Downard Laboratory WWW site


This laboratory was the first to demonstrate that specific protein interactions could be preserved on conventional MALDI targets during the ionisation of non-binding components providing an indirect means with which to probe protein interactions. The approach was later renamed "intensity fading" by others.

First reported in 1999, it was subsequently applied in the same year to a biological mixture in the form antigenicity studies of the influenza virus. It has since been applied to antibody interactions with gel-recovered antigens (2006, 2007) and in time-course experiments (2008) to measure the relative rates of binding. A computer algorithm (PRISM) to interpret such MALDI spectral pairs has also been developed (2007). The approach has also been applied to study the binding of anti-viral inhibitor drugs including the relative affinity of that binding (2012-today).  (see references below)




Downard KM (2016) Indirect Study of Non-Covalent Protein Complexes by MALDI Mass Spectrometry. Origins, Advantages and Applications of the "Intensity-Fading" Approach, Mass Spectrom. Rev., 35: 559-573.


Downard KM (2007) Softly. Softly. Detection of Protein Complexes by Matrix-assisted Laser Desorption Ionization Mass Spectrometry, in Mass Spectrometry of Protein Interactions, Downard KM ed., John Wiley & Sons, New Jersey U.S.A., pp. 25-43.


Downard KM (2013) An Immunoproteomics Approach to Screen the Antigenicity of the Influenza Virus, in Methods in Molecular Biology: Immunoproteomics (Ed. S. Twine & K. Fulton), Vol. 1061, Ch. 8, pg 141-153.


Downard KM, Morrissey B, Schwahn AB (2009) Mass Spectrometry Analysis of the Influenza Virus, Mass Spectrom. Rev. 28: 35-49.


Downard K.M. (2000) Contributions of Mass Spectrometry to Structural Immunology, J. Mass Spectrom. 35: 493-503.


Original references (from 1999):


Kiselar JG, Downard KM (1999) Direct Identification of Protein Epitopes by Mass Spectrometry without Immobilization of Antibody and Isolation of Antibody-Peptide Complexes, Anal. Chem. 17: 1792-1801.

Kiselar JG, Downard KM (1999) Antigenic Surveillance of the Influenza Virus by Mass Spectrometry, Biochemistry 43: 14185-14191.


Kiselar J.G., Downard K.M. (2000) Preservation and Detection of Specific Antibody-Peptide Complexes by Matrix-assisted Laser Desorption Ionization Mass Spectrometry, J. Am. Soc Mass Spectrom. 11: 746-750.


Ho JWK, Morrissey B, Downard KM (2007) A Computer Algorithm for the Identification of Protein Interactions from the Spectra of Masses (PRISM), J. Am. Soc. Mass Spectrom., 18, 563– 566. 


Application with Gel-Based Antigen Separation:

Morrissey B, Downard KM (2006) A Proteomics Approach to Survey the Antigenicity of the Influenza Virus by Mass Spectrometry, Proteomics 6: 2034-2041.


Other Protein-Antibody Studies:

Schwahn AB, Downard KM (2009) Antigenicity of a type A influenza virus through a comparison of hemagglutination inhibition and mass spectrometry immunoassays, J. Immunoassay Immunochem. 30: 245-261.

Morrissey B, Streamer M, Downard KM (2007) Antigenic Characterisation of H3N2 subtypes of the Influenza Virus by Mass Spectrometry, J. Virol. Methods 145: 106-114.


Time-Course Study:


Morrissey B, Downard KM (2008) Kinetics of Antigen-Antibody Interactions Employing a MALDI Mass Spectrometry Immunoassay, Anal. Chem. 80: 7720-7726.


Protein-Drug Applications:

Lu R, Muller P, Downard KM (2015) Molecular Basis of Influenza Hemaglutinin Inhibition with an Entry-Blocker Peptide by Computational Docking and Mass Spectrometry, Antiviral Chem. Chemother. 24: 109-117.

Muller P, Downard KM (2015) Catechins Inhibit Influenza Neuraminidase and its Molecular Basis with Mass Spectrometry, J. Pharmaceut. Biomed. Anal. 111: 222-230.

Swaminathan K, Muller P, Downard KM (2014) Substituent Effects on the Binding of Natural Product Anthocyanidin Inhibitors to Influenza Neuraminidase with Mass Spectrometry, Anal. Chim. Acta 828: 61-69.

Nasser Z, Swaminathan K, Muller P, Downard KM (2013) in-vitro Inhibition of the Influenza virus with the Anti-Viral Inhibitor Arbidol by a Proteomics based Approach with Mass Spectrometry, Antiviral Res. 100: 399-406.

Swaminathan K, Dyason JC, Maggioni A, von Itzstein M, Downard KM (2013) Binding of a Natural Anthocyanin Inhibitor to Influenza Neuraminidase by Mass Spectrometry, Anal. Bio. Chem. 405: 6563-6572.

Swaminathan K, Downard KM (2012) Anti-Viral Inhibitor Binding to Influenza Neuraminidase by MALDI Mass Spectrometry, Anal. Chem. 84: 3725-3730.

Additional Relevant Articles:


Downard K.M. (2000) Contributions of Mass Spectrometry to Structural Immunology, J. Mass Spectrom. 35: 493-503.

Mackun K., Downard KM (2003) Strategy for the Study of Protein-Protein Interactions of Gel- Separated Proteins by Mass Spectrometry, Anal. Biochem. 318: 60-70.


Kiselar JG, Downard KM (2001) Preservation of Specific Immune Complexes by Matrix-assisted Laser Desorption Ionization Mass Spectrometry, in Advances in Mass Spectrometry, Volume 15, E. Gelphi (ed.) John Wiley & Sons, Chichester, UK.