Opsonic Activity of Cord Serum—an Evaluation Based on Determination of Oxygen Consumption by Leukocytes

Abstract

Summarythe oxygen consumption capacity of leukocytes as well as on the opsonhtion time. The method used in this experiment turned outOpsonic activity against four kinds of particles was to be simple and reliable and appears to be applicable in the between adult and sera determining the Oxygen consump diagnosis of various opsonic and phagocytic disorders, tion capacity of leukocytes. Althoueh both sera had almost eaual activity against killed E. coli (adul~l.5 + 0.6, and cord: 1.6 f '0.3 at 10% serum concentration, respectively, when expressed in nmoles oxygen consumed/min/l~~ PMNL), cord sen& showed less activity against zymosan (adult: 7.1 f 2.3 and cord: 4.9 f 2.0) and killed S. aureus 209P (adult: 4.7 + 0.8 and cord: 2.5 f 0.6) when diluted below 10% and 1%, respectively. However, this difference was not prominent when the serum concentration was higher in the reaction system. No opsonic activity against S. fwcalb (either killed or live) was present in any cord serum tested (adult: 2.7 + 0.6 and cord: 0, respectively at 5% serum concentration).Oxygen consumption capacity was compared between adult and cord leukocytes with opsonins in pooled adult serum and zymosan and S. aureus 209P as phagocytizable particles. Although no distinction was found at higher serum concentrations (adult: 7.5 f 0.9 and cord: 6.9 f 1.1 for zymosan at 10% and adult: 4.6 & 0.9 and cord: 4.3 f 1.0 for S. aureus 209P at 58, respectively), considerably less phagocytic activity for zymosan became evident in cord leukocytes in lower serum concentrations (adult: 3.9 f 0.7 and cord: 2.9 + 0.5 at 2.5%). Among cord serum specimens, there was noted no apparent correlation between opsonic activity and immunoglobulin or complement component levels. Higher values of IgA, IgM, C3 and Factor B in adult sera apparently contribute to a generally higher opsonic activity than that of cord sera. SpeculationThese results further substantiate the opinion that cord serum has less opsonic activity against certain test particles than adult serum and that cord leukocytes have lower oxidative metabolic responses than adult leukocytes as measured by oxygen consump tion capacity. The importance of the choice of particles is stressed in interpreting the results, as opsonic requirements apparently differ from one article to another. Although further studies are obviously necessary, the current method appears to be suitable for determining opsonic and phagocytic activities.It is generally acknowledged that newborn infants are more susceptible to idkctions than adults and that this defect in the host defense mechanism is primarily due to a relative lack of humoral factors and to cellular functions as well (2,3,4,8,9,10,12,15,17,22). Although there is fair agreement on the above notion, some inconsistencies have been noted in experimental results, which are probably due to the different designs and variable conditions in the performance of theexperiments (1 1). The present investigation was undertaken to reevaluate the opsonic and phagocytic activities of cord serum a...

Serum Alpha₂-HS-Glycoprotein Levels in Neonatal Infections

“…It has been shown to possess nonspecific opsonic properties [1] and to enhance the phagocyt ic capacity of human monocytes [2], Studies of the phagocytic function in the newborn have revealed impaired polymorphonuclear (PMN) leukocyte phagocytic capacity when compared with results in adults [3], This may be related to the reduced opsonic properties of neonatal serum [4,5], Similarly, defective opsonization, especially at low serum concen trations, has been reported from studies of the immune function of severely malnour ished children [6]. Both malnourished chil dren and neonates suffer increased morbidity and mortality from bacterial infections.…”

Hyperphenylalaninaemia due to impaired dihydrobiopterin biosynthesis: Leukocyte function and effect of tetrahydrobiopterin therapy

“…Granulocyte functions were studied by the following examinations: Chemotaxis (agarose plate method, Nelson et al, 1975), bactericidal activity against Staphylococcus aureus 209 P and Streptococcus faecalis (Quie et al, 1967), oxygen consumption with opsonized zymosan (Kobayashi and Usui, 1982;Tanabe et al, 1983), and granulocyte adherence capacity (MacGregor et al, 1974). Lymphocyte functions were studied by the following: serum immunoglobulin levels, lymphocyte subpopulations (E-rosette forming cells and surface membrane immunoglobulin-bearing cells), phytohaemagglutinin and pokeweed mitogen (PWM)-induced proliferation, and PWM-induced B-cell differentiation capacity (Horino, 1982;Hyodo et al, 1983).…”

Effect of immunoglobulin therapy on phagocytosis by polymorphonuclear leucocytes in whole blood of neonates

“…The fetus receives IgG from the mother via the placenta and most of the IgG is transferred after 34 weeks of gestation [2], and therefore preterm neonates have lower levels of plasma IgG than term neonates [3]. Low concentrations of plasma IgG in premature neonates are widely speculated to be a crucial contributory factor to the increased susceptibility to infections seen in the neonatal period [4][5][6][7][8].…”