Central effects of clonazepam

The effects of oral administration of clonazepam, a new benzodiazepine derivative (F. Hoffmann-La Roche), on the central nervous system were compared with those of diazepam and several anticonvulsants in mice and rats. 1) Clonazepam exhibited a moderate inhibitory effect on the locomotor activity observed with open-field situation in mice and no effect in rats, while it inhibited markedly the rearing behavior in both animals, the duration of action being approximately six hours. 2) Clonazepam potentiated the methamphetamine-induced hyper-locomotor activity in mice whereas trimethadione had no effect. 3) Clonazepam inhibited with a moderate potency the conditioned avoidance response and response to a fixed-ratio (FR 20) schedule of food reinforcement in rats, the potency being a little weaker than that of diazepam. 4) The muscle relaxant effect of clonazepam determined by the traction test was slightly more potent as compared with that of diazepam. Thiopental hypnosis was markedly potentiated after clonazepam. 5) The clonic (CL), tonic-flexor (TF) and extensor convulsions (TE) induced by pentetrazol were strongly inhibited after clonazepam in mice, anticonvulsant potency against CL and TE of clonazepam being approximately 23 and 21 times stronger than that of diazepam, 3333 and 3846 times that of trimethadione, and over 3047 and 178 times that of phenytoin, respectively. Clonazepam reduced markedly CL and TE elicited by bemegride with about 12 to 14 times stronger potency than diazepam. On the contrary, the anticonvulsant effect of clonazepam against TE of maximal electroshock seizure evoked by supramaximal current was weak, the potency being 0.71 times weaker than that of phenacemide, 0.14 times than phenytoin and 0.24 times than phenobarbital. By the combined administration of clonazepam with other anticonvulsants such as trimethadione and phenytoin against pentetrazol convulsion, and phenacemide, phenytoin and phenobarbital against maximal electroshock seizure, the antagonistic effect of these anticonvulsants was potentiated by 4 to 5 times. 6) The acute toxicity (LD50) of clonazepam was weak but that of phenacemide or phenytoin was potentiated to a certain degree by combined administration with clonazepam. The results suggest that clonazepam has a psychopharmacological profile similar to that of benzodiazepines with a particularly potent anticonvulsant effect on pentetrazol and bemegride convulsions, and the anticonvulsant effect is synergic with that of other anticonvulsants.     

Propranolol-induced seizures in mice: the role of noradrenaline

The effects of some noradrenergic agents, phenobarbitone, diazepam and phenytoin on seizures produced by propranolol were investigated in mice. Isoprenaline and DL-threo-3,4-dihydroxyphenylserine (DOPS) effectively antagonized the seizures elicited by propranolol. Pargyline and imipramine significantly attenuated propranolol-induced seizures and also significantly potentiated the protecting effect of DOPS against the seizures. alpha-Methyl-p-tyrosine, disulfiram and reserpine significantly potentiated propranolol-elicited seizures. However, DOPS significantly antagonized the seizure-potentiating effects of alpha-methyl-p-tyrosine, disulfiram and reserpine. Phenylephrine, clonidine, prazosin, idazoxan, phenobarbitone, diazepam and phenytoin did not significantly alter propranolol-induced seizures. These results suggest that propranolol-induced seizures in mice may involve a noradrenergic mechanism mediated via central beta-adrenoceptors.     

Aberrant T-cell function in vitro and impaired T-cell dependent antibody response in vivo in vitamin A-deficient rats

We have previously reported that vitamin A deficiency resulted in a reduced IgA antibody response to cholera toxin (CT) after per-oral immunization. In the present investigation we have studied the in vivo and in vitro immune response in vitamin A-deficient rats to two parenterally applied antigens, beta-lactoglobulin (beta-LG) and picrylsulphonic acid (TNP)-Ficoll. The serum IgG and IgM antibody responses to the T-cell dependent antigen beta-LG were significantly lower in the vitamin A-deficient rats than in the pair-fed control rats. No such differences were seen with the IgG and IgM responses to the T-cell independent antigen TNP-Ficoll. However, the biliary IgA and the serum IgE antibodies against both antigens were decreased in the vitamin A-deficient rats. In vitro lymphocyte stimulation with concanavalin A (Con A) or beta-LG gave higher T-cell proliferation rates in the vitamin A-deficient than in the control rats. Interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) levels in supernatants from Con A-stimulated mesenteric lymph node cells were also higher in the vitamin A-deficient rats, while IL-6 levels were decreased, which is consistent with an up-regulated Th1 activity. Proliferation studies on purified accessory cells and T cells from the deficient and the control rats, mixed in different combinations, showed that the T cells, but not the accessory cells, were disturbed in the vitamin A-deficient rats. Despite the increased T-cell activity in vitro the vitamin A-deficient rats had a lower delayed-type hypersensitivity (DTH) reaction than the pair-fed control rats. In conclusion, the increased IL-2 and IFN-gamma levels may reflect an up-regulation of Th1 cell function, while the decreased IgA, IgE and IL-6 levels indicate a suppression of Th2 cells. The disturbed T-lymphocyte function is manifested in vivo as a decreased DTH reaction and suppressed antibody production, the latter possibly due to a lack of B-cell switching and proliferation factors in vitamin A-deficient rats.     

Systemic and mucosal IgA responses to systemic antigen challenge in IgA nephropathy

IgA nephropathy (IgAN) is characterized by the deposition of glomerular IgA. The source of the deposited IgA is not known, but both the mucosal and systemic IgA systems have been implicated. In order to investigate mucosal and systemic antibody production to systemic antigen challenge in IgAN, 20 patients and 20 controls where immunized with tetanus toxoid (TT). While patients with IgAN responded with a similar serum IgG, IgA, IgA1, and IgA2 antibody response to controls, they did, however, produce more IgA1 antibodies relative to IgA2 (P < 0.05). No salivary IgA antibody response was observed to systemic immunization in controls; however, there was a significant IgA response to TT in the saliva of patients with IgAN. IgA antibodies were produced in vitro by Epstein Barr virus (EBV)-transformed peripheral blood lymphocytes (PBLs) obtained from control blood only when taken shortly (1 or 2 weeks) after immunization. Patients with IgAN produced significantly more IgA anti-TT positive cultures than controls and for a longer period (P < 0.01) after immunization. In contrast, IgG anti-TT was produced in EBV-transformed cultures at all time points, but with no difference between IgAN and controls in the proportion of IgG producing cultures. These results demonstrate increased IgA antibody production in both the systemic and mucosal IgA systems following systemic immunization in IgAN and suggest an abnormal overlap between the two systems in IgAN.     

Induction of mucosal immunity by intranasal application of a streptococcal surface protein antigen with the cholera toxin B subunit

The level and distribution of isotype-specific antibodies in various secretions and of antibody-secreting cells in corresponding lymphoid organs and tissues were compared in mice immunized with Streptococcus mutans surface protein antigen I/II (AgI/II) conjugated to the cholera toxin B subunit (CTB), given intranasally (i.n.) or intragastrically (i.g.), with or without free cholera toxin (CT) as an adjuvant. Immunization i.n. induced stronger initial antibody responses to AgI/II in both serum and saliva than immunization i.g., but salivary immunoglobulin A (IgA)-specific antibody responses to immunization about 3 months later were not increased relative to total salivary IgA concentrations. Specific antibodies induced by i.n. immunization were as widely distributed in serum, saliva, tracheal wash, gut wash, and vaginal wash as those induced by i.g. immunization. Likewise, specific antibody-secreting cells were generated in the spleen, salivary glands, intestinal lamina propria, and mesenteric and cervical lymph nodes by either route of immunization. The strongest salivary IgA antibody response was induced by AgI/II-CTB conjugate given i.n., but the addition of CT did not further enhance it. However, free CTB could effectively replace CT as an adjuvant in i.n. immunization with unconjugated AgI/II. Booster i.n. immunization with AgI/II plus either free CT or CTB induced stronger recall serum antibody responses than conjugated AgI/II-CTB with or without CT as an adjuvant. Therefore, i.n. immunization with a protein antigen and free or coupled CTB is an effective means of generating IgA antibody responses expressed at several mucosal sites where protective immunity may be beneficial.     

Effect of complement (C3) depletion on the generation of memory in rabbits primed with antigens of Trypanosoma evansi

Using the antibody response during secondary exposure of rabbits primed with antigens of Trypanosoma evansi as an indirect measure of immunological memory, it was shown that C3 decomplementaemia resulted in a reduced antibody response, with IgM being predominant in the sera samples followed by IgG and then IgA [corrected]. While significant differences were observed in the levels of IgG produced by the C3-depleted and C3-intact rabbits no differences were recorded in the levels of IgM and IgA produced by the two groups after C3 decomplementaemia. These results demonstrate that C3 depletion did not abolish memory of the T. evansi antigen in these rabbits but only modified the magnitude and pattern of their response. The host response to reinfection may be affected by such changes as those observed in this study.     

CD40 cross-linking inhibits specific antibody production by human B cells

Ligation of CD40 on B cells is a co-stimulatory signal for proliferation, antibody secretion, heavy chain switching and rescue from apoptosis after somatic mutation in the germinal centre. The importance of these manifold responses to CD40 activation for humoral immunity is exemplified by the inability of boys with X-linked hyper IgM syndrome to make IgG, IgE or IgA due to a mutation in in the gene coding for CD40 ligand (CD40L). In the present study, we have investigated the effect of CD40 ligation on specific antibody production by human B cells to influenza virus. The antibody response was T cell dependent and specific for the strain of influenza virus used as antigen. Addition of either CD40 mAb or recombinant trimeric CD40L profoundly inhibited specific antibody production. Antibody production by unseparated tonsillar mononuclear cells and by T-depleted B cells stimulated with antigen in the presence of T cell replacing factor were equally inhibited with CD40 antibody showing that the effect was due to ligation of CD40 on B cells rather than blocking of T cell help. The specific antibody detected in these experiments was mostly IgG with little or no IgM and was obtained from surface IgM B cells consistent with activation of a secondary (memory) response. Co-stimulation of tonsillar B cells with CD40 antibody and anti-IgG induced proliferation of IgG+ B cells. These results suggest that CD40 ligation can inhibit specific antibody responses and stimulate proliferation in the same IgG+ (memory) B cell subpopulation. Addition of CD40 antibody during the first 24-48 h of the response was required for inhibition, suggesting that the effect was on early B cell activation and/or proliferation required for antibody production. There was no correlation, however, between the ability of CD40 mAb to stimulate proliferation and inhibit antibody production. We suggest that early activation of CD40 in the specific antibody response inhibits the formation of plasma cells and promotes instead the generation of memory cells.     

Role of mucosal IgA in the resistance to Acanthamoeba keratitis

PURPOSE: To determine whether oral immunization with Acanthamoeba castellanii antigens elicits mucosal antibodies of the IgA isotype and whether mucosal antibodies affect parasite adhesion to the corneal epithelium. METHODS: Chinese hamsters were immunized with 100 microg aqueous Acanthamoeba antigen mixed with cholera toxin (Ac-CT) and subsequently challenged with parasite-laden contact lenses that were applied to abraded corneal surfaces. Tears and stool samples were examined for the presence of Acanthamoeba-specific IgA antibodies by enzyme-linked immunosorbent assay (ELISA). The effect of mucosal antibody on trophozoite binding to corneal epithelium and viability of trophozoites was examined in vitro. RESULTS: Hamsters immunized orally with Ac-CT showed significantly lower infection rates than did control groups (21.4% versus 72.6%). ELISA analysis of mucosal specimens showed the presence of parasite-specific IgA in stool samples and tears from hamsters orally immunized with Ac-CT, but not in control animals. In vitro assays showed that anti-Acanthamoeba IgA did not affect parasite viability. However, mucosal anti-Acanthamoeba IgA profoundly inhibited (>75%) the binding of parasites to corneal epithelial cells in vitro. CONCLUSIONS: Oral immunization with Ac-CT induces the production of parasite-specific IgA in mucosal secretions and prevents corneal infection. Mucosal antibody does not affect the viability of Acanthamoeba trophozoites but seems to prevent infection by inhibiting parasite binding to the corneal epithelium.     

Adjuvant effects of fluoride on oral immunization of chickens

The present study was conducted to examine the antibody responses of chickens after oral immunization and the influence of sodium fluoride (NaF) on their immunological states. Bovine serum albumin (BSA) was used as an antigen, and the response was measured by enzyme-linked immunosorbent assays of serum samples, bile samples, and lachrymal fluids. Oral immunization of chickens with antigen alone hardly induced antibody responses in sera, bile samples or lachrymal fluids. Moreover, compared to control chickens, these orally immunized chickens exhibited a lower serum IgG response to subsequent parenteral immunization, suggesting that oral immunization induced immunological tolerance in chickens. A mucosal adjuvant, NaF, could abrogate oral tolerance and elicit an increase in antibody responses. Chickens, which received oral administration of antigen and NaF simultaneously, showed a significant rise in serum IgG antibody. Although there were variations among individual chickens and the titers were low, IgA antibodies were detected in bile samples and lachrymal fluids.     

A two-stage screening test for pregnancy-induced hypertension and preeclampsia

PURPOSE: To define the inductive pathways leading to rat tear IgA antibody responses. METHODS: Fluoresceinated dinitrophenylated bovine serum albumin was encapsulated in poly(lactide-co-glycolide) microparticles and was administered by intranasal, ocular topical, or gastrointestinal routes. Histologic methods were used to determine the microparticles' ability to access tissues associated with mucosal inductive pathways. Rats were immunized with microencapsulated antigen by intranasal or ocular topical routes. Tear IgA and serum IgG antibody concentrations were assessed by radioimmunoassay. The frequency of antibody-secreting cells in tissues, postulated to function in tear IgA induction, was measured by enzyme-linked immunospot assay. RESULTS: Although uptake of microencapsulated antigen was greatest at the site of delivery, ocular topical administration resulted in antigen uptake in the conjunctiva and in nasal-associated lymphoid tissue. Intranasal immunization resulted in earlier and significantly higher tear IgA and serum IgG antibody responses and in higher frequencies of antibody-secreting cells in corresponding draining cervical lymph nodes and lacrimal glands than did ocular topical immunization. CONCLUSIONS: Nasal-associated lymphoid tissue functions as a primary inductive site for tear IgA antibody responses by contributing triggered IgA-committed B cells to the lacrimal gland.     

Immunoglobulin class and subclass distribution of antibodies reactive with the immunodominant antigen of Actinobacillus actinomycetemcomitans serotype b

The aims of this study were to determine the immunodominant antigens of Actinobacillus actinomycetemcomitans serotype b (Aab) for the different immunoglobulin (Ig) classes and subclasses and to determine the relative levels of these different Igs in serum. Seropositive early-onset periodontitis patients were sampled, and the Ig classes IgG, IgA, and IgM and subclasses IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2 were studied. Reactivity with Aab antigens was assessed by using the Western blot (immunoblot) in limiting dilution analysis and radioimmunoassay with sera from 13 early-onset periodontitis subjects. A smeared antigen in the upper portion of the immunoblots, typical of high-molecular-weight LPS, was immunodominant for IgG, IgA, IgM, IgG1, IgG2, IgG3, IgA1, and IgA2. This smeared antigen was present in every patient for all of these Igs at the endpoint. A few additional antigens were also present at the endpoint in some patients, but none were present in more than half of the subjects. The distribution of antibody titers by Ig classes reactive with the Aab immunodominant antigen was IgG > IgA > IgM. The distribution of antibody titers by IgG subclass was IgG2 > IgG1 approximately IgG3. Further quantitation by radioimmunoassay revealed that the mean concentration of IgG2 (65.7 micrograms/ml) was significantly greater than that of IgG1 (8.8 micrograms/ml). The IgA subclass distribution was IgA1 > IgA2, with IgA1 apparently being second only to IgG2. Therefore, the Aab antigen eliciting the highest antibody level in virtually all Ig classes and subclasses appeared to be lipopolysaccharide, and IgG2 was markedly elevated over all other serum Ig classes or subclasses reactive with Aab.     

Relationship of impairment of schistosome 28-kilodalton glutathione S-transferase (GST) activity to expression of immunity to Schistosoma mattheei in calves vaccinated with recombinant Schistosoma bovis 28-kilodalton GST

Sera from calves vaccinated with the recombinant Schistosoma bovis-derived 28-kDa glutathione S-transferase (28GST) and subsequently naturally or experimentally exposed to Schistosoma mattheei were studied for their content of specific immunoglobulin G (IgG) and IgA antibodies to recombinant S. bovis 28GST as well as for their capacity to inhibit the enzymatic activity of the antigen. The results were analyzed in regard to the presence (natural infection) or absence (experimental infection) of a protective effect(s) (reductions in worm burden, egg load, fecal egg counts, and excretion of viable eggs) toward S. mattheei challenge. Under such conditions, no differences in the IgG- and IgA-specific antibodies to recombinant S. bovis 28GST or in the ability to block the catalytic function of the antigen between the two groups were recorded. Nevertheless, correlation analysis between the specific antibody responses to recombinant S. bovis 28GST and the inhibition of GST activity suggested an association with IgG in experimentally infected vaccinated animals, while in naturally infected vaccinated calves, the inhibitory activity appeared to be linked to a greater degree with IgA. These results suggest that in contrast to schistosomiasis in humans, IgG antibodies in calves with schistosomiasis may exhibit inhibitory functions toward GST enzymatic activity or have a modulatory effect on IgA antibody properties. Furthermore, sera from animals immunized with recombinant S. bovis 28GST recognized the native S. mattheei 28GST and achieved comparable levels of inhibition of activity of recombinant S. bovis 28GST and S. matthei 28GST, indicating the presence of cross-reactive epitopes on these two molecules.     

Neutralization of HIV-1 by secretory IgA induced by oral immunization with a new macromolecular multicomponent peptide vaccine candidate

Control of pandemic infection of human immunodeficiency virus type 1 (HIV-1) requires some means of developing mucosal immunity against HIV-1 because sexual transmission of the virus occurs mainly through the mucosal tissues. However, there is no evidence as yet that the secretory immunoglobulin A (IgA) antibody induced by immunization with antigens in experimental animals can neutralize HIV-1. We demonstrate here that oral immunization with a new macromolecular peptide antigen and cholera toxin (CT) induces a high titre (1:2") of gut-associated and secretory IgA antibody to HIV-1. Using three different neutralizing assays, we clearly demonstrate that this secretory IgA antibody is able to neutralize HIV-1IIIB, HIV-1SF2 and HIV-1MN. Our new approach may prove to be important in the development of a mucosal vaccine that will provide protection of mucosal surfaces against HIV-1.     

Comparison of cardiac findings at necropsy in octogenarians, nonagenarians, and centenarians

The Toxoplasma gondii rhoptry protein Rop2 was expressed in Escherichia coli as a fusion protein containing 44 kDa of the 55-kDa mature Rop2, supplied with six histidyl residues at the N-terminal end (Rop2196-561). Humoral response during Toxoplasma infection of humans was analyzed by immunoglobulin G (IgG), IgA, and IgM enzyme-linked immunosorbent assay with Rop2196-561 as the antigen substrate. The analyzed sera were divided according to T. gondii-specific serological tests (IgG, IgA, or IgM indirect immunofluorescence and IgA or IgM immunosorbent agglutination assay) as group A (IgG+ IgA- IgM-; n = 35), group B (IgG+ IgA+ IgM+; n = 21), group C (IgG+ IgA+ IgM-; n = 5), and group D (IgG+ IgA- IgM+; n = 16). Twenty-six T. gondii-seronegative sera from individuals with other infections were also included (group E). Anti-Rop2 IgG antibodies were detected in 82.8% of group A sera and in 97.6% of the sera with acute-phase marker immunoglobulins (groups B, C, and D). The percentage of IgA antibody reactivity against Rop2196-561 was 17.1% in group A, 50% in group D, and 80.8% in groups B and C. The percentage of IgM antibody reactivity was 0% in groups A and C and 62% in groups B and D. Sera from group E failed to show IgA, IgM, or IgG antibody reactivity. Since T. gondii Rop2 elicits a strong humoral response from an early stage of infection, it is suggested that recombinant Rop2196-561 would be suitable for use in diagnostic systems, in combination with other T. gondii antigens, to detect specific IgG, IgA, and IgM antibodies.     

Size effect on systemic and mucosal immune responses induced by oral administration of biodegradable microspheres

Induction of systemic and mucosal immune responses following oral administration of biodegradable poly(D,L-lactic acid) (PDLLA) microspheres containing a model antigen, ovalbunin (OVA) was studied using microspheres with different average diameters of 0.6, 1.0, 4.0, 7.0, 11.0, 15.0, 21.0, and 26.0 microns. They were prepared from double emulsion with the solvent evaporation method, followed by size fractionation on counterflow elutriation. OVA was released from the microspheres in vitro over 80 days, irrespective of their size. Production of the serum anti-OVA IgG antibody and secretory OVA-specific IgA antibody in the mice gut was assessed following the oral administration of PDLLA microspheres containing OVA. Microspheres with a diameter of 4.0 microns enhanced the serum antibody in contrast with that of free OVA, but were not effective in inducing the gut secretion of IgA antibody. On the other hand, OVA-containing microspheres with a diameter of 7.0 microns enhanced IgA secretion to a significant extent compared with free OVA, whereas those with 26.0 microns in diameter were ineffective. Body distribution study revealed that the amount of microspheres taken up into Peyer's patches (PP) increased with the increasing size up to 11.0 microns, thereafter decreased, and finally became zero when their diameters were 21.0 microns or larger. The microspheres taken up into PP were translocated to the spleen, but no microspheres were noticed in the spleen when the size was larger than 5 microns. After being taken up inot PP, microspheres < 5 microns in diameter seemed to be transported to the spleen, a systemic lymphoid tissue, where the released antigen stimulated a serum antibody response, but larger microspheres probably remained at PP without being translocated to the spleen over the course of their antigen release, leading to induction of IgA secretion. It was concluded that the body distribution pattern of microspheres following the PP uptake was a key factor to regulate the induction of systemic and mucosal immune responses.     

Immunization against rabies with plant-derived antigen

We previously demonstrated that recombinant plant virus particles containing a chimeric peptide representing two rabies virus epitopes stimulate virus neutralizing antibody synthesis in immunized mice. We show here that mice immunized intraperitoneally or orally (by gastric intubation or by feeding on virus-infected spinach leaves) with engineered plant virus particles containing rabies antigen mount a local and systemic immune response. After the third dose of antigen, given intraperitoneally, 40% of the mice were protected against challenge infection with a lethal dose of rabies virus. Oral administration of the antigen stimulated serum IgG and IgA synthesis and ameliorated the clinical signs caused by intranasal infection with an attenuated rabies virus strain.     

Comparison of anaesthetic and non-anaesthetic effects on depolarization-evoked glutamate and GABA release from mouse cerebrocortical slices

The aim of the study was to investigate whether patients with Aspergillus-induced lung disease can be monitored by immunoblot analysis to detect antibodies to Aspergillus fumigatus (Af). Immunoblotting was performed by incubating 57 longitudinally collected sera from 13 patients on nitrocellulose sheets, blotted with Af antigen, separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Bound antibodies were demonstrated by peroxidase-labelled antihuman immunoglobulins (Ig)G and IgA antiserum and diaminobenzidine plus H2O2 as substrate. The immunoblot patterns were related to the patients' clinical status and time. Each patient had a characteristic immunoblot pattern that varied with time. There was a relationship between disease activity or clinical response and changes in immunoblot antibody patterns: a rise in anti-Af IgG and IgA antibodies was seen in sera collected during active disease, compared with before active disease, and a significant decline in anti-Af IgG and IgA was demonstrated in sera collected during recovery, compared with during active disease. Only in the acute stage of allergic bronchopulmonary aspergillosis were IgA antibodies against Af antigens of <20,000 Da demonstrated. Immunoblot analysis can be used to monitor the disease activity and the responses to treatment of patients with Aspergillus-induced lung diseases. Changes in specific immunoglobulin A may be more informative than specific immunoglobulin G.     

Analysis of anti-Trypanosoma cruzi antibody isotype specificities by western blot in sera from patients with different forms of Chagas' disease

Infection of humans with Trypanosoma cruzi leads to either a lifelong asymptomatic infection or to symptomatic presentations such as cardiomyopathy, mega-syndromes, or both. The reasons for the different clinical manifestations are not understood. We have previously studied a group of chronically infected individuals with different clinical forms of Chagas' disease and found that the levels of some anti-T. cruzi antibody isotypes, analyzed by enzyme-linked immunosorbent assay, differed among patients with different clinical presentations. We have expanded these studies to examine the antigen specificity of these patients' IgG1, 2, 3, IgM, and IgA by western blot. We observed that binding of particular antigens by some antibody isotypes were more prevalent in some clinical groups as compared to others. For example, IgG3 from 13 of 19 (68%) individuals with digestive manifestations bound a 68-kDa antigen, but only 3 of 31 (9%) individuals with cardiac involvement detected this same moiety. We also found that, regardless of the clinical group, the profiles of antigens recognized by each antibody isotype differs dramatically from the profiles recognized by each other isotype. Together with our previous observations demonstrating that the levels of anti-parasite antibody isotypes correlates with the clinical form, these data suggest that overall anti-T. cruzi antibody reactivities may indeed be skewed toward different antigens in individuals with different clinical presentations.     

Somatic antigens of adult Dicrocoelium dendriticum recognised by bile antibodies of naturally infected cattle

Bile samples, from slaughtered cattle harbouring between 120 and 280 adult lancet flukes, were used to investigate the range of somatic proteins inducing local antibody responses in naturally infected animals. Lancet fluke infections induced local (bile) antibody responses against Tris-buffered saline (TBS) soluble, sodium dodecyl sulphate (SDS) soluble and 2-mercaptoethanol (2-Me) soluble somatic proteins of adult Dicrocoelium dendriticum. IgA antibody isotypes predominated in the response against buffer-soluble somatic antigens, whereas SDS-soluble and 2-Me-soluble proteins induced similar level of both IgA and IgG1 antibodies. Analysis of the antigens recognised by particular isotype-specific bile antibodies suggests that different antigens preferentially induce isotype restricted antibody responses. The bile antibody response was highly species specific, only one antigen from somatic protein extracts of Fasciola hepatica being precipitated by bile samples showing the highest reactivity against D. dendriticum.     

Changes in serum immunoglobulin levels during phenytoin treatment of epilepsy

Immunoglubulin concentrations were determined by radial immunodiffusion in sera from 15 epileptic patients before and during phenytoin therapy. Three reaction patterns were recorded: Two patients developed IgA deficiency (less than 0.05 mg/ml) during the first 3-4 months of treatment. Both patients also had a decrease in serum IgG and IgM, but no significant fall or increase in serum IgE. The IgA deficiency state was apparently reversible, since normalization of serum levels occurred after withdrawal of phenytoin. Five patients developed a 35-80 per cent reduction in serum IgA. In these patients, the decline in serum levels of IgG and IgM was inconsistent. Eight patients showed no significant fluctuations in serum immunoglobulins during phenytoin treatment. When a fall in serum IgA occurred, it did not correspond to a fall in serum or in red cell folate. Mean serum IgG was lower (9.37 mg/ml) in epileptic patients who had taken phenytoin for less than 1 year and had a low IgA, than in patients who had taken phenytoin for 10 years or more (11.50 mg/ml).