Simultaneous subtyping of group specific component and esterase D by isoelectric focusing on agarose gels.

A quick, sensitive and economical technique has been developed to subtype GC and ESD simultaneously on the same agarose IEF gel. This method could be a useful tool for forensic application.

Perinatal aspects of immunomodulation.

Haemopoietic stem cells migrate to liver, bone marrow and thymus, initially from the yolk sac endoderm, by the 28 mm embryo stage. B-lymphocytes differentiate from stem cells, first in the liver and later in bone marrow, becoming pre-B-cells, with cytoplasmic, but no surface, IgM, and later 'baby' B-cells, which carry surface IgM. These last cells are particularly sensitive to the induction of tolerance. Identifiable pre-T-lymphocytes migrate to the thymus, where they acquire the ability to recognize self-antigens coded by the major histocompatibility complex. Models of the generation of idiotype diversity will be discussed with reference to the known characteristics of cells which are differentiating at appropriate tissue sites in the foetus. Functional studies of both maternal and foetal lymphocytes have shown the presence of suppressor lymphocyte activity, from 14 weeks gestation in the foetus to one year in the infant, and during pregnancy in mothers. Infants who have been given blood transfusions, either in utero or in early neonatal life may show prolonged chimerism. Pregnant women may be chimeric for foetal cells and these cells may persist for long periods in the maternal lymphoid system. Antigens reaching the foetus from the mother are capable of modulating immune responses in the offspring. The implications of these and other observations will be discussed, together with the modulation of foetal immune responsiveness and the potential application of techniques designed to direct both antigen unresponsiveness in the newborn and the generation of idiotype diversity.

The materno-foetal transfer of carrier protein sensitivity in the mouse.

The anti-dinitrophenol (DNP) antibody response was examined in the 18-week-old offspring of female mice primed to bovine serum albumin (BSA) and in control unprimed animals. Comparisons were made of the response to DNP-BSA, DNP-chicken gamma-globulin (CGG) and DNP-purified protein derivative (PPD) after all offspring had been primed with DNP-CGG at 12 weeks of age. An enhanced anti-DNP antibody response was found to DNP-BSA in mice whose mothers had received BSA. It is suggested that this phenomenon demonstrates the transfer of carrier protein sensitivity from mother to foetus.

Changes in lymphocyte sub-populations in the blood of healthy and sick newborn infants.

Normal values for the percentages of lymphocytes carrying surface membrane-bound immunoglobulin, or rosetting with sheep erythrocytes, ox erythrocytes coated with rabbit immunoglobulin G, or ox erythrocytes coated with rabbit immunoglobulin M and reacted with human serum partially de-complemented with zymozan, have been estimated for populations from human umbilical cord blood and the peripheral blood of babies aged one week and one month. These samples have been compared with values obtained from normal adult volunteers and eighteen newborn infants, measured during and after a suspected infective episode. The dynamic change in those lymphocytes from normal infants staining for both IgM and IgD is shown, demonstrating that the number of circulating cells of this typeapproaches adult levels by the age of one month. Falls in the levels of all three types of rosetting lymphocyte were demonstrated over the same period. A drop in the number of lymphocytes forming sheep erythrocyte rosettes, and particularly those binding C3b-coated ox erythrocytes, in those babies suspected of infection showed a correlation with acute septicaemia or viraemia.

Intrapartum sensitisation of human infants to the Rhesus-D antigen.

A study is reported of the numbers of nonimmunoglobulin-bearing lymphocytes specifically binding to Rhesus-D positive erythrocytes in the blood of Rhesus-dd infants born to either Rhesus-dd or Rhesus-Dd mothers, at birth and at 6 months of age. There was a significant increase in the number of such antigen-binding cells by age 6 months in babies born to Rhesus-Dd mothers. It is concluded that the Rhesus-negative offspring of Rhesus-positive mothers may be sensitised against the Rhesus-D antigen at birth and that protection of such female infants by the injection of antiRhesus-D antibody should be considered.

Activity and characterization of a low molecular fraction present in human amniotic fluid with broad spectrum antibacterial activity.

The isolation of a low molecular weight fraction from amniotic fluid with broad spectrum antimicrobial activity is reported. This fraction consists of a family of peptides whose bactericidal activity is zinc dependent and can be inhibited by phosphate. Peptides are present in early gestation in low concentration increasing in amount from about 28 weeks gestation when antimicrobial activity becomes detectable in whole amniotic fluid. A simple bacteriological assay for this material is described. Its relation to the occurrence of perinatal infection is discussed.

Characterization of human AFLP systems apolipoprotein B, phenylalanine hydroxylase, and D1S80.

Methodology is presented for amplified fragment length polymorphism (AFLP) typing using a nonisotopic, PCR protocol. Human variable number tandem repeat (VNTR) loci used for identification in forensic and paternity testing were optimized for reaction and thermal-cycling parameters. Loci analyzed were the apolipoprotein B (APOB) 3' hypervariable region (HVR), phenylalanine hydroxylase 3' HVR (PAH), and D1S80. Coamplification of a monomorphic beta-globin fragment serves as an amplification control. Biotin is integrated into PCR amplicon through primer incorporation. AFLP products undergo agarose gel electrophoresis and Southern transfer to a nylon membrane. Amplicons were detected using a streptavidin-enzyme conjugate. Either colorimetric- or chemiluminescent-developed bands are genotyped using locus-specific allele ladders with known VNTR repeat numbers. Using this methodology, we have successfully typed > 500 individuals from three population groups for each locus during data basing and casework.

Double blind trial of recombinant human erythropoietin in preterm infants.

Twenty four infants between 27 and 33 weeks' gestation were recruited into a double blind study to investigate the use of recombinant human erythropoietin (r-HuEpo) for the prevention of anaemia of prematurity. Between 50 and 150 U of r-HuEpo (n = 16) or placebo was administered subcutaneously twice a week from 7 days of age until discharge. There was a significant increase in the reticulocyte count in infants receiving r-HuEpo sustained from the second week of treatment until discharge compared with placebo. There was a reduction in the number of transfusions required in the r-HuEpo group with only 47% requiring a transfusion compared with 87% in the placebo group. During treatment with r-HuEpo there was a significant rise in the red cell folate concentration, a significant fall in the ferritin concentration, and a significantly higher percentage of haemoglobin F at discharge suggesting active erythropoiesis. The study provides strong evidence for the efficacy of r-HuEpo in stimulating erythropoiesis and reducing the requirement for transfusions for anaemia of prematurity.

Erythropoietin responsive progenitors in anaemia of prematurity.

Circulating erythroid progenitors (BFU-E) in five anaemic preterm infants (haemoglobin less than 100 g/l) were about 2 and 4.4 times as abundant as in 10 preterm infants who were not anaemic and five healthy adults, respectively, and were significantly more responsive to low concentrations of recombinant human erythropoietin (rHuEpo) than those from healthy adults. These results encourage further studies in the use of rHuEpo for the treatment of the anaemia of prematurity.