concanavalin-a and Down-Syndrome

Young patients with Down's syndrome (DS) have high rates of infections, malignancies and autoimmune phenomena. Therefore, DS may be considered as a model of precocious, abnormal ageing of the thymus-dependent system in man. In DS children less than 6 years of age, the levels of serum immunoglobulins did not differ from healthy controls, but after that age, considerable hyper-IgG and -IgA were found. Furthermore, high levels of IgG1 and IgG3 have been found, whereas a progressive decline of IgG2 and IgG4 with age has been observed. The frequency of hepatitis B virus carriers even in the youngest age group is much higher among DS children. It has been reported that an IgG response was detectable in 75% of controls after HBsAg vaccination as compared to the 16.6% of DS patients. The presence of autoantibodies against human thyroglobulin did show a positive association with HB Virus Ag carriers, but only in the oldest DS subjects. Natural antibodies against intestinal antigens are low, while in the presence of cow's milk, abnormally high titres against casein and beta-lactoglobulin were present. High levels of IgG antibodies against gliadin have been observed. In spite of a normal percentage of CD3- and CD2-positive lymphocytes, a high proportion of cells express low-avidity receptors for sheep erythrocytes. Although the proportion of CD4+ T-lymphocyte helper-cells is normal, a marked imbalance in the CD4+ subpopulations has been documented. The percentage of suppressor-cytotoxic CD8+ lymphocytes is markedly increased. The responses to phytohemagglutinin and concanavalin A are within the normal range in the first decade of life and decline progressively thereafter. A recent study reported defective proliferative response to allo-mixed lymphocyte culture, with decreased expression of the membrane CD25, low secretion of interleukin 2 in the supernatant and depressed allo-specific cytotoxic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Antibodies, Monoclonal; Antibody Formation; Antigens, CD; Child; Child, Preschool; Concanavalin A; Down Syndrome; Female; Hepatitis B Surface Antigens; Hepatitis B virus; Humans; Immunity, Cellular; Immunoglobulin A; Immunoglobulin G; Male; Phytohemagglutinins; Receptors, Antigen, T-Cell, alpha-beta; Receptors, Interleukin-2; T-Lymphocytes

Topics: Biomarkers; Chorionic Gonadotropin; Chromatography, Agarose; Concanavalin A; Down Syndrome; Female; Fetal Diseases; Gestational Age; Humans; Oligosaccharides; Pregnancy; Prenatal Diagnosis

Topics: Concanavalin A; Decidua; Down Syndrome; Female; Humans; In Vitro Techniques; Lectins; Placenta; Pregnancy; Pregnancy-Associated Plasma Protein-A; Protein Binding; Wheat Germ Agglutinins

Total alpha-fetoprotein (AFP) concentrations and proportions of AFP non-reactive with the lectin concanavalin A (Con A) were studied in extracellular fluid of 22 first-trimester fetuses. Total AFP concentrations were significantly lower in fetuses with Down's syndrome than in those with Mendelian-inherited diseases and normal karyotypes. The proportion of non-Con-A-reactive AFP was low in the fetal compartment (< or = 3.5%) irrespective of the fetal karyotype. So the AFP production in the fetal liver as well as in the yolk sac seems to be reduced in Down's syndrome. The fetus itself contributes only marginally to the non-Con-A-reactive AFP pool of amniotic fluid, which is therefore almost entirely of yolk sac origin. This pool is preserved well into the second trimester of pregnancy, despite cessation of yolk sac AFP production at the end of the first trimester, indicating a very slow rate of disappearance of proteins out of amniotic fluid.

Topics: alpha-Fetoproteins; Concanavalin A; Down Syndrome; Female; Gestational Age; Humans; Karyotyping; Liver; Pregnancy; Prenatal Diagnosis; Yolk Sac

Lymphocyte capping with concanavalin A was studied in adult patients with Down's syndrome and aged patients with primary degenerative dementia. In both disorders a decreased capping was found as compared with age-matched and clinically relevant control groups. Colchicine had a strong enhancing effect on capping in Down's syndrome. In primary degenerative dementia the enhancing effect of colchicine was restricted to a subgroup of patients with onset of the dementing illness before the age of 80 years.

Topics: Adult; Age Factors; Aged; Colchicine; Concanavalin A; Dementia; Down Syndrome; Female; Humans; Lymphocytes; Male; Mental Disorders; Microtubules; Middle Aged; Receptor Aggregation

The effect of different concentrations of LiCl or KCl (0.6-20 meq/liter) on PHA-stimulated lymphocytes from young, old, and Down's syndrome subjects was studied. LiCl showed a dramatic enhancing effect on [3H]thymidine incorporation induced by a suboptimal dose of PHA in old subjects and Down's syndrome patients. An increase of [3H]thymidine incorporation in human lymphocytes stimulated by a suboptimal dose of PHA was also observed with KCl. This effect was higher in old subjects than that observed in young and Down's subjects. LiCl and KCl can modulate and partially restore the derangement in early events of mitogen stimulation which seems to be present in lymphocytes from both old and Down's syndrome subjects.

Topics: Adolescent; Adult; Aged; Aging; Child; Concanavalin A; Down Syndrome; Humans; Lithium; Lymphocyte Activation; Phytohemagglutinins; Potassium; Sodium-Potassium-Exchanging ATPase; Time Factors

Increased polyamine content is associated with increased rates of cell growth. Several Down's syndrome (D.S.) tissues have been shown to have decreased growth rates. Studies were undertaken to determine if the polyamine content of stimulated D.S. lymphocytes was similar to that of stimulated normal cells. Lymphocytes were isolated and cultured in the presence of Concanavalin A for 4 or 5 days. Polyamines were than extracted and quantitated. After 4 days spermidine content for normal cells was 930.9 +/- 127 and for D.S. cells 489.2 +/- 113.1 nmoles/10(9) cells (P less than 0.025). Spermine content of normal cells was 1152.8 +/- 157.4 and for D.S. cells 533.9 +/- 82.0 (P less than 0.005). After 5 days in culture spermidine content of normal cells was 803.0 +/- 75.9 and for D.S. cells 446.2 +/- 76.5 nmoles/10(9) cells (P less than 0.005). Spermine content was 1155.7 +/- 121.9 for normal cells and 555.1 +/- 68.4 nmoles/10(9) for D.S. cells. Decreased content of polyamines in D.S.-stimulated lymphocytes is most probably due to decreased rate of polyamine synthesis. Decreased content of polyamines in response to stimulation may be a factor in decreased growth rates and altered immune function seen in D.S. patients.

Topics: Adolescent; Adult; Cells, Cultured; Concanavalin A; Down Syndrome; Humans; Lymphocyte Activation; Lymphocytes; Spermidine; Spermine; Time Factors

Lymphocyte responses to phytohemagglutinin P (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) and incidence of serum lymphocytotoxins in 20 Down syndrome persons were investigated. There was no change in lymphocyte blastogenesis to mitogens in younger Down syndrome individuals (less than 30 years of age) as compared to control persons. The lymphocytes of Down syndrome subjects over 30 years of age showed significantly decreased responses to PHA, Con A, and PWM. Results suggest that with increasing age, Down syndrome persons seem to have an impairment in lymphocyte function. Serum lymphocytotoxins that were not related to age occurred in 4 of the Down syndrome subjects (20 percent). There was no correlation between the presence of lymphocytotoxins and lymphocyte blastogenesis in these subjects.

Topics: Adolescent; Adult; Antilymphocyte Serum; Cells, Cultured; Child; Concanavalin A; Down Syndrome; Female; Humans; Lymphocytes; Male; Phytohemagglutinins; Pokeweed Mitogens

Topics: Adolescent; Adult; B-Lymphocytes; Cell Division; Child; Child, Preschool; Concanavalin A; DNA; Down Syndrome; Humans; Interferons; Leukocyte Count; Lymphocytes; Middle Aged; Phytohemagglutinins; T-Lymphocytes; Tetanus Toxoid; Thymidine

Topics: Child; Child, Preschool; Chromosomes, Human, 21-22 and Y; Concanavalin A; Depression, Chemical; Down Syndrome; Humans; Infant; Interferons; Lectins; Lymphocyte Activation; Phytohemagglutinins

Topics: Adolescent; Adult; B-Lymphocytes; Child; Child, Preschool; Concanavalin A; Down Syndrome; Humans; Leukocyte Count; Phytohemagglutinins; Pokeweed Mitogens; Receptors, Antigen, B-Cell; Rosette Formation; Stress, Psychological; T-Lymphocytes; Thymidine

An alpha-feto-protein (AFP) is present in many mammals, in birds, and in sharks during development. The AFP present in different species have similar physicochemical properties and often have common antigenic determinants. Their study, both in health and disease, has provided a useful model for the understanding of other phase-specific antigens and the activation of the genes which control their synthesis. In the human fetus, the level of AFP falls with increasing maturity. The more sensitive methods of detection have disclosed that this fetal protein persists in trace amounts throughout life and its level increases in maternal blood during pregnancy. The principal sites of synthesis are the fetal liver and in some mammals, the yolk sac splanchnopleur. In humans as well as in mice and cows, it is notable that the synthesis of AFP is increased in liver cancer cells and that high levels of this protein are present in serum. Elevated values of AFP have also been detected in human subjects with undifferentiated tumours of the testis and ovary. A fall to normal levels has been noted in cases of complete remission after surgery and a return to high levels in patients who develop metastases. In some patients with hepatitis a temporary rise in the level of AFP has also been observed. In recent years, the detection of high levels of AFP in amniotic fluid has proved to be of great value for the prenatal diagnosis of neural-tube defects. Abnormal levels have also been found in the amniotic fluid or in maternal serum in cases of spontaneous abortion. Such measurements are now being assessed as a methodof monitoring abnormal pregnancy.

Topics: alpha-Fetoproteins; Amniotic Fluid; Anencephaly; Animals; Antigen-Antibody Reactions; Carcinoma, Hepatocellular; Concanavalin A; Cystic Fibrosis; Down Syndrome; Female; Fetal Proteins; Gastrointestinal Neoplasms; Gestational Age; Hepatitis; Humans; Immunologic Techniques; Infant, Newborn; Liver; Liver Neoplasms; Metabolism, Inborn Errors; Neoplasm Metastasis; Neoplasms, Experimental; Pregnancy; Spinal Dysraphism; Teratoma