Interleukin-4 is needed for the infection of monocytes by human cytomegalovirus.
OBJECTIVE
We studied the ability of human cytomegalovirus (HCMV) to infect peripheral blood mononuclear cells (PBMC) pretreated with or without Th2-cytokine interleukin-4 (IL-4) in vitro.


METHODS
Adherent cells and nonadherent cells were obtained from PBMC. We inoculated these cells with HCMV at concentrations ranging from 0 to 10 ng/ml of IL-4. Immediate-early antigen-1 (IE-1) and glycoprotein H (gH) mRNAs were detected using the reverse-transcription polymerase chain reaction.


RESULTS
IE-1 and gH mRNAs could be detected in monocytes pretreated with IL-4. In contrast, no IE-1 mRNA was detected in monocytes pretreated without IL-4. We tested whether higher infectious titers could result in the infection of monocytes whether or not they were pretreated with IL-4. However, no IE-1 mRNA was detected in the monocytes not pretreated with IL-4. To elucidate how HCMV-infected monocytes affect lung tissue, human embryonic lung fibroblasts MRC-5 were cocultured with HCMV-infected monocytes. The cytopathic effects of HCMV were observed microscopically and was confirmed by direct immunoperoxidase staining with a human monoclonal antibody against the HCMV IE-1.


CONCLUSIONS
Our data strongly suggest that the ability of HCMV to infect monocytes may correlate with the presence of IL-4.
Kitajima
H
H
First Department of Internal Medicine, Kurume University School of Medicine, Asahimachi 67, Kurume, Fukuoka 839-0011 Japan. kitajima@med.kurume-u.ac.jp
Okubo
Y
Y
Honda
J
J
Yonemitsu
J
J
Yoshida
N
N
Fumimori
T
T
Oizumi
K
K
D003587:Cytomegalovirus / Q000187:drug effects / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000276:immunology; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics; D015847:Interleukin-4 / Q000494:pharmacology*; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000494:pharmacology; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000235:genetics; D014779:Virus Replication
D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014759:Viral Envelope Proteins; C071440:glycoprotein H, Cytomegalovirus; C499358:glycoprotein H, Human cytomegalovirus; D015847:Interleukin-4