The distribution and morphology of prefrontal cortex pyramidal neurons identified using anti-neurofilament antibodies SMI32, N200 and FNP7. Normative data and a comparison in subjects with schizophrenia, bipolar disorder or major depression.

Alterations in the density and size of pyramidal neurons in the prefrontal cortex have been described in schizophrenia and mood disorder. However, the changes are generally modest and have not always been replicated. We investigated the possibility that specific pyramidal neuron sub-populations, defined by their immunoreactivity with the anti-neurofilament antibodies SMI32, N200, and FNP7, are differentially affected in these disorders. First, we assessed the distribution and characteristics of pyramidal neurons labelled by the antibodies in the human dorsolateral prefrontal cortex (Brodmann areas 9, 32, 46), using single and double label immunocytochemistry and immunofluorescence. Three largely separate sub-populations of pyramidal neurons were identified, although with more substantial overlap between SMI32- and FNP7-positive neurons in lamina V. We then determined the density, size and shape of the three pyramidal neuron sub-populations in area 9 in patients with schizophrenia, bipolar disorder, or major depressive disorder, compared to controls (n=15 in each group). We found a lower density of lamina III N200-positive neurons in major depressive disorder than in schizophrenia or bipolar disorder. There were no other overall differences in neuronal density, or in neuronal size or shape, although a planned secondary analysis supported the previously reported decrease of neuronal size in lamina V in bipolar disorder. In summary, our study illustrates a conceptual and methodological approach which may be of value for investigating the differential neuropathological involvement of pyramidal neuron sub-populations. However, we found no clear evidence that the prefrontal neuropathology of schizophrenia or mood disorders preferentially affects SMI32-, N200- or FNP7-immunoreactive pyramidal neurons.

Characterisation of epitopes of pan-IgG/anti-G3m(u) and anti-Fc monoclonal antibodies.

The characterisation of monoclonal antibodies (MAbs) and their epitopes is important prior to their application as molecular probes. In this study, Western blotting using IgG1 Fc and pFc' fragments was employed to screen seven MAbs before pepscan analysis to determine their reactivity to potentially linear epitopes. MAbs PNF69C, PNF110A, X1A11 and MAbs WC2, G7C, JD312, 1A1 detected epitopes within the C(H)3 and C(H)2 domains, respectively. However, only four MAbs showed pepscan profiles that highlighted likely target residues. In particular, MAbs PNF69C and PNF110A that have previously been characterised with pan-IgG and anti-G3m(u) specificity, detected the peptide motif 338-KAKGQPR-344 which was located within the N-terminal region of the C(H)3 domain. Furthermore the majority of residues were present in all four IgG subclasses. Consequently the peptide identified was consistent with the pan-IgG nature of these antibodies. By using PCImdad, a molecular display programme, this sequence was visualised as surface accessible, located in the C(H)2/C(H)3 inter-domain region and proximal to the residue arginine(435). It is speculated that this residue may be important for phenotypic expression of G3m(u) and specificity of these reagents. Pepscan analysis of MAbs G7C and JD312 (both pan-IgG) highlighted the core peptide sequence 290-KPREE-294, which was present in the C(H)2 domain and was common to all four IgG subclasses. PCImdad also showed this region to be highly accessible and was consistent with previous bioinformatic and autoimmune analysis of IgG. Overall these MAbs may serve as useful anti-IgG or anti-G3m(u) reagents and probes of immunoglobulin structure.

Insulin-like peptides are not involved in maturation or functional recovery of neural circuits in the locust flight system.

We sought to manipulate maturation and functional recovery of locust flight circuitry by treating locusts with pharmacological doses of bovine anti-insulin and insulin. Anti-insulin treatment of maturing locusts caused reduced growth of the thoracic nervous system, lower body weight, and softer cuticles compared with control locusts. We were unable to block either maturation or recovery of flight circuitry with anti-insulin. We propose that insulin-related peptides are involved in growth and cuticular changes during adult maturation, but have no role in promoting neuronal sprouting during this period or as a result of injury.

IgG anti-IgA subclasses in common variable immunodeficiency and association with severe adverse reactions to intravenous immunoglobulin therapy.

The current therapy for common variable immunodeficiency is based on the administration of intravenous immunoglobulin preparations which may cause severe adverse reactions. Some reports have associated these reactions with IgG anti-IgA antibodies, although this is not yet clear. We analyzed 20 sera from common variable immunodeficiency patients by an enzyme immunoassay to detect IgG anti-IgA and determine its subclass profile. Five patients presented high levels of these antibodies, all of them had IgG1, two had IgG2 and IgG4 and one had IgG3. Three of these five patients were receiving non IgA depleted intravenous immunoglobulin and had no severe adverse reactions. One patient had persisted with similar high levels of IgG anti-IgA during three years. Therefore, the IgG anti-IgA antibodies, regardless to their subclass profile in the common variable immunodeficiency patients sera do not seem to be associated with severe adverse reactions to intravenous immunoglobulins.

Internal image concept revisited.

Internal image of the antigen represents an essential element of network theory. From theoretical standpoint this concept considers that the idiotypes which are phenotypic markers of variable region of antigen receptor of lymphocytes represent links between the universe of self and foreign antigens and the immune system. This concept had seen rapid practical applications. Ensuing years may see whether these applications are beneficial or rather represent research tools in biological sciences.

Idiotipos y antiidiotipos: estructura y función en autoinmunidad / Anti-idiotypes and idiotypes: structure and autoimmunity function

Se presenta una revisión sobre la estructura de las inmunoglobulinas y los idiotipos que constituyen las regiones hipervariables que unen al antígeno; según la teoría de jerne, un idiotipo genera otro anticuerpo (antiidiotipo) que reconoce los epitopos de las regiones hipervariables, creando una red que en teoría regula la síntesis de anticuerpos. Funcionalmente existen dos clases: 1) Los idiotipos que constituyen imágenes internas del sitio de unión con el antígeno y 2) Los que reconocen sitios diferentes. Cuando los idiotipos son compartidos por individuos de una misma especie se denominan públicos y son generados vía línea germinal, y los que están presentes en un solo individuo corresponden a idiotipos privados y son producto de mutación somática. En autoinmunidad los idiotipos identifican autoanticuerpos patogénicos órgano-específicos como en pénfigo o penfigoide; éstos son capaces de inducir directamente lesión tisular, que es reproducible en animales. Los órgano-inespecíficos como los autoanticuerpos antinucleares de lupus, generalmente no inducen lesión directa. Finalmente, se revisan las evidencias y modelos experimentales que sugieren que un idiotipo autoinmune humano inyectado en un animal genera un antiidiotipo, que simula al antígeno, este genera un tercer anticuerpo idéntico al autoanticuerpo humano y los animales desarrollan síntomas similares a los observados en padecimientos autoinmunes como lupus

Influence of anti-IgG antibodies on graft outcome in live related donor renal transplantation.

To study the role of pretransplant IgG anti-F(ab)2 gamma and IgG anti-Fc antibodies on the outcome of live related donor (LRD) kidney transplantation, serum samples from 60 recipients and 20 normal controls (NC) were tested using enzyme immunoassay. Patients with well-functioning grafts (WFG) after 1 year of follow-up had significantly higher IgG anti-F(ab)2 gamma activity expressed as mean optical density measured at 405 nm, i.e. 0.426 +/- 0.06 as compared to NC (0.167 +/- 0.046) or patients undergoing reversible rejection (RR) (0.145 +/- 0.043) and irreversible rejections (IR) (0.26 +/- 0.01). However, patients with IR had higher IgG anti-Fc activity (0.424 +/- 0.2) than the WFG group (0.1 +/- 0.02) and NC (0.095 +/- 0.02), with the RR group values in between (0.248 +/- 0.06). The same trend was observed when the data were analysed according to the serum creatinine levels. We conclude that in the LRD renal transplant situation, pretransplant serum IgG anti-F(ab)2 gamma activity has a protective effect on graft survival while IgG anti-Fc has a detrimental effect on graft outcome.

Anti-idiotypic antibodies: biological function and structural studies.

Under a variety of circumstances antibodies can be elicited against the variable region of other antibody molecules (anti-idotypic antibodies, anti-ids). Some of the antibodies are directed against the binding sites of the eliciting antibodies. Of particular interest are the antibodies that recognize epitopes of the original antibody that are in contact with antigen. Antibodies of this kind have been produced and used in a variety of situations including attempts at using them as therapeutic agents. In recent years structural data at the atomic level have emerged for anti-idiotypic antibodies from X-ray diffraction studies. These studies provided structural basis for molecular mimicry of anti-ids. For a large globular antigen (lysozyme), where epitope is noncontinuguous, molecular mimicry is not present at the atomic level. In this case, idiotopes are largely composed of CDR residues, but framework residues are also used. For an epitope that is sequence-specific (anti-FIPV system), molecular mimicry appears to be present as evidenced by the sequence homology between the CDR loops of the anti-id and the epitope of the original antigen. In the case of a small hormone antigen (angiotensin II), an internal image of the eliciting antigen appears to be represented in a single CDR loop of the antiiodiotypic antibody.

Serum IgA class anti-IgA antibody in IgA nephropathy.

IgA class anti-IgA antibody was sought by an immunoabsorbent technique in sera from patients with IgA nephropathy (IgA-N, n = 62), other forms of primary glomerulonephritis (PGN, n = 41), seropositive rheumatoid arthritis (RF-positive, n = 18) and normal controls (c, n = 50). IgA-N (31%) and RF-positive (56%) patients showed a significant increase in IgA anti-IgA antibody levels. The subclass of IgA anti-IgA antibody was predominantly IgA1 in both IgA-N and RF-positive patients. Size analysis revealed the dimer/monomer ratio to be significantly increased in IgA-N patients compared with that of RF-positive patients (p = 0.03). These results indicate the possible existence of the dimeric form of IgA class anti-IgA antibody in the circulation of IgA-N patients.

Anti-IgA antibodies in IgA-deficient children.

IgG and IgM isotype antibodies to polyclonal human IgA, myeloma IgA1, and myeloma IgA2 were estimated in 38 IgA-deficient children aged between 0.9 and 15 years. All children had IgM anti-IgA antibodies. IgG antibodies against either polyclonal IgA, IgA1, or IgA2 were present in 63% of the IgA-deficient children. IgG anti-IgA antibodies were detected against all three antigens in 8 of 11 severely IgA-deficient children and in 7 of 27 partially IgA-deficient children, but in only 1 of 23 healthy adult controls. The proportion of children with IgG anti-IgA antibodies was significantly greater in the severely IgA-deficient group in comparison with the partially IgA-deficient group and the adult controls (chi-square test, P less than 0.01 and P less than 0.005, respectively). There was a strong correlation within each IgG subclass between antibody responses toward each of the three IgA antigens. Twenty-four children were followed over a period ranging from 0.9 to 11 years (mean, 2.3 years). Three children who were initially IgG anti-IgA antibody negative became antibody positive and three who were antibody positive became antibody negative. Five children with severe IgA deficiency remained severely IgA deficient and IgG antibodies to IgA persisted in all five at follow-up. The presence of IgG anti-IgA antibodies did not influence the normalization of serum IgA at follow-up in 14 of 19 children who were initially partially IgA deficient.

Selection of antibody repertoires by anti-idiotypes can occur at multiple steps of B cell differentiation.

These experiments were designed to evaluate whether alterations in Id expression after anti-Id treatments result from direct modulation of Id-producing B cells, and whether idiotypic selection operates in bone marrow or spleen B cells. By using the NPb Id model, we have studied the functional behavior of isolated LPS-reactive B cells transferred from B6 mice into histocompatible LPS-NR B10.Cr hosts and primed with LPS conjugates of anti-Id antibodies. We have found that previous anti-idiotypic manipulation of host mice by neonatal administration of suppressive doses of Ac 38 antibodies, or adult injection of enhancing doses of Ac 146 antibodies, modulated the T cell-independent Id response of either immature bone marrow or mature splenic responding cells, transferred from normal, untreated donors. These results are interpreted to suggest that selection of antibody repertoires by anti-Id may occur at multiple steps of B cell differentiation.

Immunoglobulin prophylaxis in patients with antibody deficiency syndromes and anti-IgA antibodies.

Sera from three hundred five patients with immunoglobulin deficiencies were analyzed for the presence of anti-IgA antibodies by using indirect agglutination and enzyme-linked immunosorbent assay (ELISA). Anti-IgA antibodies were observed in 15 of 68 (22%) patients with hypogammaglobulinemia and 53 of 185 (29%) patients with selective IgA deficiency, both groups having serum IgA less than 0.05 g/liter. The highest frequency, 6 of 10 or 60%, was noted for patients with a combined IgA-IgG2 deficiency. No anti-IgA antibodies were detected in 25 patients with serum IgA between 0.05 and 0.27 g/liter and normal amounts of serum IgM and IgG or in 17 patients with hypogammaglobulinemia who had serum IgA of 0.05-0.7 g/liter. The anti-IgA antibodies were primarily of the IgG class, but IgD and IgM anti-IgA were occasionally found. IgE anti-IgA antibodies could not be detected with the presently used technique. The IgG anti-IgA antibodies were mainly of the IgG1 subclass but occasionally also of the subclasses IgG2, IgG3, and IgG4. Of eight patients with anti-IgA antibodies, seven tolerated Ig prophylaxis with a commercial immunoglobulin preparation low in IgA when given either intramuscularly or intravenously. The titers of anti-IgA in the sera of these patients did not rise in relation to the prophylaxis. Only one of the eight patients had a history of previous anaphylactic reactions to IgA-containing blood products. He tolerated six Ig infusions during 5 months with the IgA-depleted preparation without any adverse effects but showed increasing levels of anti-IgA antibodies and ultimately experienced a near-fatal reaction at the seventh infusion.

Humoral immunity to dietary antigens in atopic dermatitis. II. Analysis of IgE and IgG subclass antibodies.

IgG subclass antibodies to two dietary antigens, ovalbumin (OA) and beta-lactoglobulin (BLG) were measured with quantitative ELISA-techniques in 16 patients with atopic dermatitis (AD) (6-21 years old) and closely matched controls. In addition, IgE-antibodies to OA, BLG and milk were determined with RAST. IgG subclass antibodies were frequently detected in IgG1 and IgG4 for both AD-patients and controls, quantitatively dominated by IgG4. The IgG4 anti-BLG antibody levels were significantly higher (P less than 0.001) in AD-patients (median: 1.1 microgram/ml, range: 0-24.0 microgram/ml) than in controls (median: 0.05 microgram/ml, range: 0-1.05 microgram/ml). No relation was found between IgG4 anti-BLG antibody levels, levels of IgE antibodies to milk or BLG, or severity of disease.

Importance of antibody isotype in monoclonal anti-idiotype therapy of a murine B cell lymphoma. A study of hybridoma class switch variants.

An initial panel of four syngeneic monoclonal antibodies directed against the idiotype of a murine B cell lymphoma was used to treat this tumor in vivo. The antibody in the panel of the IgG2a isotype was more effective in treatment than the other antibodies, which were of the IgG1 and IgG2b isotypes. To independently assess the role of antibody isotype in mediating antitumor effects, switch variant hybridoma families were isolated from the hybridomas secreting the less effective IgG1 and IgG2b antibodies. A family isolated from an IgG1-secreting parent consisted of IgG1-, IgG2b-, and IgG2a-secreting members, and an IgG2a variant was isolated from an IgG2b-secreting parent for another family. Antibody members of each family differed only in heavy chain composition and were the same with respect to their light chains and their affinity and specificity for idiotype. The IgG2a members of both families were superior to the other members in inhibiting tumor growth with an order of effectiveness of IgG2a greater than IgG1 greater than IgG2b. These in vivo results paralleled the abilities of these different isotype antibodies to mediate antibody-dependent cellular cytolysis in vitro. For the IgG2b----IgG2a family, in vivo treatment with the IgG2a member given i.p. after i.p. tumor challenge at one-tenth the dose of the IgG2b member was still superior to the latter. At one-hundredth the dose of the IgG2b, the IgG2a was still superior to the latter when the antibodies were given i.p. and tumors subcutaneously. These data and those showing that the clearance of these antibodies from the serum differed in only a relatively minor way indicate that the IgG2a antibodies in this system had greater antitumor effects primarily by virtue of their greater capacity for host effector interaction.

Significance of multiple types of antibodies on red blood cells of patients with positive direct antiglobulin test: a study of monospecific antiglobulin reactions in 85 patients.

Blood samples from 85 patients with a positive direct antiglobulin test were tested with monospecific antiglobulin reagents: anti-IgG, anti-IgM, anti-IgA, and anti-C3. No typical pattern of antiglobulin reaction could be correlated with specific diseases except for the patients with methyldopa-induced positive direct antiglobulin test, all of whom had only IgG on their red blood cells. The presence of more than 1 type of antibody on red blood cells was associated with severe haemolysis. These patients responded less frequently to steroids, and in most of them no underlying disease could be found. Most patients with complement alone on red blood cells had no evidence of haemolysis, and when present it was never severe.

Immune complexes in the reactive inflammatory vascular dermatoses.

Immune complexes are formed by the interaction of antigen and antibody. When these complexes are deposited in tissue, they activate complement that is chemotactic to neutrophils. Neutrophil release of lysozymal enzymes results in destruction of tissue. In the skin this destruction manifests itself clinically as vasculitic lesions. Occasionally other clinical lesions, such as urticaria, erythema multiforme, and so forth, may be a manifestation of immune complex disease.

Subclasses of human IgG anti-Fab antibodies: parameters for optimum detection.

In this study we have defined the parameters needed for the optimum detection of anti-Fab antibodies in the serum of patients with rheumatoid arthritis. We have found that the majority of the anti-Fab antibodies are of the IgG3 and IgG4 subclasses which were not optimally detected using polyclonal heterologous anti-human IgG antisera; subclass-specific antibodies instead were needed. Additionally we determined that dissociation of circulating immune complexes by dialysis against urea for 3-7 days was also needed for the detection of these antibodies. Lastly we have shown that the dissociated complexes can recombine with their target Fab molecules, and therefore separation of the anti-Fab antibodies from the other immunoglobulins by chromatofocusing may enhance the detection of these antibodies. When the above conditions were fulfilled it was determined that IgG anti-Fab antibodies could be detected in rheumatoid arthritis and normal sera and that acidic IgG3 and IgG4 subclasses predominated. However, IgG3 levels were 10.5-fold higher in rheumatoid arthritis sera (p less than 0.05) and IgG4 levels 5-fold higher (p less than 0.01) than in normal sera.