Tissue-Protective Cytokines: Structure and Evolution - Tissue-Protective Cytokines: Methods and Protocols - page 50

Table 4
(continued)

Gene symbol Group Description

IL22 1 Interleukin-22

IL23 1 Interleukin-23

IL24 1 Interleukin-24

IL26 1 Interleukin-26

IL27 1 Interleukin-27

IL28A/B 1 Interleukin-28A/B (interferon

lambda-2/3)

IL29 1 Interleukin-29 (interferon lambda-1)

IL31 1 Interleukin-31

IL34 1 Interleukin-34

KITLG 4 Stem cell factor

LEP 1 Leptin

LIF 1 Leukemia inhibitory factor

OSM 3 Oncostatin M

PRL 1 Prolactin

THPO 3 Thrombopoietin
Cytokines are classified into groups 1 through 4, with their official gene name. Omitted
are various close homologs and isoforms; the interferon alpha homologs; and the soma-
totropin homologs GH2, CSH1, CSH2, and CSHL1

4 Conclusions

It is tempting to hypothesize that the tissue-protective activities of
many cytokines in this structural family preceded their specific
functions developed when blood cells and immune system evolved.
A recent study has shown that a protein immunoreactive with anti-
human EPO antibodies is present in the grasshopper and leech
(though not in Drosophila), and that recombinant human EPO is
neuroprotective in insects ( 54 ). Further studies in model organ-
isms will help identifying the evolutionary relationship between the
various protective roles of cytokines.

Acknowledgments

Supported by the European Regional Development Fund, Trans-
Channel Neuroscience Network to P.G.