PMID- 9037664
OWN - NLM
STAT- MEDLINE
DCOM- 19970430
LR  - 20131121
IS  - 1121-7138 (Print)
IS  - 1121-7138 (Linking)
VI  - 20
IP  - 1
DP  - 1997 Jan
TI  - Productive HHV-6 infection in differentiated U937 cells: role of TNF alpha in 
      regulation of HHV-6.
PG  - 13-20
AB  - This study characterizes the effect of differentiation on the resistance of the 
      human monocytic cell line U937 to human herpes virus type 6 (HHV-6). The use of 
      monocytic cell line has the advantage of avoiding genetic variations among 
      different donors. The HHV-6 infection was compared in undifferentiated U937 cells 
      and U937 cells differentiated with a combination of vitamin D3 and retinoic acid. 
      Undifferentiated U937 cells were highly resistant to HHV-6 infection. 
      Differentiation of U937 cells was accompanied by an increase in permissiveness 
      for HHV-6 demonstrated in terms of extracellular virus production and viral 
      antigen positive immunofluorescent cells. Tumor necrosis factor alpha (TNF alpha) 
      appears to be an essential mediator during the first line defences of the host 
      against viruses, even though its role during viral infection remains 
      controversial. For this reason we examined the behaviour of TNF alpha in 
      differentiated U937 upon HHV-6 infection. No basal production of TNF alpha was 
      found in culture supernatants, while HHV-6 infection up-regulated TNF alpha 
      release. The addition of human recombinant-TNF alpha to HHV-6 infected cells 
      induced a marked cytotoxic effect accompanied by an increased release of 
      extracellular virus, whereas it did not affect viral replication, as shown by the 
      unmodified percentage of antigen positive cells. In conclusion, TNF alpha acts as 
      a soluble mediator of cytotoxicity against HHV-6 infected U937 cells, but it 
      fails to induce an antiviral state.
FAU - Arena, A
AU  - Arena A
AD  - Institute of Medical Microbiology, University of Messina, Italy.
FAU - Liberto, M C
AU  - Liberto MC
FAU - Capozza, A B
AU  - Capozza AB
FAU - Foca, A
AU  - Foca A
LA  - eng
PT  - Journal Article
PL  - Italy
TA  - New Microbiol
JT  - The new microbiologica
JID - 9516291
RN  - 0 (Antibodies, Blocking)
RN  - 0 (Antibodies, Monoclonal)
RN  - 0 (Antigens, Viral)
RN  - 0 (Recombinant Proteins)
RN  - 0 (Tumor Necrosis Factor-alpha)
RN  - 1C6V77QF41 (Cholecalciferol)
RN  - 5688UTC01R (Tretinoin)
SB  - IM
MH  - Antibodies, Blocking/immunology
MH  - Antibodies, Monoclonal/immunology
MH  - Antigens, Viral/immunology
MH  - Cell Differentiation
MH  - Cells, Cultured
MH  - Cholecalciferol/pharmacology
MH  - Cytotoxicity, Immunologic
MH  - Fluorescent Antibody Technique, Indirect
MH  - Herpesviridae Infections/*immunology
MH  - Herpesvirus 6, Human/*growth & development
MH  - Humans
MH  - Monocytes/cytology
MH  - Neutralization Tests
MH  - Recombinant Proteins/pharmacology
MH  - Tretinoin/pharmacology
MH  - Tumor Necrosis Factor-alpha/genetics/immunology/pharmacology/*physiology
EDAT- 1997/01/01 00:00
MHDA- 1997/01/01 00:01
CRDT- 1997/01/01 00:00
PHST- 1997/01/01 00:00 [pubmed]
PHST- 1997/01/01 00:01 [medline]
PHST- 1997/01/01 00:00 [entrez]
PST - ppublish
SO  - New Microbiol. 1997 Jan;20(1):13-20.