Cytokine production by cryopreserved human peripheral blood mononuclear cells in response to periodontal pathogens

Comparison of Type 1 and Type 2 Cytokine Production by Mononuclear Cells Cultured With Streptococcus mutans and Selected Other Caries Bacteria

A feature of pulpal immune responses is the predominance of type 1 cytokine mRNA under shallow caries and a mixed (type 1/type 2) profile under deep caries. These results prompted an examination of the cytokine profiles induced by bacteria in shallow caries (Streptococcus mutans and Actinomyces viscosus) and deep caries (Lactobacillus casei, Pseudoramibacter alactolyticus, and Prevotella intermedia). All isolates induced interferon-gamma and interleukin-10, whereas interleukin-4 and interleukin-2 titers were low to undetectable. S. mutans was the most potent and persistent interferon-gamma inducer. Differences in interleukin-10 were apparent at low doses but were less dramatic, with L. casei the dominant producer. S. mutans induced substantially more interferon-gamma than interleukin-10 over all doses and time points, suggesting strong type 1 polarization. P. alactolyticus induced significantly more interleukin-10 than interferon-gamma at higher concentrations, suggesting polarization toward type 2. A similar amount of interferon-gamma and interleukin-10 induced by L. casei, A. viscosus, and P. intermedia reflected a mixed profile. A better understanding of pulpal immune response to caries bacteria may enable us to develop an immune system-based pulp therapy in the future.

A multidonor ELISPOT study of IL-1 beta, IL-2, IL-4, IL-6, IL-13, IFN-gamma and TNF-alpha release by cryopreserved human peripheral blood mononuclear cells

Utilization of cryopreserved peripheral blood mononuclear cells (PBMCs), rather than fresh ones collected from the same donor on different dates, overcomes the variability in sensitivity of these cells to activation agents. To understand the effect of cryopreservation, frozen PBMCs from eight healthy donors were studied to release T(H)1 or T(H)2 cytokines including IL- 1 beta, IL-2, IL-4, IL-6, IL-13, TNF-alpha and IFN-gamma using ELISPOT assay. The number of spot-forming cells (SFC) was determined using three concentrations of PBMCs (5 x 10(6), 5 x 10(5) and 5 x 10(4) cells/ml). PBMCs from all eight donors were found to retain their functional capacity to release T(H)1 or T(H)2 cytokines after freezing and thawing. When PBMCs were taken in concentrations 5 x 10(6) or 5 x 10(5) cells/ml, the density of IL-1 beta-, IL-2-, IL-6- and TNF-alpha-related spots in a well for most of the donors appeared to be overly high, making SFC quantification either difficult or impossible. To the contrary, PBMCs in concentration 5 x 10(4) produced distinct and quantifiable spots. The density of spots related to IL-4 and IL-13 release appeared to be optimal for SFC quantification when PBMCs were taken in concentration 5 x 10(6) whereas in 5 x 10(5) cells/ml the spot density was very low and absent in 5 x 10(4) cells/ml concentration group. No relationship between release levels of different cytokines was found, except IFN-gamma and IL-2 cytokine indicating that cryopreserved PBMCs with a high IFN-gamma response will likely have a high IL-2 response as well. Our results indicate that a release level of one cytokine may not be reliably predicted by knowing the level of the other. This implies that it is necessary to test cryopreserved PBMCs in a broad range of concentrations to determine one, which will be optimal for producing distinct and quantifiable spots.