Absence of evidence for linkage between Booroola gene and genetic markers at 11 sheep blood polymorphic loci.

Genetic linkage between the Booroola locus (Fec) and 11 sheep blood polymorphic loci (i.e. Tf, Hb, CA, OLA, and A, B, C, D, M, R, F41 red cell blood groups) was investigated in six large sire families (163 informative female offspring). The six sires tested were heterozygous for the Booroola allele (FecB) and for several genetic markers. No evidence in favour of linkage was found. Moreover, depending on the marker locus considered, linkage closer than or as close as the recombination frequency of 10-30% was excluded.

Rejection of cultured keratinocyte allografts in the rat. Clinical implications and a possible clue to the enigma of skin graft rejection.

We have made a detailed analysis of the fate of Langerhans cell-free cultured keratinocyte allografts in two rat strain combinations, DA-to-PVG and DA-to-LEW, and compared the results with the rejection of conventional skin allografts in these strain combinations. The cultured keratinocyte layers were grafted both to the body surface using a technique to prevent wound contraction, and to the renal subcapsular site. Histological examination of grafts was made on days 2, 7, 10, 14, and 28 after transplantation. Donor-specific anti-class I MHC monoclonal antibodies were used to verify the donor origin of the keratinocytes. We report that the keratinocyte allografts are acutely rejected but, in contrast to the conventional allografts, do not evoke alloantibody responses. Rejection of the keratinocytes at the renal subcapsular site was as rapid as that of conventional skin grafts. However, rejection of keratinocyte grafts on the body surface was delayed by a few days when compared with conventional skin grafts. Immunosuppression with cyclosporine prevented the rejection of DA keratinocyte layers placed at the renal subcapsular site of PVG rats, but rejection followed soon after cessation of cyclosporine therapy. These data suggest that rejection is a major constraint for the clinical application of cultured keratinocytes, and that autografts must be used if permanent cover is required. Moreover, the findings have interesting theoretical implications relating to the much greater vulnerability to rejection of skin grafts compared with organ grafts. Our current and previous data also suggest that class II positive dendritic cells are the major stimulus to alloantibody production after tissue transplantation.

Ovine lymphocyte antigens: a comparison of Australian and European antisera.

Lymphocyte alloantigens were determined in 183 Australian merino sheep, using antisera from Australian and European laboratories. The study had two aims: (1) to compare reagents characterized in the different laboratories and to correlate antigen definition; and (2) to define lymphocyte antigens for use as genetic markers in two flocks of sheep which had been selectively bred for resistance or susceptibility to the intestinal parasite Trichostrongylus colubriformis, in order to extend a previous study which had indicated linkage between resistance to the parasite and the sheep major histocompatibility system. Good or excellent correspondence was found between four Australian and four European specificities and it was concluded that continued international collaboration would allow definition of markers for future genetic or disease susceptibility studies.

Sheep histocompatibility antigens: a population level comparison between lymphocyte antigens previously defined in France, England and Scotland, and sheep red cell groups.

A comparison test was performed to look for correlations between the three nomenclature systems for sheep histocompatibility antigens which have been previously described in France, England and Scotland. 187 French sheep from a wide variety of breeds were typed for lymphocyte antigens with antisera which detect the OLA, P and ED series of antigens; they were also tested against 387 uncharacterized French antisera. Six clusters of sera were found which showed correspondence between antigens of at least two of the three nomenclatures; five of these clusters gave high r values of 0.78-0.94. New antisera from French sheep were found which contributed to the above clusters but few additional clusters were noted. No correlation was found between any of the lymphocyte groups of antisera tested and the sheep red cell antigens which were also tested.

Analysis of the sheep MHC using HLA class I, II, and C4 cDNA probes.

Four cDNA probes for the human major histocompatibility complex (MHC) were used to investigate the sheep MHC, in conjunction with serological typing for ovine lymphocyte antigen (OLA). Lymphocytes from a family (two parents and five offspring) of Romanov sheep were subjected to genomic DNA digestion by the restriction endonuclease Eco RI, followed by gel electrophoresis. A single Southern blot representing all seven individuals was then consecutively hybridized with the class I, alpha-DC, beta-DR, and C4 probes, which were originally designed to identify HLA class I, class II (DC and DR), and C4 products, respectively. Using each of the three class I/class II probes, several bands showing DNA polymorphism were detected. The segregation of these bands in the five offspring exactly paralleled the OLA haplotype segregation established by serological typing. A further eight individuals carrying haplotypes which were phenotypically identical to those in the above-mentioned family showed bands in the corresponding positions when tested with the same three probes. Using the C4 probe, no polymorphism was detected in these fifteen individuals.

Sheep lymphocyte antigens and scrapie.

The frequencies of 15 lymphocyte antigens were determined in 2 experimental flocks of Herdwick sheep derived from the same foundation stock. The Blue Flock had been bred for resistance, and the Red flock for susceptibility, to a standard dose of the SSBP/1 source of scrapie injected subcutaneously. Although there were marked frequently differences between the 158 Red flock and 51 Blue flock sheep tested these differences could be attributed to genetic drift. Within the Red flock no significant frequency differences were observed between 16 sheep which developed natural scrapie and their healthy flockmates. All Red flock lambs born in 1980 were injected subcutaneously with SSBP/1 scrapie; there was no difference in antigen frequency between the group which subsequently developed experimental scrapie (30) and the group which did not (21). The segregation of antigen haplotypes in the Red flock pedigrees showed no evidence of MHC linkage with either natural or experimental scrapie.

Sheep lymphocyte antigens: a preliminary study.

Sera from 287 sheep were screened for cytotoxic antibodies against sheep lymphocytes. Forty four antisera were selected which provisionally define 13 lymphocyte antigens. The frequency of these antigens was studied in 305 sheep from 8 flocks of different breeds. Family studies confirm that inheritance of sheep lymphocyte antigens is controlled by the autosomal codominant genes of at least 2 linked loci.

Changes in red cell Bg antigens in haematological disease.

The red cell Bg antigens of patients with haematological diseases have been found to be more reactive than those of normal donors. Others HLA-related antigens that are of low incidence in normal donors are found in much higher incidence in these patients. A series of 40 CLL patients has been tested for both known and additional HLA-related antigens by hemagglutination and adsorption and the relationship between the antigens of the red cells and lymphocytes evaluated.

Reversal of postoperative immunosuppression in man by vitamin A.

The effects of therapy with vitamin A on immune responsiveness after extensive surgical treatment were studied in vitro. Postoperatively, in control patients, there was depression of the total lymphocyte count and the response in the mixed lymphocyte reaction to a pool of stimulating cells. Treatment with pharmacologic dosages of vitamin A prevented depression of these parameters in the postoperative period. The mitogenic response to phytohemagglutinin and monocyte mediated hemolysis was not consistently altered by operation in control patients, but there was a trend toward increased activity in those receiving vitamin A. Thus, vitamin A appears to be an immunostimulant in man.

Mixed lymphocyte reaction and graft survival in forty cadaveric renal transplants.

The value of the MLR in predicting graft outcome was evaluated in forty cadaveric grafts. The MLR was assessed by the one and two way stimulation index (SI), the relative response (RR), and the stabilized relative response (SRR). Graft function was assessed by function at 3 and 6 months after transplantation, and a rejection grading based on the number and severity of rejection episodes during the first 3 months after transplantation. No correlation was found between the MLR and graft outcome in these patients.