Table 3.

Seminal plasma proteins in spermatozoa protection, transport and interaction with the female reproductive tract

Proteins involved	Site of Action	Mechanism of action	Reference
FOXP3	Uterine regulatory T cells	Immunosuppression and improved tolerance towards paternal antigens	[96–98]
GM-CSF	Embryo	Blastocyst stage development	[72]
IL-6	Embryo	Protection from apoptosis by secreting anti-apoptotic micro RNAs	[72]
LIF	Inner cell mass	Blastocyst development	[72]
IGF-1	Germ cells	Maturation of spermatozoa	[27, 28]
α2-macroglobulin	Germ cells	Progressive motility	[27, 28]
Enkephalin	Sperm cells	Sperm motility	[27, 28]
VEGF, MMPs	Endometrium	Embryo implantation	[40, 99]
TGF-β, PGE	Female reproductive epithelial tissues	Inflammatory signaling response	[40, 99]
GM-CSF, IL-1A, IL-6, IL-8, MCP-1 (CCL2), MIP3A (CCL20)	Female epithelial layers and deeper stromal tissues	Immediate and rapid influx of inflammation to cause fertilization	[5, 65, 74, 99]

Several studies showing the importance of seminal plasma proteins in the regulation of male and female reproductive mechanisms. However, some of the studies were conducted with animal samples and still need validation by studies with human samples

Abbreviations: FOXP3 forkhead box P3, GM-CSF granulocyte-macrophage colony stimulating factor, IL interleukin, LIF leukemia inhibitory factor, IGF insulin like growth gactor, VEGF vascular endothelial growth factor, MMPs matrix metalloproteinases, TGF-β transforming growth factor beta, PGE prostaglandin E synthase, MCP-1 monocyte chemoattractant protein-1, MIP-3A macrophage inflammatory protein 3, CCL chemokine ligand