Deficient herpes simplex virus-induced interferon-alpha production by blood leukocytes of preterm and term newborn infants

The ability of peripheral blood mononuclear cells (PBMC) from newborn infants, gestational age 24-42 wk, to produce interferon-alpha (IFN-alpha) on the first day after birth was studied in vitro. Human amnion cells (WISH) coated with herpes simplex virus type I and fixed by glutaraldehyde were used as IFN-alpha inducers. Individual IFN-alpha producing cells (IPC) among PBMC were determined by an immunoplaque assay. The frequency of IPC was low in all premature (less than or equal to 36 wk) infants (median 0.3 IPC/10(4) PBMC, range 0.0-2.6), and significantly higher (median 2.0 IPC/10(4) PBMC, range 0.0-16.4) in term infants (greater than 37 wk). The frequencies were lower in both groups of infants than in adults (7.3 IPC/10(4) PBMC, range 2.0-23.7). When a conditioned medium from cultures of herpes simplex virus type I-stimulated PBMC from adults was added to the IFN induction cultures, the frequencies of IPC increased in PBMC from both preterm and term infants, and in the latter group did not differ significantly from adult levels. The median production of IFN-alpha per IPC was 1.1 U (range 0.0-2.8) in premature infants, 1.0 U (range 0.0-8.8) in term infants and 3.2 U (range 1.5-8.0) in adults. When concentrations of PBMC in the cultures [corrected] were decreased, a decline of IPC frequencies occurred. This decline was more marked and started at higher PBMC concentrations in infants than in adults, and was prevented by addition of conditioned medium from herpes simplex virus type I-stimulated cultures of PBMC from adults.(ABSTRACT TRUNCATED AT 250 WORDS)     

Deficient alternative complement pathway activity in newborn sera.

Neonatal susceptibility to overwhelming bacterial infection is commonly attributed to a relative deficiency in serum opsonic activity. However, few studies have compared the functional capacity of the classical complement pathway with that of the alternative complement pathway in the neonate. The opsonic activity of nine maternal infant serum pairs were studied by determining percent uptake of radiolabeled Escherichia coli. Seven mother-infant paired sera were studied using E. coli strains known to be opsonized via the alternative complement pathway: the mean percent uptake of E. coli opsonized in neonatal sera was 16.8%; of those opsonized in maternal sera, 54%; and of those opsonized in control sera, 45% (P less than 0.005). Two E. coli strains requiring the classical complement pathway for opsonization were phagocytized equally well in maternal and infant sera of seven mother-infant pairs. Determination of anti-O hemagglutination inhibition (HI) antibody titers in six maternal sera for one classical complement pathway activating and one alternative complement pathway strain showed no correlation between percent phagocytosis and HI antibody titer. These data would suggest that serum levels of classical pathway components are probably adequate for opsonization of E. coli via the classical pathway, but that low alternative complement pathway activity in neonatal sera may contribute to the newborn's increased susceptibility to bacterial sepsis.     

Mitogen-induced multiplication of lymphocytes from newborn infants

Marked lymphocyte responses to PHA, ConA and PWM were demonstrated in the first week of life. Prematurity up to 30 weeks gestational age did not influence the results. There were only small variations in the responses from day to day, no sex differences, and no differences between infants who were small for gestational age or of appropriate weight. Newborn infants with high serum IgM-concentrations had reduced lymphocyte responses to ConA, possibly through the influence of ConA on B-lymphocytes. Infants of mothers who had received corticosteroids prior to delivery had lower mean responses to all 3 mitogens, but the differences between the steroid- and comparable non-steroid groups were not significant. The results suggest that newborn infants have functioning cellular immune mechanisms.This study was supported, in part, by L. Meltzers Høyskolefond and Åndssvakesakens Forskningsfond     

Suppression of B lymphocytes in mature newborn infants

The ability of cord blood lymphocytes to secrete immunoglobulins during in vitro culture was investigated by means of a reverse hemolytic plaque forming cell (PFC) assay. Mononuclear cord blood cells did not differentiate into immunoglobulin-secreting cells after stimulation with the polyclonal B lymphocyte activator pokeweed mitogen (PWM), contrary to the findings in normal adults. Mononuclear cord blood cells were then separated into T-enriched and T-depleted blood lymphocyte subsets. When these were co-cultured, the PWM-induced immunoglobulin secretion was still low; following irradiation of the T-enriched cells, the numbers of IgM-PFC but not of IgG- or IgA-PFC increased considerably. The effect of irradiation of the T-enriched cells on the PWM-induced IgM response was dose-dependent, with maximal effect at 2500 rad. It is concluded that the low PWM responses obtained using cord blood lymphocytes are in part due to suppression by radiosensitive T suppressor cells. Following removal of this suppression by means of irradiation, B lymphocytes can be induced to secrete IgM, but not IgG or IgA.     

Deficient fumarylacetoacetate fumarylhydrolase activity in lymphocytes and fibroblasts from patients with hereditary tyrosinemia

Fumarylacetoacetate fumarylhydrolase (E.C.3.7.1.2.), a liver enzyme involved in tyrosine degradation, is shown to be present in many human tissues and cells including lymphocytes, fibroblasts, and cultured amniotic fluid cells. The enzyme activity in lymphocytes from six patients with hereditary tyrosinemia (hepatorenal type) and fibroblasts from three patients, was found to be less than 10% of the activity in control subjects. In lymphocytes and fibroblasts from the parents (n = 16) of the patients the enzyme values were compatible with a heterozygote genotype. The lymphocyte enzyme pattern of the control subjects (n = 97), is complicated, and indicates possible enzyme variants.     

Antigen-driven immunoglobulin production by human colostral lymphocytes

It has long been recognized that human milk contains substantial quantities of secretory IgA which is elaborated by plasma cells located proximal to the ductal epithelium. The presence of lymphocytes, granulocytes and macrophages in the milk itself raises the question of whether these "shed" milk cells might potentially serve a function with regard to protecting the suckling neonate from infection. The functionality of milk B-lymphocytes has remained particularly controversial. In this report, we describe the use of a novel technique of milk cell separation prior to cell culture and demonstrate the ability of colostral B-lymphocytes to elaborated immunoglobulin in response to antigenic stimulation using vaccine strain polio virus.     

Two different maturational stages of natural killer lymphocytes in human newborn infants.

The objective of this study was to assess the basis for the diminished natural killer (NK) lymphocyte activity of neonates. We found either severely reduced (63% of 68 neonates) or normal (similar to healthy adult) levels of NK activity. The percentages of cord blood mononuclear cells from the two groups of infants that expressed CD16, a differentiation antigen found in NK cells, were similar and within the range found in peripheral blood mononuclear cells of adults. However, infants with low NK activity had reduced numbers of cells in the CD16+56+ subpopulation, whereas the number of these effector cells present in cord blood mononuclear cells from infants with normal NK activity was within the range found in adults. Recombinant interleukin-2, but not recombinant interferon-gamma, normalized the low NK activity of infants in a dose- and time-dependent manner. Analysis of the pattern of target cell susceptibility to lysis, together with the CD16+CD3- phenotype of the precursor and effector lymphocytes, demonstrated that the induced cytotoxicity was mediated by NK cells. In contrast, NK cells from infants with normal cytotoxic levels exhibited a functional response to interleukin-2 and interferon-gamma similar to that of adults. Our results indicate that NK cells in human neonates go through two different maturational stages.     

Herpes simplex virus-stimulated gamma-interferon production by newborn mononuclear cells

Blood mononuclear cells from newborns and from adults, immune or nonimmune to herpes simplex virus, were cultured with IL 2 and herpes simplex virus and the amount of gamma-interferon in the supernatant measured after 3 days. The newborn and nonimmune adult cells made equivalent trace amounts of gamma-interferon in cultures containing either herpes simplex virus or IL 2 alone and there was a 5- to 10-fold increase in cultures containing both. Experiments in which the Leu 11+ cells were either depleted or enriched suggest that this subset of natural killer cells is both necessary and sufficient for gamma-interferon production in the absence of immune T cells.     

Response of human newborn lymphocytes to alloantigen: lack of evidence for suppression induction

Between 1:120 and 1:180 of human newborn T cells proliferate in limiting dilution cultures with allogeneic lymphocytes or with Ia-bearing monocytic stimulator cells. The proliferating responder cells were derived from both the OKT 4+ and OKT 8+ subsets as determined by immunofluorescence and by thymidine uptake. Five to seven days after an exchange blood transfusion there was a slight increase in the percentage of OKT 8+ T lymphocytes in the recipient's blood. Newborn blood also contains a population of non-T cells which proliferate in the absence of allogeneic stimulator cells. In limiting dilution cultures, the frequency of these spontaneously dividing cells was 1:3125 of mononuclear cells. Our results suggest that the newborn T lymphocyte proliferative response to alloantigen is mature by the time of birth and they provide no phenotypic explanation for the previous report of mixed lymphocyte culture-induced suppression by newborn T cells. The predominance of newborn metaphases in 2-way mixed lymphocyte cultures with adult cells (on which the previous report of suppression was based) is not seen if the non-T (stimulator) cells are irradiated. These results suggest that the data previously interpreted as evidence for suppression arose through proliferation of newborn non-T cells.     

Sensitization of lymphocytes from newborn infants and young children to pathogenic and opportunistic microflora

The nucleolar test was used to study sensitization of peripheral blood lymphocytes from the newborn and infants. The test is based on the counting of cells with a clarification area around nucleoli after incubation with antigens and microbial bodies of the pathogenic and opportunistic microflora. It has been established that the peripheral blood from children with infectious-inflammatory diseases and from those vaccinated with BCG shows an increase in the sensitized lymphocyte count which is influenced by child's trophicity at birth and by administration of antibacterial therapy. The use of the nucleolar test as a diagnostic aid is advisable to identify the disease etiology.     

B, T and null lymphocytes in newborn infants and their mothers.

Estimation of B, T and null cells were performed on 29 newborn healthy babies and 16 mothers. The lymphocytes were isolated from peripheral venous blood, which is considered to be more representative of the immune state in the newborn than the cord blood. B lymphocytes were estimated by cytofluorometric measurements, T lymphocytes by sheep red blood cell rosette technique, (SRBC-R). Combined immunofluorescence and SRBC-R technique revealed the null cells. In the newborn babies the amount of B and T cells were found to be diminished. In the mothers the amount of B lymphocytes were low compared with normal adults. The rather high null cell percentage found in the babies might represent immature precursor cells. Mothers seem to be immuno-depressed as reflected in the low amount of B cells.     

Pressure ventilation increases brain vascular prostacyclin production in newborn pigs

Using awake, chronically catheterized newborn pigs, we measured cerebral blood flow (CBF), net cerebral vascular 6-keto-prostaglandin F1 alpha production, and cerebral metabolic rate of oxygen (CMRO2) during hypercapnia and during hypercapnia at increased mean airway pressure (Paw), both before and after treatment with indomethacin. CBF nearly doubled during hypercapnia. The hypercapnia-induced cerebral hyperemia was maintained when Paw was increased from 3 +/- 2 to 16 +/- 4 cm H2O during hypercapnia. Sagittal sinus pressure increased in proportion to the increase in Paw, and cardiac output was unchanged. Net cerebral production of 6-keto-prostaglandin F1 alpha increased from 9 +/- 1 to 15 +/- 1 ng/min/100 g tissue during hypercapnia and increased dramatically to 57 +/- 1 ng/min/100 g when hypercapnia was coupled with an increase in Paw. CMRO2 was not changed by either hypercapnia or increased Paw. After indomethacin, CBF decreased and cerebral vasodilation to hypercapnia did not occur. After indomethacin, adding increased Paw during hypercapnia dropped CBF below baseline, adversely affecting CMRO2. These results suggest that cerebral hypercapnia hyperemia requires brain prostanoid production and that when Paw is increased during hypercapnia, the contribution of prostanoids to maintaining CBF is increased. Increasing ventilation pressure during hypercapnia in piglets pretreated with indomethacin compromises CBF sufficiently to reduce CMRO2.     

Interleukin-2 production of lymphocytes in food sensitive atopic dermatitis.

The proliferative responses of peripheral blood mononuclear cells (PBMC) to food antigens in 22 patients with food sensitive atopic dermatitis were significantly higher than the responses of healthy children and food sensitive children with immediate symptoms. Moreover, the activity of interleukin-2 (IL-2) in supernatants of food antigen stimulated PBMC cultures from patients with atopic dermatitis was significantly higher than that in healthy children and food sensitive children with immediate symptoms. The activity of IL-2 in culture supernatants of separated cell populations stimulated with food antigens from patients with atopic dermatitis and healthy children was investigated. The activity of IL-2 in supernatants of food antigen stimulated T cell cultures could be detected in patients with atopic dermatitis but not in healthy children. These results suggest that the increased IL-2 production after food antigen stimulation is due to increased T cell activity in food sensitive atopic dermatitis.