Open AccessImmunofluorescence Assay for Detection of Human Metapneumovirus-Specific Antibodies by Use of Baculovirus-Expressed Fusion Protein
Author(s) -
Nobuhisa Ishiguro,
Takashi Ebihara,
Rika Endo,
Xiaoming Ma,
Ryo Shirotsuki,
Susumu Ochiai,
Hiroaki Ishiko,
Hídeaki Kikuta
Publication year - 2005
Publication title -
clinical and vaccine immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.649
H-Index - 77
eISSN - 1556-6811
pISSN - 1556-679X
DOI - 10.1128/cdli.12.1.202-205.2005
Subject(s) - human metapneumovirus , virology , titer , antibody , biology , immunofluorescence , fusion protein , metapneumovirus , antibody titer , recombinant dna , microbiology and biotechnology , virus , immunology , respiratory system , respiratory tract infections , gene , biochemistry , anatomy
Human metapneumovirus (hMPV) has recently been identified as an etiological agent of acute respiratory infections. The hMPV fusion (F) protein has been indicated to be a major antigenic determinant that mediates effective neutralization and protection against hMPV infection. We developed a new immunofluorescence assay (IFA) using Trichoplusia ni (Tn5) insect cells infected with a recombinant baculovirus-expressing hMPV F protein (Bac-F IFA). A total of 200 serum samples from Japanese people 1 month to 41 years old were tested for immunoglobulin G antibodies to hMPV F protein by Bac-F IFA. The results were compared with those of the conventional IFA based on hMPV-infected LLC-MK2 cells (hMPV IFA). The titers obtained by the two IFAs correlated well (correlation coefficient of 0.88), and the concordance of seroreactivities between the two IFAs was 91% (kappa=0.76). For 192 of the 200 serum samples, the titers obtained by the Bac-F IFA were equal to or higher than those obtained by the hMPV IFA. These results indicated that the Bac-F IFA was more sensitive than the hMPV IFA and that the majority of the antibodies detected by the hMPV IFA reacted with the hMPV F protein. The Bac-F IFA is a more reliable, sensitive, and specific method for the detection of hMPV antibodies than is the hMPV IFA.