Background: Natural Killer (NK) cells are part of the innate immune defense system with the function to eradicate cancer and viral/retroviral infected cells. Selective stimulation of NK cells proliferation should be the first essential step to produce sufficient number of cells targeting selective elimination of the particular type of unwanted transformed and/or infected cells. The nature of molecules responsible for selective stimulation of proliferation of NK cells and particularly of distinct NK cell subsets, if such exist, is not completely established. Consequently tumor specific therapy using targeted NK route cannot be valuably achieved yet.
Aims of the presented study were: 1) To find a new class of molecules which can induce selective proliferation of different subsets of NK cell populations in humans. 2) To widen and complement therapeutic methods for treating cancer and viral/retroviral infections using NK cells as the “cellular magic bullet”.
Results:
1) Five classes of glyconectins and glyconectin fucosylated acidic glycans were isolated by chromatography and electrophoresis from sponges, sea urchins, humans and rodents. These glyconectins and their glycans were partially characterized and sequenced using battery of monoclonal antibodies, NMR and MS.
2) Ex vivo stimulation of human NK cells proliferation by glyconectins and glyconectin glycans was tested using peripheral blood mononuclear cells (PBMC) cultured in supplemented homologues serum for 1-3 weeks and measured by FACS analyses using antibodies markers for cell identification: CD3, TCR αβ, TCR γδ, CD4, CD8 - T cells; CD 16, CD56 - NK cells; CD20 - B cell; CD 14 monocytes. Treatment of PBMC cultures with these compounds resulted in selective stimulation of proliferation of distinct NK cell subsets from naturally occurring level of 1-5% to 30-80%. Untreated controls remained at level of 1-5 %. No significant stimulation of B or T cells was observed. NK cells of all humans tested, from a variety of ethnic and racial groups could be significantly stimulated.
3) Ex vivo co-cultures of human tumor cells with human NK cells showed massive and continuous killing of target tumor cells during a five weeks period.
4) In vivo studies using C-57 black mice were performed with syngenic B-16 melanoma cells. Mice treated with glyconectins and/or glyconectin glycans exhibited a 20% delay in the time of appearance and 50% reduction in melanoma growth, a 12% increase in the total time of survival (p = 0.0044), and complete inhibition of metastasis when compared to control untreated mice. NK cells number increased two fold after glyconectin glycans injection and correlated with anti-tumorogenic effect, however, in vivo mechanisms remain unknown.
Conclusion: In vitro results with human NK cells and in vivo mice experiments suggested that tumor-selective subsets of human NK cells, obtained from in vitro selective stimulation of proliferation by the particular type of glyconectin glycans, may ha
Tematska oblast:
SIMPOZIJUM B: Biomaterijali i nanomedicina
Datum:
27.05.2013.
Br. otvaranja:
211
Contemporary Materials - 2013 - Savremeni materijali
