Expression of inflammatory cytokine mRNA in lymphoid tissue from swine experimentally infected with Mycobacterium avium serovar 2.
OBJECTIVE
To evaluate in situ expression of inflammatory cytokine mRNA in lymphoid tissue of swine experimentally infected with Mycobacterium avium serovar 2.


METHODS
7 noninfected pigs and 7 pigs infected with M. avium serovar 2.


METHODS
Expression of mRNA of inflammatory cytokines such as tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta IL-6, and IL-8 in formalin-fixed paraffin-embedded blocks of lymphoid tissue (lymph nodes and tonsil) of swine experimentally infected with M. avium serovar 2 was compared with that of noninfected pigs. Tissues were evaluated by use of morphologic localization of cytokine mRNA, using in situ hybridization at 160 days after inoculation.


RESULTS
A noticeable increase in mRNA expression for TNFalpha and mild increases in mRNA expression of IL-8 and IL-1beta were detected in mandibular lymph nodes from infected swine, compared with noninfected swine. Mild increase in mRNA expression for 1L-6 also was observed in tonsils from infected swine. Cytokine mRNA was detected in macrophages and lymphocytes, primarily within cortical follicles and adjacent mantle zones.


CONCLUSIONS
Expression of mRNA for inflammatory cytokines was increased in lymphoid tissue of infected swine, possibly resulting from local factors on, or secreted by, M. avium. These results suggest that alterations in cytokine mRNA expression are important in the pathogenesis and clinical course of mycobacteriosis in swine. Modulation of the immune response by vaccines that selectively target cytokine expression and secretion in response to mycobacterial challenge may be effective in prevention of mycobacteriosis in swine.
Hines
M E
ME
Veterinary Diagnostic and Investigational Laboratory, College of Veterinary Medicine, University of Georgia, Tifton 31793, USA.
Frazier
K S
KS
D000818:Animals; D016207:Cytokines / Q000235:genetics*; D005786:Gene Expression Regulation / Q000276:immunology*; D007375:Interleukin-1 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D016209:Interleukin-8 / Q000235:genetics; D008198:Lymph Nodes / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology*; D009162:Mycobacterium avium / Q000145:classification; D014066:Palatine Tonsil / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D012016:Reference Values; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000382:microbiology; D014158:Transcription, Genetic; D014376:Tuberculosis / Q000276:immunology / Q000662:veterinary*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha