Human proteins incorporated into tick-borne encephalitis virus revealed by in situ proximity ligation.

JSON

Ikebuchi R, Isaac AW, Yoshii K, Doulabi EM, Löf L, Azimi A, Chen L, Fredolini C, Gallini R, Landegren U, Kamali-Moghaddam M

Biochem. Biophys. Res. Commun. 525 (3) 714-719 [2020-05-07; online 2020-03-03]

Host proteins incorporated into virus particles have been reported to contribute to infectivity and tissue-tropism. This incorporation of host proteins is expected to be variable among viral particles, however, protein analysis at single-virus levels has been challenging. We have developed a method to detect host proteins incorporated on the surface of virions using the in situ proximity ligation assay (isPLA) with rolling circle amplification (RCA), employing oligonucleotide-conjugated antibody pairs. The technique allows highly selective and sensitive antibody-based detection of viral and host proteins on the surface of individual virions. We detected recombinant noninfectious sub-viral particles (SVPs) of tick-borne encephalitis virus (TBEV) immobilized in microtiter wells as fluorescent particles detected by regular fluorescence microscopy. Counting the particles in the images enabled us to estimate individual TBEV-SVP counts in different samples. Using isPLA we detected individual calnexin-, CD9-, CD81-, CD29- and CD59-positive SVPs among the viral particles. Our data suggests that a diversity of host proteins may be incorporated into TEBV, illustrating that isPLA with digital counting enables single-virus analysis of host protein incorporation.

PubMed 32139125

DOI 10.1016/j.bbrc.2020.02.143

Crossref 10.1016/j.bbrc.2020.02.143

pii: S0006-291X(20)30432-0