Evaluation of the stimulatory activity of a fermented mistletoe lectin- I free mistletoe extract on T- helper cells and monocytes in healthy individuals in vitro

Journal/Book: Arzneim.- Forsch./Drug Res. 46 (6), 635-639. 1996;

Abstract: Previously, a strong stimulatory response of peripheral bloodmononuclear cells (PBMC) to a fermented mistletoe extract (Iscador Pini,i.p.) could be observed in normal and allergic individuals. Aim of thisstudy was therefore to analyse the cell subtypes involved in this invitro reactivity. PBMC from 11 non-mistletoe treated healthy andallergic individuals were therefore investigated. Flow cytometricanalyses revealed that this mistletoe extract stimulated T-cells (CD3+),especially T-helper cells (CD4+), as well as monocytes at concentrationsof 100 or 1,000 micrograms/ml. Furthermore, an increased proportion ofT- and T-helper cells expressing the interleukin-2 (IL-2) receptor(CD25) and monocytes expressing HLA-DR molecules, respectively, could bedemonstrated. There was no evidence for a major involvement of B-(CD19+), natural killer- (NK-; CD56+) and T-suppressor cells/cytotoxicT-lymphocytes (CD8+). To get more insights whether the T-cellproliferation induced by i.p. was the consequence of a primary or asecondary type of immune response, kinetic studies (n = 5) wereperformed hereby comparing the reactivity of the non-recall antigenkeyhole limpet hemocyanin (KLH) as well as the recall antigen purifiedprotein derivative (PPD) derived from Mycobacterium tuberculosis withthat of i.p. I.p. at a concentration of 100 micrograms/ml alwaysexhibited the kinetics of a primary immune reaction. These findings werefurther substantiated by additional flow cytometric studies analysingchanges in the proportions of naive (CD45RA+) and memory/effector cells(CD45RO+) during the exposure to i.p. It could be shown that theproportion of naive cells decreased and that of the transition stageincreased, which could indicate that there was a change towardsmemory/effector cells. In conclusion, these data demonstrate thati.p.-related antigens act like "non-recall"-antigens, and the in vitroimmune response involves T-cells as well as monocytes. Author.

Keyword(s): ADJUVANTS-IMMUNOLOGIC/ PD (pharmacology)

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