The envelope protein E1 of hog cholera virus (HCV) was isolated by immunoaffinity purification with monoclonal antibodies (MAbs) directed against HCV. E1 consisted of a doublet of glycoproteins which varied in size from 51K to 56K between the three strains tested. E1 contains major antigenic determinants of HCV which are conserved, and are involved in neutralization by MAbs. In infected ceils, E 1 was found always connected with a glycoprotein of 31K. When Nlinked glycans were removed, E1 had a polypeptide backbone of approximately 47K. After proteolytic cleavage of E1 with Staphylococcus protease V8 and after electrophoresis and electrotransfer, peptide fragments containing different antigenic domains of E1 were detected with MAbs directed against HCV.

The amplification of Variable Number of Tandem Repeats (VNTR) by the polymerase chain reaction (PCR) was used to determine the extent of chimaerism in flow sorted lymphoid and myeloid cell populations following allogeneic bone marrow transplantation (BMT). Pre-BMT screening with a set of five VNTR revealed that at least one marker was maximally informative in 95% of donor-recipient pairs. Mixing reconstruction experiments indicated that detection of 1-5% of the minor cell population in a sample of 5 x 10(3) nucleated cells is feasible. Flow sorted post-transplant peripheral blood B- and T-lymphocyte, natural killer and monocyte cell populations were subjected to PCR-VNTR marker analysis. It was shown that this procedure can be used for the early detection of engraftment and the identification of mixed chimaerism in various haematopoietic cell lineages in patients with leukaemia or severe combined immune deficiency, treated with allogeneic BMT.