Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01398176 |
| Other study ID # |
MC-95320 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
July 18, 2011 |
| Last updated |
December 2, 2013 |
| Start date |
October 2011 |
| Est. completion date |
December 2012 |
Study information
| Verified date |
December 2013 |
| Source |
University of Florida |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
United States: Institutional Review Board |
| Study type |
Interventional
|
Clinical Trial Summary
The purpose of this study is to determine whether consuming mushrooms is effective in
enhancing the function of γδ T cells.
Description:
A non-therapeutic study is described. This is an intervention study at two levels of
mushroom intake. The number of subjects and experimental assays are selected as a pilot
study to generate the dose level and the efficacy. Subjects age 21 to 50 will be recruited
and provide a baseline blood draw. The mushroom supplementation will occur for 4 weeks at
two levels 85 g (3 ounces) and 170 g (6 ounces). Immunity changes fairly rapidly; in and
early study the investigators saw changes in as little as 3 days. Blood is taken again at 4
weeks. Peripheral blood mononuclear cells are isolated from the blood and used freshly
isolated, or cultured in autologous serum for 24 hours or for 10 days. Freshly isolated
cells will be used to count γδ T cell and NK cells baseline values. After 24 hours of
stimulation with a broad based mitogen, culture medium is harvested and assayed for
cytokines secreted into the culture medium as well as NK cell activation and proliferation.
Finally, cells are harvested after 10 days and assayed for γδ T cell activation and
proliferation.
Consumers will benefit from knowing that health benefits can be derived from mushrooms.
Potentially, this will stimulate mushroom sales and increase the variety of mushrooms
consumed.
γδ T cells reside in epithelial linings of the lung, gut and reproductive tract and although
their number is not precisely known, they are in much greater numbers than the circulating
αβ T cells. γδ T cells are not activated in the same way as the αβ cells, they are activated
more like cells of the innate immune system, by recognition of pathogen-associated molecular
patterns (1,2). Recognition of pathogen-associated molecular patterns is rather
non-specific, but very effective. For example, prenyl phosphate is a molecule having a
pattern that is recognized by receptors of the γδ T cells. Interaction of prenyl phosphate
with the γδ T cell receptor results in γδ T cell proliferation; expression of cell surface
activation markers, such as cytokine receptors; and lastly, synthesis and secretion of
cytokines necessary for communicating with other branches of the immune system. The
investigators hypothesize that consuming mushrooms will result in greater proliferation when
stimulated and will also enhance their capacity for activation, defined here as cytokine
secretion and cell surface marker expression.
A second quality of γδ T cells is their ability to turn off the immune response once it is
no longer needed. Carding and Egan (3,4) showed that γδ T cells were responsible for killing
activated macrophages after the pathogen had been eliminated. Knockout mouse models show
that the elimination of γδ cells promote chronic inflammation, prevent wound healing (5) and
may increase the risk for cancer (6,7). The magnitude and the importance of the γδ T cell
are just being realized. By strengthening γδ T cells, the investigators will fight pathogen
better and resolve inflammation quicker.
It is our hypothesis that there are certain bioactive components that resemble
pathogen-associated molecular patterns and interact weakly with the epithelial γδ T cells in
such a way that they are "primed", but not activated. The bioactive food components do not
interact with the cells with enough strength to cause an actual response, but, later, when
the cells do encounter pathogen, they can react quicker and with more intensity if they have
already been primed. The primary bioactive components in mushrooms that may interact with
immune cells are polysaccharides and glycoproteins and the two major types of mushroom
polysaccharides include glucans (both β and α) and heteroglycans. Additionally, mushrooms
contain another important polysaccharide, chitin. Chitin is composed of
N-acetyl-d-glucosamine units (8,9). These compounds are some likely candidates, in addition
to other immuno-modulating compounds such as Vitamin D (10) and B vitamins.
Mushrooms have been shown to have an impact on immune cells, particularly NK cells (11,12)
but the γδ T cell has not been studied. The composition of mushroom is well suited to
interact with the γδ T cell. NK cell activity will be used in this study as a positive
control although the investigators will use flow cytometry rather than generalized
non-specific cytolytic activity.
The investigators know from our previous studies in humans (7,13,14) and from other
published studies (15,16) that foods such as tea, apples, encapsulated fruits and vegetables
contain compounds that appear to prime γδ T cells. The investigators hypothesize that
bioactive compounds in the gut are recognized by intestinal γδ T cells, resulting in a
primed cell. These cells are not static but migrate in and out of tissues, through the
circulation as well as lymph nodes (17). Thus, the investigators can measure functional
changes in the blood borne γδ T cells regardless of whether the bioactive compound is
absorbed or not.
This study will specifically study the shiitake (Lentinus edodes) mushroom. This mushroom
has been shown in other research to have a variety of health benefits, but few feeding
trials, and none in healthy humans, has been done (18-20).
5. Specific Aims:
The aim is to determine if bioactive compounds in mushroom can enhance the activity of this
cell type. Because this cell type resides in the epithelial linings and migrates via the
blood and lymph system, the investigators can measure functional changes in this cell
regardless of whether bioactive compounds are absorbed or not. It is often describe as the
first line of defense.
