386. Molecular Validation of Putative Antimicrobial Peptides for Improved Human Immunodeficency Virus Diagnostics via HIV Protein P24
Session: Poster Abstract Session: HIV Epidemiology: Screening and Testing - Outpatient to Inpatient
Thursday, October 8, 2015
Room: Poster Hall

Background:

The Human Immunodeficiency Virus-1 (HIV-1) is responsible for causing Acquired Immunodeficiency Syndrome (AIDS), and to date remains a pandemic. More than 40 million people are infected globally, with 60% of the infected people residing in Sub-Saharan Africa. Earlier detection translates into earlier treatment, which ensures improved quality of life. However, difficulties remain in the field of HIV diagnostics. The p24 antigen detection tests are preferred due to its ability to decrease the window period. The current p24 diagnostic assay displays great insensitivity, due to the p24 antibody produced by the body, binding to the C-terminal domain of the p24 antigen. This interaction obstructs the detection, the basis of the current p24 test. Using in silico approaches, novel antimicrobial peptides (AMP) were identified which bind to the N-terminal, instead of the C-terminal domain (antibody binding pocket) of the p24 antigen (Provisional patent). This is important because if the p24 antibody binds to the C-terminal, the unoccupied N-terminal domain would provide a binding pocket for the AMP. Successful conjugation of nanoparticles to the positively validated AMPs, can lead to the development of a diagnostic lateral flow device (LFD).

Methods:

In silico site-directed mutagenesis and docking studies were completed to identify additional AMPs that bind the N-terminal domain of the p24 antigen, with increased binding affinity. A preliminary study sought to design a LFD containing the identified AMPs to test HIV positive sera. P24 recombinant protein expression was performed, and binding studies were completed to validate interactions between the AMPs and the p24 antigen.

Results:

In silico studies predicted 9 AMPs which could be used to bind the p24 antigen for HIV diagnostics

 - Description: C:\Users\Monray\Desktop\Molecular validation of putative antimicrobial peptides for improved Human Immunodeficiency Virus diagnostics via HIV protein p24_files\image001.png

        Figure 1: Binding of AMP1 (turquoise) to the N-terminal domain of the p24 antigen (green)

A sensitive LFD was able to detect HIV within HIV positive sera. Successful p24 recombinant protein expression was achieved and binding interactions between the p24 and AMPs were molecularly validated

 

Conclusion:

Binding interaction between AMPs and p24 antigen is validated. Subsequently a sensitive lateral flow device could be developed which sensitively detects HIV in positive HIV sera.

 

Monray Williams, BSc (honours), Marius Tincho, MSc, Mervin Meyer, PhD and Ashley Pretorius, PhD, Biotechnology, University of the Western Cape, Cape Town, South Africa

Disclosures:

M. Williams, None

M. Tincho, None

M. Meyer, None

A. Pretorius, None

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