Appearance Of IgM Antibodies Research Articles

Mass scale screening of common arboviral infections by an affordable, cost effective RT–PCR method

Objective To develop a rapid, cost effective RT-PCR method for the mass scale diagnosis of such diseases at the viremia stage to find out the actual disease burden in that area. Methods For this purpose, cases with the history of only short febrile illness were considered. Thus 157 samples with the history of dengue/chikungunya like illness and only 58 samples with a history of acute encephalitis syndrome (AES)were selected. Results Out of 157 samples, 42 and 74 were detected as dengue and chikungunya, respectively and out of 58 AES cases only 23 could be detected as Japanese encephalitis by this RT-PCR method. Conclusions This cost effective RT-PCR method can detect the total positive cases that remain undetected by ELISA method. Moreover, this method is capable to detect the viral RNA from patients' sera even after the appearance of IgM antibody at one fifth costs as compared with the other commercially available kits.

The importance of tick-borne encephalitis virus RNA detection for early differential diagnosis of tick-borne encephalitis

Tick-borne encephalitis virus (TBEV) is one of the most important causes of human viral infections of the central nervous system in Europe. Currently, the diagnosis of TBE is based on the demonstration of specific antibodies in patient's serum, which appear only several weeks after the infection. To determine how successfully can viral RNA be detected by RT-PCR in the samples of body fluids of patients with TBE prior to and after the appearance of antibodies. Serum, whole blood and CSF samples from 34 patients with a serologically confirmed TBE were collected. Samples were tested for the presence of TBEV RNA by using RT-PCR method. Viral RNA was detected in all blood and serum samples collected before the development of antibodies. After the appearance of IgM antibodies, the number of positive samples dropped by at least one third. After the development of IgG antibodies, only 3% of serum and 16% of blood samples tested positive for viral RNA. Samples of cerebrospinal fluid were shown to be inappropriate for the molecular diagnosis of TBE using this assay, since only one sample (10%) that was collected in the sero-negative phase of disease was found positive by the PCR assay. RT-PCR is an efficient method for an early detection of TBEV in blood and serum samples collected prior to the appearance of antibodies. This method can be of valuable use for a differential diagnosis of TBEV infection in patients with febrile illness after a tick bite, particularly in regions where more than one tick-transmitted diseases are endemic.

Detection of human cytomegalovirus (HCMV) pp67-mRIMA and pp65 antigenemia in relation to development of clinical HCMV disease in renal transplant recipients

To evaluate the performance of the recently introduced method based on detection of human cytomegalovirus (HCMV) pp67 mRNA in blood by the nucleic acid sequence-based amplification (NucliSens), in comparison to semiquantitative detection of pp65 HCMV antigen in white blood cells, in relation to development of clinical HCMV disease. Thirty patients, recipients of renal transplants, were monitored prospectively for the presence of pp67 mRNA, the presence and level of pp65 antigenemia, IgG and IgM antibodies, and the development of clinical HCMV disease. A total of 148 samples were examined during the observation period. Twenty-five samples were positive for pp67-mRNA and 45 samples contained at least one pp65 positive cell, with 68% agreement between the two assays. Both assays predicted correctly the development of clinical disease in five patients, giving a sensitivity of 100%. However, the specificity of the pp67-mRNA test was 72%, and of the pp65 antigenemia test from 20 to 64%, depending on the level of antigenemia chosen for cut-off. pp67-RNA appeared somewhat earlier than pp65 antigenemia, and responded earlier to treatment. Sero-conversion and appearance of IgM antibodies were of very little clinical value. Both the pp67-mRNA and the pp65 antigenemia assay predicted correctly the development of clinical HCMV disease in renal transplant recipients. However, the specificity of both tests with respect to development of HCMV disease, especially the pp65 antigen test was moderate. Significantly positive tests not necessarily prove the development of clinical disease. Testing for pp67-mRNA may improve the diagnosis and management of HCMV disease in renal transplant patients.

Primary cytomegalovirus infection and gastric ulcers in normal host

A 42-year-old woman presented with epigastric pain and vomiting. Upper gastrointestinal endoscopy revealed three gastric ulcers. Histologic examination of biopsies from the ulcers showed cytomegalovirus inclusion bodies. The appearance of IgM antibodies to cytomegalovirus indicated a recent and primary infection. Stored serum from her last pregnancy 17 months previously contained no cytomegalovirus antibodies. A thorough evaluation of her immune system revealed no abnormality. We are aware of only two other cases where seroconversion was documented in normal hosts. Cytomegalovirus infections in the gastrointestinal tract of normal hosts are very unusual but a common cause of morbidity in immunocompromised hosts. We believe that cytomegalovirus may have a role in the pathogenesis of gastrointestinal lesions in nonimmunocompromised patients.

The transient appearance of IgM antibodies in the bile of rats injected with Salmonella enteritidis

Following the intravenous injection of 2 × 10 8 killed Salmonella enteritidis into rats, high levels of specific antibodies were detected in the serum and bile after 4 days. The level in serum persisted while that in bile had virtually disappeared by day 7. On the basis of gel filtration on Ultrogel AcA 22 the activity in bile was found to be associated with the IgM fraction. The transient nature of the biliary response was further evidenced by the association of the agglutinating activity with a four-fold increase in the concentration of IgM and the presence of complement-fixing bactericidal antibody. Initial evidence suggests that the source of the biliary IgM is from cells within the liver rather than transport of IgM from blood to bile. It is proposed that immune stimulation by blood-borne microorganisms can lead to a pulse of IgM in the bile, providing rapid augmentation of other local immune processes in the gastrointestinal tract.

Specific IgM class antibody production following infection with cytomegalovirus.

Specific IgM class antibody production was studied in different groups of patients with characterized cytomegalovirus (CMV) infections using a radioimmunoassay (RIA). In pregnant women, IgM antibodies were detected only following primary infection and generally persisted less than 4 months. The demonstration of CMV-specific IgM during pregnancy is therefore diagnostic of recent primary CMV infection. In patients with symptomatic CMV infections, the appearance of IgM antibody was shown to be closely related to the onset of symptoms and coincided with production of complement fixing (CF) antibody. IgM antibodies were at maximum levels 3-4 weeks after presentation but generally declined to low or undetectable levels by 3-4 months. The significance of the results of testing for CMV-specific IgM in relation to clinical and other serological findings in these patients is discussed. IgM antibody production was also demonstrated in renal transplant patients with primary infections and in 6 of 21 recipients with secondary infections. In both groups the antibodies became detectable 3-6 weeks after transplantation but the titres were much higher following primary infection. IgM antibodies persisted throughout follow-up periods of up to 2 years after transplantation in some cases.

Dextran Abrogates Stimulation of IgG Antibody Synthesis by Allogeneic Effect Factor

Abstract The influence of dextran upon in vitro immunization of unfractionated splenic cells and of purified splenic B cells against sheep erythrocytes has been studied with particular emphasis upon the relationship of dextran to the augmentation of antibody synthesis by allogeneic effect factor (AEF). Dextran enhanced the number of SRBC-specific IgM PFC when added to unfractionated splenic cells undergoing a primary immune response in vitro. When it was added to purified splenic B cells no such effect was observed. The established capacity of AEF to facilitate antibody synthesis by splenic B cells was found to be markedly altered by addition of dextran to the cultures. Although the capacity of AEF to increase the number of IgM PFC remained virtually unchanged, the enhancement of IgG PFC brought about by AEF was abrogated. These observations suggest that either two separate molecules may be responsible for the activities of AEF or that one molecule possesses two separable functions: one increases IgM PFC and another stimulates IgG PFC. Data are given that indicate the activity of the latter may be interfered with by dextran at the B cell surface membrane. We hypothesize that the receptor for AEF on the IgG-producing B cell may be, in part, structurally related to dextran (i.e., a polysaccharide molecule with α-1,6 glucosidic linkages) and for this reason may interfere with reception of an AEF signal by B cells. If this is the case, then antigens that cause the appearance of IgM antibodies but not IgG antibodies may be incorrectly regarded as “T cell-independent antigens” primarily because they intercept the latter activity of AEF.

ニワトリの日本脳炎血球凝集抑制抗体のIgMからIgGへの移行およびIgG抗体のヒナへの移行について (日脳疫学, 32報)

Shift of Japanese encephalitis antibody from IgM to IgG in the sera of the experimentally twice inoculated chicks with Japanese encephalitis (JE) virus was examined by the gel filtration of Sephadex G-200 column and following results were obtained.1. Titer of HI antibody rised on 7 days after the first inoculation of JE virus and that increased rapidly after second inoculation and peak of the titer maintained for 2 months then decreased. Viremia was detected till 6 hours after first inoculation.2. Hen was twice given JE virus and IgM antibody appeared 7 days after first inoculation, kept on rising, reached the peak 35 days after the first inoculation, that is 7 days after the second inoculation, then decreased, and disappeared on 120 days. IgG antibody appeared about two weeks after the appearance of IgM antibody and the titer became higher than that of IgM antibody 35 days after the first inoculation, then decreased gradually, and showed 1:16 of titer on 150 days.3. We could obtain the chicks by fertilization from experimentally infected hen, having IgM and IgG of HI antibody of Japanese encephalitis. And the localization of antibody in the sera of chicks was determined by Sephadex G-200 gel filtration. IgM antibody was detected in chick serum, though IgG antibody was not detected.

IGG AND IGM ANTIBODIES IN FOWL SERUM.

Antibody production in mammals in response to a variety of antigens has been extensively investigated. An early appearance of IgM antibodies was usually followed by IgG antibodies (Bauer, Mathies and Stavitsky, 1963). The activity of IgM antibodies was destroyed by treatment with 0·1 M 2‐mercaptoethanol (ME) (Deutsch and Morton, 1957), whilst the titre of IgG antibodies was not diminished. In the fowl a similar pattern of antibody response has been described (Uhr, Finkelstein and Franklin. 1962; Benedict. Brown and Hirsch, 1963; Drecsman, Larson, Pinckard, Groydon and Benedict, 1965). Rosenquist and Gilden (1963), however, found no IgM antibodies in fowl serum in response to bovine serum albumin (BSA) and the antibody titre in the IgG fraction was destroyed by incubation with ME.The results presented in this communication are concerned with (1) the susceptibility of fowl IgG antibodies to ME treatment; and (2) the production of IgM antibodies by the fowl.