The seroprevalence of anti-Chlamydia pneumoniae-specific immunoglobulin G (IgG) antibodies is high in the adult population. Experience is required to perform a microimmunofluorescence test (MIF), the current "gold standard" for serological diagnosis, and the assay still lacks standardization. Partially automated enzymelinked immunosorbent assays (ELISAs) and enzyme immunoassays (EIAs), which are more standardized and for which the reading of results is less subjective, have been developed. The different commercially available serological tests differ in their sensitivities and specificities, depending primarily on the antigen used. Therefore, we evaluated 11 different tests (10 were species specific, 1 was genus specific) for IgG antibodies using serum samples of 80 apparently healthy volunteers. The interpretation of the results was based on the results of the gold standard, MIF: a sample was judged positive if it was positive by at least three of the four different MIFs. Based on this internal standard, we found that 71% of the samples were positive, while 8% were false positive by some tests. The correlations between the results of the different MIFs ranged from 83 to 99%, and the correlations between the results of the MIFs and the different ELISAs and EIAs ranged from 78 to 98%. Comparison of the IgG titers measured by MIF showed good agreement (r ‫؍‬ 0.76 to 0.91). This analysis revealed that some ELISAs and EIAs fail to detect low IgG titers. The specificities of the species-specific tests varied from 95 to 100%, and the sensitivities varied from 58 to 100%. These results indicate that serological assays for the detection of anti-C. pneumoniae-specific IgG vary greatly in their sensitivities and specificities. MIF must still be considered the best method for the detection of IgG in apparently healthy subjects, but the sensitivities and specificities of new ELISAs approximate those of MIFs.

The heterozygous Asp299Gly mutation of the toll-like receptor (TLR) 4, the key receptor for lipopolysaccharide (LPS), has been associated with attenuated inflammatory responses. When 160 healthy volunteers (9% heterozygous and 0.6% homozygous) were genotyped and their LPS-inducible cytokine release was assessed in an ex vivo whole blood test, the responses of heterozygotes did not differ significantly from those of wild-type carriers for any of the cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-6, interferon-gamma, and granulocyte colony-stimulating factor) or eicosanoids measured or for serum cytokines and C-reactive protein. Ten heterozygous subjects and 12 wild-type control subjects responded similarly to a graded series of LPS and Escherichia coli concentrations, excluding the possibility that allele-specific differences are evident only at low stimulus concentrations or in response to whole pathogens. These data demonstrate that the heterozygous Asp299Gly polymorphism does not exhibit a functional defect in cytokine release after the stimulation of blood monocytes.

Endotoxin (lipopolysaccharide, LPS) inducible cytokine release by human whole blood is increasingly used to model inflammatory responses in vitro, to detect the presence of pyrogenic contaminations as well as to monitor disease states or immunomodulatory treatments ex vivo. However, the LPS-stimulated blood model primarily allows the assessment of monocyte responses. Here, a whole blood model was established which allows assessment of lymphocyte responses. Four different superantigens, namely staphylococcal enterotoxin A and B (SEA, SEB), toxic shock syndrome toxin-1 (TSST-1) or streptococcal exotoxin A (SPEA) were tested with respect to the induction of lymphokine release. All superantigens were capable of inducing significant amounts of the lymphokines interferon-v (IFN')'), interleukin 2 (IL-2), IL-4, IL-5, IL-13 and tumor necrosis factor( TNF~) after 72 h of incubation. Concentration-dependencies and kinetics were determined. Blood from 160 healthy donors was used to assess the variability of SEB-inducible lymphokine release. Interindividual differences were more pronounced compared to LPS-inducible monokine release. However, the individual response was maintained when blood from six donors was tested once a week for 8 weeks, suggesting that the individual response represents a donor characteristic. The model appears to be suitable for the evaluation of immunomodulatory agents in vitro as well as ex vivo.

Summary The separate and combined relative mobility (Rm) values of different serum protein bands of 54, 61 and 68 days old female SPF mice using polyacrylamide gel electrophoresis were determined. Studying serum electrophoretic profiles of normal as well as Rickettsia mooseri infected and/or cyclophosphamide treated mice revealed that the gammaglobulin region significantly increased in the Rickettsia infected (R) group one day, one week and two weeks after infection. In the cyclophosphamide treated and Rickettsia mooseri infected group (CR) the gammaglobulin region temporarily increased one day after infection and was suppressed one week later. No animals of this group survived till the end of the experiment. In the cyclophosphamide treated group (C) there was no statistically significant change in the gammaglobulin region as compared with their control. The increase of the gammaglobulin region in electropherograms of immunosuppressed mice after immune stimulation with Rickettsia mooseri antigen may be due to elaboration of a stimulating factor in the serum which acts on colony precursor cells and which has the same electrophoretic mobility as gammaglobulins. Transferrin levels started to increase significantly 24 hours after rickettsial infection in group R and had also increased in groups C and CR one week later. The specific mechanism of transferrin in the immune response and its role in the defence against rickettsial infection are discussed. Zusammenfassung Elektrophoretische Veränderungen des Serumtransferrin‐ und Gammaglobulin‐Spiegels in cyclophosphamidbehandelten Mäusen nach einer Infektion mit Rickettsia mooseri Unter Verwendung der Polyacrylamidgel‐Elektrophorese wurden die relativen Wanderungsgeschwindigkeiten (Rm) der verschiedenen Serumprotein‐Banden von 54, 61 und 68 Tage alten weiblichen SPF‐Mäusen bestimmt. Die Untersuchungen der Elektrophorese‐Muster der Seren von normalen und Rickettsia mooseri infizierten und/oder cyclophosphamidbehandelten Mäusen ergab, daß die Gammaglobulin‐Region in der Gruppe der Rickettsien‐infizierten Tiere (R‐Gruppe) einen Tag, eine und zwei Wochen p. i. significant vergrößert war. In der Gruppe der cyclophosphamidbehandelten und Rickettsia mooseri‐infizierten Mäuse (CR‐Gruppe) war die Gammaglobulin‐Region einen Tag p. i. vergrößert und eine Woche später wieder vermindert. Kein Tier dieser Gruppe überlebte bis zum Ende des Versuches. In der Gruppe der nur mit Cyclophosphamid behandelten Tiere (C‐Gruppe) zeigte sich verglichen mit den Kontrollen keine statistisch signifikante Veränderung in der Gammaglobulin‐Region. Die kurzfristige Zunahme der Gammaglobulin‐Region in den Elektropherogrammen von immungeschwächten Mäusen nach einer Stimulation mit Rickettsia mooseri hängt möglicherweise von der Freisetzung eines sog. «stimulierenden Faktors» ab, der auf die Zellen, die für die Immunerstantwort zuständig sind, wirkt und dessen elektrophoretische Wanderungsgeschwindigkeit vermutlich im Bereich der Rm‐Werte der Gammaglobuline liegt. Der Transferrin‐Spiegel nahm 24 Stunden na...