Porcine reproductive and respiratory syndrome (PRRS) virus down-modulates TNF-alpha production in infected macrophages.
The effect of porcine reproductive and respiratory syndrome (PRRS) virus infection on the synthesis and secretion of TNF-alpha and other pro-inflammatory cytokines by porcine alveolar macrophages (PAM) was investigated as well as the effect that TNF-alpha has on the replication of this virus. A clear reduction of phorbol myristate acetate (PMA)-induced expression of TNF-alpha mRNA was observed in cells incubated with PRRS virus. Moreover, the presence of PRRS virus also induced a decrease in IL-1 alpha and MIP-1 beta mRNAs expression with respect to PMA-stimulated uninfected cells. According to these results, exposure to the PRRS virus led to a reduction of the TNF-alpha protein in supernatants of PMA-stimulated PAM. On the other hand, addition of recombinant porcine TNF-alpha to cultures clearly reduced virus replication; however the addition of TNF-alpha to cultures containing IFN-alpha did not result in a further reduction of the produced by IFN-alpha alone. This indicates the lack of synergy in the effect of these cytokines on viral replication.
López-Fuertes
L
L
CISA-INIA, Valdeolmos 28130, Madrid, Spain.
Campos
E
E
Doménech
N
N
Ezquerra
A
A
Castro
J M
JM
Domínguez
J
J
Alonso
F
F
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D015536:Down-Regulation; D066298:In Vitro Techniques; D016676:Macrophages, Alveolar / Q000276:immunology* / Q000821:virology*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000187:drug effects / Q000472:pathogenicity* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D014779:Virus Replication / Q000187:drug effects
D017931:DNA Primers; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha