I studied P. Vivax's DBPII protein under Dr. Sai Lata De at the University of South Florida. This was a formative foray into everything molecular biology, including mammilian cell cultures, transfection, transformation, PCR, flow cytometry, and basic immunologic assays like ELISAs and western blots.
My project dealt with characterizing the effects of different variables on the immunigenicity of DBPII in both wild type and inbred mouse models. This research was inspired by previous work by Dr. Francis Ntumngia and others, and centers around DBPII's highly conserved nature and its ability to elicit high-titre inhibitory antibodies.
The reason for DBPII's highly conserved nature can be attributed to its function in the P. vivax parasite. P. vivax preferentially invades reticulocytes (young red blood cells) via binding between PvDBP and the reticulocyte's Duffy antigen receptor for chemokines (DARC). Region II of the DBP protein (DBPII) contains critical residues for heterotetramer formation when P. vivax invades the reticulocyte. Because of these critical residues, DBPII is a natural vaccine target.
Inhibitory antibodies are a subset of antibodies that block a protein's active site, therefore inhibiting its function. This makes them especially desirable for vaccine design, as they can block critical antigens on a given pathogen. To evaluate the degree to which anti-DBPII mouse antibodies blocked DBPII-DARC heterotetramer formation, we used an in vitro inhibition assay. Cos7 cells were transiently transfected with DPII_GFP and were incubated in anti-DBPII mouse serum. The cells were then incubated in human erythrocytes to evaluate neutralization of the DBPII expressed on the surface of Cos7 cells. When functional inhibition of the mouse sera sample is lower, more "rosettes" (Cos7 cell covered in erythrocytes, shown below) will be observed.