Vernix, that cheesy, white substance found on newborn humans and immediatley washed off during “baby’s first bath” in the hospital, has been found to contain AWESOME bactieria fighting properties!! Just read the article to see how you can protect your newborn from hospital-borne infections and disease. Vernix has also been shown to contain GBS-killing antimicrobial components! Think twice about dousing your baby in Johnson’s soap!
Vernix caseosa as a multi-component defence system based on polypeptides, lipids, and their interactions.
Vernix caseosais a white cream-like substance that covers the skin of the foetus and the newborn baby. Recently, we discovered antimicrobial peptides/proteins such as LL-37 in vernix, suggesting host defence functions of vernix. In a proteomic approach, we have continued to characterize proteins in vernix and have identified 20 proteins, plus additional variant forms. The novel proteins identified, considered to be involved in host defence, are cystatin A, UGRP-1, and calgranulin A, B and C. These proteins add protective functions to vernix such as antifungal activity, opsonizing capacity, protease inhibition, and parasite inactivation. The composition of the lipids in vernix has also been characterized and among these compounds the free fatty acids were found to exhibit antimicrobial activity. Interestingly, the vernix lipids enhance the antimicrobial activity of LL-37 in vitro, indicating interactions between lipids and antimicrobial peptides in vernix. In conclusion, vernix is a balanced cream of compounds involved in host defence, protecting the foetus and newborn against infection.
In previous studies, we have characterized antimicrobial peptides and polypeptides in vernix [7, 8]. In the present study we demonstrate the presence of many more proteins of immunological importance in vernix. Among the most abundant proteins now characterized are cystatin A, calgranulin A, ubiquitin, and UGRP-1, which are all implicated in innate immunity of humans. Vernix lipids were now also characterized in which antimicrobial activity was detected, in particular for free fatty acids. In addition, our results indicate that lipids may contribute to a favourable microenvironment in vernix by interacting with antimicrobial components such as LL-37. Our characterization of proteins, lipids and their interactions suggest that vernix is a complex innate defence barrier, protecting the foetus and the newborn from infectious microbes, in an apparently crucial manner, since the adaptive immunity of newborns is immature. The antimicrobial property of vernix may also act to facilitate colonization by the normal flora following birth and to block the colonization of unwanted microbes or pathogens. For example psoriasin, which is identified in vernix, directly kills E. coli but not Staphylococcus aureus [33, 34]. The shedding of the vernix in late pregnancy may suggest that the level of protection has to be adjusted to allow proper colonization of the normal flora.
Several proteins now identified are expressed in skin such as cystatin A, profilaggrin, psoriasin and calgranulin C. Due to the close contact of vernix and amniotic fluid, they share some of the same components. This is now shown regarding calgranulin A and B, proteins previously known to be present in amniotic fluid . The origin of UGRP-1 may be the lungs, and a transfer of this protein to vernix may occur via the amniotic fluid. Blood may be another source of the identified proteins in vernix. Using mass fingerprinting, we identified not only α- and β- haemoglobin but also γ-haemoglobin. During the last two trimesters of pregnancy the foetus produces γ-haemoglobin, which is replaced by β-haemoglobin after birth, enabling an efficient transfer of oxygen from the blood of the mother to the foetus. Thus, the γ-haemoglobin detected in vernix originates from the foetus.
Calgranulin A, B, and C, and psoriasin all belong to the S100 family of calcium binding proteins. The S-100 family of proteins has 2 calcium binding motifs of the EF-hand type . These proteins have been shown to exhibit chemotactic properties and may play a role in the pathogenesis of epidermal diseases . Notably, an N-terminal fragment of profilaggrin, with sequence similarity to the two EF-hands , was also identified in vernix.
Calprotectin is an antifungal and antibacterial complex consisting of a heterodimer of calgranulin A and calgranulin B . Both subunits were identified, revealing that the active holoprotein is present in vernix. Accordingly, the crude peptide/protein extract of vernix exhibited good antifungal activity. However, after separation of the protein extract by RP-HPLC we could not detect any antifungal activity in the collected fractions (data not shown). Our interpretation of this difference is that the two subunits of calprotectin have been separated upon HPLC, leading to loss of activity. Calprotectin is suggested to kill microbes by chelating zinc, thereby depriving microbes of an essential metal ion . This mode of action has also been described for lactoferrin and psoriasin, the latter being a major E. coli-killing compound in human skin .
Calgranulin C was first identified on the surface of onchoceral worms in human subcutaneous nodules . It is proposed to be released by activated neutrophils and thereby attack and kill nematodes . Thus, the presence of calgranulin C in vernix contributes to the protective role of vernix.
Cystatin A is a protease inhibitor that is mainly expressed by epithelial and polymorphonuclear cells [41, 42]. Cystatin A is also a minor cross-linking component of the cornified cell envelope  and a part of the mechanical barrier of the skin. Unlike cystatin C, cystatin A has not been shown to possess any direct antimicrobial effect. However, cystatin A has been suggested to be a first line protector against cysteine proteases released from infectious micro-organisms and parasites . Thus, cystatin A could have a dual role in the innate defence of the foetus.
Our results reveal that UGRP-1 (HIN-2/SCGBA2) is one of the major proteins in vernix, whereas UGRP-2 (HIN-1 /SCGBA1) is not as abundant. These proteins are both expressed at high levels in neonatal lungs by different subsets of secretory cells within the surface and glandular epithelia . UGRP-1 has been shown to bind bacteria and to the macrophage scavenger receptor MARCO , indicating opsonizing properties. In the lungs of mice the expression of UGRP-1 is upregulated by IL-10 , while it is downregulated by IL-5 , suggesting that UGRP-1 is a target of anti-inflammatory pathways. In vernix, we have characterised three novel forms of UGRP-1, which are N-terminally differently processed. These forms may have altered binding affinities to bacteria, leading to enhancement of the opsonizing spectra.
Vitamin A has been detected at high levels in vernix  and is proposed to serve as a nutritional depot of vitamin A. Vitamin A is secreted from the amniotic epithelium into the amniotic fluid, and is taken up by vernix . Our results show that transthyretin is present in vernix, a protein that binds to the retinol binding protein, which in turn binds vitamin A.
Like lipids previously isolated from human stratum corneum and sebum [50, 51], our results demonstrate inhibitory effects of the free fatty acids in vernix against the Gram-positive bacterium B. megaterium. We also demonstrate that palmitoleic acid (C16:1) and linoleic acid (C18:2), known to exhibit potent antimicrobial activity [14, 52], are a considerable part of the total free fatty acids. The long-chain unsaturated fatty acids found in vernix (C20 to C22 in table 2) are also antimicrobial and the activity is enhanced with an increase of the number of double bonds . Like antimicrobial peptides , fatty acids and monoacylglycerols disintegrate the lipid envelope of viruses  and bacterial plasma membranes [12, 16].
Considering the high lipid content of vernix (10%) , it seems possible that lipids influence the function of other components of vernix. It has been demonstrated that other factors such as salts and pH, influence the conformation of the human cathelicidin LL-37 . Therefore we speculate that the lipid fraction of vernix can exhibit similar functions. Under our experimental conditions, lipids isolated from vernix enhanced the antimicrobial potency of LL-37. Thus, LL-37 can be active in a lipid-rich environment.
When studying the antimicrobial activity in peptide/protein extracts of vernix, we found a high antimicrobial activity against bacteria and fungi. The most active antibacterial compound against E. coliand GBS in these samples was isolated and identified as chlorhexidine. Chlorhexidine is a microbicidal substance of vaginal cream used as a lubricant during vaginal examination prior to delivery. For this reason, some of the vernix samples were found to contain chlorhexidine. We noted that the samples with E. coli activity.
In conclusion, we have characterized proteins and lipids that add novel protective functions to vernix, such as antifungal properties, opsonizing features, protease inhibiton, and parasite inactivation. In addition, the antimicrobial action of LL-37 can be potentiated by the lipids in vernix in vitro, stressing the importance of the microenvironment for the function of antimicrobial components.
This work was supported by grants from The Icelandic Research Fund for Graduate Students, The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), and The Swedish Research Council (no. 11217, 13X-3532). We thank Ella Cederlund, Carina Palmberg, Marie Ståhlberg, Gunvor Alvelius, and Monica Lindh for excellent assistance. We also thank Milan Chromek and Annelie Brauner, for the GBS strain.