Evaluation of Four Commercial IgG- and IgM-specific Enzyme Immunoassays for Detecting Mycoplasma pneumoniae Antibody: Comparison with Particle Agglutination Assay

Diagnosis of Mycoplasma pneumoniae infection is important due to its variable clinical manifestations and absence of response to beta-lactams. Introduction of enzyme immunoassays (EIAs) for serologic diagnosis of M. pneumoniae has made it possible to separate the analyses of specific IgG and IgM antibodies. We compared four different commercial EIAs, ImmunoWELL IgG, IgM (GenBio), Medac IgG, IgA, IgM (Medac), Platelia IgG, IgM (Sanofi Pasteur), and Ridascreen IgG, IgA, IgM (r-Biopharm) with indirect particle agglutination assay (PA), Serodia-MycoII (Fujirebio). We tested 91 specimens from 73 pediatric patients (2-17 yr) hospitalized at a tertiary-care hospital between December 2005 and January 2006. The measurements of IgM EIAs were correlated with PA titers (Spearman's correlation coefficient, from 0.89 to 0.92) with high concordance rates, ranging from 82.4% to 92.3%. However, some negative IgM-EIA results in PA-positive specimens indicated that serial samplings with convalescent sera would be necessary to confirm M. pneumoniae infection.

Affinity purification and partial characterization of IgM-like immunoglobulins of African catfish, Clarias gariepinus (Burchell, 1822).

IgM like macroglobulin from bovine serum albumin (BSA)-immunized African catfish C. gariepinus was purified by affinity chromatography and partially characterized. The molecular weight of this macroglobulin was 840 kDa, as estimated by gel filtration chromatography. Purified macroglobulin was analyzed using SDS-PAGE under reducing and non-reducing conditions. The molecular weight (MW) of heavy and light chain was 74.8 kDa and 27.2 kDa respectively, in presence of a reducing agent. In non-reducing SDS-PAGE, a single high MW band was observed representing tetrameric form.

Epstein-Barr Virus Antibodies in Kawasaki Disease

The prevalent ages at onset for Kawasaki Disease (KD) and Epstein-Barr virus (EBV) infection are known to be similar in Korea and Japan. We evaluated the correlation between EBV infection and KD. The antibodies to EBV such as anti-viral capsid antigen (VCA) IgG and IgM, anti-diffuse and restricted early antigen IgG (anti-EADR IgG), and the anti-EBV determined nuclear antigen IgG (anti-EBNA IgG) were examined in 29KD patients at five separate times sequentially during a period of one year, and also in 14 other children with a past history of KD. The results of each group were compared with those of age-matched controls. The positive rates of anti-VCA IgG and IgM at presentation in the KD patients were 41.4% (12/29) and 0% (0/29), respectively. Only one patient was found to be anti-VCA IgM-positive within two months. There were no cases of anti-VCA IgG except one, anti-EADR IgG and anti-EBNA IgG positive to negative seroconversion during the year. The children with a past history of KD showed higher anti-EBNA IgG-positive rates than the controls (p=0.04). There was no difference in the seropositive rates of the antibodies to EBV, cytomegalovirus, herpes simplex virus and herpes zoster virus. In conclusion, children with KD were noted to have normal immune responses to EBV infection. Children with a past history of KD seemed to be infected with EBV at a later age than children with no history of KD.

B Cells in Murine Cervical Lymph Nodes are Conventional B-2 Cells

We investigated the characteristic features of cervical lymph node B cells to determine whether their behavior differs from that of B cells located elsewhere, because cervical lymph nodes may be exposed to continual antigenic stimulation from the naso- and/or oropharynx. B cells were isolated from cervical lymph nodes, spleen and peritoneal fluid of mice, cultured in medium, and exposed to various stimuli. The expression of various surface molecules characteristic of lymphoid B cells was assayed by flow cytometry, and immunoglobulin secreted into the culture supernatants was evaluated by enzyme-linked immunosorbent assay. B220+ cells were cultured in medium alone or with lipopolysaccharide, and their entrance into S phase in response to stimuli was measured by proliferative assays. Phenotypic characteristics of cervical lymph node B cells included CD5low, CD23high, CD43low, B7.1low, B7.2low, and Syndecan-1low. Unstimulated lymphoid B cells did not secrete immunoglobulin, but, upon stimulation, secretion of IgM was increased more than secretion of IgA and IgG. B cells actively entered S phase after 48 hr stimulation. These results show that B cells in cervical lymph nodes are conventional B2 cells, like splenic B cells.

Comparative immunogenecity of foot and mouth disease virus antigens in FMD-haemorrhagic septicaemia combined vaccine and FMD vaccine alone in buffalo calves.

Humoral immune response was evaluated by monitoring the serum antibody titres and virus specific IgM titres against Foot and Mouth Disease (FMD) virus antigens in serum samples obtained from different groups of calves inoculated with combined vaccine or FMD vaccine alone, on 0, 7, 14, 21, 28, 42 and 56 days post-vaccination (DPV). The cellular immune response was monitored by MTT based lymphoproliferation in peripheral blood mononuclear cell cultures. Higher liquid phase blocking (LPB) ELISA antibody titres were observed in calves receiving combined vaccine as compared to calves immunized with FMD vaccine alone with the peak titres in both the groups obtained on 21 days post-vaccination. However, the virus specific IgM titres were significantly higher in group of calves inoculated with combined vaccine than FMD vaccine alone. The lymphoproliferative responses against FMDV types O, A22 and Asia 1 in the groups receiving combined vaccine and FMD vaccine alone started increasing gradually after day 14 and reached peak levels on 28 DPV followed by a gradual decline subsequently. The group receiving combined vaccine showed higher proliferative responses on in vitro stimulation with FMD virus type O, whereas, with FMD virus type Asia 1, the responses were significantly higher on 14 and 21 DPV as compared to the group immunized with FMD vaccine alone. However, in the group receiving combined vaccine, the responses on in vitro stimulation with FMD virus type A22 were significantly higher than FMD vaccine alone group on all DPV except on 42 DPV.

Soroprevalencia para hanseniase em areas endemicas do estado do Para / Soroprevalence for leprosy in endemic areas of the state of Para

Analisou-se a prevalencia de anticoepos IgM utilizando teste sorologico e antigeno especifico Glicolipidio Fenolico I (PGL-I) do Mycobacterium leprae, por meio do teste rapido ML Dipstick em 1611 individuos sadios categorizados em contatos de pacientes hansenicos intradomiciliares e comunitarios, residentes em cinco municipios endemicos para hanseniase. Realizou-se estudo tranversal pela analise do banco de dados do laboratorio de hanseniase, Instituto Evandro Chagas. O estudo estendeu-se de março a dezembro de 1998, com reavaliaçoes anuais ate dezembro de 2002, no qual, os municipios selecionados-Curinopolis, Eldorado do Carajas, Xinguara, Rondon do Para e Dom Eliseu - apresentaram taxas de prevalencia em hanseniase maiores que 20 em cada 10.000 hab. e detecçao de casos novos maiores que quatro em cada 10.000 hab. A idade variou de 2 a 90 anos, devido ao fato de que a doença em areas de alta endemicidade possibilita o diagnostico de crianças. Estudou-se 957 mulheres (957/1611-59.4 por cento), 654 homens (654/1611-40.6 por cento) e observou-se predominancia de soropositividade entre as mulheres na faixa etaria entre 21 e 50 anos, 62.81 por cento contra 53.97 por cento nos homens. A analise foi realizada nos bancos de dados D-BASE, EPI-INFO 6.4 e 2002, BIOESTAT 3.0 e SINAM, existentes no Instituto Evandro Chagas e Secretaria Estadual de Saude do Para...

Haemolysin test for characterization of immune ABO antibodies.

BACKGROUND & OBJECTIVES: Antibodies with haemolytic properties are common within the ABO system. These lytic antibodies are immunoglobulin G (IgG) and in high titres cause haemolysis during blood transfusion. Information on Immunoglobulin types and concentration of ABO haemolysins in Indian population is lacking. The present study was undertaken to know the usefulness of haemolysin test for characterization of immunoglobulin class of ABO antibodies. METHODS: Serum samples from 187 O group blood donors were screened for A and B haemolysins. Thirty five samples were treated with dithiothretiol (DTT) for characterization of Ig class. Antibody titre was compared with grade of haemolysis. RESULTS: Of the 51 strongly haemolytic serum samples, 32 (62.8%) had IgG titres of > or = 64 after treatment with DTT. There was significant association (P<0.05) between grade of haemolysin and anti B IgG titre. INTERPRETATION & CONCLUSION: Haemolysin test was found to be a useful screening test to identify group O donors with high levels of IgG anti A and/or anti B for blood transfusion purposes.

Partial characterization of serum immunoglobulins of Oreochromis mossambicus.

Serum immunoglobulins of O. mossambicus were purified using chromatography methods--CM affinity gel blue chromatography followed by two step purification involving a combination of ion-exchange and gel filtration chromatography. Studies revealed that O. mossambicus produces only one class of high molecular weight macroglobulin as determined by molecular sieving by Sepharose CL 6-B. Immunoelectrophoresis of purified O. mossambicus serum against rabbit anti O. mossambicus serum gave only a single precipitin line. Further analysis of the immunoglobulin by SDS-PAGE showed that the IgM macroglobulin weighs about 900,000 Da, composed of mu-like heavy chain weighing about 90 kDa each and light chains weighing about 30 kDa each.

Estudo imunohistoquímico da gengivite-HIV / Immunohistochemical study of HIV-gingivitis

A infecçäo pelo vírus HIV induz profundas alteraçöes no sistema imune do hospedeiro, incluindo perda dos linfócitos T CD4+, supressäo das respostas a antígenos T-dependentes e ativaçäo anormal dos linfócitos B. Diversas entidades patológicas säo observadas durante o curso da infecçäo por este vírus, sendo que algumas destas, como a doença periodontal inflamatória (DPI), apresentam alto grau de morbidade. Alguns estudos clínicos e microbiológicos demonstram importantes diferenças entre a gengivite-HIV e a gengivite inespecífica (pacientes HIV-negativos), embora a nível histopatológico näo exista nenhum estudo comparativo entre elas. O objetivo deste trabalho foi avaliar quantitativamente o número de linfócitos T, linfócitos T "auxiliares", linfócitos B, macrófagos, células de Langerhans, neutrófilos, plasmócitos secretores de IgG, IgM, IgE e IgA na gengivite-HIV comparado com a gengivite inespecífica. Esta avaliaçäo foi baseada na identificaçäo imunohistoquímica pela Técnica da Streptavidina-Biotina dos seguintes antígenos: CD3 (linfócitos T), OPD4 (linfócitos T "auxiliares"), CD20 (linfócitos B), CD68 (macrófagos), S-100 (células de Langerhans), elastase (neutrófilos), IgG, IgM, IgE e IgA (plasmócitos secretores de IgG, IgM, IgE e IgA, respectivamente). Os resultados mostraram maior percentual de linfócitos T, linfócitos T "auxiliares" e macrófagos na gengivite inespecífica. O número de células intraepiteliais S-100 positivas ( células de Langerhans) por campo foi maior também na gengivite inespecífica comparado com a gengivite-HIV. A gengivite-HIV apresentou percentuais maiores de plasmócitos IgG positivos e neutrófilos em relaçäo à gengivite inespecífica. Estes resultados indicam que a severidade da DPI em pacientes HIV-positivos deve estar relacionada com a própria imunodepressäo celular presente na doença e enfatizam a importância dos linfócitos T na defesa do periodonto. Os dados encontrados sugerem também que a predominância de plasmócitos e neutrófilos no infiltrado inflamatório periodontal constitui um quadro mais compatível com lesäo destrutiva