Immunoregulatory actions of calf thymus extract (TFX®) in vitro in relation to its effect on expression of mitogen activated protein kinases.

The in vitro immunotropic actions of a calf thymus extract - thymus factor X (TFX®) preparation were investigated. The preparation did not lower the viability of the A549 epithelial cell line and mouse bone marrow cells in the investigated concentration range. TFX® exhibited a co-stimulatory action of concanavalin A (Con A)-induced mouse thymocyte proliferation and partially restored the mitogen-induced proliferation capability of mouse thymocytes exposed to hydrocortisone (HC). The preparation also inhibited Herpes virus-1 (HSV-1) replication in A549 cells when preincubated with the virus and when added to the infected cells. In addition, it weakly inhibited lipopolysaccharide (LPS)-induced TNF α, IL-1ß and IL-6 by the THP-1 monocyte cell line. The determination of mitogen activated protein kinase (MAPK) expression in Jurkat T cells revealed strong increases in ERK-2 kinase and p38α subunits. In WEHI 231 immature B cells, TFX® elevated p38α, and had a particularly strong elevating effect on p38γ. In HL-60 myeloblastic cells, the expression of p38α, ß and γ was not detectable, almost blocked for p38δ and JNK, but accompanied by an increase in ERK-1. In turn, the effects of TFX® in J744E macrophages resulted in a strong increase in p38γ expression, moderate elevations of ERK and a drop in p38δ. Significant increases in MAPK expression were also found in cells from the lymphoid organs. In the bone marrow cell population, p38α, ß and γ, in thymocytes p38α, γ and δ, and in splenocytes p38ß and γ, subunit expression was elevated. We conclude that the changes in MAPK expression may be attributed to cell maturation and differentiation, and explain the beneficial therapeutic effects of TFX®.