5–300 ng/mL), thus being most reliably measurable. Both pro-inflammatory (TNF, IFN-γ, IL-6, IL-8, GM-CSF) and anti-inflammatory cytokines (TARC,

M-CSF) were highest in vesicular-dominated fractions. Not surprising, leucocyte (PMN) counts correlated with the relative levels of TNF, IL-6 and CXCL8 (ex-IL-8) but not with those of TGFβ1-3. Consequently, phosphatase inhibitor library anti-inflammatory and tolerance-related cytokines (IL-10, LIF, M-CSF), but not of TGFβ1-3, dominated in samples with few leucocytes, being their relative concentration lowest in leucocytic samples (>1 million/mL). These preliminary results suggest differences in cytokine/chemokine levels among fractions of the human ejaculate, which might be related to specific signalling properties in vivo. The suggested functions of SP proteins include their involvement in several essential steps preceding fertilization, such as regulating capacitation, establishment of the oviductal sperm reservoir, modulation of the uterine immune response and sperm transport in the female genital tract, as well as in gamete interaction and fusion.42 Interestingly, individual proteins from the same family appear to function in a species-specific Roxadustat manner. Differences in their structure, relative abundance and patterns of expression appear to determine species-specific effects of homologous

proteins.31 SP proteins differ somewhat in functionality related to their source, more clearly seen when fractionated ejaculates

are examined. Following mating or intercourse, mammalian spermatozoa are transported from the site of deposition towards the oviduct within minutes, owing to the concerted motility of the female tract muscle.72 These spermatozoa bathe, in individuals with fractionated ejaculation, in different fluids, such as the epididymal cauda fluid and the accessory gland secretion that is verted at the time the corresponding spurt of ejaculation is issued. As mentioned Methisazone before, the secretion of the first spurts of the sperm-rich fraction is acidic, and sperm proteins demonstrated to link themselves to acidic polysaccharides such as those in the secretion of the cervix, uterus and even oviduct.8 On the other hand, binding of some SP proteins, at least in the bull and stallion, inhibits such interaction of sperm proteins with acidic polysaccharides.73 SP proteins affect differentially sperm survival post-ejaculation, and those present in the last ejaculate fractions (seminal vesicle origin) have a more pronounced negative effect, perhaps in relation to the extensive presence of several proteins. For instance, cleavage products of the human ejaculate coagulum (basically vesicular secretion) inhibit sperm motility, which indicates those spermatozoa might be in disadvantage in vivo. The primary secretion in the first spurts, however, where spermatozoa are present, promotes longer sperm survival in humans16 and boars.