Human T lymphotrophic virus type I may not be associated with multiple sclerosis in Japan.

To study the possible involvement of human T lymphotrophic virus type I (HTLV-I) or a related retrovirus in Japanese cases of multiple sclerosis (MS), we first performed a Western blot analysis with purified Ag of HTLV-I. Ten out of 31 MS patients (32.2%), 19 of 66 patients (28.8%) with other neurologic diseases, and 2 of 64 healthy blood donors (3.1%) had antibodies reactive with Ag corresponding to the group-specific Ag (gag) proteins (p15, p19, p24) on their sera. There were no significant differences between MS and other neurologic diseases concerning the patterns and the frequency. Second, we tried to establish T cell lines from PBMC of 22 MS patients with crude IL-2 without accessory cells, because HTLV-I-infected T cells can be immortalized in a high ratio under those conditions. Only one T cell line (MS-14C), however, could be maintained in long term culture. MS-14C and cultured T cells for 3 to 5 wk derived from MS patients were examined by Southern blot analysis under both stringent and low stringent conditions with HTLV-I as a probe. No HTLV-I related bands could be detected. By polymerase chain reaction examination, we also could not detect HTLV-I provirus genome in the fresh PBMC from 20 MS patients, although some of them had gag-reactive antibodies. Our data do not favor the hypothesis of HTLV-I or an HTLV-I-related human retrovirus in the etiology of MS.     

Identification of antigenic proteins encoded by human herpesvirus 8 and seroprevalence in the general population and among patients with and without Kaposi's sarcoma

To establish a sensitive and specific antibody assay, potent antigenic proteins encoded by human herpesvirus 8 (HHV8) were studied. Fifteen recombinant HHV8-encoded proteins were produced as glutathione S-transferase fusion proteins. The sera from AIDS-associated Kaposi's sarcoma (KS) patients reacted with four proteins encoded by open reading frames (ORFs) K8.1, 59, 65, and 73 in a Western blot assay. An enzyme-linked immunosorbent assay (ELISA) using these four proteins as antigens (mixed-antigen ELISA) revealed that all 26 sera derived from KS patients (24 with and 2 without human immunodeficiency virus infection) became positive for anti-HHV8 antibodies. The presence of HHV8 was demonstrated in 14 (1. 4%) of 1,004 sera from the Japanese general population and 10 (1.9%) of 527 sera from patients without HHV8-associated diseases. The presence of immunoglobulin G (IgG) and IgM antibodies against HHV8 examined further by the mixed-antigen ELISA and Western blotting revealed IgG antibody in all ELISA-positive sera, while IgM antibody against ORF K8.1 was absent. These data suggest that the ORF 73 and 65 proteins are potent antigens for a sensitive serological assay.     

Immunoglobulin subclasses of antibodies to human T-cell leukemia/lymphoma virus I-associated antigens in acquired immune deficiency syndrome and lymphadenopathy syndrome

Immunoglobulin G (IgG) and IgM antibodies to human T-cell leukemia/lymphoma virus-I (HTLV-I)-associated membrane antigens (HTLV-I-MA) were assayed by indirect cytospin immunofluorescence, and IgG and IgM antibodies to purified HTLV-I were assayed by enzyme-linked immunosorbent assay in sera from 119 immunologically well-characterized promiscuous male homosexuals in The Netherlands, of whom 9 suffered from acquired immune deficiency syndrome (AIDS), 18 suffered from lymphadenopathy syndrome (LAS), and 5 suffered from gay bowel syndrome. Antibodies to HTLV-I-MA were present in four of nine AIDS patients, including one patient with antibodies to purified HTLV-I. Antibodies to HTLV-I-MA were present in 6 of 18 LAS patients, including 3 patients with antibodies to purified HTLV-I. Of five patients with gay bowel syndrome, one had IgG and IgM antibodies to HTLV-I-MA. Of the four HTLV-I seropositive AIDS patients, two had IgG and IgM antibodies to HTLV-I or HTLV-I-MA, one had only IgG antibodies, and one had only IgM antibodies. Of the six HTLV-I seropositive LAS patients, four had IgG and IgM antibodies to HTLV-I or HTLV-I-MA, and two had only IgM antibodies. In the sera from 27 healthy homosexuals with and 60 without T-cell subset imbalances, no antibodies to HTLV-I or HTLV-I-MA were detected.     

Detection of cross-reactive antibody to BLV p24 in sera of human patients infected with HTLV

For detection of antibody to bovine leukemia virus (BLV) major core protein of p24 and cross-reactive antibody in human patients infected with human T cell leukemia virus type I (HTLV-I), monoclonal antibody, D432 against BLV p24 was used by competitive binding enzyme-linked immunoadsorbed assay (ELISA). In sera from cattle with enzootic bovine leukosis (EBL) which were positive for BLV antibodies by immunodiffusion test, 109 out of 112 (97.3%) were positive for BLV p24 antibody by competitive binding ELISA. By using the same procedures, 21 samples from adult T cell leukemia (ATL) patients and healthy carriers with HTLV-I were tested for cross-reactive antibody to BLV p24. All 21 samples were positive for HTLV-I antibodies by immunofluorescence test and/or ELISA. By competitive binding ELISA using non-treated BLV antigens, none of these 21 samples inhibited the binding of the D432. When the BLV antigen was treated by several different denaturation procedures, several HTLV-I positive samples showed the inhibition of the D432 binding and the most effective treatment was by 2-mercaptoethanol (2-ME). Sixteen out of 21 samples showed the presence of cross-reactive antibody against 2-ME-treated BLV antigens. The cross-reactivity of human sample to BLV p24 antigen was further confirmed by Western blotting of the 2-ME-treated BLV antigens. None of the 28 samples from leukemia patients other than ATL which were negative for HTLV-I antibodies showed inhibition of the D432 by the competitive binding ELISA.     

Expression of the gag gene of human T-cell leukemia virus type I in Escherichia coli and its diagnostic use

An expression plasmid, pHY202, was constructed which directs the synthesis of a fusion protein encoded by the gag sequence of human T-cell leukemia virus type I (HTLV-I) inserted into the lacZ' gene. Escherichia coli cells harboring pHY202 produced the 43-kDal LacZ'-Gag fusion protein with a yield of approx. 0.3% of total soluble proteins. The fusion protein is specifically recognized by monoclonal antibodies against the Gag proteins p19 and p24, and could be applicable for the diagnosis of HTLV-I infection, because almost all sera from HTLV-I carriers gave a positive response in the enzyme-linked immunosorbent assay (ELISA) employing the LacZ'-Gag hybrid protein purified by immunoaffinity column chromatography.     

Natural and immune human antibodies reactive with antigens of virulent Neisseria gonorrhoeae: immunoglobulins G, M, And A

Natural and immune human antibodies reactive with heat-labile and heat-stable antigens of virulent Neisseria gonorrhoeae were studied by use of an indirect fluorescent-antibody (IFA) procedure. The immunoglobulin class of the reactive antibodies was identified by using fluorescein-conjugated antisera specific for human IgG, IgA, or IgM in the IFA procedure. The effects of heat and mercaptoethanol on IFA reactivities were also studied. It appeared that antibodies of the IgG, IgM, and IgA classes present in the sera of both infected persons (immune antibodies) and normal persons with no history of gonococcal infection (natural antibodies) react with heat-stable somatic antigens. Immune IgG antibodies, however, were distinguishable from natural IgG antibodies by their ability to recognize heat-labile surface antigens. The distinction between natural and immune IgM antibodies was less obvious. IgM antibodies from both infected and normal persons appeared to react with heat-labile antigens. Some, but not all, infected persons had immune IgA antibodies to heat-labile as well as to heat-stable antigens. Treatment of sera with mercaptoethanol had no effect on IgG antibodies. The IFA activity of IgM antibodies was decreased, but not abolished. The effects of mercaptoethanol on IgA antibodies were variable. Some sera showed a decrease in IgA titer, and others showed an increase in IgA activity to certain antigens. Immune IgG antibodies were more resistant to heating than were natural IgG antibodies. Natural and immune IgM antibodies appeared equally sensitive to heating. IgA activity, on the other hand, was increased by heating sera at 60 C, but was decreased at higher temperatures. Thus, it appears that natural and immune human IgG antibodies to N. gonorrhoeae may be distinguished by their interactions with heat-labile antigens and by their resistance to heating.     

A Hospital-Based Serological Survey of Cryptosporidiosis in the Republic of Korea

The seroprevalence of cryptosporidiosis was examined using patients'' sera collected from hospitals located in 4 different areas of the Republic of Korea. ELISA was used to measure antibody titers against Cryptosporidium parvum antigens from a total of 2,394 serum samples, which were collected randomly from patients in local hospitals; 1) Chungbuk National University Hospital, 2) Konkuk University Hospital, 3) local hospitals in Chuncheon, Gangwon-do (province), 4) Jeonnam National University Hospital, from 2002 through 2003. Of the 2,394 samples assayed, 34%, 26%, and 56% were positive for C. parvum-specific IgG, IgM, and IgA antibodies, respectively. Positive IgG titers were most common in sera from Jeonnam National University Hospital, Gwangju, Jeollanam-do, and positive IgM titers were most common in sera from Chungbuk National University Hospital, Cheongju, Chuncheongbuk-do. The seropositivity was positively correlated with age for both the IgG and IgA antibodies but was negatively correlated with age for the IgM antibodies. Western blotting revealed that 92%, 83%, and 77% of sera positive for IgG, IgM, and IgA ELISA reacted with 27-kDa antigens, respectively. These results suggested that infection with Cryptosporidium in hospital patients occurs more commonly than previously reported in the Republic of Korea.     

Patterns of serologic response to human immunodeficiency virus type 1 (HIV-1) in Brazilians with different clinical forms of HIV infection

In order to investigate the IgG HIV-1 antibodies reactivity to structural components of the virus, 85 sera from infected Brazilians, comprising the total spectrum of HIV infection, were analysed by Western blot assay. The sera were confirmed as being positive to HIV with enzyme linked immuno assay (ELISA) and indirect immunofluorescence (IIF). Although the sera from patients reacted less intensively to the gag polypeptide of 55 KDa, no distinctive antigen reaction patterns were observed between sera patients with different clinical forms. Because of the higher frequency of reactivity to the gag p24 in AIDS patients, the patterns of anti-HIV IgG responses are similar to those observed in their African counterparts.     

Antibodies to the structural and nonstructural gag-coded proteins of type-D retroviruses in patients with lymphadenopathy

Screening of antibodies to structural and nonstructural gag gene-coded proteins in humans with lymphadenopathy and AIDS was performed by means of radioimmunoprecipitation (RIP) and western blotting. Pr78gag precursor of gag-coded proteins of type-D retrovirus from Hep-2 cells served as an antigen in RIP tests. Total number of sera (of humans with lymphoadenopathy) under RIP analysis was 18 and one sera of AIDS patient. Six of them reacted with Pr78gag and one out of one AIDS serum. Over 80 sera samples of humans with lymphadenopathy have been tested by means of western blotting with proteins of Mason-Pfizer monkey virus as antigens. Antibodies to p27 (major internal protein of Mason-Pfizer monkey virus) were detected in 12 sera samples of those with lymphadenopathy (dilution 1:100) and in 9 out of 12 sera of AIDS patients (dilution 1:100-1:400). Results obtained make it possible to predict that type-D retroviruses are associated with acquired immunodeficiency syndrome and generalized lymphadenopathy and could play some role in development of this illness in humans.     

Reactivity of an HIV gag gene polypeptide expressed in E. coli with sera from AIDS patients and monoclonal antibodies to gag

A segment of the gag gene of the human immunodeficiency virus (HIV) (HTLV-IIIB strain), the virus which causes acquired immunodeficiency syndrome (AIDS), has been cloned into the bacterial expression vector, pCQV2, and mapped to the right-hand portion of the gag gene containing the carboxyl-terminal portion of p24 and the amino-terminal portion of p15. Nucleic-acid sequencing of the insert-vector junctions further defined the 5'-terminal nucleotide of HIV sequence as nucleotide 997 and the 3'-terminal nucleotide as 1696. When used in an enzyme-linked immunosorbent assay (ELISA) with sera from HIV-infected patients, the cloned antigen reacted with a subset of sera which were positive on a standard ELISA using whole virus as antigen. Western-blot screening of these sera with whole virus indicated that all p24-positive sera were positive with the clone, suggesting that the carboxyl-terminal portion of p24 contains a highly antigenic epitope(s). A serum which was p24-negative p15-positive by Western blot analysis was also highly reactive, indicating that a p15 epitope is present in the cloned antigen. Epitope mapping with a series of monoclonal antibodies to gag resulted in positive ELISA with 2 of 3 anti-p24, 0 of 1 anti-p15, and 0 of 1 anti-p17 Western-blot-positive monoclonal antibodies, suggesting that one of the anti-p24 monoclonal antibodies reacts with epitopes amino-terminal to those coded from nucleotide 997, two anti-p24 monoclonals react with epitopes carboxyl-terminal to those coded from nucleotide 997, and the anti-p15 monoclonal reacts with epitopes carboxyl-terminal to those coded from nucleotide 1696.     

Schistosoma japonicum: Immunological response to circulating polysaccharide antigens in rabbits with a light infection

To study the detectability of circulating polysaccharide antigens and the immunological response to such antigens in rabbits with a light Schistosoma japonicum infection, sera of five rabbits infected with 50 cercariae were studied up to 29 weeks post infection (p.i.). While one rabbit developed no worm burden, the other rabbits developed low worm burdens (4 to 16 worms). In the sera of these rabbits, the only polysaccharide antigen demonstrable with immunoelectrophoresis (IEF), was the circulating anodic antigen (CAA). With the enzyme-linked immunosorbent assay (ELISA), CAA was detectable from 5 to 6 weeks p.i. in the sera of the two rabbits with the highest number of worm couples. The lowest CAA level which was detectable in unconcentrated sera from which serum proteins had been removed was 125 ng CAA/ml, corresponding with a worm burden of 4.5 worm/kg body wt. During the entire infection, CAA-specific immune complexes were only demonstrable in very low concentrations. Antibodies against polysaccharide antigens were assessed with immunofluorescent antibody (IFA) on Rossman's fixed sections of adult worms, with the ELISA, and with IEF. Specific IgA, IgG, and IgM antibodies were detectable from 2 to 3 weeks p.i. with IFA and ELISA. These early antibodies were shown to be directed against gut-associated antigens, while antibodies against parenchyma-associated antigens were found later in the infection. With IEF, antibodies against two trichloroacetic acid (TCA)-soluble antigens were detectable, including the major, S. japonicum-specific antigen 2.     

Human T-cell lymphotropic virus type III: immunologic characterization and primary structure analysis of the major internal protein, p24.

The major internal structural protein of human T-cell lymphotropic virus type III (HTLV-III), a virus etiologically implicated in acquired immunodeficiency syndrome (AIDS), was purified to homogeneity. This 24,000-molecular-weight protein (p24) was shown to lack immunologic cross-reacting antigenic determinants shared by other known retroviruses, including HTLV-I and HTLV-II, with the exception of equine infectious anemia virus (EIAV). A broadly reactive competition immunoassay was developed in which antiserum to EIAV was used to precipitate 125I-labeled HTLV-III p24. Although the major structural proteins of HTLV-III and EIAV competed in this assay, other type B, C, and D retroviral proteins lacked detectable reactivity. Thus, HTLV-III is more related to EIAV than to any other retroviruses. That the HTLV-III isolate is very distinct from HTLV-I and HTLV-II was further confirmed by the amino acid compositions of the major internal antigens of all three isolates. Moreover, comparison of the amino-terminal amino acid sequence of HTLV-III p24 with analogous sequences for HTLV-I and HTLV-II p24 showed that these proteins do not share significant sequence homology. In an attempt to evaluate immune response in individuals exposed to HTLV-III, sera from AIDS and lymphadenopathy syndrome patients as well as from clinically normal blood donor controls were tested for antibodies to HTLV-III p24. The results showed that sera from 93% of lymphadenopathy syndrome patients and 73% of AIDS patients exhibited high-titered antibodies to HTLV-III p24. In contrast, none of the normal control sera showed detectable reactivity to HTLV-III p24.     

Enzyme-linked immunosorbent assay (ELISA) for IgM, IgG and IgA class antibodies against Candida albicans antigens: development and comparison with other methods

An extract of Candida albicans was used as an antigen on microtitre plates in the enzyme-linked immunosorbent assay (ELISA) to measure IgM, IgG and IgA class antibodies in the sera of hospitalized patients. It was found that of these patient sera that reacted positively in Ouchterlony immunodiffusion (ID) when undiluted, 58% were also positive in the ELISA against the same antigen preparation. However, all the sera with an ID titre of 1:2 or higher were ELISA-positive, demonstrating especially IgG and IgA. Of the sera positive by counterimmunoelectrophoresis against somatic and metabolic antigens of C. albicans, 86% were positive by ELISA. Reactions in precipitin-negative sera, if they occurred, usually demonstrated IgM or IgA. The sera with high passive haemagglutination or indirect immunofluorescence titres against surface antigens of C. albicans were positive in the IgG and IgA assays, while approximately one third were positive in the IgM assay.     

Ultrastructural localization of HTLV-I gag proteins p19 and p24 by single and double immunogold labeling

We developed a post-embedding immunogold labeling procedure for the ultrastructural localization of the HTLV-I gag proteins p19 and p24 by the use of monoclonal antibodies (MAb). Both antigens were shown to withstand fixation with 1% glutaraldehyde. In addition, p19 antigenicity was found not to be affected by post-fixation with 1% osmium tetroxide. The choice of resin played a decisive role in the retention of antigenicity. P19 was preserved in Lowicryl K4M as well as in LR White, whereas p24 was preserved only in Lowicryl. Both p19 and p24 were found to be localized on the HTLV-I virions themselves, whereas no positive immunostaining could be observed on the infected cells. In Lowicryl-embedded samples, in which both antigens had been preserved, a double immunogold labeling procedure was performed that allowed the co-localization of p19 and p24 on the same section. In osmicated LR White-embedded samples the quality of ultrastructural preservation of HTLV-I virions was found to be comparable to results obtained with the traditional glutaraldehyde-osmium tetroxide-epoxy resin processing.     

Identification of antigenic components of Toxoplasma gondii by an immunoblotting technique

Proteins of Toxoplasma gondii were separated by SDS-polyacrylamide gel electrophoresis with subsequent transfer to a nitrocellulose sheet by electrophoretic blotting. Immunologically reactive polypeptides were detected by human sera with previously known toxoplasma antibody levels. Heavy chain-specific, peroxidase-conjugated anti-human immunoglobulins were used as the indicator antibodies for the separate identification of IgG and IgM reactive polypeptides. IgG toxoplasma antibodies reacted with several antigens of M_r ≈27 000–67 000, while toxoplasma-specific IgM seemed to detect only a few polypeptides. The M_r of 35 000 for the dominating IgM reactive polypeptide was observed.     

Evaluation of serological diagnostic test systems assessing the immune response to Japanese encephalitis vaccination

A new commercial anti-Japanese encephalitis virus IgM and IgG indirect immunofluorescence test (IIFT) was evaluated for the detection of the humoral immune response after Japanese encephalitis vaccination. The IgM IIFT was compared to two IgM capture ELISAs and the IgG IIFT was analysed in comparison to a plaque reduction neutralization test (PRNT50) and an IgG ELISA. Moreover, the course of the immune reaction after vaccination with an inactivated JEV vaccine was examined. For the present study 300 serum samples from different blood withdrawals from 100 persons vaccinated against Japanese encephalitis were used. For the IgM evaluation, altogether 78 PRNT50 positive samples taken 7 to 56 days after vaccination and 78 PRNT50 negative sera were analyzed with the Euroimmun anti-JEV IgM IIFT, the Panbio Japanese Encephalitis - Dengue IgM Combo ELISA and the InBios JE Detect IgM capture ELISA. For the IgG evaluation, 100 sera taken 56 days after vaccination and 100 corresponding sera taken before vaccination were tested in the PRNT50, the Euroimmun anti-JEV IgG IIFT, and the InBios JE Detect IgG ELISA. The Euroimmun IgM IIFT showed in comparison to the Panbio ELISA a specificity of 95% and a sensitivity of 86%. With respect to the InBios ELISA, the values were 100% and 83.9%, respectively. The analysis of the Euroimmun IgG IIFT performance and the PRNT50 results demonstrated a specificity of 100% and a sensitivity of 93.8%, whereas it was not possible to detect more than 6.6% of the PRNT50 positive sera as positive with the InBios JE Detect IgG ELISA. Thus, the IIFT is a valuable alternative to the established methods in detecting anti-JEV antibodies after vaccination in travellers and it might prove useful for the diagnosis of acutely infected persons.     

Western blot antibody determination in sera from patients diagnosed with Anisakis sensitization with different antigenic fractions of Anisakis simplex purified by affinity chromatography

Using Western blot techniques, the specificities of crude and purified (PAK and PAS) Anisakis simplex antigens were compared against 24 sera from patients diagnosed with Anisakis sensitization. All patients recognized a 60 kDa protein against the A. simplex crude extract, while 37.5% and 12.5% reacted with proteins of 40 and 25 kDa, respectively, when IgG was tested. In the case of IgE determination, 41.6% of sera were negative, while 12.5% and 20.8% appeared to cross-react against Toxocara canis and Ascaris suum, respectively. When the PAK antigen (A. simplex antigen purified by means of a column of IgG anti-A. simplex) was tested, immune recognition towards the 60, 40 and 25 kDa proteins increased in 83.3%, 16.7% and 4.2%, respectively, when the Ig antibodies were tested. In the case of the PAS antigen (PAK antigen purified by means of a column of IgG anti-A. suum), the reaction against the 40 and 25 kDa proteins increased to 45.8% and 25%, respectively, when Ig antibodies were used. Finally, when the EAS antigen (eluted from the anti-A. suum column after PAK purification) was tested, 83.3% of the assayed sera reacted against the 14 kDa protein, when the Ig antibodies, IgG and IgM immunoglobulins were measured. With the IgE determination, the reactions were observed in 41.7% of patients with proteins between 60 and 35 kDa against the PAS antigen. With the EAS antigen, reactive bands of 184, 84 and 14 kDa appeared. In conclusion, in the purification process of the A. simplex larval crude extract, the proteins implicated in cross-reactions with Ascaris and Toxocara were eliminated, with an important concentration of proteins responsible for the induction of specific responses.     

Prevalence of various antiphospholipid antibodies in pregnant women

Antiphospholipid antibodies (APAs) are characterized as a heterogeneous population of autoantibodies directed against different target antigens, predominantly anionic phospholipids or phospholipid-containing structures. The presence of APAs has been strongly associated with a variety of clinical disorders including adverse pregnancy complications such as spontaneous abortions, pregnancy-induced hypertension, preeclampsia and intrauterine growth retardation. The purpose of this study was to compare the prevalence of anticardiolipin antibodies (ACAs), which are routinely examined, with APAs directed against phosphatidylserine (APS), phosphatidylinositol (API), phosphatidylethanolamine (APE) and phosphatidylcholine (APC) in the sera of pregnant women. We examined 410 serum samples of pregnant women hospitalized in the department for pathological pregnancies. They underwent prenatal biochemical screening of fetal congenital abnormalities in the first and the second trimester of gravidity. Anticardiolipin IgG and IgM were measured using commercial ELISA kits (ImmuLisa Anti-Cardiolipin Antibody), whereas APS, APE, API and APC were determined by our modified ELISA kit. Among 410 pregnant women we found 21 patients (5.1%) positive for ACA IgG (>20 GPL) and 30 patients (7.3%) positive for ACA IgM (>10 MPL). It was found that 7.8% of pregnant women had at least one high-titer APA IgG and 9.8% high-titer APA IgM. One third of ACA IgG or IgM positive sera contained polyspecific autoantibodies reactive to at least two various phospholipids. In the group of IgG ACA positive women, 28.6% patients were positive for APS, 28.6% were positive or moderately positive for API, 23.8% for APC and 19% for APE. In the group of IgM ACA positive women, 33.3% were also positive for APS, 26.7% for APE, 26.7% for API and 23.3% for APC were present. IgG and IgM ACA negative patients exhibited a significantly lower incidence of other APA than the group of ACA positive pregnant women. It still remains to clarify if the routine examination of APA reacting with other anionic and zwitterionic antigens other than cardiolipin would improve the probability of identifying women liable to adverse pregnancy complications.     

IgG anti-lymphocyte antibodies in systemic lupus erythematosus react with surface molecules shared by peripheral T cells and a primitive T cell line

IgG anti-T cell autoantibodies are common in SLE serum, react preferentially with activated lymphocytes, and exert early-phase inhibitory effects on antigen-induced T cell proliferation. Little is known about the target molecules in this system, however, because the low titer and low avidity of the most interesting antibodies limit their utility in conventional immunoprecipitation analyses. Therefore, Western blotting was used to demonstrate binding of IgG in anti-T cell antibody-positive SLE sera to four surface membrane molecules shared by peripheral T cells and HSB-2 cells. Molecules of Mr 90,000 and 55,000 were particularly reactive: each target was stained by IgG anti-lymphocyte antibodies in 11 patient sera (approximately 85%) in the panel. Targets of Mr 37,000 and 105,000 were encountered less frequently (six of 13 and one of 13 patients, respectively). It is unlikely that alloantibodies contributed to the staining patterns observed because reactivity with the four targets was consistently present when cell preparations from multiple unrelated donors were examined. The target molecules were localized to the plasma membrane by whole cell absorption/elution experiments, by the failure of chromatin (DNA/histone) to absorb antibodies to these antigens, and through the use of purified membranes as substrate for Western blotting. With the possible exception of the 105,000 Mr molecule, which is a major target in the IgM anti-T cell antibody system, evidence for the existence of neoantigens as a basis for increased reactivity of SLE IgG with activated T cells was not obtained. The identity of the IgG antibody-reactive molecules with respect to known T cell antigens was not determined, although evidence against the existence of antibodies to Tac (IL 2 receptor) and the transferrin receptor was obtained in monoclonal antibody pre-clearing experiments. Nonetheless, the observation that a limited number of major IgG autoantibody target antigens on activated peripheral T cells are shared by HSB-2 cells, a primitive T cell line expressing few of the differentiation antigens characteristic of mature T cells, should provide a basis for more definitive characterization of antigens in this system in the future.     

Haemorrhagic fever with renal syndrome: evaluation of ELISA for detection of Puumala-virus-specific IgG and IgM

IgM and IgG ELISA to Puumala virus were evaluated using sera from patients with haemorrhagic fever with renal syndrome (HFRS) from different geographical regions: Sweden, Denmark, Norway, Belgium and the European USSR.IgM ELISA proved useful in the diagnosis of HFRS in patients from all the regions mentioned above. Specific IgM could be detected as early as day 1 post onset of disease, and patients remained IgM-positive for several months. Specific IgG ELISA antibodies were also frequently detected in acute sera, and acute-convalescent serum pairs often failed to show a significant titre rise or increase in optical density (OD) values. This limits the use of IgG ELISA in patient diagnosis. Sera collected 2 years after infection revealed higher IgG ELISA OD readings than convalescent sera, and very high values were still detectable 10 to 20 years postinfection. IgG ELISA is therefore useful for the testing of immunity and in seroepidemiological studies.Acute and convalescent sera from HFRS patients in Korea and the Asian USSR showed no or only very weak reactivity in the Puumala virus IgG and IgM ELISA. These results are consistent with the “one-way” crossing described earlier.