proteins traversing three concentric membranes or cellular compartments as; plasmatic membrane of the parasite, parasitophorous vacuolar membrane, and plasmatic membrane of infected erythrocyte getting alterations for own benefit and survive. Released merozoites ending the intraerythrocytic cycle after 48 hours of the invaded cell cause symptoms of disease, physiopathology and are highly immunogenic. Our group prepared monoclonal antibodies to study the event that occurs when merozoites egress from their host, this immunogen inoculated to generate the antibodies recognizing proteins localized in the Protein export compartment (PEC). PEC is a domain of the endoplasmic reticulum that could be associated with egress merozoites. However, before studying this event, it is necessary to know the identity of proteins localized in PEC. One of the proteins localized is named Pf68kDa, which is the first resident protein of PEC, identified and is recognized by a monoclonal antibody, mAb7.
We show identification of the 68 kDa antigen of P. falciparum. Recently works identified Pf68 kDa as two proteins by different methodological strategies, and the same mAb7: the first protein identified as a homolog of HSP70/BiP/GRP78, named PfHSP70-2 by affinity chromatography and mass spectrometry, and the second protein identified, Plasmodium WD40 repeat-containing protein-1 (PlasWD40-1) identified from a cDNA expression library screened with Mab7. From the plaques analyzed, two positive clones ultimately were identified. Thus, Mab7 not only recognizes PfHSP70-2 but also recognizes a protein expressed by the cloned DNA fragment (MK618679). Now, We know more about the nature of PEC, and not much about PlasWD40 and Pf68kDa is not precisely known. It is unknown if a common epitope between PfHSP70-2 and PlasWD40-1 is a coincidence or both proteins are interacting or regulating functions to directing activities in the endoplasmic reticulum to exporting proteins to the plasmatic membrane of P. falciparum-infected erythrocytes. The target from these two proteins and common epitope or each one separately, could to proposing new possible therapeutic strategies against malaria.
Dr. Gladys Thalia Cortés obtained her Ph.D. in Biotechnology from Science Faculty at Universidad Nacional de Colombia (2020), Master Science degree at Universidad Javeriana (1995), and specialization training in immunochemistry and cellular immunology at National Institute of Health from Tokyo (Japan, 1986). Her primary field is Bacteriologist. Her studies in cell Biology of Plasmodium began with profesor Winograd E. at the Instituto Nacional de Salud (Bogotá), Wiser M., as consultor and co-investigator from Tulane University. She continued searching the cell Biology of Plasmodium at National University of Colombia (2005- ) in collaboration with Biofísica y Biología de membranas, Dr. Camacho M. at Centro Internacional de Física, Public Health Department at Faculty of Medicine. Her group published recently aspects related to, identification of antigen named Pf68 kDaPlasmodium falciparum resident protein of and specialized domain of the endoplasmic reticulum, or Plasmodium export compartment (PEC), PfHSP70-2 and (2020) and Plasmodium WD40 repeat-containing protein-1 (PlasWD40-1) identified from a cDNA expression library screened with Mab7 (2021), both proteins hypothesized as share a common epitope recognized by a same monoclonal antibody, mAb7 (doctoral thesis, 2019); besides, a study of release merozoites process from its host by photoconversion fluorescent compound to electron microscopy (2011), and characterization of proteins localized to a subcellular compartment associated with an alternate secretory pathway of the malaria parasite (2003). Currently, she is a Ph.D. researcher and professor of the Department of public health Faculty of Medicine at Universidad Nacional de Colombia.