β-Glucan has been shown to enhance anti-tumor and anti-infection functions in animals. Pigs at 4 months of age were infected with porcine reproductive and respiratory syndrome virus (PRRSV), and peripheral blood monocytes (PBMC) were isolated for the detection of interferon γ (IFNγ)-producing cells. We found that soluble high molecular weight β-glucan could increase IFNγ-producing cell frequency in a dose-dependent manner in the enzyme-linked immunospot assay (ELISPOT) in the absence of antigenic restimulation. A concentration as low as 1.6 μg/ml gave a significant increase and a similarly high enhancement was achieved at concentrations from 3.2 to 100 μg/ml. In PRRSV-specific IFNγ ELISPOT, soluble β-glucan elicited increased PRRSV-specific responses at concentrations from 3.2 to 50 μg/ml, but not at 100 μg/ml, whereas insoluble β-glucan had no effect. Soluble β-glucan augmented the porcine cellular immune response in an antigen-independent fashion, whereas insoluble β-glucan had no activity. This finding suggests that soluble β-glucan may enhance innate antiviral immunity against PRRSV.
Bibliographical noteFunding Information:
We thank Arun Bahl, Immudyne, Houston, TX, for providing the β-glucan preparations used in the study and Scott Dee, University of Minnesota, for maintaining animals and providing blood samples. Support for the studies was provided by funds from the Minnesota Agricultural Experiment Station.
- Sus scrofa
- Veterinary immunology