Cytokine secretion by peripheral blood mononuclear cells from cows infected with Mycobacterium paratuberculosis.
OBJECTIVE
To compare cytokine secretion patterns of peripheral blood mononuclear cells (PBMC) from healthy cows and cows subclinically and clinically infected with Mycobacterium paratuberculosis.


METHODS
5 noninfected cows, 6 cows with subclinical paratuberculosis, and 4 cows with clinical paratuberculosis.


METHODS
PBMC were isolated, and concentrations or activities of secreted interleukin (IL)-1, IL-2, IL-6, tumor necrosis factor (TNF), and interferon-gamma (IFN-gamma) were measured after in vitro stimulation of cells with concanavalin A (ConA), lipopolysaccharide (LPS), or a whole-cell sonicate of M paratuberculosis (MpS). Proliferative responses of PBMC were also determined after stimulation with ConA, phytohemagglutinin, pokeweed mitogen (PWM), or MpS.


RESULTS
After stimulation with ConA, cells from subclinically infected cows secreted significantly more, and cells from clinically infected cows secreted significantly less, IFN-gamma, compared with cells from control cows. Cells from cows with subclinical paratuberculosis produced significantly more TNF and IFN-gamma in response to MpS than cells from the other 2 groups. Stimulation of PBMC from subclinically infected cows with ConA or MpS resulted in significantly higher proliferative responses, compared with cells from control and clinically infected cows. In contrast, clinically infected cows had significantly higher proliferative responses to PWM than cells from the other 2 groups.


CONCLUSIONS
A decrease in T-cell responses to mitogens or MpS was observed in cows clinically infected with M paratuberculosis, compared with subclinically infected cows, suggesting that activated T cells may delay the progression of paratuberculosis.
Stabel
J R
JR
Bacterial Diseases of Livestock Research Unit, USDA-Agricultural Research Services, National Animal Disease Center, Ames, IA 50010, USA.
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000382:microbiology; D002455:Cell Division; D003208:Concanavalin A / Q000276:immunology; D016207:Cytokines / Q000032:analysis / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D007371:Interferon-gamma / Q000032:analysis; D007375:Interleukin-1 / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology* / Q000472:pathogenicity; D010283:Paratuberculosis / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D010835:Phytohemagglutinins / Q000276:immunology; D011043:Pokeweed Mitogens / Q000276:immunology; D012588:Scintillation Counting / Q000662:veterinary
D016207:Cytokines; D007375:Interleukin-1; D007376:Interleukin-2; D008070:Lipopolysaccharides; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D003208:Concanavalin A; D007371:Interferon-gamma