Humoral immune functions in IL-4 transgenic mice

We have analyzed mice expressing IL-4 as a transgene, and found that expression of this lymphokine has profound effects on B cell function. B cells from transgenic mice exhibit phenotypic changes, including an increase in size and elevated expression of class II MHC. IL-4 increases the quantity of IgE produced by transgenic-derived B cells in response to LPS stimulation. In vivo, IL-4 markedly affects the serum Ig isotype repertoire. Serum levels of IgG1 and IgE are elevated, and levels of IgG2a, IgG2b, and IgG3 are depressed in IL-4 transgenic mice. Ag-specific antibody responses to immunization with hapten-carrier conjugates are also affected by IL-4. Transgenic mice show increased anti-hapten IgE and IgG1 and reduced anti-hapten IgG2a, IgG2b, and IgG3, compared with wild-type mice. Ag-specific IgE is substantially induced by T cell-dependent Ag, but not T cell-independent Ag, suggesting that cognate T-B interactions in addition to IL-4 are required for generating IgE responses in vivo. In vivo treatment with the anti-IL-4 mAb 11B11 reverses many of the isotype alterations in the transgenic mice, indicating that these changes arise as a direct consequence of IL-4 secretion.     

Humoral immune response to filarial antigens in chyluria

Humoral immune parameters like total immunoglobulins and specific antibody levels in serum were studied in filarial chyluria patients. Mean serum IgG was significantly reduced in this group compared to normal controls, while IgA and IgM levels remained comparable to controls. Anti-filarial antibody titre as measured by enzyme-linked immunosorbent assay also was significantly reduced. However, the total and specific IgE antibody titre was similar to that of controls. Specific IgE contents of the patients’ sera could be related to their microfilaraemic status.     

Altered immune response in mice deficient for the G protein-coupled receptor GPR34

The X-chromosomal GPR34 gene encodes an orphan G(i) protein-coupled receptor that is highly conserved among vertebrates. To evaluate the physiological relevance of GPR34, we generated a GPR34-deficient mouse line. GPR34-deficient mice were vital, reproduced normally, and showed no gross abnormalities in anatomical, histological, laboratory chemistry, or behavioral investigations under standard housing. Because GPR34 is highly expressed in mononuclear cells of the immune system, mice were specifically tested for altered functions of these cell types. Following immunization with methylated BSA, the number of granulocytes and macrophages in spleens was significantly lower in GPR34-deficient mice as in wild-type mice. GPR34-deficient mice showed significantly increased paw swelling in the delayed type hypersensitivity test and higher pathogen burden in extrapulmonary tissues after pulmonary infection with Cryptococcus neoformans compared with wild-type mice. The findings in delayed type hypersensitivity and infection tests were accompanied by significantly different basal and stimulated TNF-α, GM-CSF, and IFN-γ levels in GPR34-deficient animals. Our data point toward a functional role of GPR34 in the cellular response to immunological challenges.     

Humoral immune response against hepatitis C virus

Antibodies are in several instances a reliable marker indicating vigorous immune response against infectious agents and in several viral diseases presence in the blood of specific anti-viral antibodies indicates an effective protection. However, this is not always true. For example, in the case of hepatitis C virus (HCV) an important human pathogen considered the causative agent of the nonA- nonB hepatitis, in spite of an intense antibody response there is no protection against a new infection and in the majority of infected individuals the virus overcomes host defences establishing a persistent infection. Here we describe how the dissection of the humoral immune response against HCV glycoprotein E2 of infected patients was useful for a better comprehension of the virus-host interplay. Cross-reactive antibodies directed against E2 are produced by the HCV-infected patient, but not all of them are protective, and some could even result to be detrimental for the patient. The cross-reactive anti-HCV/E2 humoral antibody response is complex and not necessarily completely beneficial to the host.     

Humoral immune response to fibrillar beta-amyloid peptide

The beta-amyloid peptide (Abeta) is a normal product of the proteolytic processing of its precursor (beta-APP). Normally, it elicits a very low humoral immune response; however, the aggregation of monomeric Abeta to form fibrillar Abeta amyloid creates a neo-epitope, to which antibodies are generated. Rabbits were injected with fibrillar human Abeta(1-42), and the resultant antibodies were purified and their binding properties characterized. The antibodies bound to an epitope in the first eight residues of Abeta and required a free amino terminus. Additional residues did not affect the affinity of the epitope as long as the peptide was unaggregated; the antibody bound Abeta residues 1-8, 1-11, 1-16, 1-28, 1-40, and 1-42 with similar affinities. In contrast, the antibodies bound approximately 1000-fold more tightly to fibrillar Abeta(1-42). Their enhanced affinity did not result from their bivalent nature: monovalent Fab fragments exhibited a similar affinity for the fibrils. Nor did it result from the particulate nature of the epitope: monomeric Abeta(1-16) immobilized on agarose and soluble Abeta(1-16) exhibited similar affinities for the antifibrillar antibodies. In addition, antibodies raised to four nonfibrillar peptides corresponding to internal Abeta sequences did not exhibit enhanced affinity for fibrillar Abeta(1-42). Antibodies directed to the C-terminus of Abeta bound poorly to fibrillar Abeta(1-42), which is consistent with models where the carboxyl terminus is buried in the interior of the fibril and the amino terminus is on the surface. When used as an immunohistochemical probe, the antifibrillar Abeta(1-42) IgG exhibited enhanced affinity for amyloid deposits in the cerebrovasculature. We hypothesize either that the antibodies recognize a specific conformation of the eight amino-terminal residues of Abeta, which is at least 1000-fold more favored in the fibril than in monomeric peptides, or that affinity maturation of the antibodies produces an additional binding site for the amino-terminal residues of an adjacent Abeta monomer. In vivo this specificity would direct the antibody primarily to fibrillar vascular amyloid deposits even in the presence of a large excess of monomeric Abeta or its precursor. This observation may explain the vascular meningeal inflammation that developed in Alzheimer's disease patients immunized with fibrillar Abeta. Passive immunization with an antibody directed to an epitope hidden in fibrillar Abeta and in the transmembrane region of APP might be a better choice in the search for an intervention to remove Abeta monomers without provoking an inflammatory response.     

Humoral immune response in children with iron-deficiency anaemia.

The humoral immune response (as shown by plasma immunoglobulin concentrations and antibody response to diphtheria and tetanus toxoids) was evaluated in 14 children with iron-deficiency anaemia and in 24 normal controls. Mean concentrations of haemoglobin and serum iron and mean transferrin saturation were significantly lower in children with iron-deficiency anaemia than in controls. Serum immunoglobulin concentrations were within the normal range in both groups. Two weeks after immunisation with diphtheria and tetanus toxoids the concentrations of IgG increased significantly in both groups. Antibody titres in iron-deficient children were similar to those of controls before and after immunisation. The mean T-lymphocyte count was significantly lower in iron-deficient children than that in controls, but the mean B-lymphocyte counts were similar in the two groups. These observations suggest that humoral immunity in children is not affected by iron deficiency and that conventional immunisation programmes would be effective in children with iron-deficiency anaemia.     

Thyroid hormone and cardiac function in mice deficient in thyroid hormone receptor-alpha or -beta: an echocardiograph study

We investigated the effect of thyroid hormone (TH) receptor (TR)alpha and -beta isoforms in TH action in the heart. Noninvasive echocardiographic measurements were made in mice homozygous for disruption of TRalpha (TRalpha(0/0)) or TRbeta (TRbeta(-/-)). Mice were studied at baseline, 4 wk after TH deprivation (using a low-iodine diet containing propylthiouracil), and after 4-wk treatment with TH. Baseline heart rates (HR) were similar in wild-type (WT) and TRalpha(0/0) mice but were greater in TRbeta(-/-) mice. With TH deprivation, HR decreased 49% in WT and 37% in TRbeta(-/-) mice and decreased only 5% in TRalpha(0/0) mice from baseline, whereas HR increased in all genotypes with TH treatment. Cardiac output (CO) and cardiac index (CI) in WT mice decreased (-31 and -32%, respectively) with TH deprivation and increased (+69 and +35%, respectively) with TH treatment. The effects of CO and CI were blunted with TH withdrawal in both TRalpha(0/0) (+8 and -2%, respectively) and TRbeta(-/-) mice (-17 and -18%, respectively). Treatment with TH resulted in a 64% increase in LV mass in WT and a 44% increase in TRalpha(0/0) mice but only a 6% increase in TRbeta(-/-) mice (ANOVA P < 0.05). Taken together, these data suggest that TRalpha and TRbeta play different roles in the physiology of TH action on the heart.     

Response of serine antiproteases to growth hormone therapy in growth hormone deficient children

Growth hormone regulates the hepatic mRNA levels of alpha 1-antitrypsin and two contrapsin-like mRNAs in the rat. To determine whether growth hormone regulates similar serine protease inhibitors in humans, we measured serum alpha 1-antitrypsin, alpha 1-antichymotrypsin, and antithrombin III by radioimmunodiffusion in 16 growth hormone deficient children before and after growth therapy. Of the 19 determinations made, 17/19 showed an increase in alpha 1-antitrypsin after administration of growth hormone, 198.6 +/- 39.1 mg/dl before growth hormone and 239.4 +/- 44 mg/dl after growth hormone (p = 0.005). Specificity of the response for alpha 1-antitrypsin was indicated by the fact that neither alpha 1-antichymotrypsin or antithrombin III values changed after growth hormone (p = 0.6 and 0.5, respectively). These data are compatible with the hypothesis that growth hormone regulates serine protease inhibitors in humans and suggests that investigation of other members of the serpin gene family might prove fruitful in defining additional growth hormone target genes.     

Comparative study of biosynthetic human growth hormone immunogenicity in growth hormone deficient children

The immunogenicities of six recombinant human growth hormone (rhGH) preparations, from KABI (A rhGH191 and B rhGH192), Eli Lilly (C), Nordisk (D), Sanofi (E) and Serono (F), used to treat 260 GH-deficient children, have been compared using a common specific and sensitive procedure for antibody determination. For this purpose we developed two immunoassays: a competitive liquid radioimmunoassay using 125I-rhGH, and an immunometric solid enzymoimmunoassay in which the rhGHs were immobilized. Blood samples were collected from the GH-deficient children before treatment and after 3, 6, 9, 12, 18 and 24 months of therapy. Human GH antibodies were detected in children treated with 3 of the 6 rhGH preparations. Seven percent of the patients treated with hormone A, 14% with hormone B and 22% with hormone C formed antibodies against the respective rhGH. Differences in capacity and affinity of the hGH antibodies were observed between these anti-GH-positive groups. They could be divided into 2 groups according to their immunopotency. One group (7, 14 and 6% of the patients treated with hormones A, B and C, respectively) developed anti-hGH antibodies with very low binding capacities (30-100 fmol/ml). The other group (16% of the patients treated with hormone C) developed IgG-type antibodies to hGH with higher binding capacities (200-1,200 fmol/ml) and a measurable binding affinity (Ka = 10(8) M-1). These hGH antibodies partially inhibited the binding of labeled GH to its specific liver membrane receptor. However, because of their low titer, they did not inhibit growth in the treated children.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fertility of transgenic female mice expressing bovine growth hormone or human growth hormone variant genes

Although growth hormone (GH) exerts various direct and indirect stimulatory effects on gonadal development and function, excessive levels of GH in acromegalic patients and in transgenic animals are often associated with reproductive disorders. We have examined reproductive performance of transgenic female mice expressing the following hybrid genes: mouse metallothionein-1 (MT)/human placental GH variant (hGH.V), MT/bovine GH(bGH), and phosphoenolpyruvate carboxykinase (PEPCK)/bGH. This allowed us to evaluate the effects of chronic GH excess in three animal models and to obtain some information on the significance of the lactogenic activity of the foreign GH (hGH.V vs. bGH) and on the developmental stage of transgene expression (MT vs. PEPCK). Transgenic animals from each line had elevated plasma insulin-like growth factor-I levels and greatly increased adult body weight. Plasma bGH levels were significantly higher in PEPCK/bGH than in MT/bGH transgenic mice. Approximately 20% of transgenic MT/hGH.V and MT/bGH females and over 60% of transgenic PEPCK/bGH females were infertile. Transgenic females that did reproduce ovulated either a normal or increased number of eggs but exhibited a variety of reproductive disorders including increased interval between pairing with a male and conception, increased interval between litters, reduced number of litters, reduced fetal growth, increased pre- and postnatal mortality, and alterations in sex ratio. Among adult offspring of these females, the proportion of transgenic animals was significantly less than the expected 50%. While some characteristics (e.g., fetal crown-rump length and weight on Day 14 of pregnancy) were affected to a comparable extent in transgenic females from all three lines, MT/hGH.V and PEPCK/bGH females were, in general, more severely affected than the MT/bGH animals. Sterility of PEPCK/bGH females appeared to be due to luteal failure since treatment with progesterone led to pregnancy. Greatly increased intervals between successive litters appeared to be due to failure to mate during postpartum estrus and to sterile matings during this period. Reduced fetal size and weight may have been due to chronic glucocorticoid excess because comparable changes could be induced in normal females by injections of dexamethasone during pregnancy, and plasma corticosterone levels were previously shown to be elevated in transgenic mice from each of these lines. Comparison of these results with data obtained from matings of normal female mice to transgenic males from the same lines suggests that reduced fetal growth is due primarily to maternal genotype, while reduced "transmission" of the hybrid genes is not, and presumably reflects increased mortality of transgenic progeny at various stages of development.(ABSTRACT TRUNCATED AT 400 WORDS)     

Humoral immune response against epidermal growth factor encapsulated in dehydration rehydration vesicles of different phospholipid composition

We investigated the influence of dehydration-rehydration vesicles (DRV) phospholipid composition and the addition of other components on human recombinant epidermal growth factor (hrEGF) encapsulation efficiency and its release from liposomes. Encapsulation of EGF into DRV composed of phosphatidylcholine with different unsaturation levels was around 20-35%. The best result was obtained with dipalmitoyl phosphatidylcholine: cholesterol (DPPC:Ch) liposomes (35%) corresponding to the lowest hrEGF release during one month of storage. Even with this phospholipid composition, modification of the DRV procedure by including an extrusion step did not improve hrEGF encapsulation efficiency, rendering less stable particles. The inclusion of recombinant P64k from Neisseria meningitidis (rP64k), as such or conjugated to hrEGF, decreased the encapsulation efficiency of the latter protein into DRV or freeze and thaw multilamellar vesicles (FATMLV). The hrEGF release from liposomes could be related to the interaction between this polypeptide and the bilayer, as evidenced by increased carboxyfluorescein release from hrEGF-DRV; less susceptibility to fluorescence quenching by acrylamide in the presence of liposomes; and a measurable decrease of phospholipid phase transition Delta enthalpy (DeltaH). DRV comprising saturated phospholipids (DPPC:Ch or distearoyl phosphatidylcholine [DSPC]:Ch) and containing the conjugate EGF-P64k induced a more efficient immune response against hrEGF than unsaturated phospholipid and alum in terms of total IgG, IgG(2a), and IgG(2b) subclasses and the ability of antibody to inhibit the interaction of the EGF receptor with hrEGF.     

Humoral immune response in patients with bronchopulmanory infections to immunotherapy

The content of IgA, IgM, IgG and the level of specific antibodies in the blood serum of patients with bronchopulmonary diseases after a course of immunotherapy with polycomponent vaccine B[symbol: see text]-4 was studied. A rise in the concentration of IgM due to the synthesis of specific antibodies to Proteus vulgaris, Escherichia coli and Klebsiella pneumoniae was found to occur. The examination of sick children revealed that a high proportion of them (54%) showed a pronounced decrease in the level of IgA. The use of the preparation made it possible to enhance the level of IgA.     

Impaired melanoma growth in VASP deficient mice

Progression of tumors depends on interactions of cancer cells with the host environment. Expression of the cytoskeleton protein VASP is upregulated in various cancer entities. We analyzed the role of VASP for melanoma growth in murine allograft models. Growth of VASP expressing melanomas was retarded in VASP^?/? versus wild-type animals. Over time tumor size was <50% in VASP^?/? versus wild-type animals and independent of expression levels of Ena/VASP protein family members. Histological analyses showed smaller cells with impaired nutrition status and less vascularization in melanomas derived from VASP^?/? versus counterparts from wild-type mice. Cumulatively, the data reveal a critical role of VASP in non-tumor cells in the tumor environment for melanoma growth in vivo.     

Effects of human growth hormone on erythrocyte insulin binding in growth hormone deficient children

In this paper, the effect of acute human growth hormone (GH) administration on erythrocyte insulin binding in GH deficient children (N = 6) was studied. Following GH (0.25 U/kg) administration, the blood levels of GH peaked within 4 to 8 h and returned to basal levels 24 h later. However, the changes in somatomedin activity, free fatty acid (FFA), urea, blood glucose and 125I-insulin binding to erythrocyte were observed around 24 h following the injection, and there was a converse relationship between maximum percent 125I-insulin binding (IBmax) and FFA (P less than 0.02). By Scatchard analysis it was found that the decrease in IBmax is mainly due to the change in the number of insulin receptors. These results suggest that GH may possibly affect the insulin binding to erythrocyte indirectly through metabolic changes as a result of hormonal changes in GH deficient children.     

Global situation of growth hormone treatment in growth hormone- deficient children

Diagnostic criteria and treatment modalities were investigated through questionnaires from eleven countries and compared with those in Japan. All countries but Australia, where the patients can be treated with GH judged by only auxological data, use the combination of auxological data and peak GH value in provocation tests. GH value is still gold standard, but the cut off value differs among countries. Apart from the differences in cut off value, since it is well-known that GH concentrations vary according to the assay methods and measurement kits, standardization of the measurement kits is mandatory. GH dose ranges between 0.5 and 0.7 IU/kg/week in most countries. The lowest dose (fixed dose of 0.5 IU/kg/week) is used in Japan and the heightest dose (1.05 IU/kg/week) is used in the USA. The costs for GH treatment are most expensive in Japan.