Low IgG Titers Research Articles

Use of DNAs Expressing HIV-1 Env and Noninfectious HIV-1 Particles to Raise Antibody Responses in Mice

Two DNA constructs encoding portions of the human immunodeficiency virus type-1 (HIV-1) genome have been used to raise antibody responses in BABL/c mice. One DNA (pNL4-3.env) expresses the natural form of the envelope glycoprotein (Env) of HIV-1-NL4-3 (NL4-3). The second (pNL4-3.dpol) produces noninfectious NL4-3 particles. These two DNAs (alone or in combination) raised only transient titers of anti-Env IgG. In the same group in which pNL4-3.dpol DNA raised only transient antibody responses to Env, this DNA raised persistent antibody responses to the p24 virion capsid protein (CA). Antibody responses to Env and CA also showed different abilities to be boosted. The final boosts of pNL4-3.dpol DNA increased titers of anti-CA antibody, but failed to boost the falling titers of anti-Env antibody. At peak titers of anti-Env activity, sera with relatively low ELISA titers of anti-Env IgG (end points of 1:6250) had good titers of neutralizing antibody (∼ 1:3800 for 50 TCID 50 of NL4-3). At the end of the experiment (a time when anti-Env antibodies had fallen to near background levels), in vitro-restimulated splenocytes from both pNL4-3.env and pNL4-3.dpol DNA vaccine groups exhibited similar cytotoxic activity.

Detection of Norwalk virus or Norwalk-like virus infections in Finnish infants and young children.

Norwalk virus (NV) and Norwalk-like viruses are important causes of epidemic nonbacterial gastroenteritis in older children and adults. Serologic responses to NV of 154 Finnish infants and young children participating in a rotavirus vaccine study were examined by ELISA with a recently available baculovirus-expressed recombinant NV capsid protein. In 4 serially collected sera (at the median ages of 3, 4, 14, and 23 months), 49% of children had at least one NV infection over the approximately 2-year study period. Children with low NV-specific IgG titers (< 1:50) at the median age of 4 or 14 months were significantly more likely to acquire an NV infection by the median age of 14 or 23 months, respectively, than children who had higher NV IgG titers (> 1:50) (P < .05). Thus, NV or Norwalk-like virus infections are more common in infants and young children than previously believed, and antibody to NV may be protective against such infections.

抗グロブリン試験Ｐｏｌｙｅｔｈｙｌｅｎｅ Ｇｌｙｃｏｌ（ＰＥＧ）法の基礎的検討と抗赤血球自己抗体保有患者における臨床的意義

Compared to the conventional anti-globulin test (AGT), polyethylene glycol (PEG)-using AGT (PEG-AGT) was found to be not only simpler and easier, but also superior with regard to specificity and sensitivity to detect unexpected antibodies.In a basic study for the application of PEG to direct AGT (DAT), it was found that the addition of PEG to red cells from patients followed by incubation for 5 to 20 minutes at 37°C provided the most sensitive results.Of 1082 patients' sera for antibody screening, red cell alloantibodies in 8 and warm-type red cell autoantibody in 1 could be detected by PEG-AGT, but not by AGT. On the other hand, one anti-E IgM antibody, probably in its early stage of production, was detected by Bromelin method, but not by PEG-AGT. In two other patients PEG-AGT demonstrated a positive reaction two months before the onset of autoimmune hemolytic anemia (AIHA), whereas AGT result remained negative.PEG-AGT seemed to be an adequate method specially to detect low-titer IgG antibodies in both DAT and indirect AGT, and it will provide useful indexes for the diagnosis of AIHA and also for the observation of clinical course of patients with such diseases as AIHA.

Hemorrhagic Rhinitis: An Immunologic Disease Due to Hexahydrophthalic Anhydride

This is a descriptive study of six men who had been occupationally exposed to heated epoxy resin containing hexahydrophthalic anhydride (HHPA) who presented with rhinitis, nasal mucosal erosions, and significant epistaxis; three also had asthma. When they were removed from exposure to HHPA, the rhinitis symptoms, nasal erosions, and epistaxis resolved spontaneous. All six had high titers of IgG and IgE against HHP-HSA as determined by an enzyme-linked immunosorbent assay (ELISA). Other asymptomatic workers with similar HHPA exposure had ver low or negative titers of IgG and IgE against HHP-HSA. We conclude that these results are very suggestive of an immunologic mechanism being responsible for the rhinitis, nasal mucosal erosions, and epistaxis that occurred in the six described HHPA workers.

Use of recombinant human parvovirus B19 antigens in serological assays.

AIMS--To compare the sensitivity, specificity, and practicality of recombinant proteins in serological tests for the detection of human parvovirus B19 IgG and IgM. METHODS--Indirect enzyme linked immunosorbent assays using B19 structural proteins expressed in Escherichia coli were developed for the detection of B19 specific IgG and IgM (rELISA-G and rELISA-M). Cells infected with baculovirus expressing B19 structural proteins were also used in an indirect immunofluorescence assay for IgG and IgM antibodies (IFA-G and IFA-M). Antibody capture radioimmunoassays for IgG and IgM (GACRIA and MACRIA) were used as comparative assays. RESULTS--Twenty nine pools of intravenous immunoglobulin were clearly positive for B19 IgG by rELISA-G and contained low IgG titres by GACRIA. From 113 samples tested by all methods, sensitivities of 92% (77/84) and 97% (68/70) were obtained for ELISA and immunofluorescence, respectively, when compared with GACRIA. One hundred and sixteen samples from patients presenting with rash or arthralgia were compared by MACRIA, rELISA-M, and IFA-M. Sensitivities of both recombinant tests were more than 95%. Despite pretreatment to remove IgG or rheumatoid factor, false positive results were a problem in the rELISA-M but were not seen with the IFA-M. CONCLUSIONS--The limited supply of native antigen has severely restricted the wide application of serology for parvovirus B19. The use of recombinant antigens permitted the introduction of local screening tests which had many advantages, including quicker results and relief of the burden on the Reference Laboratory. The use of rELISA-M for sensitivity and IFA-M for specificity and confirmation proved a useful and practical combination for diagnosis of recent infection with B19, and rELISA-G allowed the immune response to be determined in selected populations.

Chronic Pseudomonas aeruginosa lung infection in normal and athymic rats

We have compared a chronic lung infection with Pseudomonas aeruginosa embedded in alginate beads in normal and athymic rats with an acute infection with free live P. aeruginosa bacteria. The following parameters were observed and described: mortality, macroscopic and microscopic pathologic changes, and antibody responses. The rats challenged with P. aeruginosa alginate beads experienced a generally more severe lung pathology and the antibody responses were more homogeneous with less dispersion as compared to the rats having free live P. aeruginosa bacteria. In general, manifestations were more severe in the athymic rats compared to the normal rats. It is, however, notable that the athymic rats developed similar microscopic lung manifestations as the normal rats when given a large number of P. aeruginosa in the beads, with dense accumulation of neutrophil granulocytes and microcolonies comparable to the lesions seen in cystic fibrosis (CF) patients. Early transitory IgM titers were demonstrated in both normal and athymic rats. Whilst athymic rats produced much lower IgG titers than the normal rats, presumably due to the absence of CD4+ cells, higher primary IgA titers were achieved. These two models in normal and athymic rats of the chronic lung infection resembling that seen in CF lungs make it possible to study the influence of the various components of the specific and nonspecific defense systems on the course of the chronic P. aeruginosa lung infection and to evaluate the effect of various immunization schedules and immunomodulatory drugs.

Evaluation of a Commercial Anti-Delta EIA Kit for Detection of Antibodies to Hepatitis Delta Virus

Anti-hepatitis delta virus (anti-HDV) antibodies were measured by solid phase IgG and IgM capture radioimmunoassays (RIA) as well as by a competitive binding enzyme immunoassay (EIA) in both acute and chronic HDV infections. EIA anti-delta test measures total delta antibody without discriminating IgM from IgG anti-delta. Low titer IgG antibodies were detected by both techniques with equal sensitivity. High titer IgG antibodies reached the end point sooner with EIA than with RIA (10(-3) versus greater than 10(-6)). When IgM anti-HDV was present without accompanying IgG anti-HDV, EIA failed to identify the antibody. Presence of high titer rheumatoid factor in the serum and lipemic samples produced false-positive results by EIA. Usage of undiluted serum samples for EIA probably exaggerates the factors contributing to false-positive reaction.

The booster injection of antigen during active sensitization of guinea‐pig modifies the anti‐anaphylactic activity of the PAF antagonist WEB 2086

1. Serum IgG levels of sensitized guinea-pigs bled at various times after the booster injection were evaluated and its capacity to sensitize passively lung strips from normal guinea-pigs assessed. Following the booster injection, both serum IgG and the ability to sensitize passively lung strips increased during the first week and decreased slowly thereafter. 2. The PAF antagonist WEB 2086 (3 mg kg-1, i.v.) blocked the anaphylactic bronchoconstriction induced by intravenous administration of ovalbumin (1 mg kg-1) when guinea-pigs were challenged 2 and 4 days after the booster injection, but became ineffective when tested in guinea-pigs challenged 7, 28 and 56 days after the booster injection. 3. The ability of WEB 2086 to reduce anaphylactic bronchoconstriction of guinea-pigs challenged 2 and 4 days after the booster injection was unrelated to either the selective involvement of one type of immunoglobulin, low IgG titres in sera or a reduced sensitizing capacity. 4. The booster injection, which accounts for the loss of efficacy of WEB 2086 from the fourth day thereafter, probably operates as a PAF-independent inflammatory challenge. 5. The protocol for immunisation and the day of experiment after the booster injection determines the sensitivity of the anaphylactic bronchoconstriction to inhibition of PAF antagonists.

Evaluation of Enzyme-Linked Immunosorbent Assays with Two Synthetic Peptides of Epstein-Barr Virus for Diagnosis of Infectious Mononucleosis

To diagnose infectious mononucleosis caused by Epstein-Barr virus (EBV), a peptide from the EBV nuclear antigen (EBNA) 1 (p107) and an EBNA 2 peptide (polyproline) were used as antigens in enzyme-linked immunosorbent assays for IgG and IgM. Well-characterized serum samples (360) from healthy individuals and patients with EBV or cytomegalovirus infections were examined. The p107 IgG and IgM assays were also tested with serum from 1000 patients with suspected EBV-related disorders. The p107 and polyproline IgG assays were 100% specific for EBV seropositivity. Low p107 IgG titers (less than 1000) were found in 98% of patients with EBV infectious mononucleosis but also in 18% of patients with other diseases. A p107-to-polyproline IgG ratio of less than 1 was 98% specific for EBV infectious mononucleosis; sensitivity was 86%. In EBV capsid antigen-IgG seropositive patients, a p107 IgG titer of less than 1000 together with a p107 IgG-to-IgM ratio of less than 1 was 98% sensitive and specific for EBV infectious mononucleosis. Thus, this ratio appears adequate to measure EBNA antibodies for diagnosis of EBV mononucleosis.

Diversity of IgG antibody responses in the patients with various types of periodontitis.

Serum IgG antibodies to seven periodontopathic bacteria were assessed with an enzyme-linked immunosorbent assay (ELISA) in 56 patients with periodontitis. Patients were selected according to the severity of bone loss, and were also classified into three categories by age: juvenile periodontitis (JP), advanced destructive periodontitis (ADP), and adult periodontitis (AP). Bacteroides gingivalis, B. loescheii, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Eikenella corrodens, B. intermedius, and Capnocytophaga ochracea were the bacterial strains of interest. Antigens were prepared by cold ultrasonication of washed bacterial cells. Association of high- or low-IgG antibody titer to the bacteria was evaluated. High or low titers of IgG were based on ELISA measurements in 28 healthy subjects. Values exceeding 100% above or below the normal standard deviation were classified as high or low titers, respectively.Most patients with three types of periodontitis (76.8%) exhibited high-IgG antibody titers against various periodontopathic bacteria. The sera mostly included high-IgG titer against one or some of B. gingivalis, E. corrodens, F. nucleatum, and/or A. actinomycetemcomitans. B. gingivalis was predominantly associated with three categories of periodontitis (60.7%). However, high-IgG antibody titer against B. gingivalis alone was found in relatively low percentage (21.4%). Most of the cases were associated with one or more of the other periodontopathic bacteria. High-IgG titer against A. actinomycetemcomitans was found in a few patients (12.5%), who showed severe and more rapid bone loss. Nine patients (16.1%) showed lower IgG antibody titer than did the healthy control subjects. Of the nine, three patients who belonged to the JP category showed the chemotaxis dysfunction of their PMNs. Some immunodepression was suspected in these patients.

Anti-herpes simplex type 1 activity in IgG subclasses produced systemically and intrathecally in patients with herpes encephalitis.

The role of the humoral immune response in herpes simplex encephalitis (HSE) is largely unknown. The finding that herpes simplex virus type 1 (HSV 1) induced IgG Fc receptor binds to all IgG subclasses except IgG 3 prompted an investigation of anti-HSV activity in IgG subclasses from serum and cerebrospinal fluid (CSF) in ten patients with proven or highly probable HSE by means of a monoclonal antibody IgG subclass-specific solid-phase radioimmunoassay (SPRIA). In contrast to serum, CSF contained no or low anti-HSV IgG titres during the first 2 weeks of disease in five of seven patients tested. The IgG titres rose thereafter for at least 4 weeks after the start of illness and remained high in both serum and CSF up to 393 days. The anti-HSV IgG subclass distribution in serum was IgG 1 (ten of ten), IgG 2 (two of ten), IgG 3 (six of ten), and IgG 4 (six of ten). Two patients had a simultaneous anti-HSV IgG 3 and IgG 4 response. With the exception of one patient lacking anti-HSV IgG 4 and two patients lacking anti-HSV IgG 2, the subclass distribution in CSF was the same as in serum. The anti-HSV subclass distribution in sera from ten seropositive patients without evidence of recent herpes infection did not differ from that of the HSE patients, except that five of ten patients had simultaneous anti-HSV IgG 3 and IgG 4 responses. Thus we could not correlate the anti-HSV subclass response in patients with HSE with the subclass preference of the HSV-induced Fc receptor.

Leishmania donovani: Cellular and humoral immune responses after primary and challenge infections in squirrel monkeys, Saimiri sciureus

Cellular and humoral immune responses were studied in squirrel monkeys after primary and challenge infection with a Khartoum strain (WR 378) of Leishmania donovani. Each of 7 squirrel monkeys, Saimiri sciureus, was inoculated intravenously with 5 × 10 7 amastigotes/ kg body weight, and one other monkey (control) was inoculated with uninfected hamster spleen homogenate. Five infected monkeys recovered from visceral leishmaniasis and two infected monkeys died. Three of the five squirrel monkeys which recovered from the primary infection demonstrated acquired resistance when challenged with an intravenous inoculation of 1.0 × 10 8 amastigotes of L. donovani/kg of body weight. Each of these same three monkeys, the two remaining monkeys which recovered from the primary infection and an uninfected control monkey, were challenged subsequently with an intradermal injection of 2.2 × 10 7 promastigotes of L. braziliensis panamensis (WR539) and developed cutaneous lesions. The reactivity of peripheral blood leukocytes from infected squirrel monkeys to phytohemagglutinin was depressed 2 to 10 weeks after infection, and the reactivity to concanavalin A was not affected. Data on responses to pokeweed mitogen were inconclusive. Reactivity to leishmanial antigens was detected at 12 weeks after infection, which coincided with a marked decrease or disappearance of parasites in liver imprints. Two of five surviving squirrel monkeys developed weak delayed skin test responses to leishmanin antigens after 23 weeks; the three remaining monkeys were anergic during the primary infection but developed strong delayed skin test responses to leishmanin antigens at 7 weeks after a challenge with L. donovani. All squirrel monkeys inoculated with L. donovani developed a hyperproteinemia, hypergammaglobulinemia, hypoalbuminemia, and a reversal of the albumin/globulin ratio between 4 to 18 weeks after infection. Plasma IgM and IgG levels were increased between 2 to 18 weeks after infection; much of this increase was due to IgG. Class-specific antileishmanial antibodies, with generally low IgM and high IgG titers, reached a maximum after 14 and 16 weeks, respectively. A correlation was observed between concentrations of -γ-globulins and plasma IgM and IgG levels, but not between γ-globulin concentrations and maximum titers of class-specific antileishmanial antibodies. Squirrel monkeys challenged with L. donovani again developed hyperproteinemia, hypergammaglobulinemia, and increased concentrations of plasma IgM and IgG which correlated with high titers of IgG class-specific antileishmanial antibody 4 weeks after reinoculation. Squirrel monkeys subsequently challenged with L. braziliensis panamensis developed persistent cutaneous lesions indicating a lack of resistance to the heterologous challenge.

Hemolytic Anemia due to a Mixture of Low-Titer IgG Lambda and IgM Lambda Agglutinins Reacting Optimally at 22° C

Hemolytic Anemia due to a Mixture of Low-Titer IgG Lambda and IgM Lambda Agglutinins Reacting Optimally at 22° C

Enzyme-linked immunosorbent assay for detection of soluble Toxoplasma gondii antigen in acute-phase toxoplasmosis.

Sixty-two sera from 51 patients with lymphadenopathy presumed to be due to acute-phase toxoplasmosis were tested for specific IgM class antibodies by both the immunofluorescence antibody to Toxoplasma gondii in sera were first dissociated in 3 M NaSCN. Antigen attached to the solid phase was detected with enzyme-coupled IgG antibody to Toxoplasma antibody to Toxoplasma gondii in sera were first dissociated in 3 M NaSCN. Antigen attached to the solid phase was detected with enzyme-coupled IgG antibody to Toxoplasma gondii. Neither hepatitis B surface antigen nor antigen of Mycoplasma pneumoniae, rubella, cytomegalovirus or herpes simplex virus interfered with this ELISA. Soluble antigen was detected in 13 (30%) of 42 IgM-positive acute-phase toxoplasmosis patients and in only one of 20 sera cleared of IgM. None of an additional 44 IgM-negative patients with low IgG titres had a positive result in the antigen ELISA. Follow-up studies in four acute-phase toxoplasmosis patients showed that the soluble antigen cleared in all cases before the specific IgM antibodies. Simultaneous detection of IgM antibodies to Toxoplasma gondii and soluble antigen would thus seem to indicate an early stage of the infection.

ELISA for the detection of specific IgM and IgG in human leptospirosis.

ELISA was used to detect specific IgM and IgG in sera from humans with current or past leptospirosis. A serological pattern of a high IgM titre (greater than or equal to 1280), or moderately increased IgM (160-640) in conjunction with a low IgG titre (less than or equal to 20), with serovar copenhageni antigen was characteristic for approximately two-thirds of the sera from serovar icterohaemorrhagiae patients obtained in the first two months of the disease. The antigen was the supernatant of a heated and centrifuged culture of leptospires. Antigens were prepared from serovars copenhageni, grippotyphosa, hardjo and patoc. Sera from patients with icterohaemorrhagiae, grippotyphosa and hardjo infections showed cross-reactivity when different antigens were used. In past infections the IgG titres were clearly higher with the homologous antigen. ELISA for IgM and IgG allows the rapid diagnosis of acute leptospirosis.

Determination of specific anti-leptospiral immunoglobulins M and G in sera of experimentally infected dogs by solid-phase enzyme-linked immunosorbent assay

The development and evaluation of an enzyme-linked immunosorbent assay (ELISA) to detect specific anti-leptospiral IgM and IgG in sera of dogs experimentally infected with Leptospira interrogans serotype canicola are reported. In all dogs specific anti-leptospiral IgM was detected from the second half of the first week after infection, the maximum being attained during the second week. Subsequently the IgM titre gradually decreased. Specific anti-leptospiral IgG was detected later and increased gradually to reach almost the same level as the IgM titre after two to three months. During the initial stage of the infection, when the microscopic agglutination titre was still negative or very low, a high IgM titre was accompanied by a negative or very low IgG titre in every case. After the initial stage a substantial IgG titre was also detectable. It is suggested that the test is suitable for serodiagnostic purposes, particularly for the diagnosis of a current infection in an individual.

Experimental urinary tract infection in rabbits by a group D Streptococcus sp.: A study of serum immunoglobulin classes by enzyme-linked immunosorbent assay

After induction of pyelonephritis and cystitis in rabbits by a group D streptococcus, the authors measured the specific serum antibody response in the three major immunoglobulin classes. The enzyme-linked immunosorbent assay was performed using group D streptococcal antigen extracted by phenol. Before experimentation, all rabbits had low IgM, IgG and IgA titres against group D streptococcal antigen. A marked increase in IgM antibodies was detected during the first month of experimental pyelonephritis. A poor IgM antibody response was observed in rabbits with cystitis. During the three months of experimentation, a significant difference in mean IgG levels was observed between rabbits with pyelonephritis and those with cystitis.

Experimental urinary tract infection in rabbits by a group D Streptococcus sp.: A study of serum immunoglobulin classes by enzyme-linked immunosorbent assay

After induction of pyelonephritis and cystitis in rabbits by a group D streptococcus, the authors measured the specific serum antibody response in the three major immunoglobulin classes. The enzyme-linked immunosorbent assay was performed using group D streptococcal antigen extracted by phenol. Before experimentation, all rabbits had low IgM, IgG and IgA titres against group D streptococcal antigen. A marked increase in IgM antibodies was detected during the first month of experimental pyelonephritis. A poor IgM antibody response was observed in rabbits with cystitis. During the three months of experimentation, a significant difference in mean IgG levels was observed between rabbits with pyelonephritis and those with cystitis.

Clinical application of measurements of serum levels of bee venom-specific IgE and IgG

Bee venom-specific IgE and IgG antibodies were measured in the serum of beekeepers, bee-allergic persons, and normal persons infrequently stung without adverse effects. Beekeepers, who are stung frequently and relatively “immune” to bee stings, are characterized by high serum levels of IgG- and low serum levels of IgE-specific antibodies. Bee-allergic individuals have high titers of bee venom-specific IgE and generally low titers of bee venom-specific IgG. Following a bee sting, allergic individuals develop a rising titer of IgE antibodies, accompanied occasionally by a rise in IgG antibodies. Therapy with whole bee body extracts fail to effect IgE or IgG antibody titers. During the course of venom immunotherapy IgG-specific antibodies are stimulated and IgE-specific antibodies continue to decline. These observations suggest that: (1) bee sting allergy is a function of bee venom-specific IgE; (2) bee sting immunity is a function of bee venom-specific IgG; and (3) bee venom is an appropriate therapeutic antigen.