The Orce skull fragment from southern Spain, dated at 1.6 Myr, has been a subject of heated controversy since it was first discovered in 1982. If it is hominid, as its discoverers contend, it is by far the oldest fossil hominid yet found in western Europe and implies that human populations settled this region much earlier than was previously realized. Numerous stone artifacts found at the Orce sites provide evidence that hominids were indeed present there in the Lower Pleistocene. Some paleontologists maintain that the 8 cm diameter occipital fragment is from a horse, not a hominid. Two independent investigations of the residual proteins in the skull were undertaken, one at the University of Granada in Spain, the other at the University of California, San Francisco. Two immunological methods of comparable sensitivity were employed for detection and species attribution of protein extracted from fossil bone: the Granada team used an enzyme-linked-immunosorbent assay (ELISA), and the UCSF team used a radioimmunoassay (RIA). Both teams obtained reactions characteristic of human albumin in the Orce skull and horse albumin in some of the horse fossils. These results support the lithic evidence that hominids were living in Andalusia 1.6 million years ago.

The immunosuppressive activity of amniotic fluid (AF) is extensively documented in the mouse. Although this property is due in part to the presence of alpha-fetoprotein (alpha-FP), other immunosuppressive factors are suspected. In this article, we demonstrate that human amniotic fluid lipid extract (AFLE) is inhibitory of, although not cytotoxic to, PHA-activated human lymphocytes, of mouse bone marrow cells, and of different established cell lines of human and mouse source. This effect is shown to be reversible. Under preparative thin layer chromatography (TLC) using chloroform:methanol:water (60:38:8) as solvents, the activity of AFLE migrates to two peaks of inhibition with Rf values of 0.46-0.62 and 0.84-1, respectively. These lipid-like factors may play a role as a nonspecific immunoregulatory mechanism which prevents maternally mediated immune rejection of the conceptus.

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