This document discusses how moderate exercise affects natural killer (NK) cells through killer immunoglobulin-like receptors (KIRs). It explains that KIRs are receptors on NK cells that can be either activatory or inhibitory, and regulate NK cell cytotoxicity. Moderate exercise increases expression of the KIR2DS2 activatory receptor and KIR2DL3 inhibitory receptor on NK cells. This is mediated by increased levels of heat shock protein 70 (HSP70) from exercise, which activates a transcription factor that increases expression of these KIR genes. Upregulating these receptors promotes NK cell immune surveillance and effectiveness, demonstrating how exercise can benefit immune system function.

1. Exercise and Natural Killer Cells
By: Stephanie Edwards and Jaclyn Woods

2. How KIR Receptors Work
 Killer cell immunoglobulin-like receptors are considered the most
important receptor for the effectiveness of NK cell cytotoxicity.
 KIRs are divided into two broad categories based on whether they
function in activation or inhibition. Activatory KIRs have short
cytoplasmic tails and inhibitory KIRs have long cytoplasmic tails.
 Activatory KIRs promote cytotoxicity, while inhibitory KIRs
suppress cytotoxicity. Both categories of receptors interact
specifically with MHC Class I.
 The combination of inhibitory and activatory signals is critical for
the stimulation of NK cell effector functions.

3. For the visually minded members of our audience.

4. KIRs and Moderate Exercise
 Moderate exercise increases the expression of two KIR genes in
particular. They are KIR2DS2 (Activation) and KIR2DL3
(Inhibition).
 Factors that stimulate KIR gene expression are IL-2, IL-15, and IL-
18, and most importantly HSP-70Exercise causes HSP-70 serum
levels in the blood to rise.
 HSP-70 expression is controlled primarily by a heat shock
transcription factor called HSF-1, that becomes activated due to
the elevated body temperature as a result of exercise.
 As a result, the two noted KIR genes increase in expression, which
results in more KIR receptors on the NK cell surface.

5. Exercise as a part of a healthy
Immune System
 The consequence of exercise induced changes in the population of
CD56 NK cell subsets and expression for KIR genes promotes the
effectiveness of immune surveillance.
 Exercise is a potential means of maintaining the integrity of the innate
and adaptive immune responses through the promotion of natural killer
cell functionality.
 Individuals experiencing minor illnesses can benefit from the
implementation of moderate exercise in order to maintain a healthy
immune system.

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