Natural killer cells act as early responders in an experimental infection with Neospora caninum in calves.

The intracellular protozoan parasite Neospora caninum is a cause of abortion and congenital disease in cattle worldwide. We have previously shown that natural killer (NK) cells produce IFN-gamma in response to N. caninum tachyzoites in vitro.

Bovine CD2-/NKp46+ cells are fully functional natural killer cells with a high activation status.

Background: Natural killer (NK) cells in the cow have been elusive due to the lack of specific NK cell markers, and various criteria including a CD3-/CD2+ phenotype have been used to identify such cells. The recent characterization of the NK-specific NKp46 receptor has allowed a more precise definition of bovine NK cells. NK cells are known as a heterogeneous cell group, and we here report the first functional study of bovine NK cell subsets, based on the expression of CD2.

Bovine NK cells can produce gamma interferon in response to the secreted mycobacterial proteins ESAT-6 and MPP14 but not in response to MPB70.

Bovine NK cells have recently been characterized and the present study describes the interaction between NK cells, antigen-presenting cells, and secreted mycobacterial proteins. Gamma interferon (IFN-gamma) production by NK cells was seen in approximately 30% of noninfected calves in response to the Mycobacterium tuberculosis complex-specific protein ESAT-6, MPP14 from Mycobacterium avium subsp. paratuberculosis, and purified protein derivative (PPD) from M.

Reference values for relative numbers of natural killer cells in cattle blood.

Natural killer (NK) cells have been studied in humans and rodents for almost 30 years, but little is known about NK cells in other mammals, such as cattle. Recently, a monoclonal antibody directed against bovine NKp46, a receptor that is expressed exclusively on NK cells, was developed. We have utilized this antibody to study the relative numbers of NK cells in blood of 254 cattle at different ages.

NKp46 defines a subset of bovine leukocytes with natural killer cell characteristics.

Natural killer (NK) cells have not previously been precisely identified or characterized in cattle or any other ruminant species. We have generated a monoclonal antibody against bovine NKp46, which is expressed exclusively by NK cells in man. NKp46+ cells comprised 1-10% of blood mononuclear cells in cattle, and did not stain with antibodies against CD3, CD4, TCR1, B cell or granulocyte markers.